IN-SITU REMOVAL OF HYDROGEN
SULPHIDE FROM LANDFILL GAS ARISING FROM THE INTERACTION BETWEEN MUNICIPAL
SOLID WASTE AND SULPHIDE MINE ENVIRONMENTS WITHIN BIOREACTOR CONDITIONS
David Andrew Lazarevic
Master of Science Thesis Stockholm 2007
David Andrew Lazarevic IN-SITU REMOVAL OF HYDROGEN SULPHIDE FROM LANDFILL GAS - A RISING FROM THE INTERACTION BETWEEN MUNICIPAL SOLID WASTE AND SULPHIDE MINE ENVIRONMENTS WITHIN BIOREACTOR CONDITIONS Supervisor and Examiner: Lennart Nilson, Industrial Ecology STOCKHOLM 2007
PRESENTED AT
INDUSTRIAL ECOLOGY ROYAL INSTITUTE OF TECHNOLOGY www.ima.kth.se
TRITA-IM 2007:30 ISSN 1402-7615
Industrial Ecology, Royal Institute of Technology www.ima.kth.se Royal Institute of Technology Stockholm, 2007 Veolia Environmental Services
ABSTRACT
This project was compiled in co operation with the Royal Institute of Technology, Stockholm and Veolia Environmental Services (Australia) at the Woodlawn Bioreactor in NSW, Australia. Hydrogen sulphide is an unwanted component of landfill gas, raising occupational health and safety concerns, whilst leading to acid gas corrosion of power generation equipment and increased emissions of SOx, a primary constituent of acidification. Australian governmental requirements to place a periodic cover over the unused proportion of the tipping surface of landfills and bioreactors create an interesting opportunity for the removal of the hydrogen sulphide component of landfill gas. Using waste materials containing a high concentration of metals as waste cover can enhance the precipitation of sulphur in the form of metal sulphides. The reduction of sulphate via sulphate reducing bacteria is prevalent in sites that have a sizeable inflow of sulphate. The Woodlawn Bioreactor is located in an area where the influence of sulphate has a critical influence of bioreactor performance and production of hydrogen sulphide. Through a series of experimental bioreactors it was established that from the use of metalliferous periodic waste covers, the hydrogen sulphide component of landfill gas was maintained at an extremely low level when compared to the levels of hydrogen sulphide produced in waste under the influence of high sulphate loads with no waste cover. KEY WORDS
Hydrogen sulphide, sulphate reduction, sulphate reducing bacteria, metal sulphide precipitation, sulphide mine environments, acid mine drainage, bioreactor, alternative waste cover. ACKNOWLEDGEMENTS
Many thanks must go to the organisations and individuals for their expertise, time and support in completing this project. Firstly to Veolia Environmental Services (Australia) for their continued support both technically and financially for the duration of the project. Specific mention must be made to VES’s Technical General Manager Shaun Rainford, Woodlawn’s Engineering and Design Manager Chris Alexander, Pablo Gonzalez, Justin Houghton and Henry Gundry from the Woodlawn Bioreactor for their support. Lennart Nilson from the Department of Industrial Ecology at the Royal Institute of Technology for his supervision throughout this project, and Dr Damien Batstone from the Australian Wastewater Management Centre at the University of Queensland was a great help in the area of anaerobic digestion and metal solubility.
D.A. Lazarevic i Royal Institute of Technology Stockholm, 2007 Veolia Environmental Services
EXECUTIVE SUMMARY
The production of hydrogen sulphide gas results from the reduction of sulphate to sulphide by sulphate reducing bacteria, it is of great concern and is a cause of ongoing issues in terms of acid gas corrosion and increased SOx emissions during the burning of landfill gas, at sites that have sustained sources of sulphate, much like the Woodlawn Bioreactor. Bioreactor biochemical process at Woodlawn have been directly affected by the influence of acid mine drainage, hence subject to waters containing extremely high sulphate concentrations, high heavy metal loads and a low pH. A long term strategy for the management of acid mine drainage at Woodlawn includes physical barriers preventing sulphate rich waters from entering the bioreactor and a leachate treatment system to remove sulphate from bioreactor leachate prior to leachate recirculation. During the design, construction and commission of this plant and equipment, sulphate reduction and hydrogen sulphide is still of great concern, especially whilst the bioreactor is ‘young’ and the proportion of acid mine drainage influence to the waste mass is greatest at this time. The deliberately enhanced precipitation of metals sulphides via the addition of iron rich materials used as alternative periodic waste covers was tested. These materials would act as an alternative daily waste cover, fulfilling the EPA requirement to intermittently cover the waste surface on areas where waste placement is not taking place. A series of 6 laboratory bioreactors were established to determine the influence of four different cover materials, an additional bioreactor tested the ability of metals contained within the acid mine drainage to precipitate metal sulphides. Two scenarios were tested, the first a point load of acid mine drainage (sulphate concentration 5000 mg/l) recirculated through the bioreactors and secondly a continuous charge of acid mine drainage at 4L of acid mine drainage added per week (sulphate concentration 34000 mg/l). The bioreactor with no alterative daily cover material experienced a negligible rise in hydrogen sulphide gas after the initial point load, even though leachate indicators showed that reduction of sulphate was taking place. Metals occurring within the waste, primarily iron, precipitated with the sulphide produced, trapping the sulphur in the waste as a solid metal sulphide precipitate. When the continuous acid mine drainage load was introduced, leachate chemistry showed a prolific reduction of sulphate to sulphide, however little metal ions were available to precipitate with the sulphide produced, as they were consumed in the previous stage. The net result of this sulphate reduction was hydrogen sulphide gas concentrations of more than 1700 ppm or 0.17 % volume (hydrogen sulphide is fatal to humans at > 1000 ppm). All bioreactors containing iron rich alternative daily cover materials experienced very similar results, with hydrogen sulphide gas concentrations remaining below 0.5 ppm in almost all measurement. In most cases there was a small peak of hydrogen sulphide after the initial continuous acid mine drainage addition, after which hydrogen sulphide gas stabilised to below 1ppm in all cases. Leachate chemistry data shows that while sulphate reduction was evident in these bioreactors the iron was able to precipitate sulphide upon its formation. Data suggest that whilst sulphate reduction was evident in these bioreactors it was not as pronounced as the previous bioreactor. It is recommended that whilst a system for the removal of sulphate from bioreactor leachate is being developed that any one of the alternative daily covers tested should be added as alterative daily cover to prevent the formation of hazardous levels of hydrogen sulphide within the landfill gas.
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TABLE OF CONTENTS
ABSTRACT ...... I KEY WORDS ...... I ACKNOWLEDGEMENTS...... I EXECUTIVE SUMMARY...... II LIST OF TABLES...... IV LIST OF FIGURES...... V 1 INTRODUCTION ...... 1 2 BACKGROUND...... 2 2.1 WASTE MANAGEMENT IN NSW...... 2 2.2 BIOREACTORS DURING NSW WASTE MANAGEMENT TRANSITIONAL PERIOD...... 3 2.3 WOODLAWN BIOREACTOR ...... 4 3 AIMS AND OBJECTIVES ...... 7 3.1 AIMS ...... 7 3.2 OBJECTIVES ...... 7 3.3 LIMITATIONS ...... 7 4 METHODOLOGY ...... 8 5 BIOREACTOR TECHNOLOGY ...... 9 5.1 BIOREACTOR LANDFILLS ...... 9 5.2 CELL DESIGN...... 11 5.3 LEACHATE RECIRCULATION ...... 12 5.4 LFG RECOVERY ...... 12 6 LANDFILL GAS BIOCHEMICAL PROCESSES ...... 13 6.1 DECOMPOSITION STAGES WITHIN BIOREACTOR LANDFILLS...... 13 6.2 FACTORS INFLUENCING METHANE POTENTIAL ...... 17 7 SULPHUR INTERACTIONS IN BIOREACTOR PROCESSES ...... 20 7.1 SULPHUR INFLOWS ...... 21 7.1.1 Sulphidic Mine Environments ...... 21 7.1.2 Woodlawn ...... 22 7.2 PROCESSES SULPHUR REDUCTION ...... 23 7.2.1 Sulphate Reduction – competition for substrates ...... 23 7.2.2 Sulphate reduction – oxidisation of methane...... 23 7.2.3 Sulphate Reducing Bacteria Competition with Methanogenesis...... 24 7.3 SULPHUR OUTFLOWS...... 26 7.3.1 Gaseous Sulphur ...... 26 7.3.2 Aqueous Sulphur ...... 28 7.3.3 Solid Sulphur...... 31 8 PERIODIC WASTE COVER AND IN SITU HYDROGEN SULPHIDE CONTROL...... 32 8.1 ENVIRONMENTAL PROTECTION AUTHORITY REQUIREMENT FOR ALTERNATIVE DAILY COVER TRIAL .... 32 8.2 ALTERNATIVE COVER MATERIALS TO BE INVESTIGATED ...... 34 9 BIOREACTOR TEST COLUMNS ...... 37 9.1 AIMS & OBJECTIVES...... 37 9.2 BIOREACTOR DESIGN...... 37 9.3 METHODOLOGY ...... 38 9.4 BIOREACTOR COMPOSITION ...... 39 9.5 MUNICIPAL SOLID WASTE...... 40 9.6 MONITORING ...... 41 10 RESULTS AND DISCUSSIONS ...... 42 10.1 LANDFILL GAS COMPOSITION...... 42 10.2 SULPHATE – SULPHIDE – HYDROGEN SULPHIDE CORRELATION...... 55 10.3 BIOREACTOR PERFORMANCE ...... 73 11 CONCLUSION AND RECOMMENDATIONS...... 75 11.1 CONCLUSION ...... 75 11.2 RECOMMENDATIONS ...... 76 12 REFERENCES ...... 77 13 APPENDICIES...... 81
D.A. Lazarevic iii Royal Institute of Technology Stockholm, 2007 Veolia Environmental Services
LIST OF TABLES
Table 5.1: Advantages and Disadvantages of Bioreactors...... 10 Table 5.2: Typical Landfill Gas Composition ...... 10 Table 6.1: Methanogenesis pH ranges...... 17 Table 6.2: Methane producing bacteria temperature ranges...... 17 Table 6.3: Optimal moisture content range...... 18 Table 7.2: Woodlawn Leachate Analysis – 2006/11/21...... 23 Table 7.3: Reduced Sulphur Compounds present in Landfill Gas...... 26 Table 7.4: Woodlawn LFG Analysis...... 26 Table 7.5: Health Effects from short term exposure to hydrogen sulphide ...... 27 Table 7.6: Source vs. Sulphate concentrations 2006/11/10 ...... 28 Table 7.7: Metal Sulphide Solubility Products ...... 31 Table 8.1: Alternative Daily Cover Material ...... 34 Table 9.1: Test Bioreactor Compositions...... 39 Table 9.2: Average Waste Composition Sydney ...... 40 Table 9.3: Waste Composition in Test Columns...... 40 Table 10.1: Acid Mine Drainage Composition ...... 55 Table 10.2: Toxic concentrations for various metals during anaerobic digestion...... 74 Table 10.3: Limiting concentrations for various metals during anaerobic digestion ...... 74
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LIST OF FIGURES
Figure 2.1: Waste Management Hierarchy European Union v Australia...... 2 Figure 2.3: Aerial view of the Woodlawn Bioreactor...... 5 Figure 5.1: Woodlawn Bioreactor Proposed Cell Design ...... 11 Figure 6.1: Idealised representation of ‘Landfill gas generation vs Time’ after placement ...... 13 Figure 6.2: Methanogenic Bacteria...... 15 Figure 6.3: Major steps in the decomposition of biodegradable waste to form landfill gas ...... 16 Figure 6.4: Effect of metabolite concentration on growth rate for methanogens...... 18 Figure 7.1: Sulphur Oxidisation and Reduction within Bioreactor Processes ...... 20 Figure 7.5: pH Vs Yield growth coefficient & specific growth rate ...... 25 Figure 7.2: Hydrosulphide vs pH...... 29 Figure 7.3: Sulphide vs pH...... 29 Figure 7.4: Hydrogen Sulphide vs pH...... 30 Figure 9.1: Test Bioreactor Design ...... 37 Figure 9.2: Test Bioreactor Composition ...... 39 Figure 10.1: Typical LFG Composition by Volume ...... 42 Figure 10.2: Bioreactor 1 – LFG Composition Analysis (GC – TCD) ...... 44 Figure 10.3: Bioreactor 1 – LFG Composition Analysis (IR & Dräger) ...... 44 Figure 10.4: Bioreactor 2 – LFG Composition Analysis (GC – TCD) ...... 46 Figure 10.5: Bioreactor 2 – LFG Composition Analysis (IR & Dräger) ...... 46 Figure 10.6: Bioreactor 3 – LFG Composition Analysis (GC – TCD) ...... 48 Figure 10.7: Bioreactor 3 – LFG Composition Analysis (IR & Dräger) ...... 48 Figure 10.8: Bioreactor 4 – LFG Composition Analysis (GC – TCD) ...... 50 Figure 10.9: Bioreactor 4 – LFG Composition Analysis (IR & Dräger) ...... 50 Figure 10.10: Bioreactor 5 – LFG Composition Analysis (GC – TCD) ...... 52 Figure 10.11: Bioreactor 5 – LFG Composition Analysis (IR & Dräger) ...... 52 Figure 10.12: Bioreactor 6 – LFG Composition Analysis (GC – TCD) ...... 54 Figure 10.13: Bioreactor 6 – LFG Composition Analysis (IR & Dräger) ...... 54 Figure 10.14: Typical Leachate Composition ...... 55 Figure 10.15: Bioreactor 1 – Sulphate and Sulphide vs Time ...... 57 Figure 10.16: Bioreactor 1 – Total Fe, Zn, Cu and Pb vs Time...... 57 Figure 10.17: Bioreactor 2 – Sulphate and Sulphide vs Time ...... 60 Figure 10.18: Bioreactor 2 – Total Fe, Zn, Cu and Pb vs Time...... 60 Figure 10.19: Bioreactor 3 – Sulphate and Sulphide vs Time ...... 63 Figure 10.20: Bioreactor 3 – Total Fe, Zn, Cu and Pb vs Time...... 63 Figure 10.21: Bioreactor 4 – Sulphate and Sulphide vs Time ...... 66 Figure 10.22: Bioreactor 4 – Total Fe, Zn, Cu and Pb vs Time...... 66 Figure 10.23: Bioreactor 5 – Sulphate and Sulphide vs Time ...... 69 Figure 10.24: Bioreactor 5 – Total Fe, Zn, Cu and Pb vs Time...... 69 Figure 10.25: Bioreactor 6 Sulphate and Sulphide vs Time...... 72 Figure 10.26: Bioreactor 6 – Total Fe, Zn, Cu and Pb vs Time...... 72
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1 INTRODUCTION The Veolia Environmental Services (VES) Woodlawn Bioreactor in NSW, Australia provides an interesting research opportunity due to the interaction between site geology, hydrogeology, and bioreactor biochemical processes. Situated in the void of a former lead, zinc and copper mine, acid mine draining (AMD), due to the oxidisation of metal sulphide minerals, plays an important role in effecting biochemical processes within the bioreactor. The primary goal of the Woodlawn bioreactor is the production of landfill gas (LFG) for the combustion in LFG engines and production of renewable energy. LFG is composed of approximately 60% methane and 40% carbon dioxide, however the combustion of trace gasses is a source of flue gas pollutants and infrastructure degradation. Hydrogen sulphide is a common trace gas within LFG, and when combusted contributes to the production of SOx emissions. The reduction of sulphate to sulphide, by sulphate reducing bacteria (SRB), is prevalent in conditions with an ongoing source or organic carbon and sulphate, such conditions exist within the Woodlawn bioreactor. Hydrogen sulphide is a product from the reduction of this sulphate. Leachate and gas data from the Woodlawn bioreactor suggests that the proliferation of SRB colonies has been prevalent and responsible for hydrogen sulphide concentrations of up to 1.7% volume. Whilst the development of a leachate treatment system is underway, to remove sulphate from bioreactor leachate, the implementation of this project may be up to 1 – 1.5 years away. Hence an interim solution that is quickly and easy to implement is needed during this period, to control the amount of hydrogen sulphide within the LFG. VES were given advice to add a soluble form of iron to the bioreactor in order to precipitate sulphide and mitigate the formation of hydrogen sulphide gas. Although municipal solid waste contains a contain percentage of ferrous and non ferrous metals (0.7% Sydney average), recycling programmes maintain a low metal component of municipal solid waste. Woodlawn data also shows the acid mine drainage influencing the bioreactor contains a high concentration of heavy metals, however it has been shown by the high levels of hydrogen sulphide within the LFG that there are insufficient metals to precipitate the amount of sulphide being formed. In addition to the above there is also a licence condition for the Woodlawn bioreactor to provide a daily waste cover to the tipping surface of the waste, to prevent the escape of LFG and stop waste from exiting the void. However, the placement of conventional soil covers is a costly exercise and also detrimental to bioreactor performance in terms of leachate recirculation and gas extraction. The EPA encourages the use of an alternative material other than ‘virgin excavated material’ that will not be detrimental to bioreactor performance. However the EPA requires the licensee to provide scientific evidence that demonstrates that these products can ‘beneficially influence landfill leachate and gas quality when used as daily cover’. Haematite currently being used as an alternative daily cover material, however this is only permitted whilst evidence is gathered to prove this material is beneficial to bioreactor performance. This thesis will look at addressing both of the issues raised above, by the use of an iron rich waste cover the daily waste cover requirement will be fulfilled and the iron within the cover will expedite the precipitation of sulphide formed by the reduction of sulphate, hence decreasing the amount of hydrogen sulphide within the LFG. A series of experimental bioreactors will be established to test the performance of various industrial waste products for use as alternative daily waste covers. From the results of these experiments it is anticipated that any one of these materials will fulfil the above requirements and be used as an interim solution for the management of hydrogen sulphide, whilst a solution for the removal of sulphate from bioreactor leachate is developed and implemented.
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2 BACKGROUND
2.1 WASTE MANAGEMENT IN NSW Australian waste management policies and practices differ somewhat from those currently being utilised in Europe, with regard to approaches taken and technology used. Using New South Wales (NSW), Australia’s most populus state, as an example, past and present government policies have lead to a crisis in waste management and treatment. Conventional landfills are used to treat the majority of municipal solid waste (MSW) produced, however space for waste placement is rapidly running out as population and waste generation increases. Comparing waste management hierarchies of the EU and Australia in Figure 2.1, the most apparent difference between the hierarchies is energy recovery. Landfill gas is the only avenue currently being utilised as ‘energy recovery’ in the Australian waste hierarchy, however this is at the lowest end of the energy recovery scale, as it a product of the land filling process. Figure 2.1: Waste Management Hierarchy - European Union v Australia
Waste Hierarchy - European Union Waste Hierarchy - Australia
Waste Reduction Avoidance Reuse Reuse Recycling & Composting Recycling & reprocessing materials Energy Recovery (CHP, Incineration, Landfill gas) Disposal Landfill
Source: (EPA NSW, 1996) This difference in approach has been partly addressed by Joseph (2003) in ‘Waste Management Policies and the Impact of Past Decisions – an Australian Case Study’ as he investigated the impact of waste management policies and past government decisions in the area of waste management. The following conclusions were reached: • The handling and disposal of putrescible waste was a state monopoly until as recent as 2000, the prevention of competition has lead to no drivers to improve operating practices, develop and implement new technologies, consult and inform adequately, or keep prices under control. • An open government decision not to go against local opinion has made the NIMBY (not in my backyard) attitude prevalent, making it difficult and in some cases impossible to get new project approval. • The development of waste management policies, waste regulations and decision to make bodies charged with waste disposal operations are all under the same government minister, causing a great concern of conflict of interest due to these converging lines of responsibility (Joseph, 2003).
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Lack of innovation of technological development in terms of energy recovery, specifically CHP and incineration, has been caused primarily by the governments ongoing decision not to go against public opinion, decisions made by less informed members of the public with no dialogue between experts in the area and the general public have stifled the development of these technologies. The lack of opportunities for the development of alternative waste treatment has left landfill gas recovery as the only area in energy recovery technology to be developed. Since 2000 only one privately owned company has been given approval to accept putrescible MSW. VES commenced operations at the Woodlawn Bioreactor (Woodlawn) in 2004. Whilst other facilities in NSW have LFG extraction and flaring in place, Woodlawn is currently the only bioreactor in NSW with primary focus on developing optimum conditions for waste degradation and the recovery of LFG. 2.2 BIOREACTORS DURING NSW WASTE MANAGEMENT TRANSITIONAL PERIOD The objective to dispose of only inert materials in landfills is a goal yet to be achieved, waste reduction strategies, recycling programmes and recent large scale composting programmes have been put in place to reduce the amount of waste going to landfill. Whilst these programmes are maturing there will be a transitional period in which landfills will continue to accept waste that will have potential adverse environmental impacts. Reinhart and Townsend (1998) have shown that ‘where leachable materials are land disposed, impenetrable barriers must be provided and waste stabilisation must be enhanced and accelerated so as to occur within the life of these barriers’. By operating a landfill as a bioreactor, accelerated waste degradation and stabilisation can increase biogas production yields during a shorter time span, improve leachate quality and assist in more rapid waste settlement. The availability of void space within the Sydney region is sparse, in 1991 the then ‘Waste Management Authority of NSW’ reported that ‘Sydney is now facing a landfill crisis. Less than 6 years landfill capacity remains’ (WMA, 1991). During this time existing waste disposal sites have been expanded to facilitate the acceptance of the ever increasing MSW stream. As traditional void space for MSW is limited, innovative methods have to be developed, VES has developed a former open cut lead, zinc and copper mine to accept volumes of waste of up to 400,000 tonnes per annum for a projected 75 years. The use of these types of vacant voids not only alleviates the requirement to create void space but also acts as vital mine remediation and rehabilitation. The use of deep voids such as the former Woodlawn mine create their own problems inherent in working in such geologically unique environments, deep voids exert great pressure on the waste, thus enhancing settlement and gas recovery and leachate recirculation infrastructure are predisposed to damage, due to high settlement rates. Probably the greatest factor influencing bioreactor performance, hence LFG production, is void geology. Bioreactors operate in semi open systems, interactions between surface and ground waters, and geological materials have an affect on environmental conditions, in this case high heavy metal concentrations, sulphate levels and high acidity.
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2.3 WOODLAWN BIOREACTOR Woodlawn was the former site of a 25 million cubic Figure 2.2: Woodlawn Bioreactor Location metre open cut and subterranean copper, lead and zinc mine, mining ceased in 1998 after 20 years of operation. The mine void is approximately 200m deep and 800m across, the mining lease consists of around 3,000 hectares and includes evaporation dams, tailings dams and a decommissioned plant and equipment area, all of which is to be rehabilitated at the end of the project. Woodlawn is located 250 km South West of Sydney and is serviced by both road and rail. The Woodlawn Bioreactor (Woodlawn) is operated by VES and commenced operation in September 2004. Woodlawn is permitted to receive up to 400,000 tonnes of MSW per annum, 652,766 tonnes of waste has been placed as of the 6th of Source: VES, 2006. September 2006, at this rate the void will take approximately 75 years to fill. Woodlawn has a planned peak energy production capacity of 20MW per annum and with a 50 MW Wind Farm (under development), located on an adjacent 6,000 hectares of land around the bioreactor acting as a buffer, approximately 37,500 homes can be powered by the project. Waste is collected in Sydney and processed at the purpose built Clyde Transfer Terminal in Western Sydney, then transported via rail to Woodlawn. Bioreactor landfills utilise leachate recirculation and landfill Gas (LFG) recovery systems to increase waste degradation, enhance gas production and advance waste stabilisation. The accelerated degradation process facilitates the production of LFG for utilisation in energy conversion much sooner after waste placement than traditional landfills. This allows revenues to be realised earlier and advanced waste stabilisation allows a greater volume of waste to be placed in the void. The first Jenbacher J320GS 1.064 Mw landfill gas engine was delivered in January 2006 and power generation is expected to commence towards the end of 2007. A bioreactor manages the decomposition of organic material much like a high solids batch process anaerobic digester, developed in geologic materials. However bioreactors are semi open systems with interactions between geological materials, atmospheric conditions, surface and groundwater’s. Several challenges that have arisen during planning and operation of the bioreactor include: • Composition of MSW entering the void Due to factors inherent in a competitive waste services industry, recent intensified competition has lead to lower volumes of putrescible waste than predicted. • Leachate recirculation and gas recovery High levels of groundwater and surface water runoff infiltration are trying to reach a natural equilibrium with surrounding ground water levels. The heterogeneous nature of waste, non uniform waste moisture levels and waste saturation all cause difficulties in maintaining an optimal waste water balance, this in turn can effect leachate recirculation and LFG extraction. • Acid mine drainage and hydrogen sulphide production The mine is the site of massive sulphide ore’s consisting mainly of Pyrite (FeS2), Sphalerite (ZnFe)S, Galena (PbS), and Chalcopyrite (CuFeS2). Ground and surface water runoff has caused water entering the void to have high levels of metals, sulphate and a
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low pH. These conditions are conducive to production of hydrogen sulphide gas, an unwanted toxic, corrosive and explosive gas. This thesis will focus on the last of these issues, sulphate reducing bacteria and hydrogen sulphide production as a result of acid mine drainage. Acid mine drainage has lead to leachate with low pH and a high concentration of sulphate (2500 – 9000 mg/l sulphate) (VES, 2006), these conditions have resulted in the establishment of sulphate reducing bacteria colonies and production of large amounts of hydrogen sulphide, maximum recorded levels of 1.7% volume around leachate recirculation wells. Sulphate reducing bacteria has the ability to retard methanogenic activity, is an occupational health and safety concern, whilst also leading to acid gas corrosion of LFG combustion equipment and increased SOx emissions from LFG combustion during power generation. LFG composition has shown hydrogen sulphide levels as high as 1.7% volume, symptomatic of prolific sulphate reduction, whilst readings of 120 ppm have been sustained. Figure 2.3: Aerial view of the Woodlawn Bioreactor Source: VES
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A range of mitigation strategies working in cooperation must be used to combat this problem. A hierarchy of strategies is suggested below: • Prevention of sulphate entering the void: o Current applications and future investigations include, removal of primary sources of sulphate and diversion of groundwater and surface water runoff from the void. • Prevention of sulphate entering the waste mass: o Current applications and future investigations include, pressure grouting (sealing of cracks/faults) of void walls preventing groundwater from entering the void and collection of water runoff within the void before coming in contact with the waste. • Sulphate removal from leachate: o Removal of sulphate from leachate via leachate treatment; including processes such as calcium addition and precipitation of calcium sulphate (gypsum) in batch reactor vessels. o The use of an alternative waste cover to precipitate metal sulphides within the waste mass, preventing sulphur from entering the gaseous phase. • LFG treatment (last resort): o Scrubbing of Hydrogen sulphide from LFG prior to combustion. The first two strategies are future planning measures and can be resolved by physical engineering solutions and the last strategy should be used as a last resort, due to high operational costs and worker safety. A mitigation strategy that can be implemented immediately and used to address sulphate existing in the void, whilst the design and construction of a long term leachate treatment strategy is being developed, is the use of an alternative waste cover for in situ removal of hydrogen sulphide from the landfill gas, and is the focus of this project.
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3 AIMS AND OBJECTIVES 3.1 AIMS The aim of this project is to investigate the use of various alternative waste cover materials to reduce the production of hydrogen sulphide gas from within the waste mass. Alternative daily cover materials will be tested in laboratory conditions, replicating actual field conditions with respect to waste composition and sulphate source. A range of commercially available products and industrial wastes have been selected for testing, these include iron oxide compounds and iron rich industrial wastes. It is important to note that the use of industrial waste products is an attractive option, because reduces adverse impacts of producing virgin materials, and utilises waste materials as a material source for secondary processes, thus closing currently open material loops. The general aim of this document is to investigate if the addition of iron rich compounds as a waste cover, will (under anaerobic conditions) react with the various forms of sulphide produced as a result of sulphate reducing bacteria to precipitate metal sulphides, such as iron sulphide and pyrite. Stemming from the above as a secondary investigation is to determine if the source of the sulphate, acid mine drainage containing high concentrations of both sulphate and various heavy metals, is able to precipitate metals sulphides in its own right. 3.2 OBJECTIVES The objectives of this project are: • To conduct a literature review in the areas of; major biochemical processes taking place in bioreactor degradation, inflows of sulphur to the system: acid mine drainage and the production of acid and sulphate rich waters, sulphur reduction within the system: sulphate reducing bacteria and hydrogen sulphide production, sulphur outflows of the system: in both the gaseous form (reduced sulphur compounds) and solid from (metal sulphide precipitation) • Determine the expected outcomes from the addition of alternative daily cover materials on municipal solid waste, under actual site conditions, low pH and high sulphate concentrations. • Test the ability of the combination of municipal solid waste and metals present in the sulphate source, acid mine drainage, to precipitate metal sulphides and reduce hydrogen sulphide concentrations in landfill gas. • Test the ability of alternative waste cover materials to remove sulphur from the system (retain in the waste as a solid precipitate) and lower hydrogen sulphide gas concentrations, this will occur in controlled laboratory test columns whilst reproducing actual conditions occurring within the Woodlawn Bioreactor. • Analysis will consist of comparisons in landfill gas and leachate composition, to determine if the acid mine drainage or alternative waste cover materials reduce hydrogen sulphide concentration whilst maintaining optimal methanogenic activity. • Recommend the optimum alternative daily cover for use in an integrated acid mine drainage mitigation strategy. 3.3 LIMITATIONS Certain limitations involved in conducting this thesis are presented below: • Time is important factor when considering this document, biodegradation can take from 6 – 18 months to reach maturity, however this time scale is unfeasible for this project, however the completion of this report within a 7 – 8 month period means bioreactor’s may not have reached maturity prior to AMD addition. • Whilst conducting the experiments on site was beneficial in terms of simulating actual conditions in terms of MSW and AMD used, laboratory conditions on site were limited, and only a limited amount of sample testing could be done on site. Testing that could not be
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conducted at Woodlawn were sent to the same independent laboratory that VES uses for all its compliance testing. 4 METHODOLOGY
An in depth literature review will be conducted on specific issues relating to Woodlawn (and other sites with similar operating environments), namely: a) The operation of bioreactors and prevailing biochemical processed b) Acid mine drainage c) Sulphate reducing bacteria and hydrogen sulphide production d) Alternative waste cover, and the in situ removal of hydrogen sulphide gas. a) Bioreactor Biochemical Processes A literature review will be conducted from recent and relevant literature to investigate the major biochemical processes and reactions during the various stages of waste degradation in bioreactors. A quick review will also be done of the operational techniques used in bioreactor technologies, specifically the Woodlawn bioreactor. b) Acid Mine Drainage A review of the major reactions causing acid mine drainage will be investigated, and the relationships these effects have upon bioreactor performance, specifically methane and hydrogen sulphide production. c) Sulphate reducing bacteria and hydrogen sulphide production Current monitoring of landfill gas composition has shown that colonies of methanogens are well established with gas compositions typical of anaerobic waste degradation during acetogenic and methanogenic phases. High levels of hydrogen sulphide present within the waste during mid 2006 (120ppm – 17,000 ppm, (Veolia, 2006)) suggest the presence of sulphate reducing bacteria colonies. A literature review will be conducted on sulphate reducing bacteria and hydrogen sulphide production, the relationships existing between sulphate reducing bacteria and methanogens, operational issues and concerns due to the production of hydrogen sulphide. d) Alternative daily cover, retarding sulphate reduction and removal of hydrogen sulphide The Environmental Protection Authority highly encourages the use of an alternative daily cover material to be used on the waste, which will not inhibit biological decomposition. This project will take this one step further in investigating daily cover materials that will actively improve bioreactor performance, methane generation and reduction of unwanted noxious gasses. A review of suitable materials including, materials source, major reactions, and expected benefits of these materials will be investigated. e) Experimental column testing, investigating the use of alternative daily covers on removal of hydrogen sulphide Materials identified in the previous section will be tested in a controlled laboratory environment, whilst replicating ‘real life’ on site conditions. Six columns will be constructed, one control bioreactor to gain background activity and landfill gas production, another to test if metals present within the MSW and sulphate source are able to reduce levels of hydrogen sulphide in the LFG, and the remaining four to test the identified alternative waste cover materials and their ability to prevent the production of hydrogen sulphide gas. f) Recommendations from Results Arising from the analysis of results, landfill gas and leachate composition, the performance of these materials can be assessed to select the most appropriate material to be used on site as a part of the total AMD and sulphate management plan.
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5 BIOREACTOR TECHNOLOGY
5.1 BIOREACTOR LANDFILLS Bioreactor Landfills A bioreactor landfill is an ‘engineered landfill or landfill cell where liquid and gas are actively managed in order to accelerate or enhance Biostabilization of waste’ (SWANA, 2004). Bioreactors involve controlling the environmental conditions within a waste mass in order to enhance MSW biodegradation. It has been shown that pH, temperature, nutrients, absence of toxins, moisture content, particle size and oxidation reduction potential are all influential factors (Reinhart & Townsend, 1998). Moisture content is the most critical of these parameters and can be regulated by leachate recirculation. Environmental conditions for MSW degradation are facilitated through leachate recirculation which, recirculates and distributes nutrients and enzymes, allows for pH buffering, dilutes any inhibitory compounds, recycles and distributes methanogens, provides for leachate storages and evaporation at lower construction and operating costs (Reinhart & Townsend, 1998). Waste stabilisation times can be reduced from 10’s of years to 2 3 years, which allows for faster access to LFG for energy conversion purposes. The goals associated with the development of bioreactors include: • Increased speed of waste stabilisation • Enhanced gas production • Increased available void space due to increased settlement of waste • Improved leachate treatment and storage, reducing leachate management costs • Reduced length and costs associated with post closure activities In order to control the degradation process, bioreactor management becomes more complicated. Liner design, gas extraction, leachate recirculation and treatment, daily cover materials, waste placement and monitoring are all required to be actively managed in order to have the utmost control of the system. Bioreactor Advantages and Disadvantages With regard to waste disposal, bioreactor technology is far superior to traditional ‘dry entombment’ of waste; by facilitating the degradation of waste, bioreactor technology is able to reduce environmental impacts associated with waste disposal, bioreactor technology can only be utilised for the biodegradable portion of waste. Through the recirculation of leachate and gas extraction systems, bioreactors are able to speed up the degradation processes within the waste mass, allowing for more rapid waste stabilisation and settlement. Bioreactors enhance landfill gas production, both in terms of quality and quantity, gas is available earlier for conversion to energy allowing a faster realisation of income for operators, enhanced quality gives greater calorific value and higher energy producing potential. Leachate recirculation reduces leachate toxicity and treatment costs, and minimises the long term liability of the operation. On a greater scale bioreactors both increase the operational capacity of the site, via enhance waste settlement, and also reduce the time of post closure operations. Adverse impacts of bioreactors are the potential for an increase in odours, resulting from increased volatile organic acid formation, the possibility of high dissolved salt concentrations and clogging of leachate recirculation systems. Williams (2005) summarises the advantages and disadvantages of bioreactors in Table 5.1.
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Table 5.1: Advantages and Disadvantages of Bioreactors Advantages Disadvantages Encourages early waste establishment and Surface flooding may be caused by either maintenance of methanogenesis. A high moisture irrigation rates being locally too high or by the content and the movement of moisture have both been formation of inorganic solid layers shown to promote methanogenesis. Develops a more uniform quality of leachate (measured Spray drift from leachate recirculation may result COD), so that the design and operation of treatment and in health concerns and increased smells, disposal facilities is easier particularly during the acetogenic phase Optimises the removal of hazardous organic Breakouts of leachate accumulated as perched contaminants by, for example, optimising conditions for water from the side slopes of landfills may biodegradation and stripping volatile organic material by occur, increased by the presence of compacted increasing gas production or low permeability layers within the waste Minimises dry zones in waste, which could otherwise Clogging of subsurface recirculation systems remain largely undergrade for many years may occur Takes up the absorptive capacity of the biodegradable Extremely high concentrations of dissolved salts waste and reduces the fluctuations in leachate flow rate may occur in sites accepting predominantly inorganic waste Promotes enhanced evaporative losses of leachate by surface spraying Provides temporary storage of short lived peak flow rates, allowing treatment facilities to be designed for flows closer to average values Source: Williams, 2005. Landfill Gas Composition Landfill gas is principally composed of methane and carbon dioxide, these gases are produced by methanogens as outlined in section 6. There are an abundance of trace gas components, resulting from the various stages of the biodegradation process, materials within the MSW and interactions with site geology and hydrology. Table 5.2 represents a summary of landfill gas components. Table 5.2: Typical Landfill Gas Composition Component Typical Value Observed Maximum (% by volume) (% by volume) Methane 63.8 88.0 Carbon dioxide 33.6 89.3 Oxygen 0.16 20.9 Nitrogen 2.4 87.0 Hydrogen 0.05 21.1 Carbon monoxide 0.001 0.09 Ethane 0.005 0.0139 Ethene 0.018 Acetaldehyde 0.005 Propane 0.002 0.0171 Butanes 0.003 0.023 Helium 0.00005 Higher alkanes <0.05 0.07 Unsaturated hydrocarbons 0.009 0.048 Halogenated compounds 0.00002 0.032 Hydrogen sulphide 0.00002 35.0 Organosulphur compounds 0.00001 0.028 Alcohols 0.00001 0.127 Others 0.00005 0.023 Source: Waste Management Paper 27, 1994.
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Bioreactor’s and reduction of greenhouse gas emissions A key aim of bioreactors is to utilise LFG for conversion to energy, this helps to reduce greenhouse gas (GHG) emissions in the following ways: • Energy derived from LFG can substitute fossil fuel based energy, thus reducing anthropogenic GHG emissions • Capture of LFG reduces methane and carbon dioxide (key components of LFG) from directly entering the atmosphere • Conversion of methane to carbon dioxide, during the gas to energy phase, reduces the global warming potential (GWP) of emissions from the entire process. 5.2 CELL DESIGN For greater control of waste degradation, bioreactors are designed as a series of purpose built cells, in which gas extraction and leachate recirculation can be controlled. Development of cells not only allows operational placement of waste to be conducted in a more controlled manner, but environmental conditions, such as pH, nutrient distribution and moisture content can be manipulated much easier in smaller volumes as opposed to a large open waste mass. The Woodlawn bioreactor cell design is shown in figure 5.1, waste is placed in 3 m layers and the construction and sections of waste are separated into various cells. Each cell has their horizontal gas extraction blankets and vertical gas extraction wells. Figure 5.1: Woodlawn Bioreactor Proposed Cell Design
Source: VES 2006
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5.3 LEACHATE RECIRCULATION The importance of leachate recirculation has been outlined in section 5.1, however uniform movement of leachate throughout the waste mass is difficult to achieve. MSW has a moisture content of between 15 – 40% (Moss, 1997 in Williams, 2005), the optimum moisture content for bioreactor waste degradation is between 40 – 70% (Reinhart & Townsend, 1998). To bring the waste to field capacity (40 70%) leachate can be recirculated throughout the waste cell by either horizontal infiltration, vertical displacement or surface spraying. Horizontal infiltration involves laying leachate distribution pipes in gravel lined trenches. Leachate can infiltrate the waste mass up to 8m horizontally and 10m vertically (Reinhart & Townsend, 1998), depending upon waste density and hydraulic conductivity. Vertical displacement involves placing a series of perforated vertical wells throughout the waste mass and pumping leachate thought these wells, the advantage of this system is that the leachate can be distributed deep into the waste mass, however horizontal saturation of the waste is typically only in a 2 – 6m radius of the well. Surface spraying involves spraying leachate on the surface of the waste each day after placement, this technique gives the waste a uniform saturation and helps bring the waste to field capacity directly after placement. Although the surface spraying of leachate does allow for the volatilisation of gasses from leachate, this practice is allowed by NSW regulations. Site location and the large buffer zone in relation to neighbouring properties prevents odour from spreading, however gasses that volatilise do escape from the system. Woodlawn currently uses surface spraying as a method of leachate recirculation, a total of 9 vertical wells pump leachate from the leachate sump to the surface where it is spread over the waste via a water spraying unit. 5.4 LFG RECOVERY Landfill gas must be extracted from the waste mass for conversion to power, this is facilitated by a combination of vertical extraction wells and horizontal gas blankets. Vertical wells can be installed as the waste is placed, rising with the waste mass, or drilled into an existing waste mass. Perforated pipe is connected to a gas extraction system under negative pressure to draw the gas from the waste mass. The benefit of wells is that they can be installed to an existing waste mass to access gas immediately after placement, reducing the time between infrastructure outlay and gas recovery. Horizontal gas blankets are placed in layers as the waste mass is rising. Perforated pipes are laid in gravel trenches to facilitate preferential pathways of gas flow. Gas blankets actively draw gas from a layer of waste above and below the blanket, hence after laying the gas extraction system waste has to be left to mature before drawing gas. Woodlawn utilised a combination of vertical gas extraction wells and gas blankets to obtain optimum volume of gas extraction.
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6 LANDFILL GAS BIOCHEMICAL PROCESSES
6.1 DECOMPOSITION STAGES WITHIN BIOREACTOR LANDFILLS The various stages of the decomposition of the biodegradable fraction on MSW are well documented in Reinhart & Townsend, 1998, Williams, 2005, Christensen, et al 1996, UK Environment Agency, 2004. The following section draws from these sources to give a brief view of the decomposition stages in MSW degradation. Figure 6.1 summaries the ‘ideal’ waste degradation process, showing LFG concentrations as each stages of degradation develops. Methane and carbon dioxide concentrations can reach 60% and 40% respectively as the methanogenic stage becomes established.
Figure 6.1: Idealised representation of ‘Landfill gas generation vs Time’ after placement
Source: Willumsen, 1990
Stage 1: Hydrolysis/aerobic degradation Aerobic hydrolysis occurs with initial placement of waste and the accumulation of water within the waste mass. Aerobic micro organisms metabolise available oxygen and the biodegradable fraction of waste (organic carbon) to produce simpler hydrocarbons, carbon dioxide, water and heat. The exothermic reaction can reach temperatures up to 90 °C, depending on waste depth. Carbon dioxide produced is released as a gas or is absorbed by water to form carbonic acid, giving the leachate acidity. The aerobic hydrolysis will last for as long as oxygen is present, it may range from days to weeks, depending upon variables such as compaction and daily cover material.
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Stage 2: Hydrolysis & Fermentation Associated with the onset of anaerobic conditions, hydrolytic and cellulolytic bacteria initiate hydrolysis and acetogenic processes, these facultative anaerobes can tolerate reduced oxygen conditions. Carbohydrates, proteins and lipids are broken down to form smaller organic compounds such as organic acids, primarily acetic acid, but also propanoic, butyric, lactic and formic acids and their derivatives. Proteins decompose to form ammonia, carboxylic acids and carbon dioxide, whilst hydrogen, water and heat are also produced as a part of the fermentation stage. Typical reactions during this phase include: C6H12O6 + 2 H2O 2CH3COOH + 4H2 + 2 CO2 (6.1) (glucose + Water acetic acid + hydrogen + carbon dioxide) C6H12O6 CH3C2H4COOH + 2H2 + 2 CO2 (6.2) (glucose butyric acid + hydrogen + carbon dioxide) C6H12O6 2CH3CH2OH + 2 CO2 (6.3) (glucose ethanol + carbon dioxide) (Christensen, et al 1996) Typical gas concentrations are approximately 80 % carbon dioxide and 20 % nitrogen, with temperatures dropping to between 30 and 50 °C. Stage 3: Acetogenesis Acetogen micro organisms dominate this anaerobic stage, converting organic acids formed in stage 2 to acetic acid and its derivatives, carbon dioxide and hydrogen. Hydrogen and carbon dioxide levels start to decrease allowing methanogens to establish, forming methane primarily from the carbon dioxide and hydrogen available and to a lesser extent the organic acids, primarily acetic acid. Typical reactions in the conversion of organic acids into acetic acid, hydrogen and carbon dioxide are as follows: CH3C2H4COOH + 2 H2O 2CH3COOH + 2H2 (6.4) (butyric acid + water acetic acid + hydrogen) CH3CH2OH + H2O CH3COOH + 2H2 (6.5) (ethanol + water acetic acid + hydrogen) CH3CH2COOH + 2 H2O CH3COOH + CO2 + 3H2 (6.6) (propionic acid + water acetic acid + carbon dioxide + hydrogen) C6H5COOH+ 6 H2O 3CH3COOH + CO2 + 3H2 (6.7) (benzoic acid+ water acetic acid + carbon dioxide + hydrogen) CO2 + 2C2H5OH CH4 + 2CH3COOH (6.8) (carbon dioxide + ethanol methane + acetic acid) (Christensen, et al 1996)
This stage typically sees concentrations of metal ions in leachate increase as acidity rises, resulting from increased organic acid concentrations. Hydrogen sulphide may start being produced if there is an abundance of sulphur compounds, as sulphate reducing bacteria favours more acidic conditions than methanogens.
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Stage 4: Methanogenesis Stage Methanogenesis is the primary stage in landfill gas production, when hydrolysis/acetogenesis and methanogenesis are in equilibrium, substrates for methanogenesis are provided at a steady rate, conductive to stable methane production at concentrations of approximately 60 % methane and 40 % carbon dioxide. Methane is produced in two ways, by carbon dioxide reduction with hydrogen, and from organic acids formed in the acetogenic stage, acetic acid is the most abundant substrate available for methane production. The predominating reactions in this stage are summarised below: Methanogenesis by organic acid cleavage: CH3COOH CH4 + CO2 (6.9) (acetic acid methane + carbon dioxide) HCOOH + 3 H2 CH4 + 2 H2O (6.10) (formic acid + hydrogen methane + water) CH3OH + H2 CH4 + H2O (6.11) (methanol + hydrogen methane + water) Methanogenesis by carbon dioxide reduction with hydrogen: CO2+ 4 H2 CH4 + 2 H2O (6.12 (carbon dioxide + hydrogen methane + water) 2 CO2 + 4 H2 CH3COOH +2 H2O (6.13) (carbon dioxide + hydrogen acetic acid + water) Figure 6.2: Methanogenic Bacteria Both mesophilic and thermophilic methanogens are present in this stage, and have a combined range of operation from 30 65 °C. As organic acids are consumed leachate pH increases to between 7 and 8, which is within the optimal pH range for methanogenesis of 6.8 – 7.5 pH. The methanogenic stage is the longest stage of waste degradation, significant methane production is from 3 12 months, however LFG can continue to be generated for a period of 15 years. Source: SpaceRef.com
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Stage 5: Oxidation The final stage of waste degradation is established after all organic acid substrates are exhausted. Aerobic micro organism gradually replace the anaerobic methanogens and convert the residual methane to carbon dioxide and water. Figure 6.3 summaries the inputs and outputs of each stage described above. Below sulphate reduction is only shown in the acetogenic stage, however sulphate reducing bacteria can become established during the fermentation stage and progress throughout the methanogenic stage, depending upon environmental conditions. Figure 6.3: Major steps in the decomposition of biodegradable waste to form landfill gas
Source: Environmental Agency, 2004
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6.2 FACTORS INFLUENCING METHANE POTENTIAL Acidity Methanogenesis has an optimal pH range as outlined in table 6.1, consensus is that pH should be maintained between pH 6.5 and pH 7.7 (average value), however methanogenic activity can occur between extremes of pH 5 and pH 9. Table 6.1: Methanogenesis pH ranges pH range Source 6.4 –7.2 (Kotze, et al 1969 in Farquhar and Rovers, 1973) 6 – 8 (Zehnder, et al 1982 in Christensen, et al 1996) 6.8 – 7.4 (Reinhart & Townsend, 1998) 6.5 – 8.5 (Environmental Agency, 2004) 6.8 – 7.5 (Williams, 2005) During Acetogenesis the production of acids, primarily acetic acid and its derivatives, can lower pH to 4 or less (Williams, 2005). The heterogeneous nature of waste has the ability to buffer pH and when equilibrium has been reached between acetogenesis and methanogenesis an optimum pH of 7.4 can be maintained (Environmental Agency, 2004). Temperature Temperature is an important factor influencing biochemical reactions and methane production; temperature varies depending upon waste decomposition stages. Temperatures can reach as high as 80 – 90 °C during hydrolysis and stabilise to 30 35 °C upon methanogenesis. Methanogenic micro organisms can be classified by temperature range into psychrophilic, mesophilic and thermophilic, temperature ranges from these micro organisms are summarised in table 6.2. Table 6.2: Methane producing bacteria temperature ranges Methanogens SOURCE Psychrophilic Mesophilic Thermophilic < 22 °C 20 – 44 °C > 44 °C (Kotze, et al 1969 in Farquhar and Rovers, 1973) 35 45 (Environmental Agency, 2004) 30 – 35 °C 45 – 65 °C (Williams, 2005) Williams (2005) reports the majority of landfill sites have temperatures between 30 and 35 °C during the main landfill gas generation phase. Temperature is also dependent on waste depth, increasing depth allows for greater insulation of the waste and deeper landfills can have temperatures over 60 °C (Environmental Agency, 2004).
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Moisture Content Much has been written (Farquhar and Rovers, 1973; Christensen, et al 1996; Reinhart & Townsend, 1998; Environmental Agency, 2004; Sponza & Agdag, 2005; Williams, 2005) on the moisture content of waste to promote optimal waste degradation. A summary of optimal moisture content range is provided in the table below. Table 6.3: Optimal moisture content range Moisture Content Minimum Optimum range Typical Source Average For raw MSW 15 – 40 % 30 % (Moss, 1997 in Williams, 2005) 15 – 25 % 15 % Woodlawn Bioreactor – own observations For Bioreactor Operation 25 – 60 % (Farquhar and Rovers, 1973) 25 % 40 – 70 % (Reinhart & Townsend, 1998) 65 % Woodlawn – own observations Nobel and Arnold (1991) in Reinhart and Townsend (1998) note that water addition and leachate recirculation serve as a reactant in the hydrolysis reactions, provides pH buffering, dilutes inhibitory compounds, exposes surface area to microbial attack and controls microbial cell swelling. Excess moisture content and saturation of the waste can have negative impacts due to poor moisture circulation, accumulation of volatile organic acids, and saturation of gas extraction layers can lead to diminished LFG extraction. Nutrients Both macro and micro nutritional requirements of degradation are generally met by the MSW. An optimum ratio of organic matter (COD), nitrogen and phosphorous as 100: 0.44: 0.08 was expressed in Christensen (1996). Research into the addition of nutrients to promote methane generation was outlined in Reinhart and Townsend (1998) with no conclusive results on increased methane yields. Nutrients such as sodium, potassium, calcium, magnesium, chlorine, iron copper, zinc, manganese, molybdenum, nickel and vanadium have been identified as micro nutrients in Chynoweth and Pullammanappallil (1996). Generally the nutritional requirements for biodegradation are not excessive and are typically met by the municipal solid waste. Inhibitors/Toxicity Micro nutrients, metals, etc., are essential to the growth of micro organisms, Kugleman and Chin (1971) illustrated the relationship between the concentration these inputs on methanogen growth rate, figure 6.4. Figure 6.4: Effect of metabolite concentration on growth rate for methanogens
Source: Kugleman and Chin, 1971
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Concentrations below the optimum are not conducive to maximum growth, where as concentrations above the optimum concentration can have an inhibitory effect. Potentially toxic inhibitors such as; alternative electron acceptors (oxygen, nitrate, sulphate), sulphides, heavy metals, halogenated hydrocarbons, volatile organic acids, ammonia and cations have been identified in Chynoweth and Pullammanappallil (1996). Heavy metals in high concentration may have an effect on the Woodlawn Bioreactor, being that Woodlawn is the site of a former metal sulphide mine. Whilst metal concentrations can be addressed by precipitation through pH control or leachate treatment, the effect of metals on LFG production and reactor performance is beyond the scope of this project. Oxygen An anaerobic environment is paramount in the cultivation methanogens and production of methane, methanogens are sensitive bacterium’s and require a low redox potential (Eh), redox potentials of –200 mV and –300 mV have been noted by Farquhar & Rovers (1973) and Christensen, et al (1996) respectively. Ammonia The build up of ammonia, from the decomposition of proteins and fats, can also have an inhibitory affect upon methane production. De Baere et al (1984) found that ammonia of 50 – 80 mg/l can decrease methanogenesis by up to 50%. This said, the average values for ammonia for bioreactors range from 32 – 1850 mg/l (Reinhart & Townsend, 1998) in the methanogenesis phase of waste decomposition. Sulphate The effect of sulphate on bioreactor performance is a fundamental part of this thesis and will be addressed in section 7.
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7 SULPHUR INTERACTIONS IN BIOREACTOR PROCESSES
In many bioreactor and landfill sites around the world the issues associated with the reduction of sulphur compound are onerous. The majority of sites that deal with this issue are sites that accept construction and demolition waste, and today the trend is towards separating these sites from those that accept biodegradable waste. In sites that accept biodegradable waste the amount of sulphur within the waste is usually finite and belongs to the MSW being accepted by the site. The Woodlawn Bioreactor is a unique situation, the void geology, of sulphidic mineral deposits, allows for a continuous supply of sulphur in the form of sulphate to the waste mass. Surface water runoff and ground waters are able to provide a constant source of sulphate and metals, which is readily consumed by sulphate reducing bacteria, and has the potential to form dangerous levels of hydrogen sulphide gas. Figure 7.1 below shows the relationships between the sulphate sources and the production of hydrogen sulphide gas. Figure 7.1: Sulphur Oxidisation and Reduction within Bioreactor Processes
Inflow Process Outflow
H2S(g) 2- SO4 Surface water Runoff
2- SO4 SRB Ground Water
- 2- 2- H2S(aq), HS , S SO4 MSW
MeS
System Boundary
Source: Own Sulphate from groundwater and surface water runoff enters the waste and is reduced by SRB to form either sulphide (S 2) or hydrosulphide (HS ). The hydrosulphide can then volatilise to from hydrogen sulphide gas. Sulphide ions can react with hydrogen ions in the waste to form hydrogen sulphide ions, that then follow the above process. Limiting the input of sulphate is obviously the primary objective, however total exclusion of sulphate from the waste mass is almost impossible, once in the system the sulphur will either remain as aqueous sulphate or sulphide, volatilise to form reduced sulphur compounds (RSC) predominantly in the form of hydrogen sulphide or precipitate to form metal sulphides. Under normal circumstances the production of LFG is not overly complicated, the recirculation of leachate acts as an in situ treatment measure and distributes beneficial bacteria. However in situations where there is an influence of large concentration of sulphur compounds, management of LFG production becomes more complicated.
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7.1 SULPHUR INFLOWS 7.1.1 Sulphidic Mine Environments As detailed by Harris (1997) and Mudder (2004) in Winchester (2005), acid mine drainage (AMD) is arguably the largest threat to long term sustainability of the mining industry, the global effects are ecologically and financially damaging to the mining industry, with impacts primarily affecting surface waters and associated ecosystems. AMD results in amplified metal and sulphate concentrations and low pH, these factors are non conducive to optimum bioreactor performance and methanogenesis. AMD at Woodlawn is a result of the aerobic oxidation of massive deposits of metal sulphide minerals, primary pyrite (FeS2), as well as galena (PbS), sphalerite (ZnS) and chalcopyrite (CuFeSs). Sources of AMD at Woodlawn occur at various locations including, water runoff from waste rock dumps (adjacent to the void), water runoff from exposed rock throughout the void walls and water infiltration from bore holes, faults and fractures in the void walls. As pyrite is the largest contributor to AMD, the following is a brief overview of the oxidation of pyrite as described in Winchester (2005) and Parker & Robertson (1999).
Pyrite oxidises in the presence of water and oxygen, liberating ferrous iron, sulphate and protons.
2+ 2 + FeS2 + 3.5 O2 + H2O Fe + 2 SO4 + 2 H (7.1) (pyrite + oxygen + water ferrous iron + sulphate + protons) As the pH lowers during Equation 7.1 ferrous iron further oxidises to ferric iron (depending on redox potential). This aqueous oxidation of ferrous iron does not directly involve pyrite. 2+ 3+ Fe + 0.25 O2 Fe + 0.5 H2O (7.2) (ferrous iron + aqueous oxygen + proton ferric iron + water) The ferric iron produced in Equation 7.2 can hydrolyse (ferrolysis) to form ferric hydroxide. Ferric hydroxide can precipitate when pH is lowered. 3+ + Fe + 3 H2O Fe(OH)3 + 3 H (7.3) (ferric iron + Water ferric hydroxide + protons) A summary of Equation 6.2 and 6.3 results in ferric hydroxide and 2 protons, thus further lowering pH. 2+ + Fe + 0.25 O2 + 3 H2O Fe(OH)3 + 2 H (7.4) (ferrous iron + oxygen +Water ferric hydroxide + protons)
The overall summary of reactions (Equations 1 – 4) for the oxidation of pyrite is: 2 + + FeS2 + 3.75 O2 + 3.5 H2O 2 SO4 + Fe(OH)3 + 4 H (7.5) (pyrite + oxygen + water sulphate +ferric hydroxide + protons) When pH reaches approximately 3.5 or lower, ferric iron becomes the primary pyrite oxidant, this further reduces the pH, via the addition of protons, until ferric iron becomes the exclusive pyrite oxidant at a pH less than 3. 3+ 3+ 2 + FeS2 + 14 Fe + 8 H2O 15 Fe + 2 SO4 + 16 H (7.6) (pyrite + ferric iron + water ferric iron +sulphate + protons)
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The net result of AMD (Equation 6.6) are high acidity, pH can reach 1, and high concentrations of sulphate and metals. In addition to pyrite oxidation, gelana (PbS), sphalerite (ZnS) and chalcopyrite (CuFeSs) are oxidised by ferric iron, contributing to AMD. The massive extent of sulphide minerals exposed to oxygen, the amount of water in contact with the minerals and the rate of oxidisation controls the load and duration of acid, metals and sulphate from the mine. At the majority of massive base metal sulphide mining sites, the effect of these acid generating processes can be expected to continue for hundreds of years, post mine closure. The effect of acid mine drainage is detrimental the immediate surrounding ecosystems and has potential consequences further ‘down stream’. The Woodlawn site, with extensive sulphide minerals exposed is expected to behave similarly to other such mine sites. 7.1.2 Woodlawn While bioreactor cells are designed to maintain isolation between groundwater/water runoff and landfill leachate during methanogenesis, the infiltration of groundwater runoff of approximately 2L/second into the waste has had the effect of introducing sulphate rich, low pH, metalliferous water into the waste. High sulphate and low pH conditions are conducive to sulphate reduction resulting in the formation of reduced sulphur compounds, mainly hydrogen sulphide. MSW contributes sulphur to the system in different forms, trade waste (especially from the construction industry) is also source of sulphur in the form of gypsum, however the amount of this waste stream compared to the sulphur inflows related to acid mine drainage would be negligible to the overall sulphur inflows of the total system. An important part of reducing the effect of AMD on bioreactor performance has been mentioned in section 2.3, reducing the amount of water runoff into the void and collection of water in the void before contact with the waste surface will limit the introduction of sulphate into the system. However it is a reality that some infiltration of water with high sulphate concentrations will inevitably reach the waste. Woodlawn Depending upon location, sulphate concentration, acidity and metal concentration vary considerably. Specific locations within the site contain higher levels of metal sulphide than other, the results below show how levels of sulphate and metal differ depending on location. Table 7.1: Woodlawn Surface Water Runoff Analysis Location PARAMETER UNITS Northern Wall Southern Wall Ground Water 2006/11/21 2006/12/27 2007/01/08 pH pH Units 7.2 2.8 4.6 Specific Conductance uS/cm 3300 16000 21000 Oxidation Reduction Potential mV 111 286 Sulphate mg/l 1400 17000 14000 Iron mg/l 740 280 Lead ug/l 1200 250 Copper ug/l 2600 110 Zinc mg/l 57000 27000 Source: VES, 2006
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Levels of sulphate and metals in leachate show a marked reduction in sulphate and metals. This is due to SRB reducing sulphate, metal precipitation and buffering occurring within the waste. Table 7.2: Woodlawn Leachate Analysis – 2006/11/21 Location PARAMETER UNITS LE4 LE6 LE7 LE15 pH pH Units 5.4 5.9 5.4 2.8 Specific Conductance uS/cm 36000 38000 37000 38000 Oxidation Reduction Potential mV 155 120 110 125 BOD mg/l 78000 78000 70000 59000 COD mg/l 120000 140000 140000 110000 Ammonia mg/l 2700 2800 2500 3100 Total Iron mg/l 1100 710 1500 1500 Total Copper ug/l 89 57 47 13 Total Lead ug/l 4900 1800 1100 670 Total zinc mg/l 150 130 160 120 Sulphate mg/l 2600 2500 2500 2100 Sulphide mg/l 2.2 2.2 1.0 6.8 Source: VES, 2006 7.2 PROCESSES - SULPHUR REDUCTION 7.2.1 Sulphate Reduction – competition for substrates Sulphate reducing bacteria (SRB) are responsible for the reduction of sulphate to sulphide during the biodegradation process. The presence of sulphate reducing bacteria in bioreactors is inevitable, several types of SRB have the ability to establish colonies in the fermentation and acetogenic biodegradation stages. These SRB can also exist in the absence of sulphate surviving on substrates such as lactate, ethanol, propanol, fumarate, malate, fructose and acetate (Elferink, et al 1994). SRB compete with methanogens for the derivatives of organic acids formed during the fermentative stage; hydrogen, formate (formic acid), acetate (acetic acid), propionate (propanoic acid), butyrate (butyric acid), ethanol and lactate (lactic acid) are all utilised by SRB (Elferink, et al 1994). Typical reactions are illustrated in Christensen et al (1996): 2 + 4H2 + SO4 + H HS + 4H2O (7.7) (Hydrogen + sulphate + proton hydrosulphide ion + water) 2 CH3COOH+ SO4 CO2 + HS + HCO3 + H2O (7.8) (acetic acid + sulphate carbon dioxide + hydrosulphide ion + hydrogen carbonate ion +water) 2 + 2CH3C2H4COOH + SO4 + H 4CH3COOH + HS (7.9) (Butyric acid + sulphate + proton acetic acid + hydrosulphide ion) 7.2.2 Sulphate reduction – oxidisation of methane Not only do SRB compete for the same substrates as methanogens but SRB can also consume methane formed during methanogenesis. Equation 6.10 illustrates the consumption of methane by SRB:
2 + 2CH4 + SO4 + 2 H 4 H2 + 2 CO2 + H2S (7.10) (methane) + (sulphate) + (proton) (hydrogen) + (carbon dioxide) + (hydrogen sulphide) (VES, 2006) This reaction directly affects the bioreactors methane producing potential, reducing performance in the later energy conversion processes. D.A. Lazarevic Page 23 of 87 Royal Institute of Technology Stockholm, 2007 Veolia Environmental Services
7.2.3 Sulphate Reducing Bacteria Competition with Methanogenesis Gurijala and Suflita (1993) outlined that methanogenesis of MSW may be limited to a degree by the availability of sulphate. The inhibition of methanogenesis by sulphate reduction has been observed in a variety of environments. Raskin et al (1996) showed that in methanogenic bioreactors, prior to sulphate injection the reactor contained up to 25% methanogens and 15% SRB, upon injection of sulphate the SBR populations increased to 30 – 40%. As acetate concentrations decreases due to SRB, the methanogenic populations decreased to approximately 8% and methane production decreased. 50 days after the initial sulphate injection methanogens began to increase as sulphate became exhausted. Similar findings have been shown in Gurijala and Suflita (1993). SRB utilise a range of substrates as shown in Elferink et al. In sulphate rich environments SRB tend to out compete methanogens for specific substrates such as hydrogen and acetate, but do not compete for substrates such as methanol to an ecologically significant extent (Gurijala and Suflita 1993). However in experiments that were conducted specifically on MSW, trends were not so obvious. Fairweather and Barlaz (1998) have conducted research to evaluate the effect of a number of sulphate sources on hydrogen sulphide production and on competition between methane production and sulphate reduction during refuse decomposition. Tests were conducted in reactors that contained a combination of MSW and decomposed refuse (as seed) and various sulphate sources; digested polymer treated sludge, anaerobically digested lime stabilised sludge and gypsum wallboard (calcium sulphate). Results showed that the reactors with sulphate added (calcium sulphate) showed a significant increase in hydrogen sulphide as expected, yet methane production was concurrent with sulphate reduction. Even though SRB populations increased by nearly 3 orders of magnitude, between 2.9 and 7 times organic carbon was consumed by methanogens than by SRB.
Yoda et al (1987) conducted a series of experiments on anaerobic fluidised beds, varying the concentrations of acetate and sulphate and found that: • SRB dominated the supply of organic substrate when there was a limited supply, i.e. the growth rate of SRB activity was not limited by substrate, except when the substrate dropped below 2 mg/l. Lovely and Klug (1986) supported this finding and found that SRB only became dominant when acetate concentrations were lower than what is viable for methanogens. • The activity of SRB was limited when sulphate levels dropped below 45mg/l, however Lovely and Klug (1986) estimated SRB to thrive in sulphate concentrations as low as 3mg/l. In personal communications with Dr Damien Batstone of the Advanced Wastewater Management Centre at the University of Queensland, personal experience showed that even with the establishment of SRB colonies potential methane yield only reduced by a factor in the order of 1 – 2 % and was negligible in overall bioreactor performance compared to other environmental factors. Reduced methane potential yield caused by other factors such as pH, toxicity, availability of substrate, oxygen ingress etc. cause a decline in volume of gas produced. Whilst a methane carbon dioxide ratio’s of 50:50 will be maintained volume of these gases may be greatly reduced and replaced by other gases such as nitrogen, oxygen, carbon monoxide, etc. This said the amount of sulphate available to the system at Woodlawn is far greater than experienced in ‘normal’ circumstances, hence there is a possibility that due to the volume of sulphate reduction taking place a reduction in methane yield may be evident.
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Figure 7.5: pH Vs Yield growth coefficient & specific growth rate Sulphate reducing bacteria has an optimum pH range of pH 5 – pH 9 (Prostgate, 1979 in Christensen, et al 1996), Reis (1992) gives a reduced range of pH 5.8 – pH 7 with an optimum growth rate of pH 6.7 as shown in figure 7.2. By maintaining a neutral or slightly alkaline pH around 7.5, methanogens growth is optimised whilst pH for SRB growth is higher than the optimal growth ranger. Sulphide reduction can be reduced and formation of H2S(aq) production will be retarded by keeping the sulphur in an aqueous state, as the pH is shifted out of the optimum range for production of hydrosulphide ions and hydrogen sulphide, thus reducing hydrogen sulphide production. Source: Reis, 1992
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7.3 SULPHUR OUTFLOWS 7.3.1 Gaseous Sulphur Reduced sulphur compounds (RSC) are trace elements of landfill gas that occur in landfill sites with sulphate loads, these landfill sites are typically those that accept construction and demolition (C&D) waste. Substantial quantities of gypsum in the form of drywall/gyprock (CaSO4 .2HsO) provide a readily available source of dissolvable sulphate, utilised by the SRB (Lee, et al 2006). The following RSC in table 7.3 below would be likely to be found in the LFG at Woodlawn as a result of sulphate inflows due to AMD. Table 7.3: Reduced Sulphur Compounds present in Landfill Gas RSC (REDUCED SULPHUR COMPOUNDS) Hydrogen Sulphide Ethyl methyl sulphide Carbonyl Sulphide Thiophene Methyl mercaptan Methyl isopropyl sulphide Dimethyl sulphide Dimethyl disulphide Ethyl mercaptan 2 Methylthiophene Carbon disulphide 3 Methylthiophene Isopropyl mercaptan sec-Butyl mercaptan Tert Butyl mercaptan Source: Lee, et al 2006. Of these gasses; hydrogen sulphide (H2S), carbon disulphide (CS2), dimethyl sulphide (CH3SCH3, DMS), methyl mercaptan (CH3SH) and dimethyl disulphide (CH3SSCH3, DMDS) are the most abundant in landfill situations (Shon, et al 2005). Hydrogen sulphide has been established as the most abundant SRC by volume in the majority of landfill sites. Research conducted by Kim et al (2005) into SRC in landfill gas in Korea shows that hydrogen sulphide production is greater that other SRC by some orders of magnitude, some landfill sites show hydrogen sulphide levels of 539,600 (ppb) whilst other SRC such as methyl mercaptan, DMS, carbon disulphide and DMDS have values of 104, 84, 1370 and 7.30 (ppb) respectively. Hydrogen sulphide is a colourless, poisonous and flammable gas. It can be detected by smell at 0.01 –0.3 ppm, however at concentrations above 100ppm sense of smell is deadened within a few minutes and death can occur from 500ppm. Woodlawn Table 7.4 below show a summary of hydrogen sulphide levels measured from the HAASE flare, when LFG is combusted prior to commissioning of the first LFG engine. Levels of > 100ppm are considered to be detrimental to combustion infrastructure as a result of acid gas corrosion. Table 7.4: Woodlawn LFG Analysis Date Sample Point CH4 (%) CO2 (%) O2 (%) N2 (%) H2 (%) H2S (ppm) 2006/10/18 HAASE Flare 47.8 39.5 0.1 12.6 0.0 35.5 2006/10/26 HAASE Flare 49.3 40.5 0.1 10.1 0.0 47.8 2006/11/01 HAASE Flare 17.8 34.4 0.2 47.7 0.0 120.0 2006/11/08 HAASE Flare 38.6 36.2 0.1 25.1 0.0 20.0 2006/11/15 HAASE Flare 43.7 51.5 0.7 4.1 0.0 16.3 Source: VES, 2006
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Operational Concerns of Hydrogen Sulphide Health and safety Increased levels of hydrogen sulphide can be an occupational health and safety risk, especially in a site such as Woodlawn where there is an abundant supply of sulphate to be reduced.
Acute exposure effects include; eye, nose, throat, lung and eye irritation and high concentrations can cause serious health effects and death. Longer term effects of hydrogen sulphide include; reduced lung function, neurological effects (headaches, depression), cardiovascular damage, eye and mucous membrane irritation (Alberta Human Resource & Employment, 2005). Table 7.5: Health Effects from short-term exposure to hydrogen sulphide Concentration (ppm) Health Effect 0.01 – 0.3 Odour threshold 1 – 20 Offensive odour, possible nausea, tearing of the eyes or headaches with prolonged exposure 20 – 50 Nose, throat and lung irritation; digestive upset and loss of appetite; sense of smell starts to become fatigued; acute conjunctivitis may occur (pain, tearing and light sensitivity) 100 – 200 Severe nose, throat and lung irritation; ability to smell odour completely disappears 250 – 500 Pulmonary oedema (build up of fluid in the lungs) 500 Severe lung irritation, excitement, headache, dizziness, staggering, sudden collapse, unconsciousness and death within a few hours, loss of memory for the period of exposure 500 – 1000 Respiratory paralysis, irregular heart beat, collapse and death without rescue >1000 Rapid collapse and death Source: Alberta Human Resource & Employment, 2005. Acid gas corrosion of gas recovery system Acid gas corrosion arises from hydrogen sulphide reacting with gas recovery and power generation equipment and results in the formation of black iron sulphide scales, under deposit corrosion can occur beneath the layers of scales and may result in deep, isolated and randomly scattered pits in pipe work and power conversion infrastructure. Acid gas corrosion causes an increase in machinery down time and increased maintenance and replacement costs. Increased SOx emissions from flaring and other combustion processes The combustion of fuels with high sulphur content can lead to flue gases with high levels of sulphur dioxides. The incomplete combustion of hydrogen sulphide forms SOx emissions, predominantly sulphur dioxide, which along with nitrogen oxides are the main precursors of acid rain. Sulphur dioxide can readily form acid aerosols contributing to global warming and having serious health implications.
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7.3.2 Aqueous Sulphur 2 2 Sulphur present in leachate is predominantly in the form of sulphate (SO4 ), sulphide (S , HS ), 2 hydrogen sulphide (H2S(aq)) and transitionally may exist as sulphite (SO3 ). Sulphate Sulphate present in Woodlawn bioreactor leachate is a direct result of AMD water runoff and affected groundwater entering the waste mass. Sulphate concentrations vary depending upon surface or ground water ingress and the location of water ingress. Rain events are directly responsible for elevated peaks of sulphate inflows due to localised increase in mineral oxidisation and weathering. Table 7.6: Source vs. Sulphate concentrations 2006/11/10 Location Parameter Units Bioreactor Groundwater Water Runoff Leachate – LE 7 – LMB5 – SW01 pH pH Units 5.4 3.5 2.8 Specific Conductance uS/cm 36000 10900 16000 Oxidation Reduction Potential mV 155 168 286 Sulphate mg/l 2600 9300 17000 Sulphide mg/l 1.0 Source: VES, 2006 As seen in table 7.6 above concentrations vary greatly depending on source. The most pure form of AMD is from the water runoff, here sulphate concentrations are extremely high and pH very low due to the sulphidic rock oxidising with runoff water. As the runoff water peculates through to the water table characteristics remain similar, groundwater concentrations of sulphate may drop however this may be due to dilution within the water table. Upon entering the bioreactor, sulphate concentrations drop dramatically as the sulphate acts as a substrate for SRB along with various organic matter, mainly in the form of volatile fatty acids including acetic, butyric and propanoic acids and their respective derivatives. The sulphate is consumed according to reactions 6.7 – 6.10. Sulphide
Sulphide that is produced as a result of SRB may be present in various forms, including H2S(aq), HS and S2 . The form of sulphide present is dependent upon leachate pH, H2S(aq) is predominate from pH 1 – 5, HS is predominate in pH range of 6 – 9.5 and S2 is the major species above pH 10 (VES, 2006). Whilst sulphate reduction is inevitable, environmental conditions can be manipulated to reduce the negative effects of hydrogen sulphide production (see section 7.3.1). Sulphate reduction becomes a major problem when the reduced sulphur forms as hydrogen sulphide. By raising the pH of leachate the formation of hydrosulphide ions is favoured reducing the amount of sulphur entering the gaseous state. 2 CH3COOH + SO4 HCO3 + HS + CO2 + H2O (moderate to high pH) (7.11) (acetic acid + sulphate hydrogen carbonate ion + hydrosulphide anion + carbon dioxide + water) In Figure 7.2, hydrosulphide concentration is plotted against pH, as pH increases hydrosulphide concentration increases, thus limiting the amount of sulphur available for conversion to H2S(aq).
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Figure 7.2: Hydrosulphide vs pH
[HS-] vs pH
10000
1000
100
10
1 1 2 3 3.44 4 5 6 6.89 7 8 9 9.5 [HS ] 0.1 [HS-] - g/L - [HS-] 0.01
0.001
0.0001
0.00001 pH Source: VES, 2006 When pH is raised to even higher pH >8 sulphide (S2 ) becomes the predominate form of aqueous sulphur. Figure 7.3: Sulphide vs pH
[S2-] vs pH
1000
100
10
1 7 8 9 9.5 10 11 12 13 14 0.1 [S2 ]
[S2-] - g/L - [S2-] 0.01
0.001
0.0001
0.00001 pH Source: VES, 2006 At lower pH the formation of hydrogen sulphide as a gas is favoured: 2 CH3COOH + SO4 2HCO3 + H2S(g) (moderate to low pH) (7.12) (acetic acid + sulphate hydrogen carbonate ion + hydrogen sulphide) Figure 7.4 shows the rise in hydrogen sulphide concentration as pH decreases.
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Figure 7.4: Hydrogen Sulphide vs pH
[H2S] vs pH
4.000
3.500
3.000 [H2S] 20oC 2.500 [H2S] 25oC [H2S] 30oC 2.000 [H2S] 35oC
[H2S] - g/L - [H2S] 1.500 [H2S] 40oC [H2S] 45oC 1.000
0.500
0.000 1 2 33.44 4 5 6 7 pH Source: VES, 2006 Both of these processes are alkaline generating (acid consuming) process, through the formation of hydrogen carbonate ions. Hydrogen sulphide will be the predominantly reduced sulphur species in solutions with pH levels below approximately 7.0. Hydrosulphide (HS ) ions will be the predominantly reduced sulphur species in solution with pH levels above or near neutral. The relationship between these species is shown in reaction 7.3 below. + H2S (aqueous) ↔ HS (aqueous) + H (aqueous) (7.13) (hydrogen sulphide hydrosulphide anion + hydrogen cation/proton) Hydrogen sulphide exists in equilibrium between soluble and gaseous hydrogen sulphide, the hydrosulphide anions and protons volatilise to produce hydrogen sulphide gas.
H2S (aqueous) ↔ H2S (gas) (7.14) Sulphide concentration in Woodlawn leachate are typically low, this suggest that two process are occurring: 1) Environmental conditions are conducive to producing hydrogen sulphide gas rather than hydrosulphide ions. This is supported by high LFG hydrogen sulphide concentrations and low sulphide concentrations. 2) The hydrosulphide ions that are present are being precipitated as metal sulphides, due the abundance of metal ions from water inflows. Sulphide concentrates within the Woodlawn bioreactor are relatively low, Yoda et al (1987) found that sulphide concentrations up to 80mg/l did not inhibit methanogenic activity. This differs to Khan and Trottier (1978) (in Yoda, 1987) who found that various sulphur compounds have an inhibitory effect on the degradation of cellulose and the inhibition on methanogens. They found 2 the following relationship between sulphur compounds and increasing toxicity, S2O3 < SO3 < S < 2 H S. They also found that concentrations as low as 60mg/l of H2S inhibited methanogenesis. A possible reason for this contention could be do to the fact that Yoda used acetate as a substrate as opposed to starch, acetogenesis may have been affected by sulphide, not methanogenic activity. In either case levels of sulphide are well below the levels given above for methane inhibition.
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7.3.3 Solid Sulphur The abundance of soluble metal ions from water runoff and ground water infiltration provide a key factor in the capture of sulphur within the bioreactor preventing excess hydrogen sulphide from being formed. In anaerobic conditions the precipitation of metal sulphides by the reduction of hydrogen sulphide follows the following equation. 2+ + Me + H2S (aq) MeS (s) + 2 H (7.15) (metal iron + hydrogen sulphide iron mono-sulphide + protons) Metal ions react with hydrogen sulphide to form various metal sulphide precipitates. These precipitates capture the sulphur in a solid state within the waste mass. Both ferric and ferrous ions react with hydrogen sulphide to produce iron sulphide and acid. 2+ + Fe + H2S (aq) FeS + 2 H (7.16) (ferrous iron + hydrogen sulphide iron(II) sulphide + protons) 3+ + Fe + 2 H2S (aq) FeS2 + 2 H + H2 (7.17) (ferric iron + hydrogen sulphide pyrite + protons + hydrogen) Total metal concentrations of zinc, lead and copper are found in abundance in the AMD entering the bioreactor void due to the oxidisation of the minerals sphalerite, galena and cuprite. Upon interaction with hydrogen sulphide precipitation of these metals in the follow forms can take place. 2+ + Zn + H2S (aq) ZnS + 2 H (7.18) (zinc ion + hydrogen sulphide zinc sulphide + protons) 2+ + Pb + H2S (aq) PbS + 2 H (7.19) (lead ion + hydrogen sulphide lead sulphide + protons) 2+ + Cu + H2S (aq) CuS + 2 H (7.20) (copper ion + hydrogen sulphide copper sulphide + protons) The ability of metals to precipitate in various forms is dependent upon a number of functions including , solubility product constants (Ksp), pH, metal concentrations, presence and interactions between various compounds and species. However due to the nature of waste and the vast number of unknown reactions taking place there are many different factors effecting metal precipitation. Table 7.7: Metal Sulphide Solubility Products K pK ( logK ) Compound Formula sp sp sp Copper (II) Sulphide CuS 6x10 37 Iron (II) Sulphide FeS 6x10 19 Lead (II) Sulphide PbS 3x10 29 Zinc Sulphide ZnS 2x10 25 Source: University of Rhode Island, No Date. Table 7.7 gives the various solubility products (Ksp) for various key metals found in abundance at Woodlawn, the Ksp is an equilibrium constant that equals the product concentration of soluble ions at equilibrium. Compounds with lower Ksp values will often be preferentially precipitated (although this is not a strong rule). Of the compounds in table 7.7, Copper sulphide is the least soluble, then lead sulphide, zinc sulphide and finally iron sulphide, however all of these metal sulphides are very insoluble. It should also be noted that iron sulphide can also form pyrite (FeS2), a complex of a neutral sulphur atom and FeS, which is less soluble, but slower forming than zinc sulphide (Batstone, 2007).
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8 PERIODIC WASTE COVER AND IN-SITU HYDROGEN SULPHIDE CONTROL
8.1 ENVIRONMENTAL PROTECTION AUTHORITY REQUIREMENT FOR ALTERNATIVE DAILY COVER TRIAL The NSW EPA in their publication ‘Environmental Guideline: Solid Waste Landfills’ states that ‘Daily soil cover should be applied to a minimum depth of 15 centimetres over wastes. All waste should be covered prior to ceasing operations at the end of each day’ (EPA NSW, 1996). However, the placement of typical daily cover (excavated material) in bioreactors is non conducive to optimal bioreactor performance and optimal daily operation. The placement of a daily 15cm cover (EPA, 2004) not only incurs time and material costs but also inhibits the recirculation of leachate and hinders LFG extraction, both vital processes in bioreactor operations. The use of an alternative daily cover (ADC) is encouraged as a part of the Environmental Protection Licence (#11436) and the Conditions of Consent set below, as established by the Environmental Protection Authority: 8 (b) take all practicable measure to operate the landfill as a bioreactor to ensure the maximum extent practicable, the biological conditions of all organic waste and productive capture of methane. 37. Cover material must be virgin excavated natural material, unless otherwise approved in writing by the EPA. Note: The applicant is encouraged to identify alternative daily cover materials and examine the feasibility of adopting such materials as to minimise impacts of utilising virgin natural excavated material. 38. Cover material must be of a quality that will not inhibit the biological decomposition of excavated waste. (EPA, Conditions of Consent) Requirements for ADC are also covered/replicated in the Woodlawn Environmental Protection Licence (#11436). For the use of alternative covers the EPA requires the licensee to provide scientific evidence that demonstrates that these products can ‘beneficially influence landfill leachate and gas quality when used as daily cover’ (EPA, 2004). The use of iron rich products in the mitigation hydrogen sulphide gas was identified in late 2005 in various consultants reports to VES. It was stated that among other strategies, such as the removal of waste rock with high sulphate potential and diversion of surface water run off, that the availability of excess soluble iron is needed to maintain soluble iron at high enough concentrations to enable the precipitation of metal sulphides.
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The use of iron rich materials to act as a daily cover for waste would work in two ways; to fulfil the role of a daily cover and to aid the in situ capture of sulphur preventing the formation of excess hydrogen sulphide gas as outlined in section 6.3.3. The relationships between iron rich ADC’s and the requirements of a daily cover material are outlined below: 1. Limiting run-off and infiltration of water The nature of bioreactors purport that leachate recirculation is extremely important in the acceleration of waste degradation. The use of iron rich products allows for leachate recirculation to be carried out more effectively, leachate can be surface spread without the need of traditional daily cover removal. There is no need to keep rainfall out of the waste as it beneficial acquiring optimal leachate volumes. 2. Controlling and minimising risk of fire The products selected for testing as ADC are non combustible. Additionally Woodlawn has an Emergency Response Plan that covers fire fighting within the void. The constant recirculation of leachate maintains high moisture within the waste mass and combined with waste compaction these efforts reduce the risk of fire. 3. Minimising emission of landfill gas Bioreactor gas extraction systems are designed to remove the LGF produced within the waste. It is expected that gas emissions will be managed as a result of the need to optimise gas extraction as a part of the bioreactor operations. This differs to traditional landfills where the lack of a negative pressure gas extraction system allows LFG to be released into the atmosphere. 4. Suppressing site odour While the ADC will not control the fresh waste odours it is expected that the bioreactor gas extraction system will assist in reducing build up of odours within the void. Also the location of the bioreactor means that odour issues from the void will have a negligible impact on local residents. 5. Reducing fly propagation and rodent attraction and Chemical spraying and baiting for flies is undertaken regularly on the emplaced waste. The compactor is fitted with a spray unit so that waste can be sprayed prior to daily cover application. A rat baiting program is in operation with a significant reduction in numbers being recorded (measured by amount of baits to be replaced) since January 2006 (VES, 2006).
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8.2 ALTERNATIVE COVER MATERIALS TO BE INVESTIGATED Four materials were tested for use as Alternative Daily Cover materials at the Woodlawn Bioreactor. The material selection criteria were based upon iron content of the material, availability, location, various particle sizes and appropriate waste products that could be used. The following products were selected for testing as alternative daily cover materials, material data sheets are available in Appendix A. Haematite, which has been intermittently added to the waste surface, was selected as a soluble source of iron due to its high iron content and its abundance. However this material is sourced from Western Australia, therefore material price increases and environmental impacts associated with the transportation of the material. Other materials selected for testing were selected with material source in mind, and all materials were sourced close to the Woodlawn region. Magnetite is a material very similar to hematite and is expected to behave in relatively the same way. The source of this material is very close to the Woodlawn area and cost significantly lower than hematite. The addition of either hematite or magnetite does not incur the ‘landfill levy’ a governmental tax imposed by weight upon the amount of waste materials deposited in landfills and bioreactors. Ferric hydroxide and the Multi Service Baghouse Dust are both waste materials from industrial process, in terms of ‘industrial ecology’ they are a better option, because they are source of waste not mined materials. However because these materials are waste materials they incur the ‘landfill levy’, a tax that hematite and magnetite are not subject to. Table 8.1 below outlines the material source locations, iron content and particle size. Table 8.1: Alternative Daily Cover Material Material Material Source Iron Content (max Particle Size %) Commercially Available Products Haematite Ferrous Oxide Western Australia 95 20 microns Magnetite Ferric Oxide Yass (NSW) 69.5 53 microns Industrial Waste Products Drinking Water Treatment Waste Kembla Grange (NSW) 110 g/kg 0.5 – 2 mm Product Ferric Hydroxide Illawarra Resource Recovery – Port Kembla (NSW) 61.7 Unknown Multi Service Baghouse Dust Source: Own
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Haematite - Ferrous Oxide Material Haematite is a very common mineral and used as a primary ore in iron/steel production. It is mined as parts of banded iron formations (grey hematite) or as clay sized hematite crystals that occur as a secondary mineral from the weathering of soil, iron oxides and oxyhydroxides. The red colour of this form allows it to be used as a pigment. Supplier: Unimin Material Source: Western Australia Predominate reactions A summary of the predominate reactions that are expected to take place are summarised below. 2+ + Fe + H2S FeS + 2 H (7.16) (ferrous iron + hydrogen sulphide iron mono-sulphide + protons) Magnetite - Ferric Oxide Material Magnetite is earths most abundant magnetic ore, hence its name. It is used as an ore in the production of iron and steel and can be found in banded formations in sedimentary rocks, and in sands. The oxidised product of magnetite is hematite. Supplier: Unimin Material Source: Gulgong, New South Wales Predominate reactions 3+ + Fe + 2 H2S FeS2 + 2 H + H2 (7.17) (ferric iron + hydrogen sulphide pyrite + protons + hydrogen)
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Drinking Water Treatment Waste Product - Ferric Hydroxide Material The material is the function of two key chemical processed used in drinking water treatment, calcium hydroxide (lime) is added to adjust water pH and increase hardness, calcium concentrations are subsequently lowered by sparging with carbon dioxide. Calcium carbonate (limestone) is precipitated as a result of this process. Ferric chloride is used in water treatment for clarification, upon contact with water ferric hydroxide is formed, absorbing particulate matter and flocculating out of the water column. (Sydney Water, No date). The ferric hydroxide sludge is then moved to drying beds where the ferric hydroxide granules form. Supplier: Veolia Water Material Source: Kembla Grange, NSW Predominate reactions
Fe(OH)3 + H2S FeS + 2.5 H2O+ 0.25 O2 (8.1) (ferric hydroxide) +(hydrogen sulphide) (ferrous mono-sulphide) + (water) + (oxygen) Fe(OH)3 + 2 H2S FeS2 + 3 H2O+ 0.25 H2 (8.2) (ferric hydroxide) +(hydrogen sulphide) (pyrite) + (water) + (hydrogen) Illawarra Resource Recovery - Multi Service Baghouse Dust Material Illawarra Resource Recovery is company involved in the recovery and recycling of products from the Port Kembla steel works region. Port Kembla is located in the Illawarra, one of Australia’s largest and oldest steel works, processes taking place at Port Kembla include iron making, steel making, continuous casting, hot rolling and further steel processing. Illawarra Resource Recovery is involved in the recovery of steel wastes from the various processes and products include, roll shop swarfs, mill sludges, baghouse dusts and casters cakes. These materials are then marketed for recycling in the steel works or other industrial applications. Supplier: Illawarra Resource Recovery Material Source: Port Kembla, NSW Predominate reactions Due to the nature of this material being a waste it contains various metals, whist predominantly iron (61%) the waste contains zinc, lead, nickel, fluoride and other trace heavy metals. The reactions taking place would follow those of equation 7.1 with each metal forming a metal sulphide precipitate depending on their various solubility product constants (Ksp) and bioreactor conditions, pH, redox potential etc. 2+ + Me + H2S (aq) MeS (s) + 2 H (7.15) (metal ion + hydrogen sulphide iron mono-sulphide + protons)
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9 BIOREACTOR TEST COLUMNS
9.1 AIMS & OBJECTIVES Laboratory sized bioreactors were established to test the ability of various alternative daily cover materials to precipitate metal sulphides, thus removing in situ, hydrogen sulphide gas, negating the need for costly hydrogen sulphide scrubbing prior to gas combustion. The study assessed the ability of four various alternative daily cover materials to reduce concentrations of hydrogen sulphide landfill gas by, precipitating iron sulphide’s. Alternative Daily Covers tested were 1) Haematite 2) Magnetite 3) Ferric Hydroxide 4) Steel industry waste baghouse dust. 9.2 BIOREACTOR DESIGN A series of test bioreactors were constructed for the purposes of this experiment. The bioreactors were constructed from 600mm diameter x 1800mm high HDPE reinforce corrugated pipe, the base of the columns consisted of a 10mm welded HDPE plate and the columns were sealed with a double O ring lid locking mechanism. A leachate extraction port was placed at the base of the column, in order to drain and recirculate leachate. A port at the top of the column with a valve connection to a 2000ml measuring cylinder was used in the recirculation of bioreactor leachate. A gas extraction valve was located approximately 1300mm from the base of the column that allowed LFG venting and testing. Figure 9.1: Test Bioreactor Design
Source: Own D.A. Lazarevic Page 37 of 87 Royal Institute of Technology Stockholm, 2007 Veolia Environmental Services
9.3 METHODOLOGY Laboratory scale bioreactors were used to simulate the degradation process of MSW. The experiment included 6 columns to simulate the effects various alternative daily cover materials and sulphate levels on bioreactor performance, methane and hydrogen sulphide production. Two sulphate loads were introduced to bioreactors 2 – 6, an initial sulphate point load and a continuous sulphate load for a period of 4 weeks. Two sulphate loads where tested to obtain any variations in both gas and leachate parameters of these two different scenarios. • Column 1 - Control Control used to generate a baseline reading of landfill gas production, landfill gas and leachate composition. • No ADC (Alternative Daily Cover) • Column 2 – No ADC Column 2 was used simulate the ability of waste to buffer AMD influenced leachate. • No ADC • Point Sulphate Load Day 105 3190 ml of AMD from the Woodlawn with sulphate concentrations 20000 mg/L was added to the approximate 10L of existing leachate to give the AMD/leachate mix a 5004 mg/l (calculated value) sulphate concentration. • Continuous Sulphate Load – Day 138 • Column 3 - Haematite Column 3 contained Haematite (Fe2O3) as an ADC material. • Haematite (Fe2O3) as ADC • Point Sulphate Load Day 105 2980 ml of AMD from the Woodlawn with sulphate concentrations 20000 mg/L was added to the approximate 10L of existing leachate to give the AMD/leachate mix a 5008 mg/l (calculated value) sulphate concentration. • Continuous Sulphate Load – Day 138 • Column 4 – Magnetite Column 4 contained Magnetite (Fe3O4) as an ADC material. • Magnetite (Fe3O4) as ADC • Point Sulphate Load Day 105 2920 ml of AMD from the Woodlawn with sulphate concentrations 20000 mg/L was added to the approximate 10L of existing leachate to give the AMD/leachate mix a 5008 mg/l (calculated value) sulphate concentration. • Continuous Sulphate Load – Day 138 • Column 5 – Ferric Hydroxide Column 5 contained Drinking Water Treatment by product – ferric hydroxide (FeOH3) as an ADC material.
• Drinking Water Treatment by product (FeOH3) as ADC • Point Sulphate Load Day 72 3290 ml of AMD from the Woodlawn with sulphate concentrations 20000 mg/L was added to the approximate 10L of existing leachate to give the AMD/leachate mix a 5007 mg/l (calculated value) sulphate concentration. • Continuous Sulphate Load – Day 105 • Column 6 – Steel Works Waste Column 6 contained Illawarra Resource Recovery – MultiService Baghouse Dust as an ADC material. • Illawarra Resource Recovery – MultiService Baghouse Dust as ADC • Point Sulphate Load Day 72 2910 ml of AMD from the Woodlawn with sulphate concentrations 20000 mg/L was added to the approximate 10L of existing leachate to give the AMD/leachate mix a 5007 mg/l (calculated value) sulphate concentration. • Continuous Sulphate Load – Day 105 D.A. Lazarevic Page 38 of 87 Royal Institute of Technology Stockholm, 2007 Veolia Environmental Services
9.4 BIOREACTOR COMPOSITION A 200mm deep gravel drainage layer at the base of the bioreactor allowed for easy leachate drainage and prevented any waste from becoming saturated. 120 kg of MSW was used in each column, two 10kg layers of ADC was placed at approximately 460mm intervals, one layer in the middle of the waste and a capping layer. Finally a 50mm layer of gravel was placed on the top of the ADC and waste. Table 9.1: Test Bioreactor Compositions Material Height Volume Density B 1 B 2 B 3 B 4 B 5 B 6 (m) (m3) (t/m3) Air Gap 0.55 0.156 Gravel/Sand Top 0.05 0.014 1.59 0.014 0.014 0.014 0.014 0.014 0.014 Haematite 0.01 0.006 5.205 20 kg Magnetite 0.01 0.006 5.046 20 kg Waste Water by 0.01 0.006 20 kg product IRR Waste 0.01 0.006 20 kg MSW 0.91 0.258 0.39 120 kg 120 kg 120 kg 120 kg 120 kg 120 kg Gravel (m3) 0.2 0.057 1.59 0.057 0.057 0.057 0.057 0.057 0.057 Source: Own Figure 9.2: Test Bioreactor Composition
Air Gap
Gravel Layer ADC
MSW
ADC
MSW
Gravel Layer
Source: Own
D.A. Lazarevic Page 39 of 87 Royal Institute of Technology Stockholm, 2007 Veolia Environmental Services
9.5 MUNICIPAL SOLID WASTE A typical sample of MSW was sourced from the Woodlawn Bioreactor, utilising waste from a transport container. Waste was reconstituted for each column to be as close as possible to the composition as outlined by the ‘Northern Sydney Waste Planning and Management Board’, table 9.2. Table 9.2: Average Waste Composition Sydney Waste Category Description Percentage of Total Rapidly Degradable Food/Kitchen Waste 29.6 Garden /Green Waste 26.6 Slowly Degradable Paper/Cardboard 15.6 Other 3.2 Inert or Hardly Degradable Glass 5.2 Plastic 1.2 Ferrous Metal 0.2 Non ferrous Metal 0.5 Non recyclable material 17.9 Total Domestic Waste 100 Source: Northern Sydney Waste Planning and Management Board Regional Waste Reference Guide However, due to the difficulties associated with handling, sorting and placing the MSW the waste category proportions could only be approximately matched. Fresh food wastes sourced from a local supermarket (primarily potatoes) were used to make up the fresh food waste fraction. Grass clippings and dry leaf matter was used to make up the garden/vegetation waste fraction. Waste office paper was used to bring the paper/cardboard fraction closer to the North Sydney Waste Planning waste fraction percentage. Table 9.3 represents the actual waste composition used in each bioreactor. Table 9.3: Waste Composition in Test Columns Waste Category Columns 1 – 6 (Kg) Columns 1 – 6 (%) Food/Kitchen Waste 36 30% Grass Clippings / Leaf Matter 32 27% Paper/Cardboard 20 17% Glass 6 5% Plastic 2 2% Textile 2 2% Metal 3 3% Aluminium Cans 1 1% Non recyclable material 18 15% 120 Kg 100 % Source: Own
D.A. Lazarevic Page 40 of 87 Royal Institute of Technology Stockholm, 2007 Veolia Environmental Services
9.6 MONITORING LFG Sampling Gas samples were collected in 3L Tetlar gas sample bags and analysed by Dr David Stone of ANSTO (Australian Nuclear Science and Technology Organisation) by ‘Gas Chromatography with Thermal Conductivity’ (GCTCD) analysis. GCTCD was used to determine bioreactor gas composition for methane (CH4), carbon dioxide (CO2), oxygen (O2), hydrogen sulphide (H2S), nitrogen (N2) and hydrogen (H2). Gas samples analysed fortnightly after month 1. Some issues arose during the course of the experiments with the GCTCD equipment, and during the last 8 weeks of the experiment sample were only sent when the equipment was available for use. Hydrogen sulphide was measured on site using ‘Dräger tube analysis’. 1 litre of each gas sample was passed through a reactive tube measuring hydrogen sulphide in ranges of 0.5 – 15 ppm and 5 – 600ppm. Using this type of analysis reduced the possibility for hydrogen sulphide to oxidise with any air present in the gas sample, giving increased accuracy. Dräger tube analysis has an accuracy of ± 10%. Daily gas samples were taken with a Geotechnical Instruments GA 2000 – an Industry Standard Landfill Gas monitor, methane (CH4), carbon dioxide (CO2), oxygen (O2), carbon monoxide (CO) and a remainder gas balance was sampled with this monitoring device. Leachate Sampling Leachate samples were analysed by Ecowise Environmental Laboratories, a NATA (National Association of Testing Authorities) certified laboratory, for pH, specific conductance, sulphate, sulphide, total iron total lead, total copper, total zinc, BOD and COD, ammonia and volatile fatty acids (VFA). These are the same laboratories that conduct all environmental compliance and licence monitoring for the Woodlawn Bioreactor site. Leachate samples analysed fortnightly after month 1 and then weekly upon sulphate injection. The lack of laboratory equipment on site meant that only a limited amount of testing could be conducted on site. On site testing was conducted every alternate day for pH, specific conductance, dissolved oxygen, and oxidisation/reduction potential. A Hydrolab Water Quality Monitoring System was used to record daily variations in pH and redox potential to monitor the degradation of waste within the test columns. The field samples were used as an indicator to track the progression of biodegradation of the waste against the typical stages of biodegradation.
D.A. Lazarevic Page 41 of 87 Royal Institute of Technology Stockholm, 2007 Veolia Environmental Services
10 RESULTS AND DISCUSSIONS
As stated is section 9.6, two separate sets of data were recorded whilst conducting this experiment, field data was recorded with the above mentioned equipment immediately after samples were taken. Gas samples tested by Dr David Stone of ANSTO and were tested within 2 5 days of sampling. Leachate samples taken on site were tested immediately after the sample was taken, samples tested by Ecowise were refrigerated to 4°C and results were obtained within 7 days of the samples being sent. Generally the two sets of results correspond with each other however the following factors could contribute to some deviation in results: • Duration before sampling: testing immediately after sampling reduces the possibility of various components reacting with one another and hence changing the chemistry of the sample from when it was sampled. • Accuracy of equipment: equipment used in the analytical analysis of samples taken will be of a higher accuracy due to the quality of equipment being utilised. Whilst field equipment was of high quality and regularly calibrated, it cannot produce the accuracy of laboratory equipment. By utilising two different methods of testing samples trends within data can be supported and inconsistencies in data can be more easily identified. 10.1 LANDFILL GAS COMPOSITION Typical LFG composition The various components of LFG are a product of the resultant gasses formed during the 5 stages of waste biodegradation. Figure 10.1 (Christensen and Kjeldsen, 1989) illustrates typical LFG composition as a function of time. Figure 10.1: Typical LFG Composition by Volume 100 CO2 N2 80 N2 CH4 60 40 O2 H2 O2 20 Source: Christensen & Kjeldsen, 1989. During the hydrolysis/aerobic degradation stage, oxygen is rapidly consumed by aerobic micro organisms depleting oxygen, thus creating anaerobic conditions. Carbon dioxide concentrations increase as a result of the breakdown of organic matter into simpler hydrocarbons. The breakdown of carbohydrates, proteins and lipids into organic acids in the hydrolysis and fermentation stages results in the production of carbon dioxide and hydrogen. The inert nitrogen from air initially in the bioreactor is also expelled from the waste mass with the gasses produced during biodegradation, thus reducing nitrogen concentrations. During acetogenesis, methanogens initially produce methane from the available carbon dioxide and hydrogen, hence methane concentrations start to increase and carbon dioxide and hydrogen degrease until all hydrogen is consumed. Methanogenesis is characterised by the increase in LFG volume and production of methane and carbon dioxide at an approximate ratio of 60:40 methane to carbon dioxide. D.A. Lazarevic Page 42 of 87 Royal Institute of Technology Stockholm, 2007 Veolia Environmental Services
General Comments Some general comments can be made in regard to LFG compositional changes, which occurred in all bioreactors. The rapid changes in methane and decrease in carbon dioxide concentrations experienced from day 94 98, day 115 125 and day 147 – 150 occurred due to recalibration of equipment used in the field analysis of the LFG. The same LFG compositional changes are evident throughout all the bioreactors. This factor does not change the validity of the data recorded because at day 98, 125 and 150 the results taken were true readings, what this does mean though is that the rate of gas compositional change is somewhat more pronounced that would have otherwise occurred. Difference in hydrogen sulphide concentration between GC TCD and Dräger analysis differed considerably in some cases. Problems with GC TCD equipment within the last 2 months of the experiment meant that samples were stored for a period of up to 2 months before they could be tested. During this time, leaks occurred within in the sample bags and the oxidation of hydrogen sulphide may have occurred. Due to this fact Dräger results were used for hydrogen sulphide analysis. Bioreactor 1 (Control) Both graphs below show the typical progression through the biodegradation stages in regard to LFG composition. Within the initial 1 3 weeks of biodegradation all oxygen was consumed and within a short period after, all nitrogen had been purged from the bioreactor. Hydrogen levels remained below 0.1% throughout the initial fermentation and acetogenesis stages, this is most likely due to the immediate reduction of hydrogen and carbon dioxide by methanogens to produce methane. Both graphs also show that methane was produced almost immediately after the depletion of oxygen. Biodegradation progressed extremely quickly in this bioreactor and within a period of 30 – 40 days methanogenesis had become well established, this could be due to the fact that the waste prior to the experiment commencement may have been degraded to a greater extent to that used in the other bioreactors. Methane and carbon dioxide concentrations had reached 50 – 50% at day 35. Methane and carbon dioxide concentrations showed stable progression from between 50 – 60 % and 35 – 45 % respectively after day 50. After an initial peak of 20 ppm hydrogen sulphide within the first 18 days of commencement, hydrogen sulphide concentrations were measured at a stable 4 – 5 ppm, during sulphate concentrations from 5 – 340 mg/l. 5 ppm can therefore be interpreted as a background rate of hydrogen sulphide production for this selection of MSW during methanogenesis. Data Discrepancies The greatest discrepancy within the data is the balance of gas within the period of day 47 – 83, field data shows that the balance of gas remained at 0% throughout this period where as analytical data showed the balance of gas measured as nitrogen reached a maximum of 16.73% at day 63. This could be the result of a number of factors including an 1) air leak within the column allowing air to ingress into the bioreactors, 2) an air leak within the gas sample bag or 3) the reaction of gasses within the samples bags during the time from sampling to testing. The second two hypothesis seem to be supported by both sets of data as the field data shows no increase in oxygen or balance gases and the increase in balance gases in the analytical data corresponds to a proportional inverse relationship with methane and carbon dioxide.
D.A. Lazarevic Page 43 of 87 Royal Institute of Technology Stockholm, 2007 Veolia Environmental Services
Figure 10.2: Bioreactor 1 – LFG Composition Analysis (GC – TCD)
BIOREACTOR 1 - LFG COMPOSION ANALYSIS (GC-TCD)
100 22 21 90 20 19 18 80 17 16 70 15 14 Methane 60 13 Carbon Dioxide 12 50 11 Oxygen 10 Nitrogen Hydrogen 40 9 8 Hydrogen Sulphide
7 Hydrogen Sulphide (PPM) 30 6 CH4, CH4, CO2, O2,H2, N2 (% Volume) 5 20 4 3 10 2 1 0 0
0 19 33 47 68 83 96 5 116 12 151 173 Time (Days) Figure 10.3: Bioreactor 1 – LFG Composition Analysis (IR & Dräger)
BIOREACTOR 1 - LFG COMPOSITION ANALYSIS (IR & DRÄGER)
100 25
90
80 20
70
60 15 Methane (CH4) Carbon Dioxide (CO2) 50 Oxygen (O2) Balance (Nitogen/Hydroen/other) H2S (ppm) 40 10 Hydrogen Sulphide (H2S)
30 CH4,CO2, O2, Bal. (% Volume)
20 5
10
0 0
0 10 17 24 31 41 52 69 93 3 105 129 139 147 159 17 Time (Days)
D.A. Lazarevic Page 44 of 87 Royal Institute of Technology Stockholm, 2007 Veolia Environmental Services
Bioreactor 2 (NO ADC) Pre-sulphate addition Bioreactor 2 showed similar LFG development to bioreactor 1 with a reduction of both oxygen and nitrogen concentrations to 0.04 % within a 3 week period. Hydrogen concentrations of less than 0.1% throughout fermentation and acetogenesis were experienced and early methane production was present in bioreactor 2. The proliferation of methanogenic colonies were later to develop in bioreactor 2 and an equal concentration of 50 – 50 % methane to carbon dioxide was reached at day 52. Point Sulphate Load At day 105 a load of 3.190 litres of AMD from Woodlawn (surface water run off) with a sulphate concentration of 20000 mg/l was added to the existing 10.0 litres of leachate with a 220 mg/l concentration to give a total leachate concentration of 5004 mg/l (see appendix D for calculations). Subsequent gas samples taken after this point load of sulphate showed a very negligible rise in the concentration of hydrogen sulphide gas reaching a maximum of 9ppm. Whilst sulphate reduction was evident, sulphide produced was precipitated by metals within the leachate hence a relatively low hydrogen sulphide gas concentration. Sulphide at this point was 14 mg/l and the significant drop of total iron from 460 – 84 mg/l within 2 weeks and total copper from 600 – 250 um/l within one week, supports the above hypothesis. Continuous Sulphate Load From day 138 a continuous load of sulphate consisting of 4.0 litres per week, of AMD from Woodlawn (surface water run off) with a sulphate concentration of 34000 mg/l was added to the bioreactor. After an initial period of inactivity with hydrogen sulphide concentrations of between 0.5 and 9 ppm, hydrogen sulphide rose from 9.9 ppm (± 10%) on day 147 to 168.9 (± 10%) ppm on day 159. From day 159 to day 167 hydrogen sulphide concentrations levelled out for 8 days and then experienced a sharp rise to 1758.9 (± 10%) ppm on day 171, the final day of testing. It would be expected that hydrogen sulphide levels would continue to rise after this date, as long as there is the required concentration of sulphate to be reduced. As previously mentioned in the general comments for this section the GC TCD analysis was not performed for some months after samples were taken, due to equipment unavailability. GC TCD data from this period was unreliable and only Dräger data was used for analysis This rapid increase in hydrogen sulphide is primarily due to the lack of available metals to precipitate the reduced sulphide. These metals were previously precipitated when the point load of sulphate was introduced, and hence low hydrogen sulphide after the point load. When the continuous sulphate load was added the availability of metals (including those from within the AMD) were of insignificant concentration to make any impact on hydrogen sulphide gas production. Data Discrepancies A discrepancy of balance gasses between analytical and field data is shown again in column 2 with a peak of 11 % on day 83 shown in the analytical data. A slight drop in methane and carbon dioxide is also apparent, the theory presented in bioreactor 1 can be used to explain this irregularity. Hydrogen sulphide data shows discrepancies during the GC TCD reading on days 151 & 173, data taken during these time periods proved to be unreliable, as samples were analysed approximately 2 months after sample collection due to equipment failure and maintenance. Results that were obtained from these samples were corrected for air leaks in samples bags, due to this and the possibility for the gasses to react with each other these results are not reliable.
D.A. Lazarevic Page 45 of 87 Royal Institute of Technology Stockholm, 2007 Veolia Environmental Services
Figure 10.4: Bioreactor 2 – LFG Composition Analysis (GC – TCD)
BIOREACTOR 2 - LFG COMPOSION ANALYSIS (GC-TCD)
Point Continuous Sulphate Load Sulphate Load 100 100
90 90
80 80
70 70
60 60 Methane Carbon Dioxide 50 50 Oxygen Nitrogen Hydrogen 40 40 Hydrogen Sulphide
30 30 Hydrogen Sulphide (PPM) CH4, CH4, CO2, O2,H2, N2 (% Volume)
20 20
10 10
0 0
0 19 33 47 68 83 96 1 116 125 15 173 Time (Days) Figure 10.5: Bioreactor 2 – LFG Composition Analysis (IR & Dräger)
BIOREACTOR 2 - LFG COMPOSITION ANALYSIS (IR & DRÄGER)
Point Continuous Sulphate Load Sulphate Load 100 2000 1900 90 1800 1700 80 1600 1500 70 1400 1300 60 1200 Methane (CH4) 1100 Carbon Dioxide (CO2) 50 1000 Oxygen (O2) 900 Balance (Nitogen/Hydroen/other) H2S (ppm) 40 800 Hydrogen Sulphide (H2S) 700 30 600 CH4,CO2, O2, Bal. (% Volume) 500 20 400 300 10 200 100 0 0
0 10 17 24 31 41 52 69 82 6 104 125 138 14 157 172 Time (Days)
D.A. Lazarevic Page 46 of 87 Royal Institute of Technology Stockholm, 2007 Veolia Environmental Services
Bioreactor 3 (Ferrous Oxide) Pre-sulphate addition Oxygen and hydrogen concentrations show a very similar rate of change and concentration as the above bioreactors. Methanogenesis was evident from the establishment of the bioreactor, meaning reduction of hydrogen and carbon dioxide and hence a maximum hydrogen concentration of 0.1 %. As opposed to bioreactor 1 and 2 the methanogenic stage in this bioreactor took a greater time to establish, with methane to carbon dioxide ratio of 50:50% being reached at day 138. Both sets of data show a correlation in the steady rise of methane and reduction in carbon dioxide concentrations as the biodegradation of the waste progressed. This is most likely due to the initial waste being of a less degraded state that of the first to bioreactors. Point Sulphate Load At day 105 a load of 2.980 litres of AMD from Woodlawn (surface water run off) with a sulphate concentration of 20000 mg/l was added to the 10.0 litres of leachate with 540 mg/l concentration to give a total leachate concentration of 5008 mg/l (see appendix D for calculations).
Methane and carbon dioxide concentrations continued their respective rise and fall as time progresses after the addition of the point sulphate load. Hydrogen sulphide concentrations remained at levels of 0.5 (± 10%) ppm.
Continuous Sulphate Load From day 138 a continuous load of sulphate consisting of 4.0 litres per week, of AMD from Woodlawn (surface water run off) with a sulphate concentration of 34000 mg/l was added to the bioreactor. Hydrogen sulphide concentrations rose to a maximum of 1.6 (± 10%) ppm, after which a consistent 0.5 (± 10%) ppm was maintained throughout the experiment. Whilst the Dräger analysis showed a consistent 0.5 (± 10%) ppm reading, on day 173 GC TCD analysis was 8.3 ppm. As previously mentioned in the general comments for this section the GC TCD analysis was not performed for some months after samples were taken, due to equipment unavailability. GC TCD data from this period was unreliable and only Dräger data was used for analysis. Hydrogen sulphide concentrations were extremely low in this bioreactor because sulphide concentrations in the leachate only reached a maximum of 1.4 mg/l, even whilst sulphate concentrations rose to levels of 3700 mg/l. Sulphide that had been reduced precipitated immediately, due to the abundance of metals, before entering the gaseous phase. Data discrepancies The same discrepancy in balance gasses between field and analytical data is apparent in bioreactor 3, however in this case a peak 4.8 % balance on day 67 within the field data is within the same time period of a peak 15.8 % balance on day 68 in the analytical data. Hydrogen sulphide data shows discrepancies during the GC TCD reading on days 151 & 173, data taken during these time periods proved to be unreliable, as samples were analysed approximately 2 months after sample collection due to equipment failure and maintenance. Results that were obtained from these samples were corrected for air leaks in samples bags, due to this and the possibility for the gasses to react with each other these results are not reliable.
D.A. Lazarevic Page 47 of 87 Royal Institute of Technology Stockholm, 2007 Veolia Environmental Services
Figure 10.6: Bioreactor 3 – LFG Composition Analysis (GC – TCD)
BIOREACTOR 3 - LFG COMPOSION ANALYSIS (GC-TCD)
Point Continuous Sulphate Load Sulphate Load 100 20 19 90 18 17 80 16 15 70 14 13 60 12 Methane 11 Carbon Dioxide 50 10 Oxygen Nitrogen 9 Hydrogen 40 8 Hydrogen Sulphide 7 30 6 Hydrogen Sulphide (PPM)
CH4, CH4, CO2, O2,H2, N2 (% Volume) 5 20 4 3 10 2 1 0 0
0 19 33 47 68 83 96 5 116 12 151 173 Time (Days) Figure 10.7: Bioreactor 3 – LFG Composition Analysis (IR & Dräger)
BIOREACTOR 3 - LFG COMPOSITION ANALYSIS (IR & DRÄGER)
Point Continuous Sulphate Load Sulphate Load 100 25
90
80 20
70
60 15 Methane (CH4) Carbon Dioxide (CO2) 50 Oxygen (O2) Balance (Nitogen/Hydroen/other) H2S (ppm) 40 10 Hydrogen Sulphide (H2S)
30 CH4,CO2, O2, Bal. (% Volume)
20 5
10
0 0
0 10 17 24 31 41 52 69 82 4 2 10 125 138 146 157 17 Time (Days)
D.A. Lazarevic Page 48 of 87 Royal Institute of Technology Stockholm, 2007 Veolia Environmental Services
Bioreactor 4 (Ferric Oxide) Pre-sulphate addition Oxygen concentrations show a very similar rate of change and concentration as the above bioreactors, in the analytical data balance gas levels reached a peak low of 5.9%, then from day 47 showed an increase to 42.9 % on day 83. Bioreactor 4 shows evidence that methanogenesis experienced trouble establishing itself, methane levels remained at around 20% from day 33 until day 98, after which greater methane production is seen to commence. Within a 33 day period after day 98 an 11.6% increase in methane was apparent from field data, from day 125 methane concentrations stabilised to just under 40%. Bioreactor 4 was most likely stuck in the acetogenic stage, with methane production resulting from the reduction of hydrogen and carbon dioxide produced during hydrolysis and fermentation, thus remaining at levels around 20%. This theory is supported by analytical leachate data showing leachate pH remaining between 5 – 5.5 pH units whilst other bioreactors showed at least some increase in pH. Low pH values are a result of the build up of organic acids from acetogenesis, as these acids increase it is harder for methanogenesis to become established because the pH is lower than the optimal range for methanogenic bacteria growth. Even though the Magnetite was the only different factor in this bioreactor when compare to other bioreactors, Magnetite behaves relatively similar to Haematite and is not believed to be responsible for the slower establishment of methanogenesis in bioreactor 4. Both sets of data confirm a spike in gas balance concentration around day 67 and maintaining this level to day 104. The reason for this sharp rise in balance gasses is unknown, if an air leak in the bioreactor did occur nitrogen concentrations (measures in gas balance) would increase, as has happened, yet oxygen levels would be expected to increase as well. Given the ration of nitrogen to oxygen in air is 3.74, the level of oxygen would be expected to be in the range of 11.5%, the maximum value of oxygen measured from analytical data was 0.42 %. Only field data showed an increase in oxygen levels during this time to a maximum level of 2.1%. The elevated gas balance levels may be due to an undetected gas being produced within the extended acetogenic phase. Point Sulphate Load At day 105 a load of 2.920 litres of AMD from Woodlawn (surface water run off) with a sulphate concentration of 20000 mg/l was added to the 10.0 litres of leachate with 630 mg/l concentration to give a total leachate concentration of 5008 mg/l (see appendix D for calculations).
After the point load of sulphate carbon dioxide concentrations remained steady, whilst an equally proportional rise in methane and drop in balance gases was experience. Methane concentrations rose to approximately 37 % and balance gasses reduced to a constant 3.5%. This rise and fall in LFG concentrations is somewhat unknown, however it seems the addition of AMD stimulated methanogenesis. The addition of AMD may have diluted any toxic inhibitors within the leachate, reducing their concentration.
Continuous Sulphate Load From day 138 a continuous load of sulphate consisting of 4.0 litres per week, of AMD from Woodlawn (surface water run off) with a sulphate concentration of 34000 mg/l was added to the bioreactor. Methane and carbon dioxide concentrations remained at a constant at 37 % and 58 % respectively during the continuous sulphate load. Hydrogen sulphide concentrations experienced a maximum of 2.2 (± 10%) with a mean of 0.5 (± 10%) ppm. Hydrogen sulphide concentrations were extremely low in this bioreactor because sulphide concentrations in the leachate only reached a maximum of 2.0 mg/l, even whilst sulphate concentrations rose to levels of 4700 mg/l. Sulphide that had been reduced precipitated immediately, due to the abundance of metals, before entering the gaseous phase.
D.A. Lazarevic Page 49 of 87 Royal Institute of Technology Stockholm, 2007 Veolia Environmental Services
Figure 10.8: Bioreactor 4 – LFG Composition Analysis (GC – TCD)
BIOREACTOR 4 - LFG COMPOSION ANALYSIS (GC-TCD)
Point Continuous Sulphate Load Sulphate Load 100 20 19 90 18 17 80 16 15 70 14 13 60 12 Methane 11 Carbon Dioxide 50 10 Oxygen Nitrogen 9 Hydrogen 40 8 Hydrogen Sulphide 7 30 6 Hydrogen Sulphide (PPM)
CH4, CH4, CO2, O2,H2, N2 (% Volume) 5 20 4 3 10 2 1 0 0
0 19 33 47 68 83 96 5 116 12 151 173 Time (Days) Figure 10.9: Bioreactor 4 – LFG Composition Analysis (IR & Dräger)
BIOREACTOR 4 - LFG COMPOSITION ANALYSIS (IR & DRÄGER)
Point Continuous Sulphate Load Sulphate Load 100 25
90
80 20
70
60 15 Methane (CH4) Carbon Dioxide (CO2) 50 Oxygen (O2) Balance (Nitogen/Hydroen/other) H2S (ppm) 40 10 Hydrogen Sulphide (H2S)
30 CH4,CO2, O2, Bal. (% Volume)
20 5
10
0 0
0 10 17 24 31 41 52 69 82 4 2 10 125 138 146 157 17 Time (Days)
D.A. Lazarevic Page 50 of 87 Royal Institute of Technology Stockholm, 2007 Veolia Environmental Services
Bioreactor 5 (Ferric Hydroxide) Pre-sulphate addition Bioreactor 5 was commenced 32 days after Bioreactors 1 4 due to problems in obtaining the alternative waste cover material. Oxygen levels dropped to below 1% within 14 days of commencement, in keeping the above bioreactors, gas balance concentrations show a steady decrease, although slower than the above bioreactors. This slow drop in balance gases (assumed nitrogen) is in keeping with the typical LFG concentrations, as in fig 10.1, when compared to its slower development of methanogenesis than in bioreactors 1 and 2. Methanogenesis progression can be compared to that of bioreactor 3, illustrating typical development of biodegradation phases. Point Sulphate Load At day 72 a load of 3.290 litres of AMD from Woodlawn (surface water run off) with a sulphate concentration of 20000 mg/l was added to the 10.0 litres of leachate with 74 mg/l concentration to give a total leachate concentration of 5007 mg/l (see appendix D for calculations). After the point load of sulphate an equally proportional rise in methane and drop in carbon dioxide was experience. Methane concentrations rose to approximately 48 % and carbon dioxide reduced to a constant 51 %. Continuous Sulphate Load From day 105 a continuous load of sulphate consisting of 4.0 litres per week, of AMD from Woodlawn (surface water run off) with a sulphate concentration of 34000 mg/l was added to the bioreactor. Methane and carbon dioxide concentrations were stable throughout this time period, at approximately 48 % and 51 % respectively. Hydrogen sulphide concentrations showed a maximum of 2.2 (± 10%) ppm on a single occasion, however the majority of samples showed levels of 0.5 (± 10%) ppm. Hydrogen sulphide concentrations were extremely low in this bioreactor because sulphide concentrations in the leachate only reached a maximum of 0.10 mg/l, even whilst sulphate concentrations rose to levels of 6800 mg/l. Sulphide that had been reduced precipitated immediately, due to the abundance of metals, before entering the gaseous phase.
D.A. Lazarevic Page 51 of 87 Royal Institute of Technology Stockholm, 2007 Veolia Environmental Services
Figure 10.10: Bioreactor 5 – LFG Composition Analysis (GC – TCD)
BIOREACTOR 5 - LFG COMPOSION ANALYSIS (GC-TCD)
Point Continuous Sulphate Load Sulphate Load 100 20 19 90 18 17 80 16 15 70 14 13 60 12 Methane 11 Carbon Dioxide Oxygen 50 10 Nitrogen 9 Hydrogen 40 8 Hydrogen Sulphide 7 30 6 Hydrogen Sulphide (PPM)
CH4, CH4, CO2, O2,H2, N2 (% Volume) 5 20 4 3 10 2 1 0 0
0 14 35 50 63 83 92 8 11 140 Time (Days) Figure 10.11: Bioreactor 5 – LFG Composition Analysis (IR & Dräger)
BIOREACTOR 5 - LFG COMPOSITION ANALYSIS (IR & DRÄGER)
Point Continuous Sulphate Load Sulphate Load
Methane (CH4) Carbon Dioxide (CO2) Oxygen (O2) Balance (Nitogen/Hydroen/other) H2S (ppm) Hydrogen Sulphide (H2S) CH4,CO2, O2, Bal. (% Volume)
0 19 36 49 71 92 4 105 113 12 137 Time (Days)
D.A. Lazarevic Page 52 of 87 Royal Institute of Technology Stockholm, 2007 Veolia Environmental Services
Bioreactor 6 (Multi Service Baghouse Dust) Pre-sulphate addition Bioreactor 6 was commenced 32 days after Bioreactors 1 4 due to problems in obtaining the alternative waste cover material. The development of waste biodegradation in bioreactor 6 shows almost identical progression throughout biodegradation phases and LFG concentrations as bioreactor 5. Hence the comments from bioreactor 5 also apply to bioreactor 6. Point Sulphate Load At day 72 a load of 2.910 litres of AMD from Woodlawn (surface water run off) with a sulphate concentration of 20000 mg/l was added to the 10.0 litres of leachate with 640 mg/l concentration to give a total leachate concentration of 5004 mg/l (see appendix D for calculations). Methane and carbon dioxide reached concentrations of 50% by volume on day 98. A methane carbon dioxide ration of less than 1 was maintained from day 98 until experiment completion. A 15 (± 10%) ppm hydrogen sulphide concentration was measured before the addition of the continuous sulphide load. Continuous Sulphate Load From day 105 a continuous load of sulphate consisting of 4.0 litres per week, of AMD from Woodlawn (surface water run off) with a sulphate concentration of 34000 mg/l was added to the bioreactor. Hydrogen sulphide concentrations showed a maximum of 21.7 (± 10%) ppm was measured immediately after the start of the continuous sulphate addition. However after this 21.7 (± 10%) ppm, hydrogen sulphide levels remained at levels between 0.5 (± 10%) and 2.2 (± 10%) ppm. Hydrogen sulphide concentrations were low in this bioreactor because sulphide concentrations in the leachate only reached a maximum of 0.95 mg/l, even whilst sulphate concentrations rose to levels of 5900 mg/l. Sulphide that had been reduced precipitated immediately, due to the abundance of metals, before entering the gaseous phase.
D.A. Lazarevic Page 53 of 87 Royal Institute of Technology Stockholm, 2007 Veolia Environmental Services
Figure 10.12: Bioreactor 6 – LFG Composition Analysis (GC – TCD)
BIOREACTOR 6 - LFG COMPOSION ANALYSIS (GC-TCD)
Point Continuous Sulphate Load Sulphate Load 100 20 19 90 18 17 80 16 15 70 14 13 60 12 Methane 11 Carbon Dioxide Oxygen 50 10 Nitrogen 9 Hydrogen 40 8 Hydrogen Sulphide 7 30 6 Hydrogen Sulphide (PPM)
CH4, CH4, CO2, O2,H2, N2 (% Volume) 5 20 4 3 10 2 1 0 0
0 14 35 50 63 83 92 8 11 140 Time (Days) Figure 10.13: Bioreactor 6 – LFG Composition Analysis (IR & Dräger)
BIOREACTOR 6 - LFG COMPOSITION ANALYSIS (IR & DRÄGER)
Point Continuous Sulphate Load Sulphate Load 100 50
90 45
80 40
70 35
60 30 Methane (CH4) Carbon Dioxide (CO2) 50 25 Oxygen (O2) Balance (Nitogen/Hydroen/other) H2S (ppm) 40 20 Hydrogen Sulphide (H2S)
30 15 CH4,CO2, O2, Bal. (% Volume)
20 10
10 5
0 0
0 19 36 49 71 92 4 105 113 12 137 Time (Days)
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10.2 SULPHATE – SULPHIDE – HYDROGEN SULPHIDE CORRELATION The reduction of sulphate and subsequent production of hydrogen sulphide gas is most prolific when sulphate is in abundance. Sulphate at various concentrations is present in all MSW, the test bioreactors will experience a background concentration of sulphate before initial sulphate addition. Figure 10.14: Typical Leachate Composition Leachate 2− SO4 − Cl HCO3 Zn,Fe Phase I II III IV V Source: Christensen & Kjeldsen, 1989. This figure shows initial sulphate concentrations rise during fermentation and hydrolysis, most likely due to a pH being lowered by the initial production of organic acids, as outlined in section 5.1. The below table gives an analytical summary of the AMD that was added to the bioreactors for both the point and continuous sulphate loads. Table 10.1: Acid Mine Drainage Composition Parameter Units Point Load Continuous Load pH pH Units 2.9 2.6 Sulphide mg/l 0.06 Sulphate mg/l 20000 34000 Copper ug/l 48000 48000 Iron mg/l 640 1100 Lead ug/l 1500 250 Zinc mg/l 1100 1300 Source: Own
D.A. Lazarevic Page 55 of 87 Royal Institute of Technology Stockholm, 2007 Veolia Environmental Services
Bioreactor 1 (Control) Hydrogen sulphide production is dependent upon sulphate for reduction, sulphate concentrations of bioreactor 1 showed low levels of between 5 and 340 mg/l. Sulphate concentration recorded from day 18, showed two peaks in sulphate of 150 mg/l and 340 mg/l on days 109 and 145 respectively, these values are very low and are most likely to be a result of naturally occurring interactions within the bioreactor. Hydrogen sulphide levels peaked on day 19 at 20 ppm then remained constant at <0.5 ppm. Initial sulphate reduction within the waste mass may explain this peak in hydrogen sulphide, and as sulphate concentrations were not recorded until day 18, sulphate may have been higher during this period. Sulphide concentrations of less than 4.4 mg/l were measured during this experiment with a mean value of 1.5 mg/l. This low sulphide value can be explained by two hypothesis, either there is insufficient sulphate that is available for reduction to sulphide or there are sufficient metals present to precipitate any sulphide that has been reduced. When looking at the available data, the level of sulphate is very low, preventing any production of sulphide. Total metal concentrations show a steady decrease in concentration, through with precipitation with either sulphides or hydroxides. Total iron showed the greatest decrease in concentration from 580 mg/l to 32 mg/l, total copper decreased from 670 ug/l to 160 ug/l, total lead decreased from 520 ug/l to 69 ug/l and total zinc showed a constant concentration throughout the experiment from 3.2 mg/l to 3.5 mg/l. The reduction in concentrations of these heavy metals is typical and is in keeping data presented for the drop in concentration of heavy metals in Christensen & Kjeldsen (1989).
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Figure 10.15: Bioreactor 1 – Sulphate and Sulphide vs Time
BIOREACTOR 1 - SULPHATE & SULPHIDE vs TIME
5000 20
4500 18
4000 16
3500 14
3000 12
Sulphate 2500 10 Sulphide
Sulphate(mg/l) 2000 8 Sulphide(mg/l)
1500 6
1000 4
500 2
0 0
8 6 8 6 9 8 9 1 32 4 6 82 9 0 17 24 3 45 5 67 73 104 1 1 1 131 1 1 152 1 1 1 Time (Days) Figure 10.16: Bioreactor 1 – Total Fe, Zn, Cu and Pb vs Time
BIOREACTOR 1 - TOTAL Fe, Zn, Cu & Pb vs TIME
1000 4000 3800 900 3600 3400 800 3200 3000 700 2800 2600 600 2400 Total Iron 2200 Total Zinc 500 2000 Total Lead 1800 Total Copper 400 1600 IronZinc & (mg/l)
1400 Lead& Copper (ug/l) 300 1200 1000 200 800 600 100 400 200 0 0
8 2 6 8 6 9 7 8 1 3 4 6 82 9 0 1 31 3 45 52 59 73 104 1 1 124 1 1 1 1 1 167 1 Time (Days)
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Bioreactor 2 (No ADC) Pre-sulphate addition Sulphate concentration decreased from its initial low level of 360 mg/l on day 18 to 140mg/l on day 104 prior to AMD addition. Sulphide concentrations remain relatively constant during this period and range from values of 1.8 mg/l to 0.7 mg/l. During the period before AMD addition all metals experienced a decrease in concentration, total iron showed the greatest drop from 720 mg/l on day 32 to 460 mg/l on day 104, total zinc decreased from 5.2 mg/l on day 18 to 0.75 mg/l on day 104, total copper decreased from 140 ug/l on day 18 to 59 ug/l on day 104 and total lead decreased from 180 ug/l on day 18 to 120 ug/l on day 104. Point Sulphate Load At day 105 a load of 3.190 litres of AMD from Woodlawn (surface water run off) with a sulphate concentration of 20000 mg/l was added to the existing 10.0 litres of leachate with a 220 mg/l concentration to give a total leachate concentration of 5004 mg/l (see appendix D for calculations). AMD composition is given in table 10.1. The AMD addition saw sulphate levels reach a maximum concentration of 910 mg/l a week after the addition of 5000 mg/l leachate. This can be explained by the combination of the immediate reduction of sulphate to sulphide and also the absorption of sulphate by porous materials within the waste such as paper, textiles or green waste, thus removing the sulphate from the leachate. During the 5 week period that this leachate was recirculated, sulphate decreased from 910 mg/l on day 104 to 20 mg/l on day 138. The reduction in sulphate corresponded to rises in sulphide from 0.7 mg/l on day 104 to 18 mg/l on day 124, at the end of the 5 week period sulphide had decreased to 3.4 mg/l on day 138. Total metal concentrations during this period also showed a dramatic decrease in concentration, correlating to sulphide available for the precipitation of metal sulphides, a result of sulphate reduction. Total iron concentrations dropped dramatically from 460 mg/l on day 104 to 84 mg/l on day 117. From day 117 total iron was further reduced to 50 mg/l on day 138. Total zinc concentrations initially increased from 0.75 mg/l on day 104 to 46 mg/l on day 109, due to the AMD addition (1100 mg/l). Total copper concentrations initially increased from 59 ug/l on day 104 to 600 ug/l on day 109, due to the AMD addition (48000 ug/l). However after day 109 total copper concentration dropped to 130 ug/l by day 138. Total lead concentrations initially increased from 54 ug/l on day 104 to 86 ug/l on day 109, due to the AMD addition (1500 ug/l). However after day 109 total lead concentration dropped to 66 ug/l by day 138. Most importantly was the precipitation of total iron during this period of time, at the end of the 5 weeks of leachate recirculation the majority of metals were consumed by sulphide precipitate. As can be seen in the continuous sulphate addition stage, sulphides increased dramatically as a lack of metals were available to enable solid sulphur precipitation. Continuous Sulphate Load From day 138 a continuous load of sulphate consisting of 4.0 litres per week, of AMD from Woodlawn (surface water run off) with a sulphate concentration of 34000 mg/l was added to the bioreactor. AMD composition is given in table 10.1. Continuous AMD addition saw sulphate levels increase from 20 mg/l on day 138 to a maximum concentration of 3200 mg/l on day 145. After day 145 sulphate concentrations steadily decreased to 52 mg/l on day 173. This prolific reduction of this sulphate by SRB is shown by the sharp increase in sulphide levels during this time from 3.4 mg/l on day 138 to 76 mg/l on day 173. The increase level of sulphide in the leachate corresponded by an increase of hydrogen sulphide in
D.A. Lazarevic Page 58 of 87 Royal Institute of Technology Stockholm, 2007 Veolia Environmental Services the LFG as shown in section 10.1. During this period of time the distinctive odour of sulphide was present during leachate recirculation. Total metal concentrations during this period, generally remained at a similar concentration to the start of this period, with the exception of total copper concentration. This supports the idea that there was a lack of metals available to precipitate the sulphide that was being produced by the SRB. Hence Levels of sulphide and the leachate and hydrogen sulphide in the LFG rose dramatically. Total iron concentrations reduced from 50 mg/l on day 138 to 14 mg/l on day 173. Total zinc concentrations increased a slightly from 3.3 mg/l on day 104 to 23 mg/l on day 109, due to the AMD addition (1100 mg/l). Total copper concentrations experienced a large increase from 130 ug/l on day 138 to 3300 ug/l on day 145, due to the AMD addition (48000 ug/l). Total copper was then progressively reduced to 1100 ug/l at day 173, with the exception of the concentration dropping to 170 ug/l on day 152 and then rising up to 1500 ug/l on day 159. Total lead concentrations decreased from 66 ug/l on day 138 to 29 ug/l on day 173, due to the AMD addition (1500 ug/l). Even with the increase in some metal concentrations, the demand from metals for utilisation in the precipitation of metal sulphides far surpassed the supply of metals, hence increased sulphide concentrations.
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Figure 10.17: Bioreactor 2 – Sulphate and Sulphide vs Time
BIOREACTOR 2 - SULPHATE & SULPHIDE vs TIME Point Continuous Sulphate Load Sulphate Load 8000 80
7000 70
6000 60
5000 50
Sulphate 4000 40 Sulphide Sulphate(mg/l) Sulphide(mg/l) 3000 30
2000 20
1000 10
0 0
8 6 8 6 9 8 9 1 32 4 6 82 9 0 17 24 3 45 5 67 73 104 1 1 1 131 1 1 152 1 1 1 Time (Days) Figure 10.18: Bioreactor 2 – Total Fe, Zn, Cu and Pb vs Time
BIOREACTOR 2 - TOTAL Fe, Zn, Cu & Pb vs TIME Point Continuous Sulphate Load Sulphate Load 1000 4000 3800 900 3600 3400 800 3200 3000 700 2800 2600 600 2400 Total Iron 2200 Total Zinc 500 2000 Total Lead 1800 Total Copper 400 1600 IronZinc & (mg/l)
1400 Lead& Copper (ug/l) 300 1200 1000 200 800 600 100 400 200 0 0
8 2 6 8 6 9 7 8 1 3 4 6 82 9 0 1 31 3 45 52 59 73 104 1 1 124 1 1 1 1 1 167 1 Time (Days)
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Bioreactor 3 (Ferrous Oxide) Pre-sulphate addition Sulphate concentration increased from an initial level of 270 mg/l on day 18 to 710mg/l on day 104 prior to AMD addition. Even though an increase in sulphate is shown, the overall level of sulphate is relatively low. Sulphide concentrations showed an overall drop during this period from 2.3 mg/l on day 18 to 0.2 mg/l on day 104. During the period before AMD addition zinc, copper and lead experienced a decrease in concentration. Zinc decreased from 6 mg/l on day 18 to 2.7 mg/l on day 104, copper decreased from 200 ug/l on day 18 to 13 ug/l on day 104 and lead decreased from 210 ug/l on day 18 to 40 ug/l on day 104. Total iron of 720 mg/l on day 18 increased to 910 mg/l on day 104, this increase was due to the iron present in the layers of hematite within the bioreactor. Point Sulphate Load At day 105 a load of 2.980 litres of AMD from Woodlawn (surface water run off) with a sulphate concentration of 20000 mg/l was added to the 10.0 litres of leachate with 540 mg/l concentration to give a total leachate concentration of 5008 mg/l (see appendix D for calculations). AMD composition is given in table 10.1. After the addition of the AMD sulphate levels reach a maximum concentration of 1600 mg/l on day 117, two weeks after the addition of 5000 mg/l leachate. An explanation for this level was discussed for bioreactor 2 and can be presented for bioreactor 3. During the 5 week leachate recirculation period, sulphate decreased from 1600 mg/l on day 117 to 1000 mg/l on day 124, but then rose again to 1600 mg/l by day 138. Even though some reduction of sulphate occurred, only a very small increase in sulphide was evident. Sulphide rose from 0.2 mg/l on day 104 to 1.4 mg/l on day 124, then dropped back to a concentration of 0.2 mg/l by day 138. Total metal concentrations during this period showed a slight increase in concentration, zinc, copper and lead all encountered small increases over this period due to AMD addition, however the overall concentration of these metals was very low. Iron was the only metal present in substantial concentrations to show a decrease in concentration, however levels of iron soon recovered due the abundance of the material within the bioreactor. Total iron concentrations reduced during the first week from 910 mg/l on day 104 to 790 mg/l on day 109. From day 117 total iron concentrations rose back to that of previous AMD addition of 1000 mg/l. Total zinc concentrations initially increased from 2.7 mg/l on day 104 to 18 mg/l on day 117, due to the AMD addition (1100 mg/l), then dropped to 12 mg/l on day 138. Total copper concentrations showed a steady increased from 13 ug/l on day 104 to 41 ug/l on day 138, due to the AMD addition (48000 ug/l). Total lead concentrations also showed a steady increase from 40 ug/l on day 104 to 68 ug/l on day 138, due to the AMD addition (1500 ug/l). Even though total metals showed an increase in concentration, the rate of increase was negligible. It can be seen clearly in figure 10.20 that within the first week of AMD addition total iron decreased by up to 13 %, and through out this period sulphide levels remained lower than 1.4 mg/l. It can be seen here that the abundance of metal ions were able to precipitate with any sulphide being formed. Continuous Sulphate Load From day 138 a continuous load of sulphate consisting of 4.0 litres per week, of AMD from Woodlawn (surface water run off) with a sulphate concentration of 34000 mg/l was added to the bioreactor. AMD composition is given in table 10.1.
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Continuous AMD addition saw sulphate levels increase from 1600 mg/l on day 138 to a maximum concentration of 4500 mg/l on day 167. Sulphide levels during this time rose from 0.2 mg/l on day 138 to 1.8 mg/l on day 159 then decreased to 0.6 mg/l by day 173. Total metal concentrations, with the exception of iron, showed an increase in concentration, however a declining tend during this period was seen due to the sharp increase in metal concentrations due to the AMD. This supports the theory that these metals were precipitating sulphide formed during the reduction of sulphate. Total iron concentrations decreased from 1000 mg/l on day 138 to 890 mg/l on day 173, a decline of 11%. Total zinc concentrations experienced a sharp increase during the first week from 12 mg/l on day 104 to 430 mg/l on day 109, due to the AMD addition (1100 mg/l), and decreased to 120mg/l by day 173. Total copper concentrations showed a similar patter as total zince, increasing from 41 ug/l on day 138 to 920 ug/l on day 145, due to the AMD addition (48000 ug/l). Total copper then decreased slowly to 640 ug/l on day 167 before rising in the last week to 880 ug/l on day 173. Total lead concentrations showed a slight decline from 68 ug/l on day 138 to 57 ug/l on day 173, Bioreactor 3 illustrated that with the source of an iron rich material, the abundance of metals were able to precipitate with sulphide immediately after being produced, thus reducing the hydrogen sulphide in the LFG.
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Figure 10.19: Bioreactor 3 – Sulphate and Sulphide vs Time
BIOREACTOR 3 - SULPHATE & SULPHIDE vs TIME Point Continuous Sulphate Load Sulphate Load 8000 20
18 7000
16 6000 14
5000 12
Sulphate 4000 10 Sulphide
Sulphate(mg/l) 8 Sulphide(mg/l) 3000
6 2000 4
1000 2
0 0
8 6 8 6 9 8 9 1 32 4 6 82 9 0 17 24 3 45 5 67 73 104 1 1 1 131 1 1 152 1 1 1 Time (Days) Figure 10.20: Bioreactor 3 – Total Fe, Zn, Cu and Pb vs Time
BIOREACTOR 3 - TOTAL Fe, Zn, Cu & Pb vs TIME
Point Continuous 1000 Sulphate Load Sulphate Load 4000 3800 900 3600 3400 800 3200 3000 700 2800 2600 600 2400 Total Iron 2200 Total Zinc 500 2000 Total Lead 1800 Total Copper 400 1600 IronZinc & (mg/l)
1400 Lead& Copper (ug/l) 300 1200 1000 200 800 600 100 400 200 0 0
8 2 6 8 6 9 7 8 1 3 4 6 82 9 0 1 31 3 45 52 59 73 104 1 1 124 1 1 1 1 1 167 1 Time (Days)
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Bioreactor 4 (Ferric Oxide) Pre-sulphate addition Sulphate concentration remained relatively static starting at 650 mg/l on day 18 and remaining at 630mg/l on day 104 prior to AMD addition. Sulphide concentrations showed a decline during this period from 1.1 mg/l on day 18 to 0.02 mg/l on day 104. During the period before AMD addition zinc, copper and lead experienced a reduction in concentration. Zinc decreased from 13 mg/l on day 18 to 4.7 mg/l on day 104, copper decreased from 120 ug/l on day 18 to 21 ug/l on day 104 and lead decreased from 170 ug/l on day 18 to 45 ug/l on day 104. Total iron increased from 570 mg/l on day 18 to 690 mg/l on day 104, this increase was due to the iron present in the layers of magnetite within the bioreactor. Point Sulphate Load At day 105 a load of 2.920 litres of AMD from Woodlawn (surface water run off) with a sulphate concentration of 20000 mg/l was added to the 10.0 litres of leachate with 630 mg/l concentration to give a total leachate concentration of 5008 mg/l (see appendix D for calculations). AMD composition is given in table 10.1. After the addition of AMD sulphate levels reach a maximum concentration of 1800 mg/l on day 117 two weeks after the AMD addition. An explanation for this level was discussed for the above bioreatcors and is the same for this bioreactor. During the 5 week leachate recirculation period, sulphate concentrations rose and fell to a final concentration of 1500 mg/l of day 138. Sulphide rose in the initial week from 0.02 mg/l on day 104 to 2.3 mg/l on day 109, sulphide then dropped back to a concentration of 0.02 mg/l by day 138. Total metal concentrations remained relatively static during this period with the exception of iron that rose 15%, the point load of AMD appeared to have no little on metal concentrations. Total iron concentrations increased during the first two weeks from 690 mg/l on day 104 to 800 mg/l on days 117 and 124. Iron then decreased to 730 mg/l on day 131 before rising again to 810 mg.l on day 138. Total zinc concentrations experienced a small increase from 4.7 mg/l on day 104 to 26 mg/l on day 138, due to the AMD addition (1100 mg/l). Total copper concentrations remained steady at 21 ug/l on day 104 and 24 ug/l on day 138. Total lead concentrations also remained steady at 45 ug/l on day 104 and 36 ug/l on day 138 Continuous Sulphate Load From day 138 a continuous load of sulphate consisting of 4.0 litres per week, of AMD from Woodlawn (surface water run off) with a sulphate concentration of 34000 mg/l was added to the bioreactor. AMD composition is given in table 10.1. During continuous AMD addition sulphate concentration increased from 1500 mg/l on day 138 to a maximum concentration of 6400 mg/l on day 173. Sulphide levels during this time rose from 0.02 mg/l on day 138 to 2.0 mg/l on day 145 then decreased to 0.4 mg/l by day 173. All total metal concentrations showed an increasing trend during this period, due to the high metal concentrations within the AMD. Total iron concentrations increased from 810 mg/l on day 138 to 890 mg/l on day 152, a decrease in iron concentration to 810 mg/l occurred between days 152 and 167, thereafter it rose to 970 mg/l by day 173. Total zinc concentrations showed a steady increase from 26 mg/l on day 104 to 340 mg/l by day 173, due to the AMD addition (1100 mg/l). Total copper concentrations experienced a sharp increase during the first week from 24 ug/l on day 138 to 830 ug/l on day 145, due to the AMD addition (48000 ug/l). Total copper then followed a saw tooth pattern of decreasing and increasing concentration, a final concentration of 810 ug/l was measured on day 173.
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Total lead concentrations showed a slight increase from 36 ug/l on day 138 to 150 ug/l on day 173, Bioreactor 3 illustrated that with source of an iron rich material the abundance of metals was able to precipitate with sulphide immediately after being produced, thus reducing the hydrogen sulphide in the LFG. Even though iron rose in concentration during the continuous AMD addition, it did experience a decline in concentration, showing that metal precipitation was taking place.
D.A. Lazarevic Page 65 of 87 Royal Institute of Technology Stockholm, 2007 Veolia Environmental Services
Figure 10.21: Bioreactor 4 – Sulphate and Sulphide vs Time
BIOREACTOR 4 - SULPHATE & SULPHIDE vs TIME Point Continuous Sulphate Load Sulphate Load 8000 20
18 7000
16 6000 14
5000 12
Sulphate 4000 10 Sulphide
Sulphate(mg/l) 8 Sulphide(mg/l) 3000
6 2000 4
1000 2
0 0
8 6 8 6 9 8 9 1 32 4 6 82 9 0 17 24 3 45 5 67 73 104 1 1 1 131 1 1 152 1 1 1 Time (Days) Figure 10.22: Bioreactor 4 – Total Fe, Zn, Cu and Pb vs Time
BIOREACTOR 4 - TOTAL Fe, Zn, Cu & Pb vs TIME
Point Continuous 1000 Sulphate Load Sulphate Load 4000 3800 900 3600 3400 800 3200 3000 700 2800 2600 600 2400 Total Iron 2200 Total Zinc 500 2000 Total Lead 1800 Total Copper 400 1600 IronZinc & (mg/l)
1400 Lead& Copper (ug/l) 300 1200 1000 200 800 600 100 400 200 0 0
8 2 6 8 6 9 7 8 1 3 4 6 82 9 0 1 31 3 45 52 59 73 104 1 1 124 1 1 1 1 1 167 1 Time (Days)
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Bioreactor 5 (Ferric Hydroxide) Pre-sulphate addition Sulphate concentration experienced a slight decline during this period from 410 mg/l on day 13 to 140mg/l on day 71 prior to AMD addition. Sulphide concentrations showed a similar decline during this period from 1.3 mg/l on day 13 to 0.02 mg/l on day 71. During the period before AMD addition zinc, copper and lead concentrations were the lowest of all bioreactors, however they all experienced a reduction in concentration. Zinc decreased from 8.9 mg/l on day 13 to 0.57 mg/l on day 71 copper decreased from 500 ug/l on day 13 to 39 ug/l on day 71 and lead decreased from 280 ug/l on day 13 to 33 ug/l on day 71. Total iron of 110 mg/l on day 13 increased to 550 mg/l on day 71, this increase was due to the iron present in the layers of ferric hydroxide within the bioreactor. Point Sulphate Load At day 72 a load of 3.290 litres of AMD from Woodlawn (surface water run off) with a sulphate concentration of 20000 mg/l was added to the 10.0 litres of leachate with 74 mg/l concentration to give a total leachate concentration of 5007 mg/l (see appendix D for calculations). AMD composition is given in table 10.1. Within one week of AMD addition sulphate levels reach a concentration of 1800 mg/l on day 77, after day 77 sulphate experienced an overall decrease to 1500 mg/l by day 105. Sulphide concentrations rose steadily from day 71 to day 91 0.02 mg/l to 1.4 mg/l respectively. During the last 2 weeks sulphide dropped back to 0.02 mg/l. AMD addition appeared to have little affect on lead and copper concentrations, however zinc concentrations showed a strong increase. Iron concentrations showed a steady 26% increase in concentration during this period. Total iron concentrations increased from 550 mg/l on day 71 to 800 mg/l on day 91, then declined to 740 mg/l by day 105. Total zinc concentrations experienced a sharp increase in the first week from 0.57 mg/l on day 71 to 220 mg/l on day 71, due to the AMD addition (1100 mg/l). Zinc was then steadily decreased to 58 mg/l by day 105. Total copper concentrations remained relatively steady from 39 ug/l on day 71 to 110 ug/l on day 105. Total lead concentrations also remained steady from 33 ug/l on day 71 to 53 ug/l on day 105. Continuous Sulphate Load From day 105 a continuous load of sulphate consisting of 4.0 litres per week, of AMD from Woodlawn (surface water run off) with a sulphate concentration of 34000 mg/l was added to the bioreactor. AMD composition is given in table 10.1. During continuous AMD addition sulphate concentration increased from 1500 mg/l on day 105 to 6800 mg/l on day 119. Sulphate decreased the following week to 6400 mg/l on day 126, after which it rose to 8000 mg/l by day 140. Sulphide levels remained below 0.15 mg/l, with the exception of day 126 where sulphide rose to 0.7 mg/l. This minor rise in sulphide corresponded to with the decline in sulphate concentration. The influence of the AMD was the greatest in bioreactor 5 with zinc and copper concentrations increasing dramatically after the addition of the AMD. Total iron concentrations remained steady during the continuous AMD addition, only decreasing 10 mg/l from 740 mg/l on day 105 to 730 mg/l on day 140. Total zinc concentrations rose sharply during the 2 weeks after AMD addition, rising from 58 mg/l on day 105 to 610 mg/l by day 119, due to AMD addition (1100 mg/l). Zinc concentration remained steady from day 119 to day 134 before increasing in the last week from 600 mg/l on day 134 to 710 mg/l on day 140.
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Total copper concentrations experienced the same pattern of change as zinc. Two weeks after AMD addition, copper rose from 10 ug/l on day 105 to 17000 ug/l on day 119. Total copper then decreased to 14000 ug/l for the following two weeks, thereafter it increased to 26000 mg/l by day 140. Total lead concentrations showed an increase from 53 ug/l on day 105 to 540 ug/l on day 140. It was well illustrated from this example that during the reduction of sulphate to sulphide, metals within the bioreactor were consumed, hence only a very small increase in sulphide concentration. Bioreactor 5 illustrated that with source of an iron rich material the abundance of metals was able to precipitate with sulphide immediately after being produced, thus reducing the hydrogen sulphide in the LFG.
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Figure 10.23: Bioreactor 5 – Sulphate and Sulphide vs Time
BIOREACTOR 5 - SULPHATE & SULPHIDE vs TIME Point Continuous Sulphate Load Sulphate Load 8000 20
18 7000
16 6000 14
5000 12
Sulphate 4000 10 Sulphide
Sulphate(mg/l) 8 Sulphide(mg/l) 3000
6 2000 4
1000 2
0 0
3 5 2 1 7 4 1 8 5 9 1 3 49 6 7 7 8 9 9 0 1 34 40 1 112 1 126 1 1 Time (Days) Figure 10.24: Bioreactor 5 – Total Fe, Zn, Cu and Pb vs Time
BIOREACTOR 5 - TOTAL Fe, Zn, Cu & Pb vs TIME
Point Continuous 1000 Sulphate Load Sulphate Load 28000
26000 900 24000
800 22000
700 20000 18000 600 16000 Total Iron Total Zinc 500 14000 Total Lead 12000 Total Copper 400 IronZinc & (mg/l)
10000 Lead& Copper (ug/l)
300 8000
200 6000 4000 100 2000
0 0
3 5 2 1 7 4 9 6 1 3 49 6 7 7 8 91 98 05 12 1 2 34 40 1 1 1 1 1 1 Time (Days)
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Bioreactor 6 (Multi Service Baghouse Dust) Pre-sulphate addition Sulphate concentration increased from an initial level of 530 mg/l on day 13 to 640mg/l on day 71 prior to AMD addition. Sulphide concentrations showed a small rise and fall yet remained low at a concentration of below 1.0 mg/l, with a lowest value of 0.02 mg/l on day 71. During the period before AMD addition zinc, copper and lead concentrations remained relatively static, iron increased 590 % due to the iron cover material. Total iron increased from 61 mg/l on day 13 to 360 mg/l on day 71, this increase was due to the iron present in the layers of baghouse dust within the bioreactor. Zinc increased from 34 mg/l on day 13 to 45 mg/l on day 71, copper decreased from 450 ug/l on day 13 to 110 ug/l on day 71 and lead increased from 34 ug/l on day 13 to 45 ug/l on day 71. Point Sulphate Load At day 72 a load of 2.910 litres of AMD from Woodlawn (surface water run off) with a sulphate concentration of 20000 mg/l was added to the 10.0 litres of leachate with 640 mg/l concentration to give a total leachate concentration of 5004 mg/l (see appendix D for calculations). AMD composition is given in table 10.1. Within 2 weeks of AMD addition sulphate levels reach a concentration of 2100 mg/l by day 84, after day 84 sulphate experienced a decrease in concentration to 1500 mg/l by day 105. Sulphide concentrations remained low at 0.1 mg/l to day 84 and then rose to 1.7 mg/l by day 71, sulphide then decreased to 0.6 mg/l by day 105. The rise of sulphide is inversely proportional to the drop in sulphate concentration. AMD addition appeared to have little affect on lead and copper concentrations, however zinc concentrations showed a strong increase due to the AMD. Iron concentrations showed a steady 32% increase in concentration during this period. Bioreactor 6 showed very similar changes in total metal concentrations to bioreactor 5. Total iron concentrations increased from 360 mg/l on day 71 to 530 mg/l on day 98, then declined to 490 mg/l by day 105. Total zinc concentrations experienced a sharp increase in the first week from 45 mg/l on day 71 to 230 mg/l on day 71, due to the AMD addition (1100 mg/l). Zinc concentration then steadily declined to110 mg/l by day 105. Total copper concentrations remained relatively steady from 45 ug/l on day 71 to 110 ug/l on day 105. Total lead concentrations also remained steady from 55 ug/l on day 71 to 65 ug/l on day 105. Continuous Sulphate Load From day 105 a continuous load of sulphate consisting of 4.0 litres per week, of AMD from Woodlawn (surface water run off) with a sulphate concentration of 34000 mg/l was added to the bioreactor. AMD composition is given in table 10.1. During continuous AMD addition sulphate concentration increased from 1500 mg/l on day 105 to 5900 mg/l by day 126. Sulphate was reduced the following week to 4900 mg/l on day 134, after which it rose to 5800 mg/l by day 140. Sulphide levels remained low during this entire period, peaking at 0.95 mg/l on day 126, ending at 0.2 mg/l on day 140. The influence of the AMD was quite pronounced bioreactor 6 with zinc and copper concentrations increasing dramatically after the addition of the AMD. Total iron concentrations remained relatively steady during the continuous AMD addition, decreasing 20 mg/l from 490 mg/l on day 105 to 470 mg/l on day 140. Total zinc concentrations rose sharply during the 2 weeks after AMD addition, rising from 110 mg/l on day 105 to 550 mg/l by day 119, due to AMD addition (1100 mg/l). After this initial increase, zinc concentrations steadied increased from 550 mg/l 119 to day to 610 mg/l on day 140.
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Total copper concentrations experienced the same pattern of change as zinc. Two weeks after AMD addition copper rose from 130 ug/l on day 105 to 13000 ug/l on day 119. Total copper then dropped to 11000 ug/l the following week; thereafter it increased to 17000 mg/l by day 140. Total lead concentrations showed an increase from 65 ug/l on day 105 to 140 ug/l on day 140. It was well illustrated from this example that during the reduction of sulphate to sulphide, metals within the bioreactor were consumed, hence only a very small increase in sulphide concentration. Bioreactor 6 illustrated that with source of an iron rich material the abundance of metals was able to precipitate with sulphide immediately after being produced, thus reducing the hydrogen sulphide in the LFG.
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Figure 10.25: Bioreactor 6 - Sulphate and Sulphide vs Time
BIOREACTOR 6 - SULPHATE & SULPHIDE vs TIME
Point Continuous 8000 Sulphate Load Sulphate Load 20
18 7000
16 6000 14
5000 12
Sulphate 4000 10 Sulphide
Sulphate(mg/l) 8 Sulphide(mg/l) 3000
6 2000 4
1000 2
0 0
3 5 2 1 7 4 1 8 5 9 1 3 49 6 7 7 8 9 9 0 1 34 40 1 112 1 126 1 1 Time (Days) Figure 10.26: Bioreactor 6 – Total Fe, Zn, Cu and Pb vs Time
BIOREACTOR 6 - TOTAL Fe, Zn, Cu & Pb vs TIME Point Continuous Sulphate Load Sulphate Load 1000 18000
900 16000
800 14000
700 12000
600 10000 Total Iron Total Zinc 500 Tota Lead 8000 Total Copper 400 IronZinc & (mg/l) Lead& Copper (ug/l) 6000 300
4000 200
100 2000
0 0
3 5 2 1 7 4 9 6 1 3 49 6 7 7 8 91 98 05 12 1 2 34 40 1 1 1 1 1 1 Time (Days)
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10.3 BIOREACTOR PERFORMANCE The results of the bioreactor LFG and leachate chemistry confirm the assumptions made in the previous sections, that bioreactors containing iron rich cover materials would experience lower hydrogen sulphide concentrations in LFG, than the bioreactor containing no iron rich cover. Bioreactor 2 containing no alterative daily cover material experienced a negligible rise in hydrogen sulphide gas after the initial point load, even though leachate indicators showed the reduction of sulphate was taking place. The metals naturally occurring within the waste, primarily iron, were able to precipitate with the sulphide produced, hence trapping the sulphur in the waste as a solid metal sulphide precipitate. When the continuous acid mine drainage load was introduced, leachate chemistry showed a prolific reduction of sulphate to sulphide, however little metal ions were available to precipitate with the sulphide produced, as they were consumed in the previous stage. The net result of this sulphate reduction was hydrogen sulphide gas concentrations of more than 1700 ppm or 0.17 % volume (hydrogen sulphide is fatal to humans at > 1000 ppm). All bioreactors containing iron rich alternative daily cover materials experienced very similar results, with hydrogen sulphide gas concentrations remaining below 0.5 ppm in almost all measurement. In most cases there was a small peak of hydrogen sulphide after the initial continuous acid mine drainage addition, after which hydrogen sulphide gas stabilised to below 1ppm in all cases. Leachate chemistry data shows that while sulphate reduction was evident in these bioreactors the availability of iron was able to precipitate any sulphide immediately upon its formation. Data suggest that whilst sulphate reduction was evident in these bioreactors was not as profuse as bioreactor 2. When reviewing the data the greatest difference between these bioreactors was bioreactor pH. Bioreactors 3 6 were of pH range 5 – 6, yet bioreactor 2 experienced a sharp rise in pH after the point AMD addition and stabilised at approximately 7.5 (see appendix B). Yet given the optimal pH range of SRB of pH 5.8 – pH 7 with an optimum growth rate of pH 6.7 (Reis, 1992) it would appear that all bioreactors are out of the optimal growth conditions for SRB. Bioreactor performance can be affected by the addition of AMD in several ways, listed below: pH The influence of AMD is an important factor in lowering bioreactor pH out of the optimum range form menthanogenesis. AMD with low pH (approx. pH 2.5) it is conducive to maintaining bioreactor pH below optimum levels, by preventing the growth of methanogenic bacteria. With methanogenesis struggling to become established the organic acids formed during the acetogenic phase build up within the bioreactor, this can cause the bioreactor to be stalled in the acetogenic phase. When this occurs pH must be artificially raised into the methangoenic range. Competition As previously discussed in section 7.2 the SRB, responsible for reducing sulphate to sulphide, are in competition with methanogenic bacteria for organic substrate, this competition can lead to reduced methane yields where SRB colonies are large and high amounts of hydrogen sulphide are experienced. In addition to SRB competition, the anaerobic methane oxidation by sulphate reduction anaerobically oxidise the methane once it has formed.
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Toxicity The influence of AMD can lead to toxic concentrations of metals within the bioreactors, harming methanogenic cellular activity and directly effecting bioreactor performance. The effective concentration of metals can often be controlled by pH, as they may exist in unionised forms, ionised forms, or stable precipitates Table 10.2 give a the toxic concentrations for copper, nickel and zinc. Table 10.2: Toxic concentrations for various metals during anaerobic digestion Constituent Toxic Concentration (mg/L) Reference Cu 150 250 Rudgel, 1941 Cu 500 Rudgel, 1946 Cu 1000 Barnes and Braidech, 1942 Ni 200 Barnes and Braidech, 1942 Ni 1000 Wischmeyer and Chapman, 1942 Zn 1000 Rudolphs and Zeller, 1932 Zn 350 McDermott et al., 1963 During the addition of AMD zinc concentrations of bioreactors 3, 5 and 6 were a maximum 430 mg/l, 710 mg/l and 610 mg/l respectively, showing that zinc was above the toxic level of 350 mg/l. Both methanogenic and SRB would have been harmed by these levels of zinc, which may provide an explanation for sulphate and sulphide figures for these bioreactors not showing the same reduction of sulphate as in bioreactor 2 that had a maximum zinc concentration of 46 mg/l. Table 10.3 gives the highest concentration of selected metals that will allow “satisfactory” anaerobic digestion. Even though the majority of metal concentrations within the bioreactors are below toxic concentrations, they above the satisfactory levels, thus limiting bioreactor performance. Leachate showed levels of copper above satisfactory limits in bioreactors 5 and 6 and above satisfactory limits for zinc in bioreactors 3, 5 and 6. Table 10.3: Limiting concentrations for various metals during anaerobic digestion Constituent Limiting Concentration (Dissolved or Reference(s) Available Form) mg/L Cu (total) 5 10 Barth et al., 1965 Ni (total) >10 40 Barth et al., 1965 Zn (total) 10 Barth et al., 1965 100 Harries et al., 1990 Products other than metals were found in toxic concentrations within the bioreactors, a sulphide concentration of 67 mg/l in bioreactor 2 is within the toxic range of 80 mg/l (Yoda, 1987) or 60 mg/l (Khan and Trottier, 1978). The combination of AMD, with high metal content and sulphate being reduced to sulphide provides a harmful environment for the development and activity of methanogens.
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11 CONCLUSION AND RECOMMENDATIONS
11.1 CONCLUSION The primary aim of this research was to establish if the addition of certain iron rich alterative daily waste covers would limit the concentration of hydrogen sulphide produced in the bioreactors, providing an interim solution for the management of hydrogen sulphide. Bioreactors 2 – 4 tested various alternative cover materials, two products were readily available commercial iron ore products, the other two were sourced from industrial waste streams close to the vicinity of the Woodlawn bioreactor, products varied in iron content from 95% 61%. All products functioned extremely well, experiencing a maximum hydrogen sulphide concentration of 20ppm and an average concentration of 1ppm. Leachate data confirmed the occurrence of sulphate reduction and consumption of total metal concentration; hence the presence of metal sulphide precipitation can be inferred. As previously stated the half life of waste within the bioreactors ranges from 3 5 years, hence waste that is subject to the influence of acid mine drainage for a period of time such as this requires the availability of metals to last the same period. Waste within these bioreactors was subject to 1/6 – 1/10 the timescale of degradation that would normally occur. As time unfolds this iron would be consumed by metal sulphide precipitation, hence the limiting factor in this equation must be iron not sulphide, to maintain hydrogen sulphide at minimal levels. The application rate of Alternative Daily Cover used in the test bioreactors was the equivalent of 35 kg/m2, or 1 ton per 28.5 m2. As shown in the above data, this application rate would be more than sufficient to deal with the reduced sulphide. It would be recommended for Veolia to conduct a mass balance study of the amount of sulphate entering the void, from groundwater and surface water runoff, to establish the minimum amount of ADC needed to precipitate the reduced sulphide. Bioreactors 3 – 4 all showed that the alternative waste cover materials succeeded in preventing the formation of hydrogen sulphide gas. Whilst there was some variation in hydrogen sulphide concentrations, this was negligible, even with varying particle size and iron content. It was expected to see a more pronounced variation between these different products. A secondary aim of this research was to test the ability for the metals contained within the municipal solid waste and acid mine drainage to limit the amount of hydrogen sulphide produced within a test bioreactor. Bioreactor 2 contained no alternative daily cover material and experienced the greatest concentration of hydrogen sulphide in LFG, concentrations of greater than 1700ppm. Both leachate and LFG data confirmed that over time metals existing within the waste and AMD were consumed to a point where concentrations were too low to precipitate the amount of sulphide produced. Thus sulphide concentrations in both leachate and LFG will rise as long as there is a source of sulphate to be reduced. Data from bioreactor 2 showed that there were not enough metals contained within the waste and AMD to prevent the formation of hydrogen sulphide within the LFG. It should be noted that levels of hydrogen sulphide within bioreactor 2 were almost twice the lethal concentration for humans. However on site conditions are conducive to lower hydrogen sulphide concentrations, negative pressure within the bioreactor void reduced the amount of LFG exposure to operators, and unlike the bioreactors the whole site is not subject to these levels of sulphate reduction, areas toward the centre of the waste mass are buffered by the peripheral zones of waste, hence what was experienced within the bioreactors is a worst case scenario.
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11.2 RECOMMENDATIONS The addition of iron rich alternative daily cover materials to retain sulphur within the waste mass is an easy and fast solution to implement. The precipitation of metal sulphide would not be expected to cause any greater problems, such as clogging of any drainage layers or gas blankets and leachate recirculation equipment with precipitate, than is currently taking place. The majority of leachate pump failure has been due to the build up of carbonates on equipment, not metal sulphides. The daily spreading of any of these alternative waste materials, and post wetting of this material through the surface spreading of leachate, will not only improve surface waste moisture content but also form a crust on the waste, preventing wind blown litter from exiting the void. It should be reiterated that the use of this method to reduce hydrogen sulphide is only one part of a total strategy. Physical barriers such as removal of high waste rock with high sulphate potential from void walls, plugging weepholes/draining holes within the void walls (from previous mining operations) and construction of surface water drainage routes to collection ponds, will all act in preventing sulphate from entering the waste mass. The most effective way of preventing the formation of hydrogen sulphide is to remove the source of sulphate, however it is inevitable that sulphate will find its way into the bioreactor leachate. Through the development of a leachate treatment system, the removal of sulphate from bioreactor leachate, most preferably through the precipitation of calcium sulphate (gypsum), will allow for a flexible way to remove sulphate from bioreactor leachate, and enable a more active approach to leachate recirculation. Although the threat of hydrogen sulphide will always be present at Woodlawn, void geometry will work in favour to reduce hydrogen sulphide production. Due to the conical shape of the void, the most favourable conditions for the production of hydrogen sulphide are currently being experienced, a small amount of waste subject to large volumes of AMD, and a saturation of the basal waste layer. In the future the increased size of the waste mass will have a greater ability to buffer the inflow of AMD and hydrogen sulphide produced will be limited to the small areas that are subject to this AMD influence. One last recommendation for Veolia is an improvement of operational leachate monitoring. One can only evaluate bioreactor performance by evaluation of both LFG and leachate data. Data collection needs to be specified to gain the most valid information for the bioreactor and also reduce testing of unwanted parameters. The most useful parameters for monitoring bioreactor 2 2 performance are pH, SO4 , S , VFA, COD, BOD, NH3, TDS, Eh, heavy metals (i.e. Fe, Zn, Cu, Pb). With this information many factors can be determined such as; areas of AMD incursions; dissociation state of hydrogen sulphide; organic matter conversion efficiency; and potential for exhaustion of organic matter.
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12 REFERENCES
References Cited Alberta Human Resource & Employment. 2005, Hydrogen Sulphide and the Worksite, Worksafe Alberta. Barnes, G.E., and Braidech, M.W., 1942, Treating Pickeling Liquors for Removal of Toxic Metals, Engineering News Record 129:496. Barth, E.F., Moore, W.A., and McDermott, G.N., 1965, Interaction of Heavy Metals in Biological Sewage Treatment Processes, U.S. Dept. of Health, Education, and Welfare Report, May, 1965, Washington, D.C. Batstone, D. 2007. Personal Communications – Advanced Waste Water Management Centre, The University of Queensland.
Christensen, T H and Kjeldsen, P, 1989. Basic biochemical processes in landfills, Chapter 2.1 of sanitary landfilling: process, technology and environmental impact, Academic Press, London, ISBN 0 12 174255 5. Christensen, T.H., Kjeldsen. P., Lindhardt. B. 1996, ‘Gas Generating Processes in Landfills’ in Landfilling of Waste Biogas, edited. Christensen, T.H., Cossu, R., Stegmann, R., E & FN Spon, London, p 27 50.
Chynoweth, D., Pullammanappallil, P. 1996, Anaerobic Digestion of Municipal Solid Wastes in Microbiology of Solid Wastes (Ed, Barlaz, A. C. P. a. M. A) CRC Press.
De Baere, L. A., Devocht, M., Van Assche, P., Verstrae, W. 1984. ‘Influence of high NaCl and NH4Cl salt levels on methanogenic associations’, Water Research, Vol. 18, no 5, pp 543 548.
Elferink, S.J.W.H. a, Visser, A., b, Hulshoff Pol, L.W., Stares, A.J.M. 1994, ‘Sulfate reduction in methanogenic bioreactors’, Federation of European Microbiological Societies Microbiology Reviews, Vol. 15, pp 119 136. Environmental Protection Authority, NSW. 1996, Environmental Guidelines: Solid Waste Landfills, Environmental Protection Authority, NSW, Sydney. Environmental Protection Authority, NSW. 2004, Woodlawn Bioreactor: Environment Protection Licence No. 11436, Environmental Protection Authority, NSW, Sydney. Farquhar, G.J., Rovers, F.A. 1973, ‘Gas Production During Refuse Decomposition’, Water, Air and Soil Pollution, vol. 2, pp. 483 – 495. Fairweather, R, J., Baralaz. M.A. 1998, ‘Hydrogen sulfide production during decomposition of landfill inputs’, Journal of Environmental Engineering, vol. 124, no. 4, pp 363 – 381. Gurijala, K.R, Suflita, J.M. 1993, ‘Environmental factors Influencing Methanogenesis from Refuse in Landfill Samples’, Environmental Science and Technology, vol. 27, no. 6, pp 1176 – 1181. Harries, C, R., Scrivens, A., Rees, J.F., and Sleat, R., 1990, Initiation of Methanogenesis in Municipal Solid Waste. 1. The Effect of Heavy Metals on the Initiation of Methanogenesis in MSW Leachate, Environmental Technology 11: 1169.
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Harries, J. 1997, ‘Acid mine drainage in Australia: Its extent and potential future liability’, Supervising Scientist Report 125, Supervising Scientist, Canberra, pp 94. Joseph, J.B. 2003, Waste Management Policies and the Impact of Past Decisions – an Australian Case Study, Ninth International Waste Management and Landfill Symposium, S. Margherita di Pula, Calgliari, Italy, by CISA, Environmental Sanitary and Engineering Centre, Italy. 6 10 October 2003. Kim, K H., Choi, YJ., Jeon, EC., Sunwoo, Y. 2004, ‘Characterisation of malodorous sufur compounds in landfill gas’, Atmospheric Environment, Vol. 39, pp 1103 1112. Kugleman, J.J., Chin, K.K, 1971. ‘Toxicity, Synergism and Antagonism in Anaerobic Waste Treatment Processes’, in Anaerobic Biological Treatment Processes, Advances in Chemistry Series, ed. Gould, R.F, vol. 105, American Chemical Society, Washington, D.C. Lee, S., Xu, Q., Booth, M., Townsend, T., Chadik, P., Bitton, G. 2006, ‘Reduced sulfur compounds in gas from construction and demolition debris landfills’, Waste Management, Vol. 26, pp 526 533.
Lovely, D.R., Klug, M.J., 1986, ‘Model for the Distribution of Sulphate Reduction and Methanogenesis in Freshwater Sediments, Geochemical et Cosmochimica Acta, vol. 50, pp 11 18. McDermott, G.N., Barth, E.F., Salotto, V., and Ettinger, M.B., 1963, Zinc in Relation to Activated Sludge and Anaerobic Digestion Processes, p. 471 in Proc. 17th Purdue Industrial Waste Conference, published by Purdue University, West Lafayette, Indiana.
Mudder, T. 2004, ‘Coming down hard on ARD’, Mining Environmental Management, vol. may 2004, pp 2.
Raskin, L., Rittmann, B.E., Stahl, D.A. 1996, ‘Competition and Coexistence of Sulfate Reducing and Methanogenic Populations in Anaerobic Biofilms’, Applied and Environmental Microbiology, Oct. 1996, p. 3847–3857 Reis, M.A.M., Almeida, J.S., Lemos, P.C., Carrondo, M.J.T. 1992, ‘Effects of Hydrogen Sulphide on Growth of Sulphate Reducing Bacteria’, Biotechnology and Bioengineering, vol. 40, pp 593 – 600. Reinhart, D,R., Townsend, T.G. 1998, Landfill Bioreactor Design & Operation, CRC Press LCC, Florida.
Rudgel, H.T., 1941, Bottle Experiments as a Guide in Operation of Digesters Receiving Copper Sludge Mixtures, Sewage Works Journal 13:1248. Rudgel, H.T., 1946, Effects of Copper Bearing Wastes on Sludge Digestion, Sewage Works Journal 18:1130.
Rudolphs, W., and Zeller, P.J.A., 1932, Effect of Sulfate Salts on Hydrogen Sulfide Production in Sludge Digestion, Sewage Works Journal 4:77.
Shon, Z H., Kim, H H., Jeon, E C., Kim, M Y., Kim, Y H., Song, S K. 2005, ‘Photochemistry of reduced sulfur compounds in a landfill environment’, Atmospheric Environment, Vol. 39, pp 48803 4814.
Sponza, D.T., Agdag, O, N., 2005. ‘Effects of shredding of wastes on the treatment of municipal solid wastes (MSWs) in simulated anaerobic recycled reactors’, Enzyme and Microbial
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Technology, Vol36, no 1, pp 25 33.
Parker, G., Robertson, A. 1999, Acid Drainage: A critical review of acid generation and Sulfide Oxidation: Process, Treatment and Control, Australia Minerals and Energy Environment Foundation, Occasional Paper no. 11, Melbourne, pp 227
Solid Waste Management Association of North America, 2004. Definitions of Terms uded in SWANA Technical Policies and Solid Waste management, T 0 SWANA Technical Policy.
Sydney Water, No Date. Water filtration at Sydney Water, Sydney Water, Sydney.
United Kingdom Environment Agency. 2004, Guidance on the Management of Landfill Gas, Environmental Agency, Bristol, pp 51 – 68. University of Rhode Island, no date. Solubility Product Constants near 25 oC [Online]. Available: http://bilbo.chm.uri.edu/CHM112/tables/KspTable.htm, Accessed: January 2007. Veolia Environmental Services, 2006. Commercial in Confidence. Waste Management Authority of New South Wales, 1991. Annual Report 1990/91. WMA, Sydney, Australia. Williams, T. 2005, Waste Treatment and Disposal, 2nd edn, Wiley, West Sussex, pp 197 – 210.
Willumsen, H., 1989. Landfill Gas, Resources, Concervation and Recycling, vol 4. pp 121 133
Winchester, S. 2005, Acid Mine Drainage Reduction by Industrial Waste co Disposal, PhD Thesis, Macquarie University. Wischmeyer, W.J., and Chapman, J.T., 1947, A Study of the Effect of Nickel on Sludge Digestion, Sewage Works Journal 19:790. Yoda, M., Kitagawa, M., Miyaji, Y., 1987, ‘Long Term Competition Between Sulphate Reducing and Methane Producing Bacteria for Acetate in Anaerobic Biofilm;, Water Resources, vol. 21, pp 1547 1556.
Other References Alvarez, M.T., Crespo C., Mattiasson, B. 2006, ‘Precipitation of Zn(II), Cu(II) and Pb(II) at bench scale using biogenic hydrogen sul•de from the utilization of volatile fatty acids’, Chemoshpere, doi:10.1016/j.chemosphere.2006.07.065 Bates, M. 2000, The Effects of Heavy Metal Speciation on Methanogenesis in Landfill Research and Development Technical Report P255, Environment Agency, Bristol. Bhagat, M., Burgess, J.E., Antunes, A.P.M., 2004, Whiteley, C.G., Duncan J.R. ‘Precipitation of mixed metal residues from wastewater utilising biogenic sulphide’, Minerals Engineering, Vol. 17, 925–932. Greben H.A, Matshusa M.P , Maree J.P. 2005, ‘The biological Sulphate removal technology’, Ninth International Mine Water Association Congress, Oviedo, Asturias, Spain. 5 7 September 2005. Greben, H.A., Maree1, J.P., Eloff1, E., Murray, K. 2005, ‘Improved sulphate removal rates at increased sulphide concentration in the sulphidogenic bioreactor’, Water SA, Vol.31, 351 – 358.
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ISSN 0378 4738 Haaning Nielsen, A., Lens, P., Vollertsen, J., Hvitved Jacobsen, T. 2005, ‘Sulfide–iron interactions in domestic wastewater from a gravity sewer’, Water Research , Vol. 39, 2747–2755. doi:10.1016/j.watres.2005.04.048 Harmandas, N.G., Koutsoukos, P.G. 1996, ‘The formation of iron(II) sulfides in aqueous solutions’, Journal of Crystal Growth, Vol. 167, 719 724. Pll S0022 0248(96)00257 6 Kennedy, L.G., Everett, J.W. 2005, ‘Microbial degradation of simulated landfill leachate: solid iron/sulfur interactions’, Advances in Environmental Research, Vol. 5, 103 – 116. Levlin, E. 1993, Material deterioration at different process conditions in waste deposits – prestudy, ‘Water Resources Engineering’, Rapport till Avfallsforskningsrådet AFR, Område 4 Miljöanpassad deponeringsteknik, Diarienr. 314, dossienr. 230. Ma, S., Noble, A., Butcher, D., Trouwborst, R.E., Luther, G.W. III. 2006, ‘Removal of H2S via an iron catalytic cycle and iron sulfideprecipitation in the water column of dead end tributaries’, Estuarine, Coastal and Shelf Science, Vol. 70, 461 – 472. doi:10.1016/j.ecss.2006.06.033 Machemer, S.D., Reynolds, J.S., Laudon, L.S., Wildeman, T.R. 1993, ‘Balance of S in a constructed wetland built to treat acid mine drainage, Idaho Springs, Colorado, U.S.A.’, Applied Geochemistry, Vol. 8, 587 603. Nichols, P.H. 2003, An Overview of Issues Relating to the Disposal if Urban Waste in Australia 1788 – 2000, Ninth International Waste Management and Landfill Symposium, S. Margherita di Pula, Calgliari, Italy, by CISA, Environmental Sanitary and Engineering Centre, Italy. 6 10 October 2003. Olivier,F., Gourc, JP., Moreau Le Golvan, Y., Low, D., Smith, L. 2002, ‘Simulation of waste settlement in deep landfill: Woodlan Bioreactor Case Study’, 2nd Asian Pacific Landfill Symposium – APLAS Seoul, Korea, 25 28 September 2002. Rickard, D. 2005, ‘Kinetics of FeS precipitation: Part 1. Competing reaction mechanisms’, Geochimica et Cosmochimica Acta, Vol. 59, No. 21. 4367 – 4379. Sinan Bilgili, M., Demir, A., Ozkaya, B. 2006, ‘Influence of leachate recirculation on aerobic and anaerobic decomposition of solid wastes’, Journal of Hazardous Materials (doi:10.1016/j.jhazmat.2006.09.012) Suna Erses, A., Onay, T.T. 2003, ‘In situ heavy metal attenuation in landfills under methanogenic conditions’, Journal of Hazardous Materials, B99, 159–175 doi:10.1016/S0304 3894(02)00354 0 Themelis, N.J., Ulloa, P.A. 2006, ‘Methane Generation in Landfills’, Renewable Energy’, Wilumsen, H. 1990, ‘Landfill Gas’, Resources, Conservation and Recycling, Vol 4, p 121 – 133.
D.A. Lazarevic Page 80 of 87 APPENDIX A - ALTERNATIVE DAILY COVER MATERIAL ANALYSIS
O HAEMATITE O MAGNATITE O FERRIC HYDROXIDE o MULTISERV BAGHOUSE DUST
TECHNICAL INFORMATION SHEET
PRIMOX G (Interim)
Description: An iron ore powder suitable for use in glass manufacture. Produced at Welshpool WA
Specification: Sizing 10% maximum + 106 microns (Note: This product is manufactured to the requirements of the process specification above. Typical properties are a consequence of the process, nature of raw material, and are measured at a lower frequency than the specified properties. These results are an average of historical data.)
Typical Chemical & Physical Typical Particle Size Distribution Properties: by Sedimentation:
Total Iron as Fe2O3 95.0% % Finer Silica SiO2 2.4% 100
Alumina Al2O3 2.7% 90 Magnesia MgO 0.1% 80 Manganese Oxide MnO 0.2% 70 Titania TiO2 0.1% Lime CaO 0.2% 60 Loss on Ignition (1000°C) 2.4% 50
Specific Gravity 4.78 40 30 20
10
0 2 4 6 10 20 38 53 75 150 Microns
TEST METHODS: Particle Size UAL 2.17 Sedigraph 5100 Sizing UAL 2.5(B) Chemical Analysis UAL 8.5 XRF Specific Gravity UAL 2.13 Multipycnometer Loss on Ignition UAL 2.3 Date: SEPTEMBER 2003 Issue No: Interim TIS No: 20.3.4 Authorised By:
All information is given in good faith but no guarantee of accuracy is Unimin Australia Limited A.B.N 20 000 971 844 made nor can we anticipate every possible application of our product nor variations in manufacturing equipment and methods. Our Principle & Registered Office: Level 16, 111 Pacific Highway, North Sydney, NSW 2060 Australia Ph: +61 2 9458 2929 Fax +61 2 9458 2900 products are therefore sold without warranty express or implied, and AUSTRALIA Sydney : +61 2 9637 7066 Brisbane : +61 7 3275 2499 NEW ZEALAND Auckland :+64 9 914 7010 on the condition that the purchaser relies on his own ability to determine the suitability of each product for a particular purpose. Adelaide : +61 8 8240 8200 Melbourne : +61 3 9586 5400 Statements concerning the possible use of our products are not intended as recommendations for use. No liability is accepted for Newcastle : +61 2 4967 1222 Perth : +61 8 9362 1411 infringement of any patents.
Technical Information Sheet UNIMIN AUSTRALIA LIMITED
HEAD OFFICE Branches: Level 6, 80 George Street NEWCASTLE (02) 4967 1222 Parramatta NSW Australia 2150 MACKAY (07) 4955 1501 Telephone: +612 9354 2929 TALLAWANG (02) 6375 9666 Facsimile: +612 9891 2074
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DESCRIPTION TYPICAL APPLICATION
1 Dense medium mineral separation A high purity magnetic iron oxide 2. Filler 3. Ballast for counterweights Chemical Formula Fe3O4 4. Ferro-cement 5. Oxidising
TYPICAL CHEMICAL ANALYSIS TYPICAL PHYSICAL PROPERTIES
Si02 1.4% Specific gravity 4.9 minimum Al 203 0.8% 5.0 typical Magnetic content: Total Fe 69.5% (Davis Tube, 700 gauss) 98% typical Fe304 95.0% 96% minimum Free Fe203 1.0% Packing density: Compacted (kg/m3) 2800 S 0.2% Loose (kg/m3) 1600 P 0.02% Cu 0.005% TYPICAL SIZING ANALYSIS 0 H20 (110 C) 10.0% maximum (Passing 53 microns) 7.0% typical Coarse 50-60% Medium 65-75% TYPICAL MAGNETIC PROPERTIES Fine 85-90% Superfine 90-95% Saturation Moment Ultrafine 95-99% Not less than 80 e.m.u./g, (83.5 typical) Maxifine 98-100%
Susceptibility @ 800 Oersteds not less than PACKAGING 0.050 e.m.u./oe/g, (0.053 typical) 1. 25kg & 33kg Plastic Bags Coercive Force 2. 0.5, 1 & 1.5 tonne Bulker Bags Less than 40 Oersteds, (33.0 typical) 3. Bulk Truck
The above figures are as determined by Acirl Ltd on the 45 x 38 micron fraction ILLAWARA WATER TREATMENT PLANT- HYDROXIDE SLUDGE COMPOSITION
Client sample ID (Primary): IWS1 IWS2 IWS3 IWS4 IWS5 IWS6 Sample date: 17/05/2005 17/05/2005 17/05/2005 17/05/2005 17/05/2005 17/05/2005 Analyte grouping Sample Method CAS Number Units LOR Moisture (@ 103°C) EA055 (Initial Sample) % 1 47.7 47.8 47.6 47.2 40.3 40 Moisture (@ 103°C) EA055 (Rebatched) % 1 47.9 48.9 42.4 54.9 40.5 40.2 Average 47.8 48.35 45 51.05 40.4 40.1 Analysis Below on Dry Weight Basis Sulphur ED042T:LECO % 0.01 0.35 0.37 0.34 0.35 0.34 0.33 Sodium ED093T 7440-23-5 mg/kg 10 900 390 320 260 280 270 Potassium ED093T 7/09/7440 mg/kg 10 4690 2770 2220 1970 2030 1830 Calcium ED093T 7440-70-2 mg/kg 10 85200 88300 71000 56100 87100 79500 Magnesium (Initial) ED093T 7439-95-4 mg/kg 10 3100 3110 2970 2510 3210 3170 Magnesium (Rebatched) ED093T 7439-95-4 mg/kg 50 3230 3020 2420 2650 3700 3470 Average 3165 3065 2695 2580 3455 3320 Aluminium EG005T:ICP-AES 7429-90-5 mg/kg 50 3870 3390 2820 3550 3970 3760 Arsenic EG005T:ICP-AES 7440-38-2 mg/kg 5 <5 <5 <5 <5 <5 <5 Barium EG005T:ICP-AES 7440-39-3 mg/kg 10 270 280 300 260 400 370 Beryllium EG005T:ICP-AES 7440-41-7 mg/kg 1 <1 <1 <1 <1 <1 <1 Cadmium EG005T:ICP-AES 7440-43-9 mg/kg 1 5 5 4 4 6 6 Chromium EG005T:ICP-AES 7440-47-3 mg/kg 2 29 28 26 24 29 26 Cobalt EG005T:ICP-AES 7440-48-4 mg/kg 2 9 9 8 8 12 10 Copper EG005T:ICP-AES 7440-50-8 mg/kg 5 42 37 33 32 40 36 Iron EG005T:ICP-AES 7439-89-6 mg/kg 50 110000 101000 83800 92900 133000 121000 Lead EG005T:ICP-AES 7439-92-1 mg/kg 5 11 11 10 5 10 11 Manganese EG005T:ICP-AES 7439-96-5 mg/kg 5 3310 3310 4450 3440 4840 4560 Nickel EG005T:ICP-AES 7440-02-0 mg/kg 2 38 37 36 33 41 38 Vanadium EG005T:ICP-AES 7440-62-2 mg/kg 5 25 24 21 23 25 22 Zinc EG005T:ICP-AES 7440-66-6 mg/kg 5 131 132 111 104 151 133 Mercury EG035T:FIMS 7439-97-6 mg/kg 0.1 3.4 2.7 2.2 2.7 2.8 2.5 Total Phosphorus EK067 mg/kg 2 1000 1130 1000 1170 1140 1400 MEICP85: Borate Silica 7631-86-9 % 0.01 9.33 8.9 7.23 7.88 7.05 6.9 Fusion
Hydroxide Content of Iron Hydroxide (Fe(OH)3) 10.04 9.22 7.65 8.48 12.15 12.15 Total Dry Material Analysed % (Dry weight incl Silica) 30.95 29.66 24.46 24.48 31.04 28.86 Sample Loss at 500 deg 42.30 42.80 34.00 44.90 51.80 40.20 Sample Loss at 1000 deg 57.40 57.20 50.70 57.80 66.70 58.00
Weight % of sample accounted for by analysis 88.35 86.86 75.16 82.28 97.74 86.86
Source: Verolia Water, 2006 ILLAWARRA RESOURCE RECOVERY – IRON BEARING SLUDGES
MultiServ CPCM Rollshop Material Baghouse dust swalf WGEP1 Sample Date 17/01/05 17/01/05 17/01/05 Chem Analysis 01/01/97 01/01/97 XRF (BSL Lab) Unit Fe % 61.70 40.80 43.6 SiO2 % 1.62 1.28 5.4 Al2O3 % 0.65 0.87 1.9 CaO % 0.86 8.85 11.2 P % 0.07 0.50 0.05 Mn % 0.51 0.13 0.30 MGO % 0.37 0.41 1.10 ZN % 2.39 0.15 0.013 K2O % 0.06 0.01 1.80 CL % 0.04 0.06 0.81 TiO2 % 0.19 0.01 0.11 V % 0.03 0.01 0.01 S % 0.11 0.35 0.23
Moisture Content (dried @ 103°C) % 20.1 8.6
Waste Classification Solid Industrial Solid
Total Concentration Unit Arsenic mg/kg 128 62 11 Beryllium mg/kg <1 <1 <1 Cadmium mg/kg 2 7 10 Hexavalent Chromium - Soluble mg/kg <1 <1 <1 Fluoride mg/kg 200 <40 640 Lead mg/kg 228 68 728 Mercury mg/kg <0.1 <0.1 3.2 Molybdenum mg/kg 91 265 17 Nickel mg/kg 194 1200 28 Selenium mg/kg 8 17 18 Silver mg/kg <2 <2 <2 Thorium mg/kg 0.2 <0.1 1.1 Uranium mg/kg 0.1 <0.1 1.8
Leachates Unit Arsenic mg/L <0.1 0.2 <0.1 Beryllium mg/L <0.05 <0.05 <0.05 Cadmium mg/L <0.05 <0.05 <0.05 Hexavalent Chromium mg/L <0.100 <1.00 <0.010 Fluoride mg/L 15.6 2.3 12 Lead mg/L <0.1 <0.1 <0.1 Mercury mg/L <0.0001 0.0001 <0.0001 Molybdenum mg/L <0.1 1.2 <0.1 Nickel mg/L 0.4 6.9 <0.1 Selenium mg/L <0.05 0.15 0.11 Silver mg/L 0.6 <0.1 <0.1
TCLP Leach pH Initial pH pH Unit 7.6 8.9 10.6 Final pH pH Unit 5.3 6.5 7.8 Source: Illawarra Resource Recovery, 2006.
APPENDIX B – LEACHATE ANALYSIS RESULTS
O ANALYTICAL RESULTS O FIELD RESULTS O WATER BALANCE
Once printed this document is an uncontrolled version and should be checked against the electronic version for validity Document:: Thesis Temp2 | Last printed: 6/19/2007 2:46 PM Page 2 of 5 Royal Institute of Technology LEACHATE ANALYSIS - ANALYTICAL Stockholm, 2007
BIOREACTOR 1 Date Parameter Units 18 32 46 68 82 96 109 117 124 131 138 145 152 159 167 173 24-Oct-06 07-Nov-06 21-Nov-06 13-Dec-06 27-Dec-06 10-Jan-08 24-Jan-07 31-Jan-07 07-Feb-07 14-Feb-07 21-Feb-07 28-Feb-07 07-Mar-07 15-Mar-07 22-Mar-07 28-Mar-07 Temp oC pH pH units 5.6 5.7 6.2 7.1 7.4 7.5 7.5 7.6 7.6 7.3 7.4 7.5 7.4 7.5 7.4 7.4 Specific Conductance uS/cm 16000 18000 20000 20000 20000 20000 20000 20000 19000 Vol Fatty Acids mg/L 7700 9400 16000 13000 34000 1300 10 BOD mg/L 12000 19000 18000 11000 6400 2000 1200 870 650 240 COD mg/L 17000 27000 13000 5300 4800 3700 5000 2100 Ammonia mg/L 750 970 1200 1400 1400 1400 1500 1500 1500 1500 TDS mg/L 14000 15000 16000 14000 12000 9800 9300 8500 6800 Sulphate mg/L 6 5 5 5 5 5 150 50 5 16 20 340 17 5 21 5 Sulphide mg/L 1.4 1.7 1.8 4.4 3.4 0.1 3.8 0.9 2.1 1.3 0.5 0.44 0.6 0.3 0.35 0.85 Total Copper ug/L 670 640 510 500 410 320 340 260 290 200 240 210 190 130 180 160 Total Iron mg/L 540 580 430 210 100 53 34 35 40 34 34 31 35 26 29 32 Total Lead ug/L 520 200 160 240 180 170 120 140 170 140 140 130 67 63 68 69 Total Zinc mg/L 3.2 1.8 1.6 1.7 1.4 1.4 1.8 1.9 2.2 1.6 1.4 1.3 1.1 .77 3.3 3.5
BIOREACTOR 2 Date Parameter Units 18 32 46 68 82 96 109 117 124 131 138 145 152 159 167 173 24-Oct-06 07-Nov-06 21-Nov-06 13-Dec-06 27-Dec-06 10-Jan-08 24-Jan-08 31-Jan-08 07-Feb-07 14-Feb-07 21-Feb-07 28-Feb-07 07-Mar-07 15-Mar-07 22-Mar-07 28-Mar-07 Temp oC pH pH units 5.3 5.2 5.3 5.4 5.7 5.8 6.2 6.7 7.4 7.4 7.6 7.6 7.3 7.4 7.3 7.4 Specific Conductance uS/cm 18000 22000 22000 23000 22000 22000 22000 22000 22000 VFA mg/L 10000 12000 23000 23000 26000 15000 2800 BOD mg/L 22000 33000 37000 34000 27000 32000 20000 19000 12000 310 COD mg/L 36000 49000 55000 57000 36000 30000 22000 8200 Ammonia mg/L 930 1300 1400 1600 1700 1700 1700 1700 1700 1600 TDS mg/L 17000 22000 21000 22000 21000 18000 17000 15000 13000 Sulphate mg/L 360 410 440 260 220 140 910 5 200 63 20 3200 2800 2000 430 52 Sulphide mg/L 1.2 0.88 1 0.8 1.8 0.7 14 6.5 18 6.4 3.4 5 60 69 76 76 Total Copper ug/L 140 99 47 42 44 59 600 250 190 140 130 3300 170 2500 1400 1100 Total Iron mg/L 610 720 680 670 560 460 290 84 57 58 50 30 21 21 18 14 Total Lead ug/L 180 130 62 56 48 54 86 58 63 70 66 32 22 36 61 29 Total Zinc mg/L 5.2 1.9 1 0.90 0.6 0.75 46 20 8.2 5.4 3.3 11 31 39 28 23
BIOREACTOR 3 Date Parameter Units 18 32 46 68 82 96 109 117 124 131 138 145 152 159 167 173 24-Oct-06 07-Nov-06 21-Nov-06 13-Dec-06 27-Dec-06 10-Jan-08 24-Jan-08 31-Jan-08 07-Feb-07 14-Feb-07 21-Feb-07 28-Feb-07 07-Mar-07 15-Mar-07 22-Mar-07 28-Mar-07 Temp oC pH pH units 5.5 5.2 5.4 5.4 5.6 5.4 5.5 5.5 5.6 5.6 5.7 5.7 5.8 5.8 5.9 5.9 Specific Conductance uS/cm 22000 27000 31000 33000 32000 32000 32000 32000 32000 VFA mg/L 12000 20000 38000 32000 37000 29000 13000 BOD mg/L 28000 42000 48000 58000 26000 59000 57000 54000 49000 36000 COD mg/L 45000 59000 84000 110000 80000 80000 77000 57000 Ammonia mg/L 1300 1800 2100 2400 2500 2500 2500 2500 2700 2400 TDS mg/L 23000 28000 31000 40000 40000 41000 36000 37000 31000 Sulphate mg/L 270 410 330 520 540 710 950 1600 1000 1500 1600 2900 3700 4300 4500 4400 Sulphide mg/L 2.3 0.78 0.7 0.2 1 0.2 0.7 1 1.4 0.8 0.2 0.4 0.7 1.8 1 0.6 Total Copper ug/L 200 150 85 52 36 13 13 21 33 46 41 920 790 670 640 880 Total Iron mg/L 720 830 750 830 1000 910 790 980 1000 970 1000 960 980 920 900 890 Total Lead ug/L 210 170 100 85 76 40 16 32 37 32 68 62 45 51 77 57 Total Zinc mg/L 6 2.5 2.7 2.2 5.6 2.7 13 18 17 14 12 430 88 110 100 120
Page 1 of 3 Royal Institute of Technology LEACHATE ANALYSIS - ANALYTICAL Stockholm, 2007
BIOREACTOR 4 Date Parameter Units 18 32 46 68 82 96 109 117 124 131 138 145 152 159 167 173 24-Oct-06 07-Nov-06 21-Nov-06 13-Dec-06 27-Dec-06 10-Jan-08 24-Jan-08 31-Jan-08 07-Feb-07 14-Feb-07 21-Feb-07 28-Feb-07 07-Mar-07 15-Mar-07 22-Mar-07 28-Mar-07 Temp oC pH pH units 5.3 5.2 5.2 5.2 5.3 5.2 5.4 5.4 5.5 5.4 5.5 5.4 5.4 5.4 5.4 5.3 Specific Conductance uS/cm 19000 23000 25000 27000 27000 27000 28000 28000 28000 VFA mg/L 11000 16000 32000 28000 36000 14000 6800 BOD mg/L 25000 36000 39000 49000 47000 51000 52000 51000 44000 35000 COD mg/L 39000 52000 75000 85000 70000 67000 66000 55000 Ammonia mg/L 960 1300 1600 1700 1900 1800 1900 1900 2100 1900 TDS mg/L 19000 25000 25000 31000 32000 33000 30000 30000 31000 Sulphate mg/L 650 770 620 870 630 630 1100 1800 1400 1800 1500 3700 4700 5900 5800 6400 Sulphide mg/L 1.1 0.18 0.58 0.66 0.4 0.02 2.3 0.02 0.5 0.1 0.02 2 1.6 0.4 1 0.4 Total Copper ug/L 120 82 47 30 23 21 77 15 26 40 24 830 550 860 570 810 Total Iron mg/L 570 770 790 830 880 690 710 800 800 730 810 860 890 810 810 970 Total Lead ug/L 170 130 65 50 45 45 43 33 33 67 36 90 77 120 150 150 Total Zinc mg/L 13 6.9 4.4 3.5 5.4 4.7 24 27 28 25 26 190 210 290 260 340
BIOREACTOR 5 Date Parameter Units 13 35 49 62 77 84 91 98 105 112 119 126 134 140 21-Nov-06 13-Dec-06 27-Dec-06 10-Jan-08 24-Jan-07 31-Jan-07 07-Feb-07 14-Feb-07 21-Feb-07 28-Feb-07 07-Mar-07 15-Mar-07 22-Mar-07 28-Mar-07 Temp oC pH pH units 5.8 5.4 5.5 5.4 5.3 5.4 5.5 5.5 5.5 5.5 5.2 5.2 5.3 5.1 Specific Conductance uS/cm 13000 16000 16000 17000 16000 17000 17000 VFA mg/L 11000 14000 26000 16000 5700 BOD mg/L 13000 20000 24000 28000 26000 22000 20000 14000 COD mg/L 34000 43000 29000 30000 31000 20000 Ammonia mg/L 350 630 680 670 610 620 680 460 TDS mg/L 12000 17000 19000 19000 18000 18000 23000 Sulphate mg/L 410 230 74 140 1800 1900 2300 1700 1500 5200 6800 6400 7200 8000 Sulphide mg/L 1.3 0.9 0.7 0.02 0.2 0.7 1.4 0.15 0.02 0.02 0.1 0.7 0.04 0.15 Total Copper ug/L 500 120 61 39 640 360 240 140 110 2300 1700 14000 14000 26000 Total Iron mg/L 110 400 650 550 600 690 800 740 740 720 710 710 720 730 Total Lead ug/L 280 130 51 33 190 100 82 73 53 440 450 580 690 540 Total Zinc mg/L 8.9 1.8 0.8 0.57 220 170 110 75 58 430 610 590 600 710
BIOREACTOR 6 Date Parameter Units 13 35 49 62 77 84 91 98 105 112 119 126 134 140 21-Nov-06 13-Dec-06 27-Dec-06 10-Jan-08 24-Jan-07 31-Jan-07 07-Feb-07 14-Feb-07 21-Feb-07 28-Feb-07 07-Mar-07 15-Mar-07 22-Mar-07 28-Mar-07 Temp oC pH pH units 5.5 5.1 5.3 5.3 5.2 5.3 5.4 5.4 5.5 5.6 5.3 5.3 5.2 5.2 Specific Conductance uS/cm 8500 13000 14000 15000 15000 15000 15000 VFA mg/L 6600 18000 19000 14000 6300 BOD mg/L 78000 17000 19000 18000 18000 17000 19000 10000 COD mg/L 27000 34000 26000 1300 25000 21000 Ammonia mg/L 180 390 420 440 410 400 430 310 TDS mg/L 8000 16000 16000 17000 18000 18000 21000 Sulphate mg/L 530 760 640 640 1800 2100 1700 1700 1500 4800 5200 5900 4900 5800 Sulphide mg/L 0.33 0.9 0.95 0.02 0.3 0.1 1.7 0.4 0.6 0.02 0.5 0.95 0.24 0.2 Total Copper ug/L 450 160 110 110 330 220 160 140 130 2100 1300 11000 13000 17000 Total Iron mg/L 61 210 310 360 400 490 510 530 490 430 520 450 470 470 Total Lead ug/L 100 90 64 55 170 120 83 66 65 160 210 130 220 140 Total Zinc mg/L 34 38 47 45 230 230 150 140 110 400 550 520 560 610
Page 2 of 3 Royal Institute of Technology LEACHATE ANALYSIS - ANALYTICAL Stockholm, 2007
ACID MINE DRAINAGE Date Parameter Units 19-Jan-07 Temp oC pH pH units 2.9 Specific Conductance uS/cm 16000 VFA mg/L - BOD mg/L - COD mg/L - Ammonia mg/L - TDS mg/L 32000 Sulphate mg/L 20000 Sulphide mg/L - Total Copper ug/L 48000 Total Iron mg/L 640 Total Lead ug/L 1500 Total Zinc mg/L 1100
Page 3 of 3 pH EVOLUTION
Point Continuous 8 Sulphate Load Sulphate Load
7.5
7
6.5 Bioreactor 1 Bioreactor 2 Bioreactor 3 6 Bioreactor 4
pHUnits Bioreactor 5 5.5 Bioreactor 6
5
4.5
4
8 2 6 8 2 6 1 3 4 6 8 9 04 09 17 24 31 38 45 52 59 67 73 1 1 1 1 1 1 1 1 1 1 1 Time (Days) Royal Institute of Technology LEACHATE ANALYSIS - FIELD Stockholm, 2007
Day No. 1 - 4 Parameter Units 5 6 10 11 12 13 14 17 18 20 21 24 25 26 27 28 31 32 34 40 42 11/10/06 12/10/06 16/10/06 17/10/06 18/10/06 19/10/06 20/10/06 23/10/06 24/10/06 26/10/06 27/10/06 30/10/06 31/10/06 1/11/06 2/11/06 3/11/06 6/11/06 7/11/06 9/11/06 15/11/06 17/11/06 Column 1 Temp oC 19.00 19.00 17.00 17.20 19.69 18.25 18.84 14.44 15.14 16.83 17.77 14.62 16.19 16.98 18.66 18.13 17.81 17.48 16.68 16.19 16.19 Specific Conductance mS/cm 9.0 2.1 11.3 12.1 12.7 13.4 14.2 16.0 15.5 12.8 12.0 9.8 17.1 17.4 17.7 17.2 17.6 17.8 17.5 18.1 18.1 DO mg/L 0.79 0.71 0.56 0.64 0.48 0.40 1.52 1.00 0.59 0.90 1.20 1.45 0.80 0.54 0.38 0.45 0.84 0.83 0.64 0.55 0.55 pH Units 6.00 5.76 5.76 5.70 5.62 5.64 5.66 5.83 5.83 5.92 5.83 5.90 5.96 5.87 5.84 5.72 5.76 5.78 5.82 5.95 5.95 Salinity PPS 5.01 1.06 6.37 6.82 7.24 7.64 8.13 8.61 8.93 7.28 6.80 5.46 10.01 10.14 10.35 10.03 10.28 10.34 10.20 10.58 10.58 ORP mV -5 -10 -6 -2 4 -4 -55 25 65 -84 -117 -49 -45 -94 -137 -97 -189 -83 -94 -121 -121 Column 2 Temp oC 18.00 18.00 17.00 17.00 19.35 18.33 18.90 14.11 14.74 16.72 17.76 14.39 16.03 16.80 18.39 17.96 17.73 17.37 16.33 15.95 13.76 Specific Conductance mS/cm 5.9 6.8 10.8 6.4 14.2 15.2 13.0 17.2 18.0 19.7 19.6 20.2 20.5 13.8 21.1 19.2 20.9 21.2 19.2 20.1 20.5 DO mg/L 0.60 1.04 0.80 0.70 0.52 0.48 2.14 0.74 0.54 0.68 0.70 1.04 0.60 0.66 0.42 0.67 0.56 0.45 0.53 0.42 0.61 pH Units 5.36 5.16 5.26 5.26 5.25 5.28 5.34 5.45 5.42 5.49 5.47 5.54 5.48 5.45 5.43 5.30 5.32 5.32 5.26 5.35 5.39 Salinity PPS 3.19 3.67 6.05 3.17 8.18 8.78 7.42 9.98 10.50 11.28 11.62 11.89 12.04 7.87 12.53 11.30 12.39 12.58 11.28 11.84 12.07 ORP mV 69 51 48 51 33 34 2 79 92 -71 -104 -22 -36 -64 -110 -69 -154 -62 -67 -77 -203 Column 3 Temp oC 17.00 19.39 18.05 18.74 13.68 14.74 16.58 17.46 14.15 15.85 16.77 18.29 17.86 17.66 17.30 16.18 15.84 13.73 Specific Conductance mS/cm 12.2 6.9 5.5 18.0 19.5 21.2 23.3 23.8 13.0 24.6 25.3 25.8 5.1 22.9 26.6 27.2 27.9 28.6 DO mg/L 0.53 0.36 0.35 2.30 0.84 0.30 0.28 0.20 0.38 0.25 0.23 0.17 0.40 0.26 0.20 0.19 0.19 0.30 pH Units 5.52 5.45 5.50 5.60 5.63 5.80 5.63 5.58 5.62 5.57 5.54 5.50 5.37 5.35 5.38 5.36 5.40 5.45 Salinity PPS 6.88 3.77 2.94 10.61 11.43 12.53 13.92 14.27 7.27 14.76 15.24 15.60 2.76 13.68 16.11 16.48 16.93 17.48 ORP mV 38 8 7 -13 50 61 -96 -127 -36 -43 -61 -120 -71 -158 -58 -68 -64 -156 Column 4 Temp oC 17.00 16.50 20.13 17.72 18.44 12.96 14.28 16.26 17.17 13.54 15.50 16.41 18.08 17.62 17.17 17.04 15.85 15.54 13.06 Specific Conductance mS/cm 8.4 10.4 12.6 14.2 13.0 17.5 17.9 1.3 20.1 1.4 21.3 21.8 22.3 21.7 22.4 22.7 22.8 23.2 23.8 DO mg/L 0.74 0.50 0.33 0.38 2.97 0.32 0.30 0.49 0.30 0.70 0.31 0.26 0.19 0.32 0.33 0.30 0.28 0.15 0.26 pH Units 5.16 5.15 5.19 5.27 5.43 5.49 5.67 5.50 5.47 5.50 5.44 5.41 5.38 5.25 5.24 5.26 5.22 5.25 5.27 Salinity PPS 4.64 5.79 7.16 8.17 7.39 10.15 10.36 0.62 11.57 0.66 12.61 12.95 13.30 12.90 13.35 13.54 13.59 13.90 14.24 ORP mV 58 52 39 34 -4 89 103 -63 -100 -3 -14 -22 -99 -40 -122 -38 -47 -42 -144 Day No. 5 & 6 0 1 7 9 Column 5 Temp oC 12.18 Specific Conductance mS/cm 11.2 DO mg/L 0.30 pH Units 5.70 Salinity PPS 6.30 ORP mV -47 Column 6 Temp oC 12.00 Specific Conductance mS/cm 6.0 DO mg/L 0.99 pH Units 5.47 Salinity PPS 3.19 ORP mV -45 Royal Institute of Technology LEACHATE ANALYSIS - FIELD Stockholm, 2007
Day No. 1 - 4 Parameter Units 45 46 47 49 52 54 67 68 69 75 94 96 101 105 108 110 115 117 119 122 20/11/06 21/11/06 22/11/06 24/11/06 27/11/06 29/11/06 12/12/06 13/12/06 14/12/06 20/12/06 8/01/07 10/01/07 15/01/07 19/01/07 22/01/07 24/01/07 29/01/07 31/01/07 2/02/07 5/02/07 Column 1 Temp oC 18.31 20.61 23.07 21.62 19.40 23.44 20.21 20.40 21.24 18.06 21.77 19.64 20.74 23.55 22.06 24.02 20.26 22.05 20.62 22.87 Specific Conductance mS/cm 18.9 19.7 18.8 19.2 19.5 19.8 20.3 19.9 19.3 19.3 19.2 19.1 19.0 18.7 19.4 19.6 18.9 19.0 18.2 18.4 DO mg/L 0.49 0.25 0.30 0.13 0.25 0.25 0.32 0.13 0.27 0.25 0.39 0.42 0.19 0.48 0.40 0.28 0.25 0.20 0.10 0.16 pH Units 6.06 6.17 6.29 6.49 6.79 6.76 7.09 7.03 7.04 7.30 7.42 7.49 7.50 7.45 7.41 7.42 7.48 7.50 7.41 7.40 Salinity PPS 11.11 11.59 11.11 1.28 11.51 11.76 12.09 11.78 11.41 11.37 11.29 11.26 11.21 11.12 11.48 11.64 11.20 11.23 10.76 10.85 ORP mV -114 -177 -296 -214 -146 -69 -198 54 109 118 -181 73 -228 -157 -252 -289 -194 -225 -227 -223 Column 2 Temp oC 18.07 20.57 22.61 21.02 19.24 23.23 19.76 19.89 21.62 18.19 21.58 19.64 20.74 22.76 22.28 24.06 20.41 22.16 20.79 23.07 Specific Conductance mS/cm 21.1 22.0 19.8 20.6 21.1 21.4 22.0 21.5 21.1 21.5 21.2 21.5 21.4 21.7 21.2 21.5 20.8 20.8 20.1 20.4 DO mg/L 0.52 0.30 0.26 0.26 0.27 0.23 0.20 0.20 0.23 0.25 0.45 0.37 0.20 0.40 0.23 0.15 0.13 0.18 0.08 0.09 pH Units 5.34 5.39 5.44 5.52 5.58 5.42 5.55 5.47 5.51 5.77 5.80 5.91 6.00 6.16 6.12 6.18 6.59 6.70 6.94 7.20 Salinity PPS 12.52 13.08 11.75 12.25 12.54 12.86 13.07 13.01 12.64 12.28 12.58 12.81 12.56 12.99 12.65 12.89 12.37 12.39 11.92 2.11 ORP mV -90 -177 -273 -192 -216 -28 -153 101 185 197 -127 101 -330 -180 -182 -229 -353 -329 -275 -236 Column 3 Temp oC 17.87 20.87 22.23 20.80 19.05 22.81 19.91 19.72 21.10 18.01 21.46 19.34 20.76 22.49 21.92 23.68 20.00 21.91 20.57 22.85 Specific Conductance mS/cm 29.2 30.6 30.8 31.2 31.2 31.6 31.7 32.0 32.2 31.8 31.5 31.2 31.4 31.8 31.2 31.3 30.6 30.8 30.4 30..4 DO mg/L 0.24 0.18 0.15 0.13 0.14 0.17 0.16 0.20 0.25 0.22 0.29 0.33 0.20 0.29 0.21 0.10 0.09 0.15 0.07 0.11 pH Units 5.37 5.47 5.51 5.57 5.61 5.44 5.58 5.48 5.46 5.60 5.54 5.53 5.59 5.73 5.73 5.66 5.94 5.86 5.85 5.95 Salinity PPS 17.85 18.80 19.04 19.28 19.23 19.61 19.52 19.88 19.90 19.61 19.57 19.24 19.41 19.66 19.31 19.42 18.85 18.97 18.73 18.50 ORP mV -55 -131 -264 -192 -222 -31 -181 123 182 196 -94 112 -210 -156 -208 -253 -177 -149 -148 -158 Column 4 Temp oC 17.53 20.52 22.21 20.41 18.62 22.62 19.36 19.69 20.73 17.38 21.37 19.34 20.19 22.13 21.45 23.31 19.58 21.57 20.10 22.51 Specific Conductance mS/cm 24.1 25.4 25.6 25.8 26.3 26.5 26.2 26.2 26.1 25.8 26.6 26.3 26.3 26.6 26.2 26.5 21.1 26.0 26.4 25.5 DO mg/L 0.22 0.14 0.14 0.17 0.15 0.15 0.13 0.21 0.24 0.21 0.33 0.46 0.21 0.22 0.17 0.12 0.09 0.14 0.09 0.13 pH Units 5.20 5.29 5.33 5.38 5.40 5.24 5.33 5.27 5.24 5.37 5.26 5.31 5.37 5.51 5.52 5.48 5.74 5.71 5.70 5.75 Salinity PPS 14.47 15.38 15.55 15.64 15.94 16.09 15.89 15.89 15.85 15.58 16.19 15.95 15.97 16.28 15.93 16.17 12.55 15.80 16.03 15.24 ORP mV -51 -139 -285 -193 -221 -36 -127 138 189 196 -62 133 -159 -150 -193 -209 -159 -130 -133 -143 Day No. 5 & 6 12 13 14 16 19 21 34 35 36 42 61 63 68 72 75 77 82 84 86 89 Column 5 Temp oC 17.00 19.87 21.80 19.84 17.92 21.99 18.64 18.95 20.14 16.96 20.96 18.57 19.59 21.26 20.61 22.50 18.80 20.65 19.30 21.75 Specific Conductance mS/cm 11.6 12.7 12.3 12.7 13.2 14.3 15.1 15.7 14.0 15.3 15.7 16.0 15.2 15.5 15.4 15.7 15.7 16.0 15.8 16.0 DO mg/L 0.80 0.40 0.74 0.54 0.57 0.48 0.28 0.47 0.37 0.30 0.68 0.44 0.42 0.75 0.42 0.55 0.16 0.53 0.44 0.55 pH Units 5.66 5.74 5.76 5.74 5.69 5.48 5.50 5.46 5.41 5.58 5.39 5.41 5.45 5.48 5.41 5.35 5.64 5.64 5.65 5.70 Salinity PPS 6.53 7.22 6.98 7.26 7.82 8.24 8.72 9.10 8.03 8.83 9.12 9.38 8.76 8.99 8.92 9.13 9.09 9.30 9.16 9.31 ORP mV -33 -126 -252 -257 -265 -100 -148 147 181 173 -55 126 -190 -177 -119 -117 -82 -54 -74 -67 Column 6 Temp oC 17.47 20.66 22.43 19.98 17.89 22.22 18.12 19.32 20.38 16.86 20.60 18.75 19.67 21.24 20.81 22.68 18.82 21.03 19.36 21.91 Specific Conductance mS/cm 7.3 8.5 8.6 9.5 10.4 11.2 12.5 13.0 11.8 13.0 14.0 14.3 14.2 14.4 14.4 14.8 14.4 14.8 14.3 14.6 DO mg/L 0.20 0.17 0.66 0.29 0.68 0.51 0.46 0.45 0.53 0.67 0.70 0.57 0.48 0.50 0.50 0.48 0.19 0.46 0.44 0.45 pH Units 5.39 5.52 5.57 5.54 5.47 5.24 5.20 5.21 5.21 5.40 5.24 5.29 5.32 5.35 5.29 5.29 5.58 5.63 5.61 5.66 Salinity PPS 4.01 4.72 4.74 5.27 5.83 6.34 7.11 7.40 6.67 7.39 8.05 8.21 8.14 8.32 8.28 8.58 8.30 8.55 8.23 8.43 ORP mV 28 -104 -214 -169 -202 -21 -30 169 190 181 14 126 -71 -53 -105 -118 -73 -44 -73 -61 Royal Institute of Technology LEACHATE ANALYSIS - FIELD Stockholm, 2007
Day No. 1 - 4 Parameter Units 124 126 129 131 133 138 140 143 145 148 150 152 154 157 159 164 7/02/07 9/02/07 12/02/07 14/02/07 16/02/07 21/02/07 23/02/07 26/02/07 28/02/07 3/03/07 5/03/07 7/03/07 9/03/07 12/03/07 14/03/07 19/03/07 Column 1 Temp oC 22.35 21.58 19.74 19.40 20.94 22.38 20.09 20.19 20.12 19.13 19.07 20.32 19.81 18.25 20.10 19.78 Specific Conductance mS/cm 18.4 18.0 18.0 18.0 17.6 19.0 18.2 18.4 18.6 17.7 18.2 18.4 17.7 17.9 17.4 17.6 DO mg/L 0.14 0.11 0.08 0.29 0.26 0.21 0.06 0.28 0.20 0.27 0.23 0.42 0.32 0.19 0.23 0.18 pH Units 7.55 7.44 7.54 7.46 7.42 7.05 7.03 7.02 7.10 7.02 7.06 7.08 7.10 7.10 7.08 7.05 Salinity PPS 10.91 3.27 10.56 10.55 10.32 11.23 10.70 10.82 10.95 10.42 10.68 10.82 10.43 10.42 10.18 10.30 ORP mV -243 -288 -305 -195 -205 -207 102 -206 -173 -179 -214 -156 -200 -192 -196 -224 Column 2 Temp oC 22.56 21.74 19.87 19.67 21.05 22.38 20.80 20.21 20.38 19.58 19.12 20.36 19.81 18.07 20.97 19.97 Specific Conductance mS/cm 20.8 20.0 20.4 20.2 19.5 21.5 21.0 16.9 23.5 23.2 23.0 23.2 23.0 23.0 22.6 23.0 DO mg/L 0.07 0.07 0.07 0.08 0.12 0.14 0.10 0.12 0.13 0.12 0.13 0.17 0.19 0.11 0.07 0.07 pH Units 7.35 7.35 7.67 7.57 7.46 7.13 6.98 7.17 7.16 7.10 7.13 7.02 7.05 6.97 6.96 6.90 Salinity PPS 12.40 11.87 12.03 11.97 11.54 12.85 13.57 9.80 14.12 13.98 13.77 13.93 8.62 13.82 13.55 13.86 ORP mV -267 -278 -292 -223 -214 -226 -182 -190 -153 -390 -415 -397 -392 -395 -393 -387 Column 3 Temp oC 22.43 21.54 19.77 19.39 20.67 22.04 21.14 20.04 20.27 19.33 18.98 20.33 19.55 18.08 20.45 19.65 Specific Conductance mS/cm 30.6 30.0 30.0 29.6 29.7 31.8 32.0 32.1 32.2 32.2 31.8 32.5 32.1 32.5 31.5 31.6 DO mg/L 0.07 0.09 0.07 0.10 0.11 0.13 0.22 0.12 0.21 0.12 0.15 0.15 0.18 0.29 0.20 0.16 pH Units 6.03 6.06 6.05 6.06 6.06 5.61 5.67 5.71 5.75 5.79 5.91 5.83 6.01 5.98 5.98 5.91 Salinity PPS 18.91 18.50 18.50 18.16 18.26 19.72 19.82 19.87 20.01 19.92 19.63 20.15 19.92 20.08 19.47 19.52 ORP mV -184 -187 -207 -141 -140 -123 -66 -143 -106 -179 -174 -127 -154 -105 -133 -116 Column 4 Temp oC 22.02 21.11 19.44 18.99 20.86 21.65 20.26 19.58 19.86 18.68 18.38 19.90 19.09 17.47 20.68 19.37 Specific Conductance mS/cm 10.7 5.0 26.1 25.9 26.2 28.5 28.1 28.0 28.0 27.6 26.9 28.5 27.6 28.3 26.8 28.4 DO mg/L 0.11 0.07 0.07 0.09 0.11 0.16 0.35 0.19 0.23 0.16 0.38 0.19 0.26 0.38 0.33 0.20 pH Units 5.80 5.83 5.81 5.82 5.81 5.35 5.47 5.38 5.44 5.41 5.54 5.49 5.64 5.56 5.54 5.50 Salinity PPS 6.06 2.64 15.82 15.68 18.92 17.47 17.17 17.09 17.60 16.80 16.33 17.43 16.81 17.17 16.38 17.35 ORP mV -160 -164 -182 -127 -130 -96 -49 -130 -83 -143 -139 -99 -108 -66 -60 -83 Day No. 5 & 6 91 93 96 98 100 105 107 110 112 115 117 119 121 124 126 131 Column 5 Temp oC 21.13 20.20 18.74 18.91 19.98 21.54 19.45 18.94 19.30 18.16 17.84 19.20 18.64 16.80 20.21 18.84 Specific Conductance mS/cm 16.2 15.7 15.9 15.8 13.3 17.0 17.5 18.5 18.4 18.0 11.5 18.2 17.6 17.6 12.8 17.8 DO mg/L 0.39 0.24 0.37 0.28 0.36 0.57 0.80 0.51 0.50 0.23 0.50 0.23 0.47 0.46 0.39 0.32 pH Units 5.74 5.77 5.76 5.78 5.76 5.33 5.21 5.35 5.40 5.41 5.40 5.31 5.50 5.32 5.42 5.28 Salinity PPS 9.43 9.11 9.22 9.16 7.59 9.88 10.24 10.80 10.87 10.54 6.50 10.68 10.28 16.27 7.17 10.36 ORP mV -79 -92 -133 -57 -59 -33 163 12 20 -24 64 147 119 165 155 157 Column 6 Temp oC 21.22 20.08 18.66 18.88 19.78 21.54 19.34 19.07 19.49 18.11 17.96 19.31 18.47 16.00 20.01 18.87 Specific Conductance mS/cm 14.8 14.4 14.6 14.7 12.1 15.9 15.7 17.0 17.0 14.7 11.6 16.8 16.0 16.6 11.9 16.5 DO mg/L 0.04 0.30 0.64 0.74 1.20 0.62 0.49 0.61 0.70 0.29 0.46 0.50 0.46 0.45 0.31 0.47 pH Units 5.70 5.74 5.74 5.78 5.77 5.34 5.19 5.55 5.48 5.49 5.48 5.36 5.53 5.46 5.45 5.23 Salinity PPS 8.55 8.33 8.37 8.40 6.93 9.25 9.18 9.96 9.92 8.44 6.52 9.79 9.28 9.64 6.63 9.54 ORP mV -73 -80 -89 -42 -45 -29 211 -3 49 29 82 156 142 158 162 161 Royal Institute of Technology Stockholm, 2007
BIOREACTOR 1 - WATER BALANCE
55.0 53.0 51.0 49.0 47.0 45.0 43.0 41.0 39.0 37.0 35.0 33.0 31.0 29.0 Cumulative Water Balance 27.0 Leachate Recirculation 25.0 23.0 21.0 Volume (Litres) 19.0 17.0 15.0 13.0 11.0 9.0 7.0 5.0 3.0 1.0 -1.0 0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 105 110 115 120 125 130 135 140 145 150 155 160 165 170 Time (Days)
BIOREACTOR 2 - WATER BALANCE
Point Continuous Sulphate Load Sulphate Load 55.0 53.0 51.0 49.0 47.0 45.0 43.0 41.0 39.0 37.0 35.0 33.0 31.0 29.0 Cumulative Water Balance 27.0 Leachate Recirculation 25.0 23.0 21.0 Volume (Litres) 19.0 17.0 15.0 13.0 11.0 9.0 7.0 5.0 3.0 1.0 -1.0 0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 105 110 115 120 125 130 135 140 145 150 155 160 165 170 Time (Days) Royal Institute of Technology Stockholm, 2007
BIOREACTOR 3 - WATER BALANCE Point Continuous Sulphate Load Sulphate Load 55.0 53.0 51.0 49.0 47.0 45.0 43.0 41.0 39.0 37.0 35.0 33.0 31.0 29.0 Cumulative Water Balance 27.0 Leachate Recirculation 25.0 23.0 21.0 Volume (Litres) 19.0 17.0 15.0 13.0 11.0 9.0 7.0 5.0 3.0 1.0 -1.0 0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 105 110 115 120 125 130 135 140 145 150 155 160 165 170 Time (Days)
BIOREACTOR 4 - WATER BALANCE Point Continuous 55.0 Sulphate Load Sulphate Load 53.0 51.0 49.0 47.0 45.0 43.0 41.0 39.0 37.0 35.0 33.0 31.0 29.0 Cumulative Water Balance 27.0 Leachate Recirculation 25.0 23.0 21.0 Volume (Litres) 19.0 17.0 15.0 13.0 11.0 9.0 7.0 5.0 3.0 1.0 -1.0 0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 105 110 115 120 125 130 135 140 145 150 155 160 165 170 Time Days) Royal Institute of Technology Stockholm, 2007
BIOREACTOR 5 - WATER BALANCE Point Continuous Sulphate Load Sulphate Load 54.0 52.0 50.0 48.0 46.0 44.0 42.0 40.0 38.0 36.0 34.0 32.0 30.0 28.0 Cumulative Water Balance 26.0 Leachate Recirculation 24.0 22.0
Volume (Litres) 20.0 18.0 16.0 14.0 12.0 10.0 8.0 6.0 4.0 2.0 0.0
0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 105 110 115 120 125 130 135 140 Time (Days)
BIOREACTOR 6 - WATER BALANCE Point Continuous Sulphate Load Sulphate Load 54.0 52.0 50.0 48.0 46.0 44.0 42.0 40.0 38.0 36.0 34.0 32.0 30.0 Cumulative Water 28.0 Balance 26.0 Leachate Recirculation 24.0 22.0
Volume (Litres) 20.0 18.0 16.0 14.0 12.0 10.0 8.0 6.0 4.0 2.0 0.0
0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 105 110 115 120 125 130 135 140 Time (Days)
APPENDIX C – LFG ANALYSIS RESULTS
O ANALYTICAL RESULTS O FIELD RESULTS
Once printed this document is an uncontrolled version and should be checked against the electronic version for validity Document:: Thesis Temp2 | Last printed: 6/19/2007 2:46 PM Page 3 of 5 Royal Institute of Technology Stockholm, 2007
Hydrogen Sulphide - Dräger Tube Analysis
Tube Information Date Time Sampling Atm. Pressure Correction Tube Brand Element Range Units No. Pumps Result Adjusted Comments Point (hPa = mBar) Factor on tube Result All samples are collected in 3lt bag 14/02/2007 15:35 C1 929 1013 Dräger H2S 0.5 to 15 ppm 10 2 2.2 Tested from Tedlar bags 21/02/2007 11:30 C1 932 1013 Dräger H2S 0.5 to 15 ppm 10 4 4.3 Tested from Tedlar bags 23/02/2007 14:30 C1 928 1013 Dräger H2S 0.5 to 15 ppm 10 0.5 0.5 Tested from Tedlar bags 26/02/2007 14:00 C1 929 1013 Dräger H2S 0.5 to 15 ppm 10 4 4.4 Tested from Tedlar bags 28/02/2007 14:00 C1 922 1013 Dräger H2S 0.5 to 15 ppm 10 4 4.4 Tested from Tedlar bags 02/03/2007 9:30 C1 920 1013 Dräger H2S 0.5 to 15 ppm 10 5 5.5 Tested from Tedlar bags 05/03/2007 11:20 C1 923 1013 Dräger H2S 0.5 to 15 ppm 10 4 4.4 Tested from Tedlar bags 07/03/2007 12:00 C1 922 1013 Dräger H2S 0.5 to 15 ppm 10 5 5.5 Tested from Tedlar bags 09/03/2007 12:30 C1 920 1013 Dräger H2S 0.5 to 15 ppm 10 4 4.4 Tested from Tedlar bags 12/03/2007 15:35 C1 924 1013 Dräger H2S 0.5 to 15 ppm 10 4 4.4 Tested from Tedlar bags 14/03/2007 16:00 C1 926 1013 Dräger H2S 0.5 to 15 ppm 10 3 3.3 Tested from Tedlar bags 19/03/2007 14:00 C1 928 1013 Dräger H2S 0.5 to 15 ppm 10 5 5.5 Tested from Tedlar bags 22/03/2007 11:00 C1 932 1013 Dräger H2S 0.5 to 15 ppm 10 4.5 4.9 Tested from Tedlar bags 26/03/2007 16:30 C1 933 1013 Dräger H2S 0.5 to 15 ppm 10 5 5.4 Tested from Tedlar bags
14/02/2007 15:35 C2 929 1013 Dräger H2S 0.5 to 15 ppm 10 3 3.3 Tested from Tedlar bags 21/02/2007 11:30 C2 932 1013 Dräger H2S 0.5 to 15 ppm 10 8.5 9.2 Tested from Tedlar bags 23/02/2007 14:30 C2 928 1013 Dräger H2S 0.5 to 15 ppm 10 0.5 0.5 Tested from Tedlar bags 26/02/2007 14:00 C2 929 1013 Dräger H2S 0.5 to 15 ppm 10 0.5 0.5 Tested from Tedlar bags 28/02/2007 14:00 C2 922 1013 Dräger H2S 0.5 to 15 ppm 10 0.5 0.5 Tested from Tedlar bags 02/03/2007 9:30 C2 920 1013 Dräger H2S 0.5 to 15 ppm 10 9 9.9 Tested from Tedlar bags 05/03/2007 11:20 C2 923 1013 Dräger H2S 5 to 600 ppm 10 38 41.7 Tested from Tedlar bags 07/03/2007 12:00 C2 922 1013 Dräger H2S 5 to 600 ppm 10 19 20.9 Tested from Tedlar bags 09/03/2007 12:30 C2 920 1013 Dräger H2S 5 to 600 ppm 1 120 132.1 Tested from Tedlar bags 12/03/2007 15:35 C2 924 1013 Dräger H2S 5 to 600 ppm 1 230 252.2 Tested from Tedlar bags 14/03/2007 16:00 C2 926 1013 Dräger H2S 5 to 600 ppm 1 520 568.9 Tested from Tedlar bags 19/03/2007 14:00 C2 928 1013 Dräger H2S 5 to 600 ppm 1 510 556.7 Tested from Tedlar bags 22/03/2007 11:00 C2 932 1013 Dräger H2S 5 to 600 ppm 1 500 543.5 Tested from Tedlar bags 26/03/2007 16:30 C2 933 1013 Dräger H2S 100 to 2000 ppm 1 1620 1758.9 Tested from Tedlar bags
14/02/2007 15:35 C3 929 1013 Dräger H2S 0.5 to 15 ppm 10 0.5 0.5 Tested from Tedlar bags 21/02/2007 11:30 C3 932 1013 Dräger H2S 0.5 to 15 ppm 10 1.5 1.6 Tested from Tedlar bags 23/02/2007 14:30 C3 928 1013 Dräger H2S 0.5 to 15 ppm 10 0.5 0.5 Tested from Tedlar bags 26/02/2007 14:00 C3 929 1013 Dräger H2S 0.5 to 15 ppm 10 0.5 0.5 Tested from Tedlar bags 28/02/2007 14:00 C3 922 1013 Dräger H2S 0.5 to 15 ppm 10 0.5 0.5 Tested from Tedlar bags 02/03/2007 9:30 C3 920 1013 Dräger H2S 0.5 to 15 ppm 10 0.5 0.6 Tested from Tedlar bags 05/03/2007 11:20 C3 923 1013 Dräger H2S 0.5 to 15 ppm 10 0.5 0.5 Tested from Tedlar bags 07/03/2007 12:00 C3 922 1013 Dräger H2S 0.5 to 15 ppm 10 0.5 0.5 Tested from Tedlar bags 09/03/2007 12:30 C3 920 1013 Dräger H2S 0.5 to 15 ppm 10 0.5 0.6 Tested from Tedlar bags 12/03/2007 15:35 C3 924 1013 Dräger H2S 0.5 to 15 ppm 10 0.5 0.5 Tested from Tedlar bags 14/03/2007 16:00 C3 926 1013 Dräger H2S 0.5 to 15 ppm 10 0.5 0.5 Tested from Tedlar bags 19/03/2007 14:00 C3 928 1013 Dräger H2S 0.5 to 15 ppm 10 0.5 0.5 Tested from Tedlar bags 22/03/2007 11:00 C3 932 1013 Dräger H2S 0.5 to 15 ppm 10 0.5 0.5 Tested from Tedlar bags 26/03/2007 16:30 C3 933 1013 Dräger H2S 0.5 to 15 ppm 10 0.5 0.5 Tested from Tedlar bags
Page 1 of 2 Royal Institute of Technology Stockholm, 2007
Hydrogen Sulphide - Dräger Tube Analysis
Tube Information Date Time Sampling Atm. Pressure Correction Tube Brand Element Range Units No. Pumps Result Adjusted Comments Point (hPa = mBar) Factor on tube Result All samples are collected in 3lt bag 14/02/2007 15:35 C4 929 1013 Dräger H2S 0.5 to 15 ppm 10 0.5 0.5 Tested from Tedlar bags 21/02/2007 11:30 C4 932 1013 Dräger H2S 0.5 to 15 ppm 10 2 2.2 Tested from Tedlar bags 23/02/2007 14:30 C4 928 1013 Dräger H2S 0.5 to 15 ppm 10 0.5 0.5 Tested from Tedlar bags 26/02/2007 14:00 C4 929 1013 Dräger H2S 0.5 to 15 ppm 10 0.5 0.5 Tested from Tedlar bags 28/02/2007 14:00 C4 922 1013 Dräger H2S 0.5 to 15 ppm 10 0.5 0.5 Tested from Tedlar bags 02/03/2007 9:30 C4 920 1013 Dräger H2S 0.5 to 15 ppm 10 0.5 0.6 Tested from Tedlar bags 05/03/2007 11:20 C4 923 1013 Dräger H2S 0.5 to 15 ppm 10 0.5 0.5 Tested from Tedlar bags 07/03/2007 12:00 C4 922 1013 Dräger H2S 0.5 to 15 ppm 10 0.5 0.5 Tested from Tedlar bags 09/03/2007 12:30 C4 920 1013 Dräger H2S 0.5 to 15 ppm 10 0.5 0.6 Tested from Tedlar bags 12/03/2007 15:35 C4 924 1013 Dräger H2S 0.5 to 15 ppm 10 0.5 0.5 Tested from Tedlar bags 14/03/2007 16:00 C4 926 1013 Dräger H2S 0.5 to 15 ppm 10 0.5 0.5 Tested from Tedlar bags 19/03/2007 14:00 C4 928 1013 Dräger H2S 0.5 to 15 ppm 10 0.5 0.5 Tested from Tedlar bags 22/03/2007 11:00 C4 932 1013 Dräger H2S 0.5 to 15 ppm 10 0.5 0.5 Tested from Tedlar bags 26/03/2007 16:30 C4 933 1013 Dräger H2S 0.5 to 15 ppm 10 0.5 0.5 Tested from Tedlar bags
14/02/2007 15:35 C5 929 1013 Dräger H2S 0.5 to 15 ppm 10 0.5 0.5 Tested from Tedlar bags 21/02/2007 11:30 C5 932 1013 Dräger H2S 0.5 to 15 ppm 10 2 2.2 Tested from Tedlar bags 23/02/2007 14:30 C5 928 1013 Dräger H2S 0.5 to 15 ppm 10 0.5 0.5 Tested from Tedlar bags 26/02/2007 14:00 C5 929 1013 Dräger H2S 0.5 to 15 ppm 10 0.5 0.5 Tested from Tedlar bags 28/02/2007 14:00 C5 922 1013 Dräger H2S 0.5 to 15 ppm 10 0.5 0.5 Tested from Tedlar bags 02/03/2007 9:30 C5 920 1013 Dräger H2S 0.5 to 15 ppm 10 0.5 0.6 Tested from Tedlar bags 05/03/2007 11:20 C5 923 1013 Dräger H2S 0.5 to 15 ppm 10 0.5 0.5 Tested from Tedlar bags 07/03/2007 12:00 C5 922 1013 Dräger H2S 0.5 to 15 ppm 10 0.5 0.5 Tested from Tedlar bags 09/03/2007 12:30 C5 920 1013 Dräger H2S 0.5 to 15 ppm 10 0.5 0.6 Tested from Tedlar bags 12/03/2007 15:35 C5 924 1013 Dräger H2S 0.5 to 15 ppm 10 0.5 0.5 Tested from Tedlar bags 14/03/2007 16:00 C5 926 1013 Dräger H2S 0.5 to 15 ppm 10 0.5 0.5 Tested from Tedlar bags 19/03/2007 14:00 C5 928 1013 Dräger H2S 0.5 to 15 ppm 10 1 1.1 Tested from Tedlar bags 22/03/2007 11:00 C5 932 1013 Dräger H2S 0.5 to 15 ppm 10 0.5 0.5 Tested from Tedlar bags 26/03/2007 16:30 C5 933 1013 Dräger H2S 0.5 to 15 ppm 10 0.5 0.5 Tested from Tedlar bags
14/02/2007 15:35 C6 929 1013 Dräger H2S 0.5 to 15 ppm 10 14 15.3 Tested from Tedlar bags 21/02/2007 11:30 C6 932 1013 Dräger H2S 0.5 to 15 ppm 10 20 21.7 Tested from Tedlar bags 23/02/2007 14:30 C6 928 1013 Dräger H2S 0.5 to 15 ppm 10 0.5 0.5 Tested from Tedlar bags 26/02/2007 14:00 C6 929 1013 Dräger H2S 0.5 to 15 ppm 10 0.5 0.5 Tested from Tedlar bags 28/02/2007 14:00 C6 922 1013 Dräger H2S 0.5 to 15 ppm 10 0.5 0.5 Tested from Tedlar bags 02/03/2007 9:30 C6 920 1013 Dräger H2S 0.5 to 15 ppm 10 0.5 0.6 Tested from Tedlar bags 05/03/2007 11:20 C6 923 1013 Dräger H2S 0.5 to 15 ppm 10 2 2.2 Tested from Tedlar bags 07/03/2007 12:00 C6 922 1013 Dräger H2S 0.5 to 15 ppm 10 0.5 0.5 Tested from Tedlar bags 09/03/2007 12:30 C6 920 1013 Dräger H2S 0.5 to 15 ppm 10 1 1.1 Tested from Tedlar bags 12/03/2007 15:35 C6 924 1013 Dräger H2S 0.5 to 15 ppm 10 1.5 1.6 Tested from Tedlar bags 14/03/2007 16:00 C6 926 1013 Dräger H2S 0.5 to 15 ppm 10 0.5 0.5 Tested from Tedlar bags 19/03/2007 14:00 C6 928 1013 Dräger H2S 0.5 to 15 ppm 10 1.5 1.6 Tested from Tedlar bags 22/03/2007 11:00 C6 932 1013 Dräger H2S 0.5 to 15 ppm 10 1 1.1 Tested from Tedlar bags 26/03/2007 16:30 C6 933 1013 Dräger H2S 0.5 to 15 ppm 10 1 1.1 Tested from Tedlar bags
Page 2 of 2 Royal Institute of Technology Stockholm , 2007
ANSTO - GAS CHROMOTOGRAPHY WITH THERMAL CONDUCTIVITY DETECTION
RATIO Dry Gas Concentration corrected for air leak in sample bag 25-Oct-06 %CH4/%CO2 % CH4 % CO2 % O2 % N2 ratio N2/O2 % H2 H2S ppm Column 1 0.75 41.1 54.9 0.07 3.94 57.9 0.010 21 Column 2 0.36 25.5 71.9 0.04 2.52 58.9 0.039 9 Column 3 0.15 12.5 84.2 0.04 2.22 51.6 0.968 3 Column 4 0.11 9.4 84.2 0.04 5.88 139.0 0.478 11
airtest 0.00 0.00 0.04 21.9 78.0 3.56 0.0 0.0 standard 1.23 47.9 38.9 1.94 7.76 4.00 3.5 50.0
RATIO Dry Gas Concentration corrected for air leak in sample bag 8-Nov-06 %CH4/%CO2 % CH4 % CO2 % O2 % N2 ratio N2/O2 % H2 H2S ppm Column 1 1.13 52.5 46.5 0.04 0.93 22.4 0.01 0.3 Column 2 0.70 40.5 58.1 0.04 1.31 31.0 0.0 6.9 Column 3 0.34 24.6 73.4 0.04 2.00 50.0 0.0 4.2 Column 4 0.19 15.0 77.9 0.05 6.99 129.5 0.0 5.8 airtest 0.00 0.00 0.04 21.9 78.0 3.56 0.0 0.0 standard 1.23 47.9 38.9 1.94 7.76 4.00 3.5 50.0
RATIO Dry Gas Concentration corrected for air leak in sample bag 22-Nov-06 %CH4/%CO2 % CH4 % CO2 % O2 % N2 ratio N2/O2 % H2 H2S ppm Column 1 1.22 49.0 40.1 0.06 10.89 167.8 0.00 0.3 Column 2 0.95 47.4 49.7 0.05 2.89 58.8 0.0 6.0 Column 3 0.42 27.8 66.6 0.05 5.37 116.8 0.3 4.0 Column 4 0.24 17.0 71.2 0.16 11.57 70.5 0.0 2.7 Column 5 0.09 3.9 42.1 0.21 53.67 256.1 0.1 3.4 Column 6 0.10 4.4 42.5 0.28 52.54 186.8 0.2 3.2 airtest 0.00 0.00 0.04 21.9 78.0 3.6 0.0 0.0 standard 1.23 47.9 38.9 1.94 7.76 4.00 3.5 50.0
RATIO Dry Gas Concentration corrected for air leak in sample bag 13-Dec-06 %CH4/%CO2 % CH4 % CO2 % O2 % N2 ratio N2/O2 % H2 H2S ppm Column 1 1.16 44.7 38.4 0.10 16.73 160.1 0.001 0.3 Column 2 1.11 51.1 46.0 0.05 2.91 56.7 0.005 0.3 Column 3 0.54 29.7 54.5 0.05 15.77 322.6 0.017 1.3 Column 4 0.26 14.2 54.6 0.08 31.03 411.8 0.007 0.8 Column 5 0.36 20.3 55.7 0.04 24.00 583.6 0.008 1.1 Column 6 0.35 19.0 54.5 0.04 26.42 652.7 0.004 0.7 airtest 0.00 0.00 0.04 21.9 78.0 3.6 0.0 0.0 standard 1.23 47.9 38.9 1.94 7.76 4.00 3.5 50.0
RATIO Dry Gas Concentration corrected for air leak in sample bag 10-Jan-07 %CH4/%CO2 % CH4 % CO2 % O2 % N2 ratio N2/O2 % H2 H2S ppm Column 1 1.47 59.0 40.2 0.05 0.71 14.9 0.006 0.3 Column 2 1.23 54.7 44.6 0.05 0.61 13.3 0.015 0.3
Dr. David Stone, ANSTO Page 1 of 2 Royal Institute of Technology Stockholm , 2007
ANSTO - GAS CHROMOTOGRAPHY WITH THERMAL CONDUCTIVITY DETECTION
RATIO Dry Gas Concentration corrected for air leak in sample bag 30-Jan-07 %CH4/%CO2 % CH4 % CO2 % O2 % N2 ratio N2/O2 % H2 H2S ppm Column 1 1.57 60.3 38.4 0.06 1.20 21.1 0.005 0.3 Column 2 1.21 52.5 43.3 0.06 4.14 66.2 0.007 0.3 Column 3 0.81 41.9 51.8 0.05 6.06 122.8 0.194 0.7 Column 4 0.40 18.7 47.0 0.10 34.16 335.4 0.015 0.7 Column 5 0.77 39.4 51.3 0.06 9.25 168.0 0.002 0.7 Column 6 0.82 40.3 49.4 0.05 10.13 214.3 0.036 0.3 airtest 0.00 0.00 0.04 21.9 78.0 3.6 0.0 0.0 standard 1.23 47.9 38.9 1.94 7.76 4.00 3.5 50.0
RATIO Dry Gas Concentration corrected for air leak in sample bag 8-Feb-07 %CH4/%CO2 % CH4 % CO2 % O2 % N2 ratio N2/O2 % H2 H2S ppm Column 1 1.37 51.6 37.6 0.07 10.71 146.5 0.011 < 0.3 Column 2 1.34 56.0 41.8 0.05 2.15 39.8 0.012 < 0.3 Column 3 0.84 42.6 50.9 0.06 6.28 114.1 0.241 < 0.3 Column 4 0.46 25.2 55.1 0.06 19.37 351.9 0.264 < 0.3 Column 5 0.81 39.3 48.5 0.06 12.09 195.4 0.003 < 0.3 Column 6 0.85 40.0 46.9 0.06 13.05 214.3 0.001 < 0.3 airtest 0.00 0.00 0.04 21.9 78.0 3.6 0.0 0.0 standard 1.23 47.9 38.9 1.94 7.76 4.00 3.5 50.0
RATIO Dry Gas Concentration corrected for air leak in sample bag 6-Mar-07 %CH4/%CO2 % CH4 % CO2 % O2 % N2 ratio N2/O2 % H2 H2S ppm Column 1 1.23 54.3 44.2 0.05 1.40 26.8 0.002 < 0.3 Column 2 1.34 56.5 42.1 0.15 1.20 8.2 0.007 < 0.3 Column 3 1.07 50.1 46.7 0.29 2.90 9.8 0.036 < 0.3 Column 4 0.59 33.8 57.7 2.30 6.15 2.7 0.024 < 0.3 Column 5 0.82 42.3 51.9 1.21 4.60 3.8 0.002 < 0.3 Column 6 0.90 44.0 48.9 1.32 5.79 4.4 0.002 < 0.3 airtest 0.00 0.00 0.04 21.9 78.0 3.6 0.0 0.0 standard 1.23 47.9 38.9 1.94 7.76 4.00 3.5 50.0
RATIO Dry Gas Concentration corrected for air leak in sample bag 28-Mar-07 %CH4/%CO2 % CH4 % CO2 % O2 % N2 ratio N2/O2 % H2 H2S ppm Column 1 1.07 50.4 47.3 0.05 2.22 2.4 0.013 < 0.3 Column 2 1.37 57.7 42.1 0.07 0.14 0.7 0.024 59.3 Column 3 1.36 56.9 41.9 0.05 0.96 1.3 0.243 8.6 Column 4 0.95 47.5 49.8 0.95 1.23 2.9 0.535 < 0.3 Column 5 1.02 48.9 48.1 0.85 2.12 0.6 0.010 < 0.3 Column 6 0.79 42.2 53.5 1.12 3.21 1.7 0.006 < 0.3 airtest 0.00 0.00 0.04 21.9 78.0 3.6 0.0 0.0 standard 1.23 54.9 44.6 0.06 0.48 7.42 3.5 50.0
Dr. David Stone, ANSTO Page 2 of 2 Royal Institue of Technology Stockholm, 2007
BIOREACTOR GAS COMPOSITION (GA - GAS MONITOR/INRFA RED)
Barometric Day Draeger ID Date CH4 CO2 O2 H2S CO CO2/CH4 Peak CH4 Peak CO2 Balance Pressure No. H2S (ppm) vol % vol % vol % ppmV ppmV Ratio vol % vol % vol % mb COLUMN01 2006/10/06 0 0 0 21 0 0 0.00 0 0 79 928 COLUMN01 2006/10/09 3 3.1 21.1 12.1 6.81 63.7 928 COLUMN01 2006/10/10 4 8.6 62.5 0.6 7.27 28.3 928 COLUMN01 2006/10/11 5 10.9 66.7 0.1 6.12 22.3 928 COLUMN01 2006/10/13 7 14.2 77.7 0 5 >>> 5.47 14.2 77.8 8.1 928 COLUMN01 2006/10/16 10 18.7 81.3 0 13 >>> 4.35 21.4 83.8 0 933 COLUMN01 2006/10/17 11 19.9 80.1 0 11 >>> 4.03 23.5 83.8 0 928 COLUMN01 2006/10/18 12 21.1 78.8 0.1 14 >>> 3.73 25.9 83.1 0 923 COLUMN01 2006/10/19 13 22.9 77.1 0 >>> >>> 3.37 28.5 82.7 0 928 COLUMN01 2006/10/20 14 25.3 74.7 0 13 >>> 2.95 31 80.4 0 923 COLUMN01 2006/10/23 17 32.9 67.1 0 7 813 2.04 38.8 72.7 0 931 COLUMN01 2006/10/24 18 34.8 65.2 0 2 923 1.87 40.3 70.7 0 926 COLUMN01 2006/10/25 19 35.55 64.45 0 5 722 1.81 41.5 70.3 0 919 COLUMN01 2006/10/26 20 36.55 63.35 0.1 4 569 1.73 42.5 69.4 0 926 COLUMN01 2006/10/27 21 38.35 61.65 0 4 575 1.61 44.2 67.3 0 918 COLUMN01 2006/10/30 24 42.65 57.35 0 2 232 1.34 48.5 63.5 0 927 COLUMN01 2006/10/31 25 43.95 56.05 0 0 257 1.28 50.1 62.4 0 924 COLUMN01 2006/11/01 26 42.25 57.45 0.3 0 834 1.36 49.1 64.2 0 922 COLUMN01 2006/11/02 27 45 55 0 0 466 1.22 51.4 61.5 0 918 COLUMN01 2006/11/03 28 45.55 54.45 0 3 269 1.20 51.6 60.7 0 921 COLUMN01 2006/11/06 31 45.55 54.05 0.4 <<< 884 1.19 49.7 58.2 0 925 COLUMN01 2006/11/07 32 47.75 52.25 0 <<< 187 1.09 51.5 55.9 0 923 COLUMN01 2006/11/09 34 49.15 50.85 0 <<< 143 1.03 53.1 55.1 0 929 COLUMN01 2006/11/10 35 49.6 50.4 0 <<< 110 1.02 53.3 54.3 0 922 COLUMN01 2006/11/15 40 50.8 49.2 0 0 128 0.97 55.4 53.4 0 906 COLUMN01 2006/11/16 41 51.9 48.1 0 <<< 157 0.93 57.9 52.1 0 919 COLUMN01 2006/11/17 42 53.05 46.95 0 <<< 110 0.89 57.5 52 0 930 COLUMN01 2006/11/20 45 52.9 47.1 0 0 161 0.89 56.8 51.1 0 928 COLUMN01 2006/11/23 48 51.85 48.15 0 <<< 342 0.93 55.1 51.2 0 924 COLUMN01 2006/11/24 49 50.35 49.35 0.3 <<< >>> 0.98 66.1 54.4 0 927 COLUMN01 2006/11/27 52 53.75 46.25 0 <<< 202 0.86 56.5 49.1 0 924 COLUMN01 2006/11/29 54 52.4 47.5 0.1 <<< 673 0.91 55.5 50.6 0 917 COLUMN01 2006/12/01 56 54.35 45.25 0.4 <<< 449 0.83 57.3 48.2 0 920 COLUMN01 2006/12/12 67 54.35 45.65 0 <<< 198 0.84 55.5 46.8 0 930 COLUMN01 2006/12/13 68 55.5 44.5 0 <<< 228 0.80 58.5 46.4 0 923 COLUMN01 2006/12/14 69 55.75 44.25 0 <<< 216 0.79 57.9 46.4 0 921 COLUMN01 2006/12/18 73 57.4 42.6 0 0 136 0.74 60.5 45.4 0 927 COLUMN01 2006/12/20 75 57 43 0 0 154 0.75 59.8 45.7 0 929 COLUMN01 2006/12/22 77 56.7 43.3 0 0 165 0.76 59.7 45.7 0 927 COLUMN01 2006/12/27 82 55.95 44.05 0 0 121 0.79 56.7 44.7 0 922 COLUMN01 2007/01/07 93 55.3 44.7 0 <<< 213 0.81 61.30 47.7 0 914 COLUMN01 2007/01/08 94 54.7 45.2 0.1 0 370 0.83 66.10 48.2 0 917 COLUMN01 2007/01/12 98 60.45 39.15 0.4 <<< 27 0.65 63.90 42.4 0 916 COLUMN01 2007/01/15 101 60.9 38.8 0.3 <<< 0 0.64 65.90 43 0 925 COLUMN01 2007/01/18 104 60.45 39.15 0.4 <<< 0 0.65 64.30 42.8 0 928 COLUMN01 2007/01/19 105 60.9 38.7 0.4 <<< 3 0.64 64.10 42.1 0 925 COLUMN01 2007/01/20 106 60.25 39.25 0.5 2 0 0.65 63.10 41.9 0 922 COLUMN01 2007/01/24 110 58.9 36.9 4.2 3 0 0.63 63.10 41.1 0 923 COLUMN01 2007/01/29 115 60.95 37.05 2 4 0 0.61 65.00 40.4 0 920 COLUMN01 2007/02/08 125 64.95 32.65 2.4 <<<< 213 0.50 74.20 41.3 0 919 COLUMN01 2007/02/12 129 62.45 36.95 0.6 3 0 0.59 66.00 40.6 0 928 COLUMN01 2007/02/14 131 2.2 62.45 37.05 0.5 3 0 0.59 66.00 40.8 0 929 COLUMN01 2007/02/16 133 2.5 61.9 37.5 0.6 16 16 0.61 66.90 41.2 0 930 COLUMN01 2007/02/20 137 3.5 60.9 38.7 0.4 0 5 0.64 64.50 42.3 0 930 COLUMN01 2007/02/21 138 4.3 60.65 38.75 0.6 <<<< 39 0.64 70.90 43 0 932 COLUMN01 2007/02/22 139 4.4 61.05 38.35 0.6 6 0 0.63 65.10 42.3 0 928 COLUMN01 2007/02/26 143 4.4 61.35 38.15 0.5 17 7 0.62 47.40 41.6 0 929 COLUMN01 2007/02/27 144 4.4 62.15 37.25 0.6 3 1 0.60 48.00 41.2 0 925 COLUMN01 2007/02/28 145 4.4 60.45 39.05 0.5 4 0 0.65 46.90 40.6 0 922 COLUMN01 2007/03/01 146 4.4 59.35 40.05 0.6 0 5 0.67 59.90 40.7 0 918 COLUMN01 2007/03/02 147 5.5 59.1 40.1 0.8 4 0 0.68 60.60 41.5 0 920 COLUMN01 2007/03/05 150 4.4 54 42.4 0.3 0 0 0.79 54.30 42.8 3.3 923 COLUMN01 2007/03/07 152 5.5 56.3 42.8 0.4 <<<< 0 0.76 56.30 42.8 0.5 922 COLUMN01 2007/03/09 154 4.4 56.5 42.6 0.7 <<<< 0 0.75 66.20 42.7 0.2 920 COLUMN01 2007/03/12 157 4.4 57 41.7 0.5 186 0 0.73 57.10 41.5 0.8 924 COLUMN01 2007/03/14 159 3.3 57.1 41.5 0.3 <<<< 0 0.73 57.30 41.5 1.1 926 COLUMN01 2007/03/19 164 5.5 56.5 42.3 0.7 0 0 0.75 56.60 42.4 0.5 928 COLUMN01 2007/03/22 167 4.9 56.2 43.1 0.5 0 0 0.77 59.60 43.2 0.2 932 COLUMN01 2007/03/26 171 5.4 57.4 42.1 0.5 <<<< 0 0.73 57.80 42.2 0 933
Page 1 of 6 Royal Institue of Technology Stockholm, 2007
BIOREACTOR GAS COMPOSITION (GA - GAS MONITOR/INRFA RED)
Barometric Day Draeger ID Date CH4 CO2 O2 H2S CO CO2/CH4 Peak CH4 Peak CO2 Balance Pressure No. H2S (ppm) vol % vol % vol % ppmV ppmV Ratio vol % vol % vol % mb COLUMN02 2006/10/06 0 0 0 21 0.00 79 928 COLUMN02 2006/10/09 3 4.2 51.2 0.1 12.19 44.5 928 COLUMN02 2006/10/10 4 4.2 58.4 0.6 13.90 36.8 928 COLUMN02 2006/10/11 5 5.5 63.1 0 11.47 31.4 928 COLUMN02 2006/10/13 7 7.8 77.1 0 5 >>> 9.88 7.8 77.2 15.1 928 COLUMN02 2006/10/16 10 10.65 89.35 0 18 >>> 8.39 13.3 93.1 0 934 COLUMN02 2006/10/17 11 10.95 89.05 0 20 >>> 8.13 14.7 92.8 0 928 COLUMN02 2006/10/18 12 11.55 88.45 0 23 >>> 7.66 16.7 93.4 0 923 COLUMN02 2006/10/19 13 12.65 87.35 0 16 >>> 6.91 17.9 93.1 0 928 COLUMN02 2006/10/20 14 13.55 86.45 0 23 >>> 6.38 19.5 93.5 0 923 COLUMN02 2006/10/23 17 19.15 80.85 0 14 619 4.22 25.9 87.5 0 931 COLUMN02 2006/10/24 18 19.55 80.45 0 3 758 4.12 26.6 87.8 0 926 COLUMN02 2006/10/25 19 20.3 79.7 0 11 655 3.93 27.8 87.7 0 919 COLUMN02 2006/10/26 20 21.4 78.6 0 15 578 3.67 28.5 86.2 0 926 COLUMN02 2006/10/27 21 23.05 76.95 0 13 570 3.34 30.3 84.4 0 917 COLUMN02 2006/10/30 24 26.85 73.15 0 9 275 2.72 34.1 80.4 0 927 COLUMN02 2006/10/31 25 28 72 0 6 310 2.57 35.1 79.2 0 924 COLUMN02 2006/11/01 26 26.3 73.5 0.2 3 922 2.79 34.6 81.9 0 922 COLUMN02 2006/11/02 27 30.2 69.8 0 3 394 2.31 37.3 76.9 0 918 COLUMN02 2006/11/03 28 31.15 68.85 0 10 367 2.21 38 75.8 0 921 COLUMN02 2006/11/06 31 31.7 67.9 0.4 <<< >>> 2.14 40.7 75.6 0 925 COLUMN02 2006/11/07 32 35.1 64.9 0 <<< 308 1.85 40.4 70.5 0 923 COLUMN02 2006/11/09 34 37.15 62.85 0 <<< 303 1.69 42.1 67.9 0 928 COLUMN02 2006/11/10 35 37.5 62.5 0 <<< 217 1.67 42.9 68.1 0 922 COLUMN02 2006/11/15 40 41.1 58.9 0 0 234 1.43 46.2 63.6 0 906 COLUMN02 2006/11/16 41 42.55 57.45 0 <<< 249 1.35 47.7 62.6 0 919 COLUMN02 2006/11/17 42 43.3 56.7 0 <<< 207 1.31 48.3 61.8 0 930 COLUMN02 2006/11/20 45 44.35 55.65 0 2 247 1.25 49.7 60.6 0 928 COLUMN02 2006/11/23 48 44.4 55.6 0 <<< 553 1.25 48.3 59.5 0 924 COLUMN02 2006/11/24 49 42.25 57.45 0.3 <<< >>> 1.36 48.1 63.8 0 928 COLUMN02 2006/11/27 52 46.9 53.1 0 <<< 324 1.13 51.1 57.1 0 924 COLUMN02 2006/11/29 54 44.75 54.95 0.3 <<< >>> 1.23 50.2 60.2 0 920 COLUMN02 2006/12/01 56 47.65 51.95 0.4 <<< 666 1.09 51.4 56 0 920 COLUMN02 2006/12/12 67 49.05 50.95 0 <<< 423 1.04 52.7 54.5 0 930 COLUMN02 2006/12/13 68 49.5 50.5 0 <<< 437 1.02 53.1 53.6 0 923 COLUMN02 2006/12/14 69 49.95 50.05 0 <<< 362 1.00 53.4 53.6 0 921 COLUMN02 2006/12/18 73 51 49 0 0 205 0.96 54.5 52.4 0 927 COLUMN02 2006/12/20 75 51.05 48.95 0 1 233 0.96 54.8 52.5 0 928 COLUMN02 2006/12/21 75 51.1 48.9 0 0 205 0.96 54.6 52.6 0 929 COLUMN02 2006/12/22 77 51.05 48.95 0 0 248 0.96 54.7 52.4 0 926 COLUMN02 2006/12/27 82 51.15 48.85 0 0 226 0.96 54.9 52.8 0 922 COLUMN02 2007/01/07 93 50.1 49.9 0 <<< 353 1.00 53.7 53.5 0 914 COLUMN02 2007/01/08 94 49.8 50.2 0 136 574 1.01 53.3 53.5 0 917 COLUMN02 2007/01/12 98 56.05 43.55 0.4 <<< 71 0.78 59.4 46.4 0 916 COLUMN02 2007/01/15 101 55.9 43.8 0.3 <<< 0 0.78 58.8 46.4 0 924 COLUMN02 2007/01/18 104 55.75 43.95 0.3 <<< 0 0.79 58.9 46.9 0 928 COLUMN02 2007/01/19 105 55.55 43.95 0.5 <<< 6 0.79 58.5 46.8 0 925 COLUMN02 2007/01/20 106 55.55 44.25 0.2 0 0 0.80 58.5 46.9 0 922 COLUMN02 2007/01/24 110 54 42.1 3.9 0 5 0.78 57.9 46 0 923 COLUMN02 2007/01/29 115 55.45 43.75 0.8 0 7 0.79 58.6 47 0 921 COLUMN02 2007/02/08 125 59.65 39.05 1.3 <<<< 228 0.65 66 43.9 0 919 COLUMN02 2007/02/12 129 60.2 39.4 0.4 0 1 0.65 63.7 42.9 0 928 COLUMN02 2007/02/14 131 3.3 60.4 39.2 0.4 0 0 0.65 64.2 43.6 0 929 COLUMN02 2007/02/16 133 5 59.45 40.15 0.4 0 12 0.68 63.1 43.5 0 930 COLUMN02 2007/02/20 137 7 57.95 41.55 0.5 <<<< 12 0.72 61.1 45.6 0 930 COLUMN02 2007/02/21 138 9.2 57.5 42.1 0.4 <<<< 83 0.73 62.1 45.5 0 932 COLUMN02 2007/02/22 139 4.5 56.55 43.05 0.4 <<<< 0 0.76 60.1 46.6 0 929 COLUMN02 2007/02/26 143 0.5 55.9 43.8 0.3 <<<< 2 0.78 46 44.2 0 928 COLUMN02 2007/02/27 144 0.5 56.3 43.3 0.4 0 0 0.77 46.6 43.9 0 926 COLUMN02 2007/02/28 145 0.5 55.8 43.8 0.4 0 0 0.78 45.8 43.7 0 923 COLUMN02 2007/03/01 146 4.5 56.15 43.45 0.4 0 0 0.77 57.2 45 0 917 COLUMN02 2007/03/02 147 9.9 55.8 43.7 0.5 4 0 0.78 57 44.9 0 920 COLUMN02 2007/03/05 150 41.7 50.5 48.2 0.4 21 0 0.95 50.5 47.9 0.9 923 COLUMN02 2007/03/07 152 20.9 49.8 49.7 0.4 >>>> 0 1.00 50 49.9 0.1 922 COLUMN02 2007/03/09 154 132.1 49.45 50.05 0.5 >>>> 0 1.01 50.4 50.4 0 920 COLUMN02 2007/03/12 157 252.2 49.8 49.2 0.3 >>>> 0 0.99 49.8 49.4 0.7 923 COLUMN02 2007/03/14 159 568.9 50.4 48.9 0.4 >>>> 0 0.97 50.6 49 0.3 926 COLUMN02 2007/03/19 164 556.6 49.6 49.3 0.4 >>>> 0 0.99 50 49.5 0.7 928 COLUMN02 2007/03/22 167 543.5 49.6 49.9 0.5 0 0 1.01 49.7 50 0 932 COLUMN02 2007/03/26 171 1758.9 50.6 48.7 0.2 >>>> 0 0.96 51.3 49 0.5 933
Page 2 of 6 Royal Institue of Technology Stockholm, 2007
BIOREACTOR GAS COMPOSITION (GA - GAS MONITOR/INRFA RED)
Barometric Day Draeger ID Date CH4 CO2 O2 H2S CO CO2/CH4 Peak CH4 Peak CO2 Balance Pressure No. H2S (ppm) vol % vol % vol % ppmV ppmV Ratio vol % vol % vol % mb COLUMN03 2006/10/06 0 0 0 21 0.00 79 928 COLUMN03 2006/10/09 3 1.125 50.825 1.05 45.18 47 928 COLUMN03 2006/10/10 4 1.4 61.8 0.6 44.14 36.2 928 COLUMN03 2006/10/11 5 2.2 65.3 0 29.68 32.5 928 COLUMN03 2006/10/13 7 3.2 79.1 0 26 >>> 24.72 3.3 79.2 17.7 928 COLUMN03 2006/10/16 10 5.85 94.15 0 43 >>> 16.09 5.7 94.3 0 934 COLUMN03 2006/10/17 11 5.35 94.65 0 49 >>> 17.69 6.6 96.5 0 928 COLUMN03 2006/10/18 12 4.55 95.45 0 54 >>> 20.98 7.7 98.9 0 923 COLUMN03 2006/10/19 13 4.2 95.8 0 95 >>> 22.81 8.3 99.9 0 928 COLUMN03 2006/10/20 14 4.6 95.4 0 90 >>> 20.74 9.1 99.9 0 923 COLUMN03 2006/10/23 17 7.15 92.85 0 54 >>> 12.99 13.7 99.9 0 974 COLUMN03 2006/10/24 18 7.2 92.8 0 60 >>> 12.89 14 99.9 0 925 COLUMN03 2006/10/25 19 7.5 92.5 0 55 >>> 12.33 14.9 99.9 0 919 COLUMN03 2006/10/26 20 8.25 91.75 0 52 >>> 11.12 15 98.5 0 926 COLUMN03 2006/10/27 21 8.85 91.15 0 55 >>> 10.30 15.8 98.5 0 917 COLUMN03 2006/10/30 24 11.4 88.6 0 28 >>> 7.77 18.7 96 0 927 COLUMN03 2006/10/31 25 12.25 87.75 0 28 >>> 7.16 19.8 95.5 0 924 COLUMN03 2006/11/01 26 10 89.7 0.3 49 >>> 8.97 20.2 99.9 0 921 COLUMN03 2006/11/02 27 13.35 86.65 0 35 >>> 6.49 21.1 94.6 0 918 COLUMN03 2006/11/03 28 14.05 85.95 0 39 >>> 6.12 21.7 93.7 0 921 COLUMN03 2006/11/06 31 14.2 85.5 0.3 <<< >>> 6.02 22.5 94.1 0 925 COLUMN03 2006/11/07 32 16.65 83.35 0 <<< >>> 5.01 23.9 90.6 0 922 COLUMN03 2006/11/09 34 18.55 81.45 0 <<< >>> 4.39 24.7 88.5 0 929 COLUMN03 2006/11/10 35 18.55 81.45 0 <<< >>> 4.39 25.2 88 0 922 COLUMN03 2006/11/15 40 21.55 78.45 0 0 >>> 3.64 26.8 83.8 0 906 COLUMN03 2006/11/16 41 23.1 76.9 0 <<< >>> 3.33 28 81.8 0 919 COLUMN03 2006/11/17 42 23.3 76.7 0 <<< >>> 3.29 28.6 82.2 0 930 COLUMN03 2006/11/20 45 24.15 75.85 0 9 >>> 3.14 29.7 82.1 0 928 COLUMN03 2006/11/23 48 23.5 76.5 0 <<< >>> 3.26 28.9 81.8 0 924 COLUMN03 2006/11/24 49 19.45 80.35 0.2 <<< >>> 4.13 28.4 89.8 0 927 COLUMN03 2006/11/27 52 25.2 74.8 0 <<< >>> 2.97 29.9 79.7 0 924 COLUMN03 2006/11/29 54 22.95 76.85 0.2 <<< >>> 3.35 29.9 83.7 0 920 COLUMN03 2006/12/01 56 25.85 73.85 0.3 <<< >>> 2.86 31.4 79.6 0 919 COLUMN03 2006/12/12 67 28.9 65.5 0.8 <<< 470 2.27 29.2 66.6 4.8 930 COLUMN03 2006/12/13 68 29.4 66.3 0.3 <<< 683 2.26 29.9 67.1 4 923 COLUMN03 2006/12/14 69 30 66.6 0 <<< 481 2.22 30.4 67.1 3.4 921 COLUMN03 2006/12/18 73 31.6 66 0 0 523 2.09 31.9 66.5 2.4 927 COLUMN03 2006/12/20 75 32.8 66.1 0 3 >>> 2.02 32.9 66.1 1.1 929 COLUMN03 2006/12/21 75 33.7 66.2 0 4 >>> 1.96 33.7 66.3 0.1 929 COLUMN03 2006/12/22 77 33.75 66.25 0 4 >>> 1.96 33.7 66.3 0 925 COLUMN03 2006/12/27 82 33.2 66.4 0 0 >>> 2.00 33.9 67 0.4 922 COLUMN03 2007/01/07 93 34.05 65.85 0.1 <<< >>> 1.93 36.1 69.2 0 914 COLUMN03 2007/01/08 94 33.85 66.15 0 <<< >>> 1.95 35.7 67.9 0 917 COLUMN03 2007/01/12 98 40.95 58.75 0.3 <<< 296 1.43 43.6 58.5 0 916 COLUMN03 2007/01/15 101 41.9 57.5 0.6 0 62 1.37 43.6 56.1 0 924 COLUMN03 2007/01/18 104 41.95 57.55 0.5 <<< 118 1.37 43.9 57.2 0 928 COLUMN03 2007/01/19 105 42.4 57.3 0.3 <<< 147 1.35 43.5 56.9 0 925 COLUMN03 2007/01/20 106 42.55 57.15 0.3 20 135 1.34 43.4 56.9 0 922 COLUMN03 2007/01/24 110 42.3 56 1.7 16 0 1.32 43.9 56.6 0 923 COLUMN03 2007/01/29 115 43.2 54.9 1.9 1 <<< 1.27 45.4 56.8 0 921 COLUMN03 2007/02/08 125 46.5 52.7 0.8 51 433 1.13 49.2 55.2 0 919 COLUMN03 2007/02/12 129 47.3 52.4 0.3 16 26 1.11 49.2 53.9 0 928 COLUMN03 2007/02/14 131 0.5 47.65 52.15 0.2 17 51 1.09 50 54.3 0 928 COLUMN03 2007/02/16 133 0.5 48 51.6 0.4 51 154 1.08 51.1 54.7 0 930 COLUMN03 2007/02/20 137 0.5 48.8 50.9 0.3 43 119 1.04 51.8 53.5 0 930 COLUMN03 2007/02/21 138 1.6 48.6 50.9 0.5 <<<< 263 1.05 51.5 53.6 0 931 COLUMN03 2007/02/22 139 0.5 49.35 50.25 0.4 <<<< 27 1.02 52.4 53.4 0 928 COLUMN03 2007/02/26 143 0.5 48.5 51.4 0.1 23 121 1.06 40.7 52.1 0 929 COLUMN03 2007/02/27 144 0.5 49 50.6 0.4 12 72 1.03 40.5 50.7 0 925 COLUMN03 2007/02/28 145 0.5 49.2 50.5 0.3 15 50 1.03 40.7 50.5 0 922 COLUMN03 2007/03/01 146 0.5 50.2 49.7 0.1 0 32 0.99 51 50.9 0 917 COLUMN03 2007/03/02 147 0.6 50.4 49.2 0.4 24 0 0.98 50.8 49.9 0 920 COLUMN03 2007/03/05 150 0.5 48.2 49.9 0.3 62 0 1.04 48.3 49.8 1.6 923 COLUMN03 2007/03/07 152 0.5 51.7 48 0.3 <<<< 0 0.93 54.2 50.6 0 922 COLUMN03 2007/03/09 154 0.6 54.85 44.85 0.3 <<<< 0 0.82 60.5 50.4 0 921 COLUMN03 2007/03/12 157 0.5 58.1 41.6 0.3 <<<< 0 0.72 66 49.6 0 924 COLUMN03 2007/03/14 159 0.5 58.9 40.8 0.3 38 0 0.69 67.3 49.1 0 927 COLUMN03 2007/03/19 164 0.5 57.9 41.9 0.2 19 0 0.72 64.5 48.4 0 928 COLUMN03 2007/03/22 167 0.5 55.9 43.7 0.4 0 0 0.78 61.5 49.3 0 932 COLUMN03 2007/03/26 171 0.5 56.5 43 0.5 >>>> 0 0.76 61.8 47.7 0 933
Page 3 of 6 Royal Institue of Technology Stockholm, 2007
BIOREACTOR GAS COMPOSITION (GA - GAS MONITOR/INRFA RED)
Barometric Day Draeger ID Date CH4 CO2 O2 H2S CO CO2/CH4 Peak CH4 Peak CO2 Balance Pressure No. H2S (ppm) vol % vol % vol % ppmV ppmV Ratio vol % vol % vol % mb COLUMN04 2006/10/06 0 0 0 21 0.00 79 928 COLUMN04 2006/10/09 3 0.1 44.6 0.8 446.00 54.5 927 COLUMN04 2006/10/10 4 0.7 56 0.5 80.00 42.8 927 COLUMN04 2006/10/11 5 1.2 59.5 0 49.58 39.3 927 COLUMN04 2006/10/13 7 2 72.4 0 25 >>> 36.20 3.3 78.2 25.6 927 COLUMN04 2006/10/16 10 7.35 92.65 0 47 >>> 12.61 4.5 90.1 0 933 COLUMN04 2006/10/17 11 5.3 91.4 0 53 >>> 17.25 5.3 92.1 3.3 928 COLUMN04 2006/10/18 12 5.45 94.55 0 49 >>> 17.35 6.3 95.6 0 923 COLUMN04 2006/10/19 13 5 95 0 117 >>> 19.00 6.9 97.4 0 929 COLUMN04 2006/10/20 14 4.3 95.7 0 79 >>> 22.26 7.5 98.9 0 923 COLUMN04 2006/10/23 17 5.55 94.45 0 32 >>> 17.02 11 99.9 0 930 COLUMN04 2006/10/24 18 5.6 94.4 0 27 >>> 16.86 11 99.9 0 925 COLUMN04 2006/10/25 19 5.9 94.1 0 38 >>> 15.95 11.7 99.9 0 918 COLUMN04 2006/10/26 20 5.7 94.3 0 37 >>> 16.54 11.4 99.9 0 926 COLUMN04 2006/10/27 21 6.1 93.9 0 40 >>> 15.39 12.2 99.9 0 917 COLUMN04 2006/10/30 24 8.25 91.75 0 15 >>> 11.12 13.6 96.9 0 927 COLUMN04 2006/10/31 25 8.7 91.3 0 17 >>> 10.49 14.3 97.3 0 924 COLUMN04 2006/11/01 26 6.9 93 0.1 33 >>> 13.48 14 99.9 0 922 COLUMN04 2006/11/02 27 8.3 91.7 0 34 >>> 11.05 15.1 99.9 0 919 COLUMN04 2006/11/03 28 9.2 90.8 0 28 >>> 9.87 15.4 97.3 0 921 COLUMN04 2006/11/06 31 7.55 92.15 0.3 <<< >>> 12.21 15.5 99.9 0 925 COLUMN04 2006/11/07 32 10.7 89.3 0 <<< >>> 8.35 16.4 95 0 923 COLUMN04 2006/11/09 34 11.3 88.7 0 <<< >>> 7.85 17.4 94.8 0 929 COLUMN04 2006/11/10 35 11.55 88.45 0 <<< >>> 7.66 17.8 95.7 0 922 COLUMN04 2006/11/15 40 13.15 86.85 0 33 >>> 6.60 19.5 93.1 0 906 COLUMN04 2006/11/16 41 13.8 86.2 0 <<< >>> 6.25 20 92.3 0 919 COLUMN04 2006/11/17 42 14.65 85.35 0 <<< >>> 5.83 20.6 91.5 0 930 COLUMN04 2006/11/20 45 15.65 84.35 0 11 >>> 5.39 21.7 91.1 0 928 COLUMN04 2006/11/23 48 15.25 84.75 0 <<< >>> 5.56 21.1 91.1 0 923 COLUMN04 2006/11/24 49 10.95 88.75 0.3 <<< >>> 8.11 21.4 99.8 0 927 COLUMN04 2006/11/27 52 18.05 81.65 0.3 <<< >>> 4.52 21.3 86.6 0 924 COLUMN04 2006/11/29 54 14.4 85.3 0.3 <<< >>> 5.92 21.1 93.1 0 920 COLUMN04 2006/12/01 56 18.55 80.85 0.6 <<< >>> 4.36 22.1 85 0 919 COLUMN04 2006/12/12 67 15.8 61.7 2 <<< >>> 3.91 15.8 61.9 20.5 930 COLUMN04 2006/12/13 68 16.9 64 1.1 <<< >>> 3.79 17 64.2 18 923 COLUMN04 2006/12/14 69 17 65.1 0.5 <<< >>> 3.83 17 65.3 17.4 921 COLUMN04 2006/12/18 73 18.5 66.7 0 0 >>> 3.61 18.7 67.4 14.8 927 COLUMN04 2006/12/20 75 18.3 67.2 0 0 >>> 3.67 18.4 67.6 14.5 928 COLUMN04 2006/12/21 75 19.2 67.5 0 0 >>> 3.52 19.2 67.9 13.3 928 COLUMN04 2006/12/22 77 19.6 68.5 0 0 >>> 3.49 19.6 68.9 11.9 926 COLUMN04 2006/12/27 82 17.9 62.2 1 0 >>> 3.47 17.9 63.4 18.9 921 COLUMN04 2007/01/07 93 18.3 63 0.3 <<< >>> 3.44 18.3 63.7 18.4 914 COLUMN04 2007/01/08 94 18.3 65.8 0.3 <<< >>> 3.60 18.3 66.1 15.6 917 COLUMN04 2007/01/12 98 23.1 57.1 0.5 <<< 490 2.47 28.9 56.2 19.3 915 COLUMN04 2007/01/15 101 22.1 54.4 1 3 304 2.46 28.8 54.1 22.5 924 COLUMN04 2007/01/18 104 22.7 55.4 0.3 <<< 363 2.44 30.5 55.4 21.6 928 COLUMN04 2007/01/19 105 23.6 56.9 0.2 <<< 396 2.41 30.4 56.4 19.3 925 COLUMN04 2007/01/20 106 23.5 57.4 0.3 29 421 2.44 28.1 57.6 18.8 922 COLUMN04 2007/01/24 110 24.5 58.8 1.5 40 218 2.40 24.9 58.8 15.2 923 COLUMN04 2007/01/29 115 26.7 60.5 2.1 6 125 2.27 26.7 60.5 10.7 920 COLUMN04 2007/02/08 125 31.9 60.2 0.9 144 644 1.89 33.5 60.2 7 918 COLUMN04 2007/02/12 129 32.9 61.2 0.3 26 365 1.86 32.8 62.1 5.6 928 COLUMN04 2007/02/14 131 0.5 34.7 61.6 0.1 28 367 1.78 35.7 60.7 3.6 929 COLUMN04 2007/02/16 133 0.5 35.5 61.2 0.5 82 494 1.72 35.7 61 2.8 930 COLUMN04 2007/02/20 137 0.5 37.2 61.1 0.2 72 418 1.64 36.7 60.9 1.5 930 COLUMN04 2007/02/21 138 2.2 37 62 0.5 <<<< 655 1.68 40.1 61.9 0.5 931 COLUMN04 2007/02/22 139 0.5 37.4 60.4 0.2 0 302 1.61 37.5 60.3 2 928 COLUMN04 2007/02/26 143 0.5 36.75 59.45 0.4 38 282 1.62 29 59.7 3.4 928 COLUMN04 2007/02/27 144 0.5 38.2 58.2 0.2 16 239 1.52 31.3 58.4 3.4 926 COLUMN04 2007/02/28 145 0.5 38 58.3 0.3 19 249 1.53 30.1 58.4 3.4 922 COLUMN04 2007/03/01 146 0.5 37.3 58.1 0.3 0 41 1.56 38.8 58.8 4.3 917 COLUMN04 2007/03/02 147 0.6 37.5 58.7 0.4 30 0 1.57 37.3 58.3 3.4 919 COLUMN04 2007/03/05 150 0.5 35.9 58.1 0.3 86 0 1.62 36.1 58.7 5.7 923 COLUMN04 2007/03/07 152 0.5 37 58.2 0.2 <<<< 0 1.57 54.4 58.2 4.6 922 COLUMN04 2007/03/09 154 0.6 37.1 58.7 0.4 <<<< 0 1.58 40.2 59.2 3.8 920 COLUMN04 2007/03/12 157 0.5 38.2 58.6 0.3 <<<< 0 1.53 42.4 58.2 2.9 923 COLUMN04 2007/03/14 159 0.5 38.8 57.9 0.6 97 0 1.49 38.9 58.3 2.7 927 COLUMN04 2007/03/19 164 0.5 39.5 58 0.4 31 0 1.47 44.8 57.8 2.1 928 COLUMN04 2007/03/22 167 0.5 39.7 59 0.4 0 0 1.49 39.6 58.8 0.9 932 COLUMN04 2007/03/26 171 0.5 41.4 56.9 0.4 >>>> 0 1.37 41.1 57 1.3 933
Page 4 of 6 Royal Institue of Technology Stockholm, 2007
BIOREACTOR GAS COMPOSITION (GA - GAS MONITOR/INRFA RED)
Barometric Day Draeger ID Date CH4 CO2 O2 H2S CO CO2/CH4 Peak CH4 Peak CO2 Balance Pressure No. H2S (ppm) vol % vol % vol % ppmV ppmV Ratio vol % vol % vol % mb COLUMN05 2006/11/08 0 0 0 21 0.00 79 928 COLUMN05 2006/11/17 9 1.7 39.9 0 <<< 844 23.47 1.8 40 58.4 930 COLUMN05 2006/11/20 12 3.3 49 0 0 698 14.85 3.3 50.6 47.7 928 COLUMN05 2006/11/23 15 5.2 56.8 0 <<< 889 10.92 5.2 57.1 38 923 COLUMN05 2006/11/24 16 5.9 63.1 0.3 <<< >>> 10.69 6.1 64.7 30.7 927 COLUMN05 2006/11/27 19 8.6 63 0 <<< 321 7.33 8.8 63.2 28.4 923 COLUMN05 2006/11/29 21 9.6 68 1.2 <<< >>> 7.08 9.7 69 21.2 920 COLUMN05 2006/12/01 23 11.5 65.5 0.8 <<< 608 5.70 11.7 65.6 22.2 919 COLUMN05 2006/12/12 34 18.6 70.3 0 <<< 104 3.78 18.9 70.7 11.1 930 COLUMN05 2006/12/13 35 20.5 69.7 0 <<< 386 3.40 21 70.1 9.8 923 COLUMN05 2006/12/14 36 20.5 69.6 0 <<< 263 3.40 21.3 70.1 9.9 920 COLUMN05 2006/12/18 40 23.6 69.5 0 <<< 219 2.94 23.6 69.4 6.9 927 COLUMN05 2006/12/20 42 24.3 69.4 0 <<< 194 2.86 24.3 69.5 6.3 928 COLUMN05 2006/12/21 43 25.2 67.7 0 <<< 232 2.69 25.5 68.2 7.1 928 COLUMN05 2006/12/22 44 25.3 69.2 0 <<< 273 2.74 25.5 69.8 5.5 926 COLUMN05 2006/12/27 49 27.6 70.2 0 <<< 161 2.54 27.8 70.6 2.2 921 COLUMN05 2007/01/07 60 30.45 69.55 0 <<< 161 2.28 31.1 71.2 0 914 COLUMN05 2007/01/08 61 30.3 69.7 0 <<< >>> 2.30 31.6 71 0 917 COLUMN05 2007/01/12 65 35.8 60.7 0.3 <<< 98 1.70 36.4 60.8 3.2 916 COLUMN05 2007/01/15 68 37.4 59.2 0.3 <<< 15 1.58 38.2 59.9 3.1 924 COLUMN05 2007/01/18 71 38.4 59.3 0.3 <<< 27 1.54 38.7 59.7 2 928 COLUMN05 2007/01/19 72 39 58.6 0.2 <<< 32 1.50 39.4 59 2.2 925 COLUMN05 2007/01/20 73 39 58.7 0.2 <<< 11 1.51 39.1 58.8 2.1 922 COLUMN05 2007/01/24 77 39.75 56.75 3.5 0 19 1.43 40.4 57.4 0 923 COLUMN05 2007/01/29 82 42.15 55.85 2 <<< 2 1.33 43.4 57.1 0 920 COLUMN05 2007/02/08 92 45.25 53.95 0.8 <<<< 308 1.19 47.6 56.1 0 919 COLUMN05 2007/02/12 96 47.15 52.45 0.4 <<<< 0 1.11 48.7 54 0 928 COLUMN05 2007/02/14 98 0.5 47.9 51.8 0.3 <<<< 10 1.08 49.6 53.5 0 929 COLUMN05 2007/02/16 100 0.5 47.85 51.95 0.2 <<<< 44 1.09 49.4 53.6 0 930 COLUMN05 2007/02/20 104 0.5 48.15 51.55 0.3 <<<< 40 1.07 50.8 53.9 0 930 COLUMN05 2007/02/21 105 2.2 48.25 51.35 0.4 <<<< 130 1.06 50.2 53.2 0 932 COLUMN05 2007/02/22 106 0.5 48.7 51.1 0.2 <<<< 18 1.05 51 53.5 0 928 COLUMN05 2007/02/26 110 0.5 46.7 52.9 0.4 <<<< 20 1.13 38.8 52.5 0 929 COLUMN05 2007/02/27 111 0.5 48.4 51.3 0.3 <<<< 3 1.06 39.1 51.3 0 925 COLUMN05 2007/02/28 112 0.5 48.85 50.75 0.1 <<<< 3 1.04 38.6 51 0.3 922 COLUMN05 2007/03/01 113 0.5 48.4 50.9 0.4 0 <<<< 1.05 48.6 51.1 0.3 917 COLUMN05 2007/03/02 114 0.6 48.35 51.15 0.5 0 0 1.06 48.8 51.6 0 919 COLUMN05 2007/03/05 117 0.5 45.8 52.5 0.4 <<<< 0 1.15 45.4 51.9 1.3 923 COLUMN05 2007/03/07 119 0.5 47.3 50.8 0.3 <<<< 0 1.07 47.3 50.7 1.6 922 COLUMN05 2007/03/09 121 0.6 46.8 52 0.3 <<<< 0 1.11 47.3 52.1 0.9 921 COLUMN05 2007/03/12 124 0.5 47.7 49.9 0.3 171 0 1.05 48 50 2.1 923 COLUMN05 2007/03/14 126 0.5 48.8 50.1 0.1 0 0 1.03 48.5 49.9 1 927 COLUMN05 2007/03/19 131 1.1 48.6 50.5 0.3 <<<< 0 1.04 48.6 50.5 0.6 928 COLUMN05 2007/03/22 132 0.5 47.5 50.8 0.4 0 0 1.07 48.1 50.7 1.3 932 COLUMN05 2007/03/26 136 0.5 49.2 49.8 0.4 >>>> 0 1.01 50.6 57.4 0.6 933
Page 5 of 6 Royal Institue of Technology Stockholm, 2007
BIOREACTOR GAS COMPOSITION (GA - GAS MONITOR/INRFA RED)
Barometric Day Draeger ID Date CH4 CO2 O2 H2S CO CO2/CH4 Peak CH4 Peak CO2 Balance Pressure No. H2S (ppm) vol % vol % vol % ppmV ppmV Ratio vol % vol % vol % mb COLUMN06 2006/11/08 0 0 0 21 0.00 79 928 COLUMN06 2006/11/17 9 1.1 31.4 2.2 <<< 403 28.55 1.1 31.4 65.3 930 COLUMN06 2006/11/20 12 3 47 0 <<< >>> 15.67 3 47.3 50 928 COLUMN06 2006/11/23 15 5.9 59.5 0 <<< >>> 10.08 5.9 59.7 34.6 923 COLUMN06 2006/11/24 16 7.1 67 0.2 <<< >>> 9.44 7.2 67.4 25.7 928 COLUMN06 2006/11/27 19 10.1 69.1 0 <<< 331 6.84 10.5 69.7 20.8 924 COLUMN06 2006/11/29 21 11.8 77.7 0.2 <<< >>> 6.58 11.8 77.7 10.3 920 COLUMN06 2006/12/01 23 13.2 73.4 0.4 <<< 705 5.56 13.3 74.2 13 919 COLUMN06 2006/12/12 34 17 66.5 0.4 <<< 58 3.91 17.4 66.9 16.1 930 COLUMN06 2006/12/13 35 18.6 68.8 0 <<< 261 3.70 19 69.3 12.6 923 COLUMN06 2006/12/14 36 19.1 68 0 <<< 267 3.56 19.4 69.4 12.9 920 COLUMN06 2006/12/18 40 21.2 67.3 0 <<< 60 3.17 21.5 68.7 11.5 927 COLUMN06 2006/12/20 42 22.5 68.5 0 <<< 155 3.04 22.7 68.6 9 928 COLUMN06 2006/12/21 43 23.6 67.5 0 <<< 139 2.86 23.8 67.9 8.9 928 COLUMN06 2006/12/22 44 23.6 68.5 0 <<< 175 2.90 23.9 69 7.9 925 COLUMN06 2006/12/27 49 24.4 65.2 0 <<< 83 2.67 24.5 65.4 10.4 921 COLUMN06 2007/01/07 60 27.9 63.7 0 <<< 70 2.28 28.2 64.6 8.4 954 COLUMN06 2007/01/08 61 27.9 65.5 0 <<< >>> 2.35 28.7 65.7 6.6 917 COLUMN06 2007/01/12 65 34.3 57.6 0.3 <<< 108 1.68 34.6 57.6 7.8 915 COLUMN06 2007/01/15 68 34.2 54.4 0.2 <<< 34 1.59 34.6 55.2 11.2 924 COLUMN06 2007/01/18 71 36.6 55.6 0.4 <<< 32 1.52 36.5 55.3 7.4 928 COLUMN06 2007/01/19 72 37.2 54.8 0.3 <<< 37 1.47 37.6 54.9 7.7 925 COLUMN06 2007/01/20 73 37.8 55.8 0.3 <<< 26 1.48 37.7 55.7 6.1 922 COLUMN06 2007/01/24 77 40.4 54.8 1.4 0 0 1.36 40.3 54.8 3.4 922 COLUMN06 2007/01/29 82 42.8 54.4 2 0 2 1.27 42.9 54.5 0.8 920 COLUMN06 2007/02/08 92 47.35 51.35 1.3 <<<< 272 1.08 49.2 53.2 0.0 919 COLUMN06 2007/02/12 96 49.3 50.4 0.3 1 8 1.02 50.5 51.3 0.0 928 COLUMN06 2007/02/14 98 15.3 50.15 49.65 0.2 0 24 0.99 51.4 50.6 0.0 929 COLUMN06 2007/02/16 100 0.5 50.25 49.45 0.3 0 44 0.98 52 51.4 0.0 930 COLUMN06 2007/02/20 104 0.5 50.6 49.2 0.2 0 46 0.97 52.1 50.8 0.0 930 COLUMN06 2007/02/21 105 21.7 50.9 48.8 0.3 <<<< 122 0.96 53.1 51.2 0.0 931 COLUMN06 2007/02/22 106 0.5 51 48.6 0.4 <<<< 20 0.95 53.4 51.2 0.0 928 COLUMN06 2007/02/26 110 0.5 50.6 49.2 0.2 <<<< 22 0.97 40.5 50 0.0 928 COLUMN06 2007/02/27 111 0.5 51 48.6 0.4 <<<< 4 0.95 41.2 49.1 0.0 925 COLUMN06 2007/02/28 112 0.5 50.9 48.9 0.2 <<<< 4 0.96 40.7 49.2 0.0 922 COLUMN06 2007/03/01 113 0.5 50.9 48.7 0.4 0 <<<< 0.96 50.9 48.7 0.0 917 COLUMN06 2007/03/02 114 0.6 51.15 48.55 0.3 0 0 0.95 51.6 49 0.0 919 COLUMN06 2007/03/05 117 2.2 47.6 48.7 0.1 <<<< 0 1.02 48.2 48.9 3.6 923 COLUMN06 2007/03/07 119 0.5 49.2 48.4 0.3 <<<< 0 0.98 49.8 49.2 2.1 922 COLUMN06 2007/03/09 121 1.1 49.1 49.3 0.3 <<<< 0 1.00 49.1 49.3 1.3 920 COLUMN06 2007/03/12 124 1.6 49.7 48 0.4 171 0 0.97 49.8 48.3 1.9 923 COLUMN06 2007/03/14 126 0.5 50 47.7 0.2 0 0 0.95 50.3 47.7 2.1 927 COLUMN06 2007/03/19 131 1.6 50.6 48.8 0.1 <<<< 0 0.96 50.9 48.5 0.5 928 COLUMN06 2007/03/22 132 1.1 50.2 49.4 0.4 0 0 0.98 50.2 49.3 0.0 932 COLUMN06 2007/03/26 136 1.1 51.2 47.8 0.3 >>>> 0 0.93 51.3 47.9 0.7 933
Page 6 of 6
APPENDIX D – SULPHATE LOAD CALCULATIONS
Once printed this document is an uncontrolled version and should be checked against the electronic version for validity Document:: Thesis Temp2 | Last printed: 6/19/2007 2:46 PM Page 4 of 5
5000 MG/L SULPHATE LOAD CALCULATION
When the simulated effect of AMD was added to the bioreactors the average leachate free leachate collected from the leachate sump was 7.6L. Using this as an average value and considering that there is leachate remaining in the column beneath the drainage port - an average value of 10L was used as a value for the available free leachate in each column.
AMD was sampled from a site where surface water runoff enters the void. Below is a summary analysis of this surface water: 2007/01/19 Parameter Units Value Temp oC 21.56 pH pH units 2.9 Specific Conductance uS/cm 16000 TDS mg/L 32000 Sulphate mg/L 20000 Total Copper ug/L 48000 Total Iron mg/L 640 Total Lead ug/L 1500 Total Zinc mg/L 1100
The obtain a leachate with concentration of approximately 5000 mg/L of sulphate - one of the higher ranges of leachate found in leachate of the Woodlawn bioreactor – the following calculations were made to allow for addition of the appropriate amount of AMD.
Sulphate Sulphate Leachate Leachate Sulphate in Volume of (Total) AMD Concentration Sulphate Volume Leachate AMD Sulphate AMD /Leachate AMD Concentration (Assumed) (Total) Concentration added Mix /Leachate Mix (mg/L) (L) (mg) (mg/L) (L) (mg) (mg/L) C2 220 10 2200 20000 3.19 66000 5004 C3 540 10 5400 20000 2.98 65000 5008 C4 630 10 6300 20000 2.92 64700 5008 C5 74 10 740 20000 3.29 66540 5007 C6 640 10 6400 20000 2.91 64600 5004
TRITA-IM 2007:30 ISSN 1402-7615
Industrial Ecology, Royal Institute of Technology www.ima.kth.se