Waste Management for Low Carbon Cities Improving Waste Management and Recycling
Contributors: June E Lombard Rosemary K Lombard Icando Environmental Management & Training
CHAPTER CONTENTS
1. Waste’s contribution to greenhouse gas emissions ...... 2 2. Current initiatives in eThekwini Municipality that reduce carbon emissions ...... 2 2.1 Materials recovery for recycling ...... 2 2.1.1 Separation at source with kerbside collection ...... 3 2.1.2 Materials Recovery Facilities ...... 3 2.2 Composting ...... 8 2.3 Energy recovery in eThekwini Municipality ...... 9 2.3.1 Landfill gas to electricity projects in eThekwini ...... 9 2.3.2 Waste water to energy projects ...... 13 2.3.3 Additional carbon reduction projects in planning stages in eThekwini Metro ...... 14 3. Further opportunities to reduce GHG emissions in the waste sector ...... 16 3.1 Waste avoidance and recycling ...... 16 3.2 Mechanical Biological Treatment incorporating Waste to Energy ...... 17 3.2.1 Mechanical treatment as part of MBT ...... 17 3.2.2 Biological treatment as part of MBT ...... 18 3.3 Carbon sequestration – CO2 fertiliser ...... 23 3.4 Biofuels and industrial processes ...... 24 3.5 Composting ...... 24 4. Overcoming barriers to implementing waste management strategies ...... 27 4.1 Waste to electricity options ...... 27 4.2 Public Private Partnerships ...... 28 4.3 Recycling constraints ...... 28 4.4 Incineration options ...... 29 5. Financing opportunities for waste projects ...... 29 5.1 CDM ...... 29 5.1 Other opportunities ...... 33 6. Recommendations...... 33 Waste avoidance and recycling ...... 34 Mechanical Biological Treatment incorporating Waste to Energy ...... 34 Carbon sequestration – CO2 fertiliser ...... 35 Biofuels and industrial processes...... 35 Composting ...... 35 Waste-to-energy systems ...... 35 7. USEFUL WEB SITES ...... 36 8. BIBLIOGRAPHY ...... 36
1 ‘The convenient truth about waste management is that the waste industry could act as role model and make partnerships with cities and other industries in a global and result- oriented action for significant GHG emission reduction..’ Jens Aage Hansen.’
1. Waste’s contribution to greenhouse gas emissions
South Africa recognises waste and associated polluting gases as significant sources of greenhouse gas emissions, particularly in urban areas. Methane and carbon dioxide from the anaerobic biodegradation of organic wastes in landfills, which are still the main method of disposal in the country, as well as the emissions of nitrous oxide, N2O, from combustion processes are the most significant of these. Worldwide it is estimated that waste management activities, especially the disposal of waste to landfill and concomitant generation of methane, contribute to global greenhouse gas (GHG) emissions by approximately 4 %1.
There is a growing body of evidence based not only on Life Cycle Assessment2 but also on real-life studies3 that local government can lead integrated waste management activities and make a significant difference in terms of GHG reduction, changing what initially is a per capita net positive GHG emissions to a net GHG negative emissions situation (by replacing fossil fuel generated electricity with renewable energy, avoiding manufacturing energy consumption for virgin materials, and reducing methane emissions from landfills).
The reduction of greenhouse gases has become an important driver for managing waste differently from past practices. Cleaner production, recycling and more energy efficient waste management technologies with less potential to generate greenhouse gases are being actively promoted, not only by South Africa’s recent waste-related legislation, but also by the economic incentives offered. eThekwini Metro Municipality is one of the leading municipalities in the country in this regard. This chapter examines the initiatives currently underway in the Metro as well as those still being planned. It also considers other opportunities and constraints to improving waste management and recycling, in the drive to reduce eThekwini’s carbon footprint even further.
Reduction of GHG emissions in the waste sector can be achieved in a variety of ways:
• Recovering materials for recycling into new products, thus avoiding the energy-consuming beneficiation and primary manufacturing processes that is otherwise necessary in the use of virgin materials. • Reducing emissions of landfill gas (an approximately 50:50 mixture of methane (CH4) and carbon dioxide (CO2) by better landfill practice and by reducing the organic wastes entering the site. • Utilising and/flaring off landfill gas for both heat and electricity generation. • Reducing methane emissions from wet anaerobic processes e.g. sludges. • Recovering energy and reducing carbon emissions from waste using Mechanical Biological Treatment processes. • Utilising the carbon dioxide from combined heat and power plants as a carbon dioxide fertiliser in greenhouses.
2. Current initiatives in eThekwini Municipality that reduce carbon emissions
2.1 Materials recovery for recycling
To maximise the recycling potential of materials, sorting recyclable materials from non-recyclables at source to recover relatively clean, and therefore higher value, materials is essential.
1 Bogner et al. (2007) 2 Waste Management and Research, Vol 27, Issue 9, Nov 2009. Special issue: Applied Green House Gas Accounting: methodologies and cases. ISWA ISSN 0734-242X. http://wmr.sagepub.com 3 Hansen, J.A. (2009) Editorial. Waste Management and Research, Vol 27, Issue 9, p 837-838.
2 The eThekwini Metro Waste Management Agency, Durban Solid Waste (DSW), has promoted a variety of alternative options for recovering materials that would otherwise end up on a landfill. The most desirable option is to recover discarded materials as close to their source as possible, before they become contaminated by other wastes and reduced in value. Kerbside collection, drop-off and/or buy- back centres for recyclable materials all achieve this objective of separation at source. If mixed wastes are received, the recyclable materials have to be sorted from the waste stream at what is often referred to as a ‘dirty MRF’ i.e. a Materials Recovery Facility where recyclables contaminated by other waste are recovered. Theoretically, reference is sometimes made to a ‘clean MRF’, where separated but ‘co- mingled’ recyclables are further sorted into their respective categories, but it is questionable whether such a facility exists in reality, given that there is generally a relatively high level of soiling of materials due to unwashed containers in any stream of co-mingled recyclables .
2.1.1 Separation at source with kerbside collection
The Mondi Recycling Company’s4 orange bag collection system in eThekwini Metro has been successfully implemented in approximately 800 000 households. Mondi supplies the orange plastic bags to households (1 per household per week) for mixed paper and plastic, while DSW supplies the black bags for residual waste to houses on a quarterly basis (2 per household per week). Mondi contracts their agents to pick up the orange bags on the same day as the municipal kerbside collection of black bags takes place. The materials are transported to the Mondi Recycling Company’s Materials Recovery Facility (MRF) at Maydon Wharf, where the waste is sorted and sent to appropriate recycling companies for processing. This system is currently operating in middle class and affluent areas, and there are plans to extend it to less affluent areas. To dispose of garden refuse, residents are required to buy additional blue Durban Solid Waste plastic bags; the price of the blue bags includes the service fee.
Education of residents to use the Orange Bag system is carried out through DSW’s doorstep programme; media coverage and publicity (print and radio); advertising on orange bags; word of mouth; promotions at the malls and other public areas; message on wheels; and pamphlet and letter distribution.
Approximately 60 % of the orange bags that are distributed are returned and some 1,200 tons per month of recyclable materials are recovered per month5. Approximately 916,500 tons of waste per annum6 are landfilled at DSW’s three sites (Bisasar Road, Mariannhill and Buffelsdraai landfills). Assuming a monthly quantity of 76,400 tons per month, the percentage of waste diverted from landfill is 1.5 % by mass via the Mondi Orange bag system.
2.1.2 Materials Recovery Facilities
Drop-off Centres
A drop-off centre is a facility where recyclable materials are delivered by residents who place them into bins for the respective categories, without receiving payment for the materials. Drop-off centres rely on voluntary recycling of materials by the general public and are generally located in middle- to higher- income areas. This type of facility also operates successfully in shopping malls and commercial centres where people can bring their recyclables at the same time as they do their shopping. Specialised storage containers are provided by the recycling company at agreed locations. These containers are also used for transporting recovered materials to the recyclers' processing plants.
Drop-off centres may become unsightly open dumps if strict supervision is not exercised over the deposition of recycled material, but generally work well when placed under the direct control of local authorities who can enforce by-laws that prevent littering. These centres also work successfully when located at garden refuse transfer stations that are managed by local authorities.
4 www.paperpickup.co.za 5 DSW N Govender, Public Relations Officer, DSW 6 DSW J Parkin, Landfill annual quantities, supplied 2010
3 eThekwini – Municipal Drop Off Centres
In eThekwini Metro there are numerous drop-off centres operating in more affluent areas:
• Hillcrest Drop Off Centre, Hillcrest, Durban Drop off centre with separate containers for paper, cardboard, PET and PE-HD plastics, glass, cans.
• Bellair Road Drop Off Centre Drop-Off Materials Recovery Facility with separate containers for paper, plastic and e-waste, where the public can drive into a centrally-located facility.
Private Company ‘Re’ Pavilion Shopping Mall Drop Off Centre
Re- Recycling Drop-Off Centre, at the Pavilion Shopping Centre, Westville, which is owned and operated by Re-. This drop-off centre includes an adjacent MRF with separate storage for paper, plastic - Low Density Polyethylene (LDPE), High Density Polyethylene (HDPE), Polyethylene teraphthalate (PET), and Polypropylene (PP)- scrap metal, glass bottles, e-waste etc.
Community Recycling Drop-Off Sites7
Area Drop-off Site Materials Accepted Amanzimtoti Nyati Road and Seadoone Road Sites tetrapak, paper, cardboard, plastic, glass, used motor oil, garden waste Bellair Cnr Bellair & Edwin Swales Drive tetrapak, paper, cardboard, plastic, glass, used motor oil, garden waste Bluff Cnr Tara & Greys Inn Roads tetrapak, paper, cardboard, plastic, glass, used motor oil, garden waste Chatsworth Sagittarius Road tetrapak, paper, cardboard, plastic, glass, used motor oil, garden waste Clermont Kwa-Dabeka Highway, off Freese Road tetrapak, paper, cardboard, plastic, glass, garden waste Durban North Riverside Road & Hyper-by-the-Sea sites tetrapak, paper, cardboard, plastic, glass, used motor oil, garden waste Hillcrest Hillcrest Civic Centre, Cnr Delamore & tetrapak, paper, cardboard, Hospital Roads plastic, glass Kloof Civic Offices, Emolweni Road tetrapak, paper, cardboard, plastic, glass Merewent Travencore Drive tetrapak, paper, cardboard, plastic, glass, garden waste Mount Edgecombe Transfer Station, Mount Edgecombe tetrapak, paper, cardboard, Drive plastic, glass, used motor oil, garden waste Newlands West Pipdale Road tetrapak, paper, cardboard, plastic, glass, used motor oil Phoenix Canehaven Drive tetrapak, paper, cardboard, plastic, glass, used motor oil, garden waste Pinetown Mariannhill Site, Richmond Road tetrapak, paper, cardboard, plastic, glass, used motor oil, garden waste, e-waste Redhill Malacca Road tetrapak, paper, cardboard, plastic, glass, used motor oil, garden waste
7 Eduself-DSW Recycling Booklet, Recycling for a better Durban, 2010 www.eduself.co.za
4 Area Drop-off Site Materials Accepted Shallcross 1 Rashidan Street garden waste Tongaat Off Edmund Moorwood Road garden waste Umkomaas Call 031 903 6943 garden waste Westville Civic Centre, William Lester Drive tetrapak, paper, cardboard, plastic, glass RE site, Lower Parking Level, Pavilion tetrapak, paper, cardboard, Mall plastic, glass, e-waste Woodlands/Montclair Glanville Road tetrapak, paper, cardboard, plastic, glass, used motor oil, garden waste Wyebank 1 Fernleigh Road garden waste Source: DSW Eduself, 2010
Buy-back Centres
Buy-back centres, as the name suggests, are facilities where people are paid for recyclable materials brought to the centre. This type of recycling facility operates successfully in lower income areas as it provides an economic incentive for recycling and encourages entrepreneurship. If volumes warrant it, there may be sorters and a baler on site as well.
Buy-back centres are operated by entrepreneurs, who make a brokerage income from the difference between the price for which they sell the recycled materials to the recycling companies and the price that they pay the collectors who bring the materials to the buy-back centre. The collectors are otherwise unemployed or under-employed people who collect recyclable material in their neighbourhoods to sell to the entrepreneur managing the buy-back centre located close to their homes. This ensures relatively clean recyclables, since the waste is collected and sorted at source by collectors because they are paid more for uncontaminated materials.
Most of the buy-back centres in South Africa are linked to the formal recycling industry, which provides support and guarantees acceptance of the material recovered at each centre. The entrepreneur usually employs a number of assistants on a permanent basis to help in the management of the facility. The collectors derive an income for this work and may become successful entrepreneurs as well. eThekwini - Durban Solid Waste Buy-Back Centres
Durban Solid Waste has established a number of buy-back centres. The outputs vary from centre to centre with the small centres in Warwick Junction trading small volumes, e.g. Brook St: waste paper, 168 tonnes per annum (2003) and larger centres in Redhill, Westmead, Queensmead and Isipingo trading at higher levels. In every case support of formal recyclers is required to ensure the viability of these centres. Formal recyclers include organisations such as Collect-a-Can, Mondi Recycling Company, the Glass Recycling Company, the Plastics Federation, Scrap Metal Dealers and Buyisa-e-Bag. Buyisa-e- Bag has assisted in setting up numerous buy-back centres throughout the country, including eThekwini, with funding from the plastic bag levy that everyone in South Africa pays. This non-profit organisation falls under the auspices of the National Dept of Environment and is supported by all the other major recycling companies.
Entrepreneurs running buy-back centres receive training from these organisations as well as from the DSW Education and Training organisation.
DSW Buy-back Centres8 are located at:
Area Address Contact Name Redhill 1288 North Coast Road Apple Green Pinetown 38 Westmead Road, Westmead Sabelo Ngcobo Queensmead Cnr Turquoise & Piet Retief Streets Harry Roshan Isipingo Lot 1029, Isipingo Main Road Ravesh Ramgobin Warwick Junction Lourne Street Richard Buthelezi
8 Eduself-DSW Recycling Booklet, Recycling for a better Durban, 2010 www.eduself.co.za
5 Source: DSW Eduself, 2010
Mixed waste Materials Recovery Facilities (MRFs).
The Materials Recovery Facilities (MRFs) currently operating in South Africa are all “dirty MRFs” which recover recyclable materials from the mixed waste stream at formally established facilities.
• eThekwini – DSW Mariannhill MRF
Owned by DSW and operated by Re- on an area located on DSW’s Mariannhill general waste landfill (GLB+)9 in Pinetown. This was a pilot project that has evolved with time and continues to operate successfully. This facility diverts 30% by volume of the domestic waste stream collected by the DSW collection fleet from landfill. This amounts to approximately 10% of the total waste stream entering the site. According to Re-, far more of the waste stream could be diverted if more space was allocated10. Apparently, almost 50% of the waste entering this landfill site is industrial and that material is being landfilled because Re- cannot handle this material due to space constraints.
This MRF employs approximately 100 people, mainly unskilled, to work at the sorting conveyors and other skilled people to operate and maintain the conveyors and balers. The MRF sorts the incoming domestic waste stream to recover and bale plastic (PET, polypropylene, polystyrene, polyethylene), paper (office white, K4/cardboard) and tin cans. Glass is also collected and stored in skips.
Material from this MRF is sold to best advantage, which means that business is mostly conducted with traders in the Peoples’ Republic of China. The volatility experienced during the 2009 global recession was a severe setback. It became apparent that, for a MRF such as this to remain viable, it needs to receive a share of the tipping fees recovered by DSW through the weighbridge operation. This MRF remains viable because of the formal commitment by DSW and Re- to diverting waste and recovering recyclables as part of the eThekwini Metro carbon footprint reduction and metro greening effort.
Fig ..: Schematic of Typical Separation achieved by EU MRF Installations
• Re- Ethical Environmental Re-engineering (Pty) Ltd MRFs11
9 DWAF Minimum Requirements for Waste Disposal by Landfill, 2nd Ed, 1998 10 Sharon Purchase, Re- (Pty) Ltd, Personal Communication 2010 11 http://www.re-sa.co.za
6 In addition to the MRF at the Mariannhill Landfill, this company runs several similar facilities and drop-off centres at large shopping malls in the Durban area, e.g. the Pavilion, and at its own premises in Prospecton. Having installed the equipment which runs at no cost to eThekwini Municipality, Re- sell the recovered materials and keep the proceeds.
• Mondi MRF
As mentioned above, Mondi operates its own MRF at Maydon Wharf for separating out various categories of recyclable materials.
In summary, therefore (not exhaustive):
Summary of recycling activities in eThekwini Metro Municipality area (June 2010)
Project Name Where When Who Comments Mariannhill GLB+ Mariannhill Landfill current Re Problems with Landfill MRF unsorted health care risk waste Mondi Waste City-wide amongst current Mondi Waste Paper Only separating plastic Paper Orange Bag the more affluent supplies Orange and paper ratepayers Bags, DSW manages contractors Garden Refuse City-wide bags are current DSW Expensive to Blue Bag bought at shops, household – should be e.g. Pick n Pay, free and bags break Spar, etc. easily only really suitable for leaves and lawnclippings Large BuyBack Westmead and current DSW appointed Not well managed fires Centres Durban North contractors have occurred Small BuyBack 15 or more have current Several Appears to be Centres been established entrepreneurs have successful been established with the backing of recyclers such as Mondi Waste Paper and others together with DSW Community Based Approximatley 20 current DSW supported Operating well Drop-Off Centres available
Advantages
Recovery of reusable material through an MRF has the following benefits:– • Plastics recovery reduces emissions related to the refining of fossil fuels, from which plastics are derived. • Production of any type of paper involves the capture of carbon through the growth of trees used as raw material. Approximately 30% less energy is required to produce good quality recycled paper than to produce virgin paper. • Recovered metals, whether ferrous or non-ferrous, may be re-smelted with substantial energy savings. • Glass re-smelted saves substantial energy. • Opportunities for job creation in the sorting system: the Mariannhill MRF employs 100 previously unemployed workers. • Rejected material and biodegradable organic waste is either landfilled or,better still, passed on to the next step in Mechanical Biological Treatment, which could include the anaerobic digestion treatment stage, where energy may be generated. This is already under consideration at Mariannhill Landfill.
7 Challenges12
• Many people abuse the Mondi recycling service and use the orange bags for other waste. • The population do not care about recycling • Glass is not currently being recycled due to the transportation costs of getting the glass to the recyclers • Recycling must be considered not only from a materials recovery perspective but also from the point of view of energy usage in transportation, water consumption of rinsing soiled recyclable materials • It seemed unlikely to the DSW official that incentives would work to encourage people to dispose of waste
2.2 Composting
Composting: Small scale, low technology treatment of organic waste at household/ community level
An indeterminate number of households in eThekwini practice recycling in the form of backyard composting. This presents an opportunity, especially in peri-urban to rural areas, to introduce shallow trench gardening as an option for organic waste management. Composting and shallow trench gardening achieve the following: • Promote responsibility for wastes at household level; • Promote and encourage awareness in waste management and the broader environment; • Save resources required for hauling and disposing wastes; • Encourage good sanitation practice by getting waste out of the house; • Promote greater self-reliance and food security.
Composting: Larger scale treatment of organic waste at municipal level
National Plant Foods in eThekwini
The large scale National Plant Foods low-technology composting operation in Cato Ridge (Gromor products) has been operating successfully for several decades, High quality compost is manufactured using using chicken litter, abattoir lairage, paunch contents and ingesta from slaughtered animals, along with knottings and finely divided material from Sappi Saiccor. Windrows turned with conventional earthmoving equipment such as rubber-tyred loaders are used to process the material.
Pilot composting on site at Bisasar Road Landfill
Composting pilots were run in an area set aside at the Bisasar Road landfill in conjunction with the School of Civil Engineering, Surveying and Construction of the University of KwaZulu Natal. The results have been written up in a series of publications13. The findings were as follows:
^^^^^^^^^^^^^^^^^^^^^^^^^^^ publications summary pending
12 John Parkin, Durban Solid Waste Personal Communication, July 2010 13 UKZN publications ^^^ awaited from Prof Cristina Trois, Head of School of Civil Engineering, Survey and Construction at University of KwaZulu-Natal
8 Table … Summary of some composting operations discussed
Project Name Where When Who Comments Composting trials Bisasar Rd 2008-9 UKZN with experimental at Bisasar Rd Landfill DSW work in conjunction with UKZN under Prof Trois –aerobic composting – not using the heat Gromor/National Cato Ridge Current and Rolf Hagen This operation is Plant Food operating low tech and very successfully successful for decades nationally over an extended period of time
Other initiatives in SA
Nelson Mandela Bay Metro Municipality The sustainability of three different basic composting (aerobic biodegradation) operations using municipal waste as community initiatives was the subject of a study in the Nelson Mandela Metro Municipality area funded by the Swedish International Development Cooperation Agency (SIDA)14.
All of the projects studied succeeded in producing a marketable product, but none generated enough income to cover their respective costs. Some of the projects were close to breaking even, or being profitable, with an increase in volume processed. Some were already considered economically sustainable when taking the savings from alternative treatment into account. The study further suggested that co-operatives of were the most effective organisational arrangement when running composting schemes in communities.
2.3 Energy recovery in eThekwini Municipality
2.3.1 Landfill gas to electricity projects in eThekwini
Landfill gas, generated by the anaerobic digestion of organic waste, comprises roughly 50% methane and 50% carbon dioxide, both of which are greenhouse gases that contribute to global warming and climate change, methane 21 times more so than carbon dioxide. The National Waste Management Strategy15 promotes treatment of waste by microorganisms (aerobic or anaerobic biological treatment) or by thermal treatment (either high temperature incineration or alternative non-combustion processes) all with the aim of reducing the amount of waste sent to landfill. To this end, several new policies and standards are being developed in South Africa and the waste classification system is being reviewed. Full cost accounting of landfill management, historically not carried out, is now a requirement, to enable more realistic comparisons between waste treatment technologies and disposal to landfill.
eThekwini runs its landfills to high standards, controlling emissions of landfill gas and leachate, thus facilitating the containment and capture of landfill gas. It achieves this by conducting regular external audits and monitoring committee report-back meetings, essential controls that are in place on an ongoing basis.
The methane in landfill gas is a source of energy and can be extracted and safely utilised to generate heat and electricity which is renewable “green energy”. The aim of a CDM project is to realize reductions in green house gas (GHG) emissions to the atmosphere with the sale of carbon credits being a source of revenue. The eThekwini Landfill Gas to Electricity Clean Development Mechanism (CDM) project was conceptualised in 2003, when it was decided to install landfill gas extraction and electricity generating
15 Dept Environmental Affairs, National Waste Management Strategy (Draft 2010)
9 plants at the three DSW landfills, namely La Mercy, Mariannhill and Bisasar Road, with a potential to produce a maximum total of 10MW at gas peak of electricity.
In 2009, the Mariannhill and La Mercy landfills contained approximately 2.7 and 1.2 million m3 of municipal solid waste respectively. Landfill gas is extracted through gas wells that arevertically driven into the waste, or inclined “gas riser” pipes located around the landfill perimeter laid on top of the slope lining system (Figure … below). Wells are typically no greater than 25m in depth. The landfill gas is sucked from the landfill at low pressure (15 -50 millibars), then blown into a flare unit and reciprocating spark ignition engine through a roots blower system. Previously gas was flared off at Mariannhill Landfill through 6 “baseline” gas wells.
Figure … Diagram of a typical site layout showing extraction of landfill gas
The project was split into two components to accommodate delays in one of the related Environmental Impact Assessment (EIA) processes. Component 1 was a 1 MegaWatt (MW) plant at Mariannhill and a 0.5 MW plant at La Mercy, for which the environmental authorisation and Designated National Authority (DNA) approvals had been received. Component 2 was for an 8 MW plant at Bisasar Road, for which approvals were still pending. The World Bank ERPA was signed for Component 1 only which was registered as a Clean Development Mechanism (CDM) project in terms of the Kyoto Protocol. Component 2 received its environmental authorization and DNA approval and was registered as a CDM project with the CDM Executive Board later. Construction of the initial 4MW plant at Bisasar Road Landfill was completed in April 2008 and an additional two 1MW engines and the relocated O.5 MW engine from La Mercy (which did not yield sufficient gas) increased the plant output to 6.5MW.
The eThekwini Municipality owns the project implementation landfill sites while the CDM project is developed and implemented by Durban Solid Waste (DSW).
The landfill-gas-to-electricity activity consists of two complementary parts:
• Collection, flaring, and combustion of landfill gas; and • Generation of electricity, feeding into the Municipality’s electricity grid.
10
Production of Landfill Destruction of Generation of Supply to Municipal Gas (CH4, CO2) Methane (CH4) Electricity Electricity Grid
GE Jenbacher
Gas Collector Landfill Gas Landfill Gas Engine Step-up Wells in Landfill Pump & Flare and Electricity Transformer
G Figure …. Schematic Layout of Landfill Gas-to-Electricity Project16
Project Performance
This project demonstrated that eThekwini Municipality was capable of implementing and managing a CDM project, and has resulted in over thirty potential new projects being identified, which are under preparation by the Municipality.
The results of a review of the project in 200917 reported that Mariannhill is an active landfill site where waste will be deposited until 2024. It extends over 49 ha and receives 550 to 700 tonnes of waste per day. In January 2009 the site has received approximately 850,000 tonnes. It was predicted that by 2024 1,775Nm³/hr of landfill gas would be produced at this site. Construction commenced on 31 January 2006 for the installation of extraction wells and flare systems, as well as the supply and the installation of a 1 MW purpose-built spark ignition engine. The review reported that La Mercy was an old landfill site, closed in 2006, which received 350 tonnes of waste per day and had about 1 million tonnes of waste in place. Bisasar Road landfill is an active site, expected to be in operation at least until after 2020, currently receiving up to 2,500 tonnes of waste per day and flaring only a portion of the methane generated for local, site-specific reasons. Over the course of the initial seven-year carbon reduction crediting period, the generators are projected to produce nearly 350,000 MWh, amounting to an estimated CO2 reduction of 340,000 tonnes. It is estimated that the project will reduce an aggregated 2,466,957 tonnes of CO2 in the first seven-year crediting period. The Bisasar Road project was commissioned in January-February 2008. The lessons learnt from Component One have made it possible to achieve almost double the gas yield in Component Two (Bisasar Road). The current 18 emission reduction is about 15 – 20,000 t CO2 equivalents per month .
Project Financing
The Durban Landfill Gas to Electricity CDM project is financed as follows:
Grant donor funding from: • Department of Trade and Industry: Critical Infrastructure Programme (CPI) • Department of Minerals and Energy
Loan funding from: • French Development Bank
Total project capital expenditure in 2004 was estimated at R 61,670,255.
Operational costs were projected at R 27,754,876.
16 The eThekwini Municipality - World Bank Prototype Carbon Fund’s Durban Landfill Gas To Electricity Clean Development Mechanism (CDM) Project, Project Information Sheet (2007) 17 AFD - Baobab Consult & Infrastructure Développement Consultants (2009), Ex-post Evaluation of the AFD Credit Line to the eThekwini Municipality Gas to Electricity Project 18 John Parkin, Durban Solid Waste, Personal Communication (July 2010)
11
Total project income revenue projections were R33.9 million, realised from: • Sale of carbon credits (R20.7 million), and • Sale of electricity (R13.2 million).
Carbon Emission Reduction Credits (CERs)
According to the report19 , the 2009 world market for carbon credits showed that eThekwini could negotiate a price around €11.00 per CER over a project period of 10-14 years for Component Two. This price was substantially different to the US$ 3,95 per ton gained from Component One. While there was consensus on the substantial benefit to be derived from CERs, the process leading to actually receiving the revenue is arduous and protracted, and greatly increases the management burden and administrative costs. A timeline of no less than three years to achieve a possible income must also be factored into the preparation phase.
Bisasar Road landfill produces a high flow of landfill gas, in excess of 7,000 m3 per hour (equivalent to 7 tons of coal per hour) that is neither extracted nor utilised. Every day that the financial transaction of the CER is delayed translates to a loss by eThekwini Municipality of almost R100,000 in potential sales of CERs and electricity.
All the electricity produced by the Project is sold to eThekwini Electricity through a ten-year Power Purchase Agreement (PPA) at parity with the Eskom Local Authority Tariff.
A project management team was established in 2003 to manage the design, project preparation, commissioning and implementation of the Project. Without this team the project would not have got off the ground. The organizational structure involved a strategic inner-hub made up of representatives of the key functional areas that were central to the Project: DSW, eThekwini Electricity, Environmental Management Branch, eThekwini Water Services, Treasury and Legal Services, with project management reporting direct to the City Manager. External specialist resources were contracted for EIA, engineering, financial analysis, and legal aspects. The Project was located in the DSW functional area, hence the overall management of the Project devolved upon DSW.
Impact of the Project
It was important for South Africa to have a working reference case, and the eThekwini Municipality’s landfill gas to electricity project has demonstrated that, despite the obstacles posed by the Municipal Finance Management Act MFMA, it is possible to: • Build and operate a renewable energy power plant; • Sell the electricity back to the Municipality; and • Achieve CDM registration and CER verification. Approximately 2,500 m3 of landfill gas per hour (equivalent to 2,5 tons of coal per hour) is captured on a continuous basis. The Project is reproducible and contributes to technology and knowledge transfer – even more so because this type of project is uncommon in developing countries. More than thirty potential CDM projects have already been identified for further investigation in eThekwini. These potential projects are situated in various operational areas of the Municipality and cover a wide range, e.g. small- scale hydro-electric power and transport-related projects. Another CDM landfill project was registered in South Africa in April 2007, while a further twenty CDM submissions have been made, of which, by 2009, thirteen were registered and seven were undergoing the registration process. The AFD loan was probably a key factor that made the Project possible. Knowledge gained from this successful project is valuable for informing other potential gas-to-electricity projects and building capacity to replicate similar projects. The report found that there was a need for a practical follow-up workshop with decision makers and implementers from other Municipalities and larger cities that contemplate engaging in similar projects to assist them in moving forward.
19 AFD - Baobab Consult & Infrastructure Développement Consultants (2009), Ex-post Evaluation of the AFD Credit Line to the eThekwini Municipality Gas to Electricity Project
12 Summary of landfill gas to energy activities in eThekwini Metro Municipality area (June 2010)
Project Name Where When Who Comments Cdm Reg. Status GLB+ Bisasar Road, operating DSW provisional Landfill20 Springfield Park GLB+ Landfill Mariannhill operating DSW provisional H:h Landfill Bulbul Drive planned WasteMan - Group H:h Landfill Shongweni planned EnviroServ - Group
2.3.2 Waste water to energy projects
Municipal Waste Water Treatment Works The Department of Water Affairs in the Ministry of Water and Environmental Affair released its Green Drop report21, an assessment of the performance of sewage treatment works. The report indicated that, countrywide, only 7% of Waste Water Treatment Works (WWTWs) out of a total of 850 were actually effective; the rest were pumping polluting effluent into sea and water courses. South Africa, being a water deficit country, needs to address this situation urgently. Municipalities are under immense pressure from regulating authorities to upgrade their WWTWs.
The Green Drop report showed that the overall waste water quality management performance of eThekwini Metropolitan Municipality was very good. Out of the 27 WWTWs, 11 achieved scores of equal or higher than 90%. A further 3 works, with minor improvements, could potentially qualify for Green Drop Status in the near future. Of concern was that all of the WWTWs, including the higher scoring ones above, required improvement in ensuring that the works were registered and that the relevant documentation was readily available. The 13 WWTWs which did not qualify for Green Drop Status required further improvements, specifically in relation to waste water quality compliance and capacity planning.
The aerobic waste water treatment processes used at most WWTWs are energy-intensive, in that they consume large amounts of electricity to drive the activated sludge process. One mitigation measure to avoid this is to revert to anaerobic digesters which have much lower energy requirements: this is the reason for the concerted move by all larger municipalities in South Africa, including eThekwini, to revamp their waste water treatment works and return to anaerobic digestion technology.
Anaerobic digesters, when managed correctly, produce significant quantities of biogas, with methane levels averaging about 65% by volume. Added benefits can be achieved by using this methane to generate electricity in gas engines, which achieve conversion efficiencies approaching 48% (almost double the efficiency of a comparable gas or steam turbine operating within the same range of gas production).
The heat from the engine block and exhaust of the gas engine may be used in conjunction with a heat exchanger to warm the anaerobic digester and improve the rate of biodegradation. Engine exhaust gases are pumped through a plate heat exchanger to warm the mixed sludge to 37o C, the optimal temp for digestion, thus obviating the need to use electrical energy to heat sludge. The electricity generated can be used to drive the mixers within the anaerobic digesters which are essential for efficient biodegradation.
Small scale anaerobic digesters
Research22 into the environmental burdens associated with the provision of potable water and sanitation was undertaken in the eThekwini Municipality. Life Cycle Assessment was carried out on the individual
20 DWAF 1998, Landfill classification in terms of Minimum Requirements for Waste Disposal by Landfill, 21 Dept of Water Affairs. Green Drop Report April 2009 Version 1. South African Waste Water Quality Management Performance. 22 E. Friedrich, S. Pillay, C.A. Buckley (2009) Carbon footprint analysis for increasing water supply and sanitation in South Africa: a case study Journal of Cleaner Production 17, 1–12
13 parts of the urban water system (impoundment, water treatment, distribution, collection, sewage treatment and water recycling) for municipalities striving to achieve the Millennium Development Goals. Results showed that wastewater treatment plants with activated sludge units have very high-impact global warming scores (carbon footprinting) due to their high electricity requirements. The study concluded that, wherever appropriate, safe on-site sanitation should be promoted because of the environmental advantages associated with lower energy requirements (collection and secondary treatment are not necessary) and sustainability.
Aligned to this concept, Ethekwini Metro is supporting development projects where small on-site anaerobic digesters are being tested by Agama Biogas to digest agricultural wastes and sewage. A small scale system using the sewage from a community centre and adjacent houses is already operational in Cato Crest and yields 60 kW of electricity for use at the community centre. The treated water from the digester is used in a local food garden attached to the centre and there are also plans to use some of the effluent for aquaculture of tilapine fish.23
Urine diversion toilets
The Department of 90,000 composting urine-diversion toilets have been installed in eThekwini periurban areas where there is no sewerage system24. This is an example of on site sanitation requiring no electricity or significant amounts of water, and therefore not contributing to the carbon footprint of the city. If properly used, odours are minimal. The eThekwini Water and Sanitation Department is researching the extraction of phosphorous (which essential for agriculture) from urine.
2.3.3 Additional carbon reduction projects in planning stages in eThekwini Metro
• A biodiesel project is planned by eThekwini Water and Sanitation for two to three years’ time to transform algae from maturation ponds at the city’s wastewater treatment plants to biodiesel and other products. . Studies have shown …..
• A sewage sludge disposal plan is currently being implemented by eThekwini Water and Sanitation Department to manage the disposal of sludge stockpiles at all the wastewater treatment works. Currently the disposal of sludge costs some R 20 million per annum, and requires that the sludge is transported via tanker to various sites some distance away, including to agricultural land (Hammarsdale, Ballito), landfill sites and the Southern Treatment Works, South Durban. The municipality is planning to accelerate its stockpiling for agriculture, and to make pellets with the remainder (a process that requires electrical power). Incineration may be used to treat some of the sludge, and an incinerator at the KwaMashu Treatment Works has been refurbished recently and is handling approximately 90 tons of sludge per day. Unfortunately this process requires energy to incinerate the dry sludge. A pre-feasibility study has also looked into the use of sludge to generate electricity using methane to power turbines in the system. If feasible, this will likely take a couple of years to implement.
• Planned Mariannhill Mechanical Biological Waste Treatment (MBT) to Energy CDM Project, eThekwini due for 201225 was designed by the eThekwini Environmental Planning and Climate Protection Department in conjunction with DSW (MBT is discussed in more detail in Section 3.1 below).
This project will entail the removal of organic wastes from the existing mixed municipal solid waste streams of the western regions of eThekwini Municipality for Composting and Anaerobic Digestion and electricity generation. Project will comprise a Materials Recovery Facility, a composting plant, an anaerobic digestion plant and a reciprocating spark ignition gas engine.
Anticipated benefits: o “Carbon” Capacity Building
23 Ray Lombard Personal Communication August 2010. 24 Neil McLeod, Head eThekwini Water and Sanitation, Personnel Communication, July 2010. 25 Greening Durban 2010: CDM Project summary June 2010. The Mariannhill Mechanical Biological Waste Treatment (MBT) to Energy CDM Project, eThekwini , South Africa Durban , South Africa
14 o Financial return through the sale of carbon credits, o Compost and fertilizer blend produced o Landfill airspace savings o Provision of renewable electrical energy o Job creation and sustainable development o Combating global climate change
Anticipated results: o Job creation: 34 posts at varying levels. o Average CERs per year: 24,872 o Total CERs over 14 years: 348,215 o Average kWh electricity output per year: 4,032,00 o Total kWh electricity output over 14 years: 56,448,000 o Average tonnes of compost per year: 5,940 o Total tonnes of compost or pellets over 14 years: 83,160 o Average tonnes of fertiliser per year: 405 o Total tonnes of fertiliser over 14 years: 5,670
26 • The eThekwini Southern WWTW Anaerobic Digestion (AD) Biogas to Energy Project is an initiative of eThekwini Environmental Planning and Climate Protection Department with the eThekwini Water and Sanitation (EWS) Unit as project partner. It entails the treatment of raw sewage sludge by way of anaerobic digestion biological processes, the generation of electricity using the methane-rich biogas produced from the AD plants, and the production of compost and nutrient-rich fertiliser materials from the digestate of the AD processes at the Southern Wastewater Treatment Works.
• Project technologies o The construction of a new Anaerobic Digestion (AD) Plant comprising several AD tanks; o a new sludge management facility comprising sludge separation, sludge drying, o a composting plant and liquid fertiliser (digestate) storage; o an electrical generation compound of gas-fired spark ignition engine generators of up to 3MW total capacity. • Anticipated benefits: o Job creation: 21 jobs at various levels. o “Carbon” capacity building o Financial return through the sale of carbon credits, electricity generated, compost and fertiliser blend o Provision of renewable energy o Job creation and sustainable development o Combating global climate change o Technology Transfer • Anticipated results: o Average CERs per year : 97,038 o Total CERs (14 years) : 1,358,537 o Average kWh electricity output per year : 18,679,900 o Total kWh electricity output (14 years): 261,518,600 o Average tonnes of agricultural pellets per year: 5,440 o Total tonnes of agricultural pellets over 14 years: 76,160 o Average tonnes of fertiliser per year: 656 o Total tonnes of fertiliser over 14 years : 9,185
Other Landfill Gas to Energy projects in South Africa
There are other initiatives in some of the larger cities in South Africa, listed in Table… below:
26 Greening Durban 2010: CDM Project summary. June 2010. The eThekwini Southern WWTW (Waste Water Treatment Works) AD (Anaerobic Digestion) Biogas to Energy Project, Durban , South Africa
15 Table … A few other landfill gas-to-energy projects in SA (not exhaustive)
Project Name Where When Who Comments Ekhurhuleni Metro Sebenza Landfill Currently Ekurhuleni Metro Recovery of LFG Pilot Project (closed site) underway which is enriched to natural gas quality for use as fuel substitute for LPGas in 8 refuse collection vehicles City of Cape Town Vissershok Due for tender City of Cape LFG extraction and Municipal site Town in flaring, followed by conjunction with gas to electricity CEF and General within 12 months Energy Systems SA (GESSA) City of Goudkoppies, In planning stage City of Jhb in LFG extraction and Johannesburg/ Linbro Park, Marie conjunction with flaring, followed by GESSA Louise, Robinson CEF and General gas to electricity Deep Landfills Energy Systems within 12 months SA (GESSA) PMB Msunduzi - New England In planning stage Msunduzi in LFG extraction and GESSA Road Landfill conjunction with flaring, followed by CEF and General gas to electricity Energy Systems within 12 months SA (GESSA) Umhlathuze Alton Landfill Current Umhlathuze Recovery of LFG Municipality- District and generation of GESSA Municipality with electricity supplying GESSA to Hillside Aluminium Plant
3. Further opportunities to reduce GHG emissions in the waste sector
3.1 Waste avoidance and recycling Significant progress can be made in reducing a municipality’s carbon footprint by increasing waste avoidance and recycling in the following areas:-
Ewaste recovery
The E-Waste Association of SA (EWASA), a non-profit organisation, is driving the recovery and recycling of e-waste, supported by the Information Technology Association (ITA). Comprising all formal ICT industry players, including Dell, Siemens-Fujitsu, Microsoft, IBM, Hewlett Packard etc, the ITA’s membership represents 85% all ICT hardware and software sold in SA. Recovery and recycling of e- waste will be achieved by the levying of an Advanced Recycling Fee (ARF), a mechanism used with proven success in Switzerland. The process of establishing the required infrastructure to implement this is at an advanced stage27.
Policy should state that hardware should be purchased only from members of EWASA to ensure that its recovery and recycling is assured. Similarly electronic hardware should not be disposed of except to EWASA-accredited recyclers (list on EWASA website28).
Green procurement policies
The use of paper with guaranteed recycled fibre content should be written into municipal procurement policy and procedures. If every government department implemented such a policy, it would significantly stimulate demand and create a market for recycled paper.
27 www.ewasa.org 28 E-Waste Association of South Africa: www.ewasa.org
16
Cleaner production processes
Cleaner production in industry, supported through the formation of Waste Minimisation Clubs29, will significantly reduce wastage and the quantities of waste going to landfill. This will need the commitment of industry and will need to be driven by a champion, whether this is an organisation or an individual, with strong support from the municipality.
Waste Exchanges
Industry and municipalities can implement waste exchanges: structured, synergistic relationships which reduce material sent to landfill (especially chemical wastes). Waste products from one industrial process may be used as feedstock for another process by a different industry. These initiatives have been successfully set up in areas such as Cape Town but are highly dependent on there being an active product champion, usually an individual with strong backing from the municipality.
3.2 Mechanical Biological Treatment incorporating Waste to Energy MBT options must be considered if a low carbon footprint is a priority. The Kyoto Protocol, aimed at reducing greenhouse gas emissions and therefore the effect on climate change, as well as EU Directives banning indiscriminate disposal to landfill, have driven a new wave of waste treatment technologies known as Mechanical Biological Treatment (MBT), as well as waste-to-energy systems and combined heat and power technologies to reduce the carbon footprint30 of the waste management system.
Especially in European countries, the trend is towards pre-treatment of municipal solid wastes prior to disposal, to reduce the volumes of waste to be transported and disposed of at landfills, as well as negative emissions from the organic contents of municipal solid waste. This pre-treatment may consist of appropriate mechanical/biological treatment technologies. As reported above, the feasibility of Mechanical Biological treatment (MBT) options as a means of managing waste is currently being investigated at the Mariannhill Landfill.
MBT options might include only one or a combination of the following treatment processes:
3.2.1 Mechanical treatment as part of MBT
Mechanical treatment begins with pre-sorting and recovery of recyclable fractions from the waste stream at a MRF to reduce the need for extracting and processing virgin materials. This may involve any of the following: pre-sorting, screening, sorting, shredding, inspection, magnetic separation, and homogenisation This physical processing reduces carbon emissions which would have resulted from the extraction and beneficiation processes upfront. Separating out the organic fraction of the waste stream for biodegradation is also necessary to then apply either aerobic or anaerobic, and wet or dry biological treatment.
29 National Cleaner Production Centre: www.ncpc.co.za 30Sharon Purchase Personal Comm 30 Carbon footprint refers to the "the total set of greenhouse gases (GHG) emissions caused by an organization, event or product" http://en.wikipedia.org/wiki/Carbon_footprint (Accessed 25 July 2010)
17
Figure … Diagram showing the Mariannhill MRF facility (2009) 31 an example of mechanical pretreatment
3.2.2 Biological treatment as part of MBT
• Low-technology aerobic biodegradation (in the presence of oxygen) of the organic fraction of waste could range from composting at source at household level to a larger scale regionalised operation. The latter could involve simple open windrows for composting with limited to no automation and low cost technical and operational requirements. • Aerobic biodegradation could involve more complicated, enclosed systems, where there is a high degree of automation, full process control, and complex technologies and may be carried out under ‘wet’ or ‘dry’ conditions. • Anaerobic biodegradation (in the absence of oxygen) could also be used, usually in combination with in-vessel (enclosed) aerobic biological degradation. These combinations represent the most advanced MBT technologies. • MBT options may also include the production of refuse-derived fuel; and conversion of waste gas to electricity.
The residual material left after processing according to MBT principles is greatly reduced i.e. 5% of the original mass which can then be landfilled.
MBT technologies require a high degree of management. Technically, the processes are more complicated than landfilling and the concept is also fairly new concept in South Africa. eThekwini would have to ensure that the operator of such a plant is technically competent in running the facility as well as create an awareness and education campaign to drive the separation of waste at source.
31 Designed by the Re-ethical recycling company.
18
Figure … Summary of Mechanical Biological Treatment (MBT) Process Flow32
Fig ..: Diagram of Typical Power Generation Installation linked to Anaerobic Digester 33
Benefits/Outputs
Energy recovery from anaerobic digesters is in the form of methane which is then burned:- • in boilers, to raise steam for steam turbines to produce electricity. Electrical energy recovery at this scale of operation is not highly efficient. Space occupied by the plant, expensive air pollution control equipment, disposal of pollutants extracted from the flue gas and the opposition of the Green Lobby to any form of incineration seriously mitigates against this technology. •
32 http://en.wikipedia.org/wiki/Mechanical_biological_treatment 33 Jenbacher: Siggerwiesen Plant in Austria
19 OR • in gas engines, to produce electricity. This process is more efficient, with up to 40% electrical energy recovery. Most of the balance is heat energy, which may also be recovered either through the Organic Rankine Cycle34 to produce more electricity, or by using the thermal energy in the exhaust gas to heat the anaerobic digesters and dry the anaerobic compost material produced by the process. Overall energy recovery efficiencies can be improved up to 80%. Gas engines operate within the stringent EU emission standards – their efficacy has been demonstrated with the CDM projects at Bisasar Road and Mariannhill landfills.
Soil ameliorant/cover material: • Anaerobic digestate from the ADs is dried using recovered heat from gas engines and milled for use as a soil ameliorant. • Produces electricity and recovered compost – this is a method currently favoured in the EU. • If this material is not used as compost or plant mulch it can be used as cover material on the landfill much the same way as soil.
Wet Anaerobic Digestion Anaerobic digesters may be used instead of aerobic processes for composting, allowing the recovery of methane to generate electricity as well as the use of the heat energy to warm the digesters, thus increasing the system’s energy efficiency.
Wet anaerobic digestion is used extensively in the EU for agricultural and sewage wastes. There are 1,150 successful projects using agricultural waste to generate electricity35. Sewage sludge and agricultural wastes have great potential for generating renewable electricity. For example, chicken farms and energy rich poultry waste are an area worth considering, having the potential to yield 580 MW nationally36.
There are 939 carbon sequestration projects operational in the Benelux countries at various scales, which use agricultural and domestic wastes to produce electricity, recovering the exhaust gas to warm greenhouses and to enrich the atmosphere with CO2 in the greenhouses where salad crops (e.g. tomatoes) and cut flowers are produced.
Figure … below shows the potential biogas yield per ton of various waste streams. Domestic waste water would have a biogas yield similar to pig manure.
34 The Rankine Cycle refers to a cycle which converts heat into work 35 Ref from Jenbacher (2009) 36 R Lombard Personal communication 2010.
20
Figure …. Potential biogas yield per ton of various waste streams37
“Dry” Anaerobic Digestion
Dry anaerobic digestion is a series of processes in which micro-organisms break down biodegradable material in the absence of oxygen utilising renewable resources as a feedstock to produce a methane and carbon dioxide rich biogas suitable for energy production. The nutrient-rich solids left after digestion can be used as a fertiliser and compost. Emission of GHGs are reduced by replacement of fossil fuels, reduction of landfill methane emissions, displacing chemical fertilisers and reducing vehicle movements.
Almost any organic material including sewage sludge, waste paper, grass clippings, food waste, animal wastes and other agricultural wastes can be processed with dry fermentation. The plants comprise a number of anaerobic digesters and Combined Heat and Power (CHP) plants.
Process38
Organic material is received at the plant and fed, in batches, into the digesters. The digesters are then sealed and the organic matter warmed. The interior of the digester is sprayed with a water vapour containing micro-organisms that feed upon the organic matter converting it, via a number of chemical stages, into biogas. The energy requirement for the process is low and leachate generated by the biodegradation is collected and re-percolated over feedstock. The chambers are sealed; therefore there are no emissions or odours. The biogas is piped from the digester into a CHP plant which then converts it into heat and electricity. The final stage of the process involves transferring the electricity from the CHP unit to the electricity grid.
Every type of feedstock has different gas yield characteristics. Depending on the type of organic matter utilised, a dry fermentation plant with 20 digesters could process 60,000 tonnes of organic matter per annum and produce between two and four megawatts of electricity.
37 GE Jenbacher Brochure, March 2008, Biogas application 38 http://www.kedco.com/clean-tech-energy/technologies/dry-fermentation/
21 Advantages39
• Utilisation of presently unused high-energy content substrates (green cuttings, solid manure, garden waste) • Compact design of the plant thanks to a substrate with a high concentration of dry matter (up to 50%) • Low maintenance and noise-reduction costs, low investment cost for plant and mechanical devices • Hardly any moving parts in the biogas plant itself, thus reducing the cost of wear and tear • Highly developed modern, computer-controlled system • Low process energy consumption (less than 10% of the energy produced in the co-generation unit) • High, good quality gas yields (about 80% of methane content, about 20 ppm hydrogen sulphates, which makes desulphurisation generally unnecessary) • Possibility of modular expansion • Use of wheel loaders and front-end loaders to fill and empty the digesters - no need for sophisticated equipment • Simple process that allows a large variety of non-organic substances (sand, wood plastic etc) in the substrate throughout the digesting process; interfering substances can be sieved out after digestion • Relatively inexpensive: No costly storage of the digested substrates, as with liquid substances; cheaper transport costs • Additional income for waste disposers, municipalities, farmers • Generation of a direct source of income in rural areas through highly valuable end products (electricity, heat, compost) • Low maintenance requirements and robust technology, therefore particularly suitable for export • Contributes to reducing fossil fuel consumption and thus combating climate change. • Requires a smaller geographical footprint than a landfill site: the average AD plant can be built on approximately 2.5 hectares, thus enabling it to be built near residential areas which can be easily serviced with the electricity and heat from the AD plant.
Figure … Diagram of dry digestion according to the BEKON process40
39 http://www.kedco.com/clean-tech-energy/technologies/dry-fermentation/ 40 http://www.anaerobic-digestion.com/html/hot_rot-bekon_process.php Lutz P, New BEKON Biogas Technology Batch Process Dry Fermentation (Secured by Various Patents)
22
Fig … Diagram showing MBT process that includes sorting at a MRF, wet and dry anaerobic digestion treatment41
Although dry Anaerobic Digestion technology is in the very early stages of development world-wide, it would seem to be very appropriate for a water deficit country like SA. There are 16 reported projects in Germany and Italy, one in Ireland and two in Western Australia42. Some processes use agricultural waste such as chicken litter while others are processing the biodegradable organic fraction extracted from municipal waste streams by MRFs in MBT processes. Initial indications are that this is a technology of the future and eThekwini should investigate dry AD options in the urban solid waste application.
3.3 Carbon sequestration – CO2 fertiliser Methane gas (either natural gas or that from anaerobic biodegradation processes) may be utilised in carbon sequestration projects; this is common practice in the EU, and is also known as CO2 fertilization. Examples include greenhouses in Maasland and Westland, Netherlands, some of which produce 14 million cut roses and others that produce more than 80 million kilograms of vine tomatoes every year. Using gas-powered cogeneration systems that provide power for assimilation lighting, heat and CO2, the greenhouse production capabilities are increased to the extent that almost the same crop yields can be produced in the winter months as in the summer.
In tomato greenhouses, the system creates the optimal environment for cultivating vine-ripened tomatoes. In addition to providing electricity, the cogeneration systems also generate heating for the greenhouses. The gas engines generate 76 MW of power and 81 MW of thermal energy. Electricity from the engines is used for the lighting of 1,500,000 square-meter greenhouse, and the excess is fed into the public grid, generating revenue. Other byproducts are used on site: thermal energy heats the greenhouses, and CO2 derived from the exhaust gas serves as a fertilizer for the tomato crop. When fueled with natural gas, approximately 0.2 kg of CO2 is produced per kWh of energy input. This CO2 is present in the gas engine exhaust in a concentration of approximately 5 to 6% by volume. After purification of the exhaust gas with catalytic converters, the exhaust gas is cooled by a heat exchanger to about 50ºC and delivered to the greenhouse for CO2 enrichment. An overall efficiency of 93.8% is achieved and there is the additional flexibility of being able to supply excess electricity capacity to the public grid.
41 Bekon Plant illustrated in GE Jenbacher Brochure: June 2005. Biogas – a renewable energy source 42 R Lombard Personal Communication (Aug 2010)
23 3.4 Biofuels and industrial processes Biofuels are any fuels which are derived from biological matter and include solid biomass, liquid fuels and various biogases43. The use of biofuels reduces Greenhouse Gas (GHG) emissions from fossil fuels as well as reducing the cost of fuel and risks associated with fuel supply.
Bioethanol is an alcohol made by fermenting the sugar components of plant material and is derived mostly from sugar and starch crops but also from non-food cellulosic biomass, such as trees and grass. Ethanol can be used directly as a fuel for vehicles in or, more commonly, as a additive to petrol to increase the octane rating and improve vehicle emissions. Bioethanol is not commonly used in South Africa although is it commonly used in USA and in Brazil.
In the eThekwini Metro area there are significant improvements that can be made within the sugar and related industries relating to the use of biofuels to reduce GHG emissions. Wastes from sugar refinery by-products have long been used for the production of ethanol from the fermentation of molasses. Ethanol in itself could be used as a fuel additive for vehicles. The ethanol production process leaves a residue, vinesse, which is rich in nitrogen, phosphorous and potassium, but is typically disposed of to landfarming, thus losing the valuable phosphorous context and posing a potential pollution threat from leachate and GHG emissions. There is a world wide shortage of phosphorous, a macronutrient essential for plant growth. It is recommended that the vinesse be anaerobically digested further under controlled conditions to harvest the methane gas. Electricity could be generated, or the gas could be burned for process heat. The solid residue can then be used as an NPK fertilizer.
Ethanol from cane sugar is also used to produce phthalates for the manufacture of plastics in eThekwini. A by- product of this process is glycerol from which soaps can be made. There is a surfeit of glycerol for soap-making, however, and therefore its marketability is low. A recommended alternative, again, is to recover the energy from the glycerol by anaerobic digestion which yields energy-rich methane which can be utilised for heat and/or power generation.
An example of where this approach has been successfully applied is the Shakarganj Foundation in Pakistan. A distillery has been set up for manufacturing alcohol/ethanol which can be easily blended with conventional petrol and used in vehicles. The production of ethanol is an environmentally friendly option as its emission on usage as a fuel does not pollute air.44 This same organisation produces biocompost from sugarcane waste (concentrated molasses (vinesse) to recover methane but retain the NPK) and uses the engine’s exhaust heat to evaporate as much water as possible to reduce the volume to be transported to the organic fertiliser formulator for the benefit of sugarcane farmers and the land. This process which has been functioning since 2001 has provided some 247,469 tonnes of bio-compost distributed on 61,841 acres of land under sugarcane cultivation which over time depletes the soil of important nutrients. The rich bio-compost has turned barren land into arable farmland.
Biodiesel is the combustible fraction extracted from oil seeds and vegetable matter (e.g. jatropha seeds), animal fats or recycled greases. The pressed crude oil is treated with solvents to separate the fuel oil fraction from the fatty acid glycerol fraction. The biodiesel can be used directly as a fuel for vehicles or as a diesel additive to reduce levels of particulates, carbon monoxide, and hydrocarbons from diesel- powered vehicles. Biodiesel, although not commonly used in SA, is the most common biofuel in Europe. . The by-product of the biodiesel process is glycerol which offers a further opportunity for energy recovery in that it can be anaerobically digested to produce methane, a fuel for heating or for electricity production from a suitable gas engine. This should be considered in the eThekwini context as well.
3.5 Composting
Vermiculture can also be considered: this would be a suitable system for individual households in eThekwini, whether rural or urban45. A worm farm or wormery is an easy, cost effective and efficient method to compost vegetable wastes. Rapidly breeding earthworms digest organic wastes to form a rich organic soil conditioner (vermicompost) as well as a liquid fertiliser called ‘worm tea’ or plantonic that can greatly enhance plant growth of crops, garden plants or pot plants.
43 http://en.wikipedia.org/wiki/Biofuel 44 Shakarganj Foundation: production of ethanol http://shakarganj.com.pk/foundation/environment.html 45 Wizzard Worms www.wizzardworms.co.za
24
Waste-to-energy (WtE) is the process of recovering energy in the form of electricity or heat from the incineration of a waste source. Most WtE processes produce electricity directly through combustion, or produce a combustible fuel, such as methane, methanol, ethanol or synthetic fuels.
Fig … Diagram showing possibilities of WtE system46
Mass Burn/incineration Incineration of the waste stream under controlled conditions in purpose built incinerators (usually moving hearth or rotary kiln type incinerators) with the necessary gas scrubbing devices allows the use of heat energy to raise steam to produce electricity by means of steam turbines.
Refuse Derived Fuel (RDF) RDF is produced by processing the waste stream to extract the more combustible fractions which are pelletised, briquetted or converted into “fluff” for burning under controlled conditions in purpose built incinerators (usually moving hearth, rotary kiln or fluidised bed type incinerators). In this way energy is recovered and used to raise steam to produce electricity. The process heat from the generation of electricity or the heat generated by aerobic biodegradation processes can be utlised to dry the combustible fraction.
Co-incineration of tyres in cement kilns A new national policy47 has recently been published on the co-incineration of waste, e.g. waste tyres, as a fossil fuel substitute in cement kilns. The closest cement kiln to eThekwini is at Simuma to the south of Durban. eThekwini Metro has recognised this option 48 as a way to deal with the difficult tyre waste stream, however transport logistics will have to be considered.
Benefits • Destruction of waste stream whilst recovering energy • Faciltates the management of health care risk waste particularly the anatomical component of this waste stream which is a vexatious issue for the authorities governing waste management in SA at this time. • Recovery of scrap metal and a drastically reduced residue for ultimate disposal. The residue will have to go through a de-listing process to avoid disposal in H:H or H:h landfills.
46 Waste to energy http://www.wastetoenergyplan.com/index.html 47 Govt Notice 777 National Policy On Thermal Treatment Of General And Hazardous Waste in terms of National Environmental Management: Waste Act, 2008 (Act No. 59 Of 2008) 48http://www.durban.gov.za/durban/services/cleansing/environmental-education/recycling/waste-minimisation-and- recycling/tyres
25 Life cycle assessment studies are showing increasingly that if landfilling, MBT and incineration options are considered, those that combined MBT with waste-to-energy incineration saved the highest quantities of carbon dioxide equivalents per ton of municipal waste (assuming that recyclables were separated at source)49. Preliminary comparison of energy balance and GHG emissions indicates that incineration with power generation achieves better resulta than MBT50.
Note: Any technology that involves incineration will elicit the implacable opposition of the environmental lobby who are particularly active in KwaZulu Natal.
49 Christensen TH, Simion F, Tonini D, Moller J (Nov 2009) Global warming factors modelled for 40 generic municipal waste management scenarios Waste Management and Research, Vol 27, Issue 9. pp 871-884 50 Knox K and Robinson H. (Oct 2008). MBT or Thermal Treatment? CIWM
26
4. Overcoming barriers to implementing waste management strategies
4.1 Waste to electricity options
Eskom reluctance
The National Energy Regulator of SA (NERSA) is the body which licences Independent Power Producers (IPPs) and evaluates potential projects. Potential renewable energy projects require a Basic Assessment type EIA if they are to generate more than 10MW electricity. There have been significant delays in obtaining these approvals because of the extended application process which involve: • Obtaining environmental authorisation • Submitting business plan with EIA authorisation to NERSA that evaluates the viability of the proposal. • Once the applicant has the necessary licence it must then negotiate with ESKOM for a contract to supply renewable energy. • Only then can the green electricity be sold into the grid.
ESKOM would prefer to recover the Renewable Electricity Feed In Tariffs (REFIT) from users wanting “green power” as these are substantially higher than the tariffs that ESKOM are allowed to chargeHowever, ESKOM cannot differentiate between power derived from renewable sources or that from their coal-powered electricity. Eskom negotiated with government and increased charges for electricity to eThekwini.
The Metro is currently charged R 0,28 per kWh for most of the year, except for 2 high-demand winter months when they are charged R 0,41 per kWh. eThekwini recovers electricity costs from its consumers at R 0,54 kWh. (Jhb charges R 0,62 kWh – supplied at high profit.) The REFIT tariff for biogas is currently much higher being set at R 0,94 per kWh.
Figure … : Diagram of the NERSA & ESKOM Single Buyers Office Model for the development of the Independent Power Producers Licensing Procedure51
The complexity of the relationships involved in the independent production of power and its sale to Eskom through the Single Central Buying Office (managed by ESKOM), has seriously delayed South Africa’s implementation of Renewable Energy despite government undertakings to change the situation. The problems experienced by independent Power Producers (IPPs) are both political and bureaucratic
51 R Lombard, 2010 Personal communication
27 and until there is clarity on the rules of engagement the investment banking sector have indicated that they have serious reservations about investing in projects that typically have twenty year lifespans (Investec Power Summit – 7 September 2009 Creamers Daily Engineering News 8 September 2010.
Renewable Energy Feed In Tariffs (REFIT) and the revenue potential from sale of electricity
REFIT Tariffs – 2009 Technology R/kWh Wind 1.25 Small hydro 0.94 Biogas 0.96 Solid Biomass 1.18 Concentrated solar 3.13 – 4.49
‘Wheeling’ option for IPPs
The second way to become an IPP is the ‘wheeling’ option, where power is wheeled through the grid to designated users in a wheeling agreement. Wheeling only involves producing power for your own needs, e.g. a mining company may produce power in the Southern Cape and wheel it to its mines in the North West Province using Eskom’s grid infrastructure for which Eskom charges a wheeling fee of around R 0,18 kWh. This appears much easier to negotiate than the sale of power to Eskom under REFIT conditions.
1100 MW of electricity derived from renewable energy sources from REFIT legislation but ESKOM will not cooperate. Single buyer’s office – should be an open system so can sell to best advantage. eThekwini is using its own grid and feeds into its own electricity supply, using the power for WWTW and high consumption areas.
The Central Energy Fund was set up to facilitate renewable energy projects. This is another bureaucratic body that is a constraint because there is no incentive for fast tracking projects to allocate the funds. This fund is supposed to provide seed capital to projects and supply support by way of business plans and identification of opportunities for projects.
4.2 Public Private Partnerships
Municipalities lack skills and need to harness the capacity within the private sector using Public Private Partnerships (PPPs). PPPs are notoriously difficult to set up unless one partner is prepared to take the financial and business risk or find external funding.
ESKOM 90% cap See Limited finance seen hurting African energy projects - engineering news article Legislation Financing See Bright prospects for a cleaner-energy era –engineering news article
4.3 Recycling constraints
Supply and demand is a constraint. The South African market for recyclable materials cannot absorb everything that can potentially be extracted from the waste stream. Currently, some recycling companies already export recovered materials to countries in the Far East, particularly China, especially when the materials have been taken out of a mixed waste stream and are therefore contaminated. Recycling companies in SA will not buy dirty materials because they require extra water for washing.
28 4.4 Incineration options The vociferous green lobby will not support any technology that involves incineration, however well- designed and controlled – this is an issue that has become highly emotive due to past cases of pollution.
[LEAVE ALL OF THIS TURQUOISE HIGHLIGHTED PART OUT?]
5. Financing opportunities for waste projects
5.1 CDM The trading of Carbon Emission Reduction credits and the sale of renewable energy on the basis of Renewable Energy Feed-in Tariffs (REFIT) can be a source of significant additional income. Electricity is currently being sold by Eskom to LMs at about R0.33 per kWh and REFIT allows R0.94 per kWh. Carbon credits are negotiable, but presently are worth €12 per ton of carbon – the potential revenue is more than three times the value of the sale of electricity. DSW, for example, earned R1.8m for the month of June 2010 at Eskom rates for the internal sale of electricity from its two landfill gas-to-electricity projects into eThekwini municipal grid.
Various waste management activities may be eligible as CDM projects, including: • Biological waste treatment avoiding methane emissions • Covering existing landfill sites with so called methane oxidation layer derived from stabilized biomass • Degasification of landfill, if waste has not been pre-treated • Greening activities utilizing compost or stabilized biomass • Renewable energy production from digestion, organic waste incineration or landfill gas to energy projects • Energy savings from secondary raw material utilization • Energy shift by fuel replacements (co combustion)
Clean Development Mechanism (CDM) is a carbon emission reduction trading initiative which falls under the Kyoto Protocol. Kyoto Protocol, the International agreement linked to the UNFCCC (United Nations Framework Convention on Climate Change) was produced at the Rio de Janeiro Earth Summit in (YEAR?). The protocol is aimed at stabilising the earth’s greenhouse gas concentrations to avoid pollution interference, resulting in climate change. It sets mandatory greenhouse gas limits for signatory countries.
As of November 2009 – 187 countries have signed the Kyoto Protocol. Signatories are fall into one of two categories: Annexure I (developed countries) Non – Annexure 1 countries (SA is included as a non-Annexure 1 country and therefore qualifies for CDM). The protocol’s main objectives are to: Achieve sustainable development in Non-Annexure I countries Achieve compliance to emission limits in Annexure I countries.
Clean Development Mechanism is one of 3 “flexible mechanisms” defined in the Kyoto Protocol as intended to lower the overall costs of achieving its emissions targets. These mechanisms are:
Emission Trading Joint Implementation Clean Development Mechanism
29
CDM is the world’s biggest carbon offsets market. It allows industrialised countries to support sustainable development in developing countries, through CDM credits. Industrialised countries can support projects that decrease GHG emissions in developing countries, then use the resulting emissions reduction credits towards their own reduction targets under the Kyoto protocol. Developing countries have supported this initiative as they in turn receive funds for “sustainable development”.
Each CDM credit is known as a Certified Emission Reduction (CER) and represents one metric ton of Carbon Dioxide not emitted into the atmosphere. Greenhouse Gases have been rated on a scale according to their Global Warming Potentials (i.e. how dangerous they are to the atmosphere). Carbon Dioxide is the benchmark (least harmful) at 1. Methane is rated at 21 according to the GWP. That means that any metric ton of Methane reduced to CO2 is multiplied by 21. So if a waste to energy plant combusts 1000 tons of Methane a month, it is equivalent to 21000 CERs. It is estimated that CERs produced through 2012 are expected to be worth between $35 to $85 billion dollars.
• Drawing shows a basic overview of a CDM project cycle from top to bottom. • Idea, design and formulation as well as the draft PDD of the project • Project approval by national government before it is submitted to the UNFCCC for • validation and registration • Implementation • Monitoring and reporting (done on a continual – monthly basis) • Verification – Done by a registered verification company accredited by the UNFCCC (also done throughout the lifetime of the project at various intervals). Project validation and project verification must be done by different organisations. • CERs Issued and CERs paid for by the buyer.
Data Collection & Reporting • A CDM project has stringent data recording and reporting requirements that will be specified in the project PDD and/or methodologies adopted for that specific project.
30
• Typical recording and reporting process: o Raw data is downloaded into spreadsheet format for manipulation (the actual data capturing device is not able to be edited or tampered with to ensure data integrity) o Any monthly anomalies or faults that may effect CERs are noted and clearly recorded for evaluation during the CER verification period o Manipulate data and relevant calculations into presentable/required format according to PDD and methodologies o Scrutinise CER calculations to iron out errors or non-compliance o Quality Assure (QA)
Challenges to CDM
• Carbon leakage This is the term used when the emission mitigation actions in one country or economic sector result in an increase in pollution in another country or sector due to differing pollution regulations. The result is that the NET emissions are actually increased rather than reduced. • “Hot-air” trading This is considered to be the most important effectiveness problem related to the carbon trading system. According to the Kyoto Protocol, GHG emission levels should be at least 5% lower than 1990 levels. If the official emission ceiling level in a country is higher than its current business-as-usual emissions (i.e. It pollutes less than Kyoto Protocol limits) , it can sell pollution rights without having to reduce emissions. Countries like Russia and Ukraine are an example of this as their emissions are way below the ceiling level, so they sell pollution rights instead. The US has already made its intentions clear that they will buy this “hot-air” to achieve their sustainable reduction goals.
• Additionality opposed to business-as-usual Critics argue that many current Carbon Credit projects would have happened anyway, even without the Carbon Credit revenue. A CDM project is only beneficial to the NET environmental emission reduction if it is truly “additional” to the business as usual scenario.
• Post 2012 in South Africa and globally Registering for a UNFCCC CDM project can be a lengthy process and there is still uncertainty around what will come of the Carbon Trading market once the Kyoto Protocol expires in 2012. Not much was decided in the latest Copenhagen climate change conference and it remains uncertain what the future may hold for South Africa. SA is a developing country but is a major contributor to GHG emissions, so we may find ourselves being re-categorised in the future.
Advantages of CDM • Offset or reduction in global greenhouse gas emissions Despite the critics, many people argue that this is at least a step in the right direction to globally decrease the greenhouse gas emissions.
• Waste gas use (avoidance of fossil fuels) If CDM projects are additional and correctly implemented, apart from decreasing atmospheric pollution, they also contribute to the avoidance of fossil fuel use as CDM projects are increasingly being run from the destruction of waste gases to generate electricity.
• Improves project feasibility CDM projects contribute greatly to the feasibility of a project which would otherwise never have been a viable project.
31
The graph shows the profit margins of CERs compared to sales from electricity generation alone.
Advantages of CDM • Forward selling – assists in setup costs One of the options available to a CDM project is forward selling. This means that a buyer can pay in advance for CERs that will be created once the infrastructure is built. The credits are bought at a lower rate than otherwise, but it allows for a capital investment into the project to get it started.
• Useful trending and forecasting is possible In the process of running a CDM project, data and information are being recorded constantly. This data can be used to in trending analyses to assist operators in the running the plant. Potential problems can be detected and possibly help avoid costly breakdowns or instrumental failures.
Additional trending of captured data is simple and can help with proactive maintenance and the running of the plant. The following graph is an example of the life time of mainline filters and flame arrestors that slowly become blocked due to poor gas quality. Differential Pressure is measured and trended. When this gets too high, the filter and flame arrestor is changed (See white arrows showing change intervals).
32
• CDM projects need to be approached in the correct manner • CDM registration and CER verification can be difficult and complicated, but benefits outweigh the negatives
5.1 Other opportunities
• REFIT – NERSA – Ruth Rabinowitz – why not working – how much per kW – RAY TO PROVIDE THIS INFO • Single buyer’s office • Independent power producers – we have 3 projects – SAPPI, small scale hydro elec in Free State – Bethlehem, Darling Wind Project – aesthetic objections from greens
Carbon Traders
AAP, Promethium Carbon
Whole network of carbon traders
6. Recommendations [TO BE DEVELOPED] There is a growing body of evidence based not only on Life Cycle Assessment52 but also on real-life studies53 that local government can lead integrated waste management activities and make a significant difference in terms of GHG reduction
Reduction of GHG emissions in the waste sector can be achieved in a variety of ways:
• Recovering materials for recycling into new products, thus avoiding the energy-consuming beneficiation and primary manufacturing processes that is otherwise necessary in the use of virgin materials. • Reducing emissions of landfill gas (an approximately 50:50 mixture of methane (CH4) and carbon dioxide (CO2) by better landfill practice and by reducing the organic wastes entering the site. • Utilising and/flaring off landfill gas for both heat and electricity generation. • Reducing methane emissions from wet anaerobic processes e.g. sludges. • Recovering energy and reducing carbon emissions from waste using Mechanical Biological Treatment processes. • Utilising the carbon dioxide from combined heat and power plants as a carbon dioxide fertiliser in greenhouses.
DROP-OFF CENTRES Drop-off centres may become unsightly open dumps if strict supervision is not exercised over the deposition of recycled material, but generally work well when placed under the direct control of local authorities who can enforce by-laws that prevent littering. These centres also work successfully when located at garden refuse transfer stations that are managed by local authorities.
MRFS a MRF such as this to remain viable, it needs to receive a share of the tipping fees recovered by DSW through the weighbridge operation. This MRF remains viable because of the formal commitment by DSW
52 Waste Management and Research, Vol 27, Issue 9, Nov 2009. Special issue: Applied Green House Gas Accounting: methodologies and cases. ISWA ISSN 0734-242X. http://wmr.sagepub.com 53 Hansen, J.A. (2009) Editorial. Waste Management and Research, Vol 27, Issue 9, p 837-838.
33 and Re- todiverting waste and recovering recyclables as part of the eThekwini Metro carbon footprint reduction and metro greening effort. COMPOSTING introduce shallow trench gardening as an option for organic waste management
The study further suggested that co-operatives of were the most effective organisational arrangement when running composting schemes in communities.
CDM The AFD loan was probably a key factor that made the eThekwini Landfill Gas to Electricity Project possible. Knowledge gained from this successful project is valuable for informing other potential gas-to- electricity projects and building capacity to replicate similar projects. The report found that there was a need for a practical follow-up workshop with decision makers and implementers from other Municipalities and larger cities that contemplate engaging in similar projects to assist them in moving forward.
WASTE WATER TO ENERGY The aerobic waste water treatment processes used at most WWTWs are energy-intensive, in that they consume large amounts of electricity to drive the activated sludge process. One mitigation measure to avoid this is to revert to anaerobic digesters which have much lower energy requirements.
Added benefits can be achieved by using this methane to generate electricity in gas engines. The electricity generated can be used to drive the mixers within the anaerobic digesters which are essential for efficient biodegradation.
Wastewater treatment plants with activated sludge units have very high-impact global warming scores (carbon footprinting) due to their high electricity requirements. Wherever appropriate, safe on-site sanitation should be promoted because of the environmental advantages associated with lower energy requirements (collection and secondary treatment are not necessary) and sustainability.
Waste avoidance and recycling Significant progress can be made in reducing a municipality’s carbon footprint by increasing waste avoidance and recycling in the following areas:-
Ewaste recovery Policy should state that hardware should be purchased only from members of EWASA to ensure that its recovery and recycling is assured. Similarly electronic hardware should not be disposed of except to EWASA-accredited recyclers.
Green procurement policies The use of paper with guaranteed recycled fibre content should be written into municipal procurement policy and procedures, to stimulate demand and create a market for recycled paper.
Cleaner production processes 54 Cleaner production in industry, supported through the formation of Waste Minimisation Clubs , will significantly reduce wastage and the quantities of waste going to landfill. This will need the commitment of industry and will need to be driven by a champion, whether this is an organisation or an individual, with strong support from the municipality. .
Waste Exchanges Industry and municipalities can implement waste exchanges. These initiatives have been successfully set up in areas such as Cape Town but are highly dependent on there being an active product champion, usually an individual with strong backing from the municipality.
Mechanical Biological Treatment incorporating Waste to Energy MBT options must be considered if a low carbon footprint is a priority.
Pre-treatment of municipal solid wastes prior to disposal, to reduce the volumes of waste to be transported and disposed of at landfills, as well as negative emissions from the organic contents of municipal solid waste.
54 National Cleaner Production Centre: www.ncpc.co.za
34
MBT technologies are new to South Africa and more complicated than landfilling; thus requiring a high degree of management. eThekwini would have to ensure that the operator of such a plant has the requisite technical competence in running the facility. An awareness and education campaign to drive the separation of waste at source would also be necessary.
Although dry anaerobic digestion technology is in the very early stages of development world-wide, initial indications are that it would be highly appropriate for a water deficit country like SA. It is recommended that eThekwini investigate dry AD options in the urban solid waste application.
Carbon sequestration – CO2 fertiliser Utilise methane gas (either natural gas or that from anaerobic biodegradation processes) in carbon sequestration projects. In addition to providing electricity, any excess of which may be fed into the public grid, cogeneration systems also generate heating, e.g. for greenhouses, and CO2 derived from the exhaust gas serves as fertilizer.
Biofuels and industrial processes In the eThekwini Metro area there are significant improvements that can be made within the sugar and related industries relating to the use of biofuels to reduce GHG emissions.
Bioethanol, produced from sugar refinery waste, could be used as a fuel additive for vehicles. It is recommended that the residual vinesse be anaerobically digested further under controlled conditions to harvest methane gas. Electricity could be generated, or the gas could be burned for process heat. The solid residue can then be used as a Nitrogen Phosphorus Potassium (NPK) fertilizer.
Glycerol, a by-product of petrochemical processes, including the production of plastics and biodiesel, offers an opportunity for energy recovery in that it can be anaerobically digested to produce methane, a fuel for heating or for electricity production from a suitable gas engine. This should be considered in the eThekwini context.
Composting The promotion of vermiculture is suggested as a suitable system for individual households in eThekwini, whether rural or urban.
Waste-to-energy systems A new national policy55 has recently been published on the co-incineration of waste, e.g. waste tyres, as a fossil fuel substitute in cement kilns. The closest cement kiln to eThekwini is at Simuma to the south of Durban. eThekwini Metro has recognised this option 56 as a way to deal with the difficult tyre waste stream, however transport logistics will have to be considered.
Combine mechanical biological treatment (MBT) with waste-to-energy incineration when landfilling to save the highest quantities of carbon dioxide equivalents per ton of municipal waste (assuming that recyclables were separated at source)57. Preliminary comparison of energy balance and GHG emissions indicates that incineration with power generation achieves better results than MBT58.
NB: Any technology that involves incineration will elicit the implacable opposition of the environmental lobby, who are particularly active in KwaZulu Natal.
55 Govt Notice 777 National Policy On Thermal Treatment Of General And Hazardous Waste in terms of National Environmental Management: Waste Act, 2008 (Act No. 59 Of 2008) 56http://www.durban.gov.za/durban/services/cleansing/environmental-education/recycling/waste-minimisation-and- recycling/tyres 57 Christensen TH, Simion F, Tonini D, Moller J (Nov 2009) Global warming factors modelled for 40 generic municipal waste management scenarios Waste Management and Research, Vol 27, Issue 9. pp 871-884 58 Knox K and Robinson H. (Oct 2008). MBT or Thermal Treatment? CIWM
35
GENERAL CONCLUDING REMARKS
It is more likely that smaller projects gain traction than "really grand" ones. "In the short term, the big regional initiatives are not necessarily the things that are going to make a difference,"
Manchester City59: Environmental Business Pledge: Over 1,300 businesses have signed up to the Environmental Business Pledge which had saved over 2,000 tonnes of CO2 and realised over £500,000 of savings to business together with nearly £6 million in increased sales.
7. USEFUL WEB SITES http://durbanportal.net/ClimateChange/default.aspx Durban Industry Climate Change Partnership Project http://saaea.blogspot.com/search/label/energy%20from%20waste Blog of Southern African Alternative Energy Association(SAAEA) - represents and actively promotes Renewable Alternative Energy Solutions in our region. Has a links page and some interesting articles.
The United Nations Framework Convention on Climate Change http://cdm.unfccc.int/index.html http://en.wikipedia.org/wiki/Kyoto_Protocol
Climate Change Flexibility Mechanisms — Global Issues http://www.globalissues.org/article/232/flexibility-mechanisms
EWASA www.ewasa.org
8. BIBLIOGRAPHY
Bogner J., Abdelrafie Ahmed M., Diaz C., Faaij A., Gao Q., Hashimoto S., Mareckova K., Pipatti R. & Zhang T. Waste Management, In Metz B., Davidson O.R., Bosch P.R., Dave R. & Meyer, L.A. (eds): Climate Change 2007: Mitigation. Contribution of Working Group III to the 4th Assessment Report of the Intergovernmental Panel on Climate Change. Cambridge University Press, Cambridge, UK and New Your, NY, USA.
Fakir, Saliem. Published 18 Jun 2010. “How realistic is the green economy?” http://www.polity.org.za/article/how-realistic-is-a-green-economy-2010-06-07
WESSA. May 2010. Background Information Document for Ethekwini South Durban Basin Area Based Management Climate Change Initiative: Participatory Climate Risk Screening and Climate Adaptation Projects.
Ken Breetzke. 2009. Chapter 8 of “Quantitative Models: Spatial planning in the Durban metropolitan area, South Africa—the link to housing and infrastructure planning”. Case study prepared for Revisiting Urban Planning: Global Report on Human Settlements 2009. Available from http://www.unhabitat.org/grhs/2009
59 See http://www.manchester.gov.uk/info/500117/green_city/178/manchester_green_city_team/1 and http://www.manchesterclimate.com/
36 Clarke, Christopher. 2010. Bright prospects for a cleaner-energy era Published: 05 Mar 10. Creamer Media (Pty) Ltd. http://www.engineeringnews.co.za/article/renewable-energy-2010-03-05
Reuters. 2010. Limited finance seen hurting African energy projects Published: 30 Jun 10. Creamer Media (Pty) Ltd http://www.engineeringnews.co.za/article/limited-finance-seen-hurting-african-energy-projects-2010-06- 30 de Bruyn, Chanel . 2009. Lesedi to build R150m manure-to-power plant in Heidelberg Published: 21 Aug 09. Creamer Media (Pty) Ltd. http://www.engineeringnews.co.za/article/lesedi-to-build-r150m-manure-to-power-plant-in-heidelberg- 2009-08-21
NON-SA David M. Kargbo. 2010. Biodiesel Production from Municipal Sewage Sludges. U.S. EPA Region III, Office of Innovation, Environmental Assessment & Innovation Division, Philadelphia, Pennsylvania 19103. Energy Fuels 2010, 24, 2791–2794 : DOI:10.1021/ef1001106 Published on Web 04/13/2010
G Redman. 2010. National Non-Food Crops Centre 10-010 A Detailed Economic Assessment of Anaerobic Digestion Technology and its Suitability to UK Farming and Waste Systems 2nd Edition (Andersons) With cost calculator. This is an update to NNFCC project 08-006. Outlines the options for anaerobic digestion (AD) production technologies in the UK. In collaboration with Andersons. http://www.nnfcc.co.uk/metadot/index.pl?id=7198;isa=DBRow;op=show;dbview_id=2457 Published: 19 Mar 2010 Accessed 30 June 2010 Note: The AD cost calculator http://www.biogas-info.co.uk/index.php/ad-calculator, produced by The Andersons Centre on behalf of the NNFCC, lets you assess the economics of AD facilities. The results are comprehensive and include the capital costs, profits and the land required to use the digestate. Also calculated are the cost per kWh electricity, the cost per m3 of biogas, the cost per m3 of feedstock and the percentage return on capital. A sensitivity table ranks the variables that have the greatest impact on business profitability. See the associated report A Detailed Economic Assessment of Anaerobic Digestion Technology and its Suitability to UK Farming and Waste Systems, which explains the terms used in the calculator.
37