Landfill Mining: Prospecting Metal in Gärstad Landfill

Landfill Mining: Prospecting metal in Gärstad landfill

Ariana Tanha Daniel Zarate Division of Environmental Technology and Management

Master Thesis Department of Management and Engineering LIU-IEI-TEK-A- -12/01454- -SE

Landfill Mining: Prospecting metal in Gärstad landfill

Master Thesis in Landfill Mining Department of Management and Engineering Division of Environmental Technology and Management Linköping University by

Ariana Tanha Daniel Zarate

LIU-IEI-TEK-A- -12/01454- -SE

Supervisors: NILS JOHANSSON

IEI, Linköping University

MAGNUS HAMMAR

Tekniska Verken i Linköping

Examiner: JOAKIM KROOK

IEI, Linköping University

Linköping, 19 September, 2012

Linköping University Electronic Press

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Abstract All processes in society produce waste. In nature, the waste is normally used as a resource for another process, but in human societies waste is often discarded. These discarded materials end up in places for depositing waste known as landfills. The increase in population, and humans’ tendency to improve their quality of life, has led to an increase in consumption of material. More material consumption means generating more waste, and more waste means bigger landfills. The increasing size of landfills has brought some other issues, such as increased land use and higher environmental impact. However in these landfills a lot of valuable materials are discarded and the concept of landfill mining (LFM) has been proposed in order to solve these issues and use landfills as a possible source of materials. Landfill mining is not yet a common practice, and the first barrier for this is the uncertainty of the amount and value of materials within landfills.

The purpose of this study is to prospect the amount of metals in one specific landfill, in this case Gärstad landfill in Linköping, Sweden. This is a first step to show the feasibility of landfill mining as an alternative way of extracting materials. The study is limited only to metals because they are one of the most important resources in today’s society.

The theoretical background of the study is based on material flow analysis (MFA). Two approaches are used to study the materials in the landfill. The first is top‐down which studies the flows of materials and the second is bottom‐up which studies the stocks of material in the landfill. Based on these approaches the method was developed. First the system boundaries in time and space were defined. Then the amount of waste in landfill was estimated from the two mentioned approaches. In the end the metal content of the waste was estimated. Some criteria are also defined to compare the accessibility of the metals in the landfill.

The results of this study show that there is a considerable amount of metals in the landfill, and that ash deposits resulting from incineration are the most interesting source of metals; with iron, aluminium, copper and zinc being the most abundant. The results are presented by type of waste, area of the landfill and accessibility in order to identify the hotspots.

Later it is discussed that the method is cheap and fast but highly depends on previous data and available information. Also the metal content of the landfill is compared with natural ores. In the end the metal content of the landfill is evaluated and estimated to be around 3 billion SEK. It shows that aluminium, titanium and copper have the highest value money wise.

As conclusion it was shown material flow analysis is a valid way to prospect landfills. But further cost‐ benefit analysis must be carried out to determine if landfill mining is justifiable. Also some recommendations are proposed to Tekniska Verken in order to facilitate future studies. The first is to develop a systematic way for landfilling different kind of waste and document them. Second is to include metals which have economic potential in the regular sampling from landfill.

Keywords waste, landfill, landfill mining, material flow analysis, metals, metal stocks, ashes.

Acknowledgements We would like to thank Nisse, our supervisor, who despite of being on parental leave met with us regularly to provide guidance and feedback, and his son Mio, who brought joy to our supervisory meetings.

We would like to thank Magnus Hammar from Tekniska Verken, our contact person, who always provided us with necessary data, information and amusing comment in his emails, even though he was very busy at work.

We would like to thank Joakim Krook, our examiner, for his guidance and help during writing the thesis.

Finally we would like to thank all the people who in some way or another where involved and helped in this process.

Linköping, September, 2012 Ariana Tanha Daniel Zarate

Table of Contents 1 Introduction ...... 15 1.1 Aim ...... 15 1.2 Limitation ...... 16 1.3 Background ...... 16 2 Theoretical Framework ...... 19 2.1 Industrial Ecology ...... 19 2.2 Landfill Mining ...... 20 2.3 MFA (Material Flow Analysis) ...... 21 3 Method ...... 23 3.1 Assumptions ...... 25 4 Collected Data and Estimations ...... 27 4.1 Gärstad Landfill History ...... 28 4.1.1 The old Incinerator ...... 28 4.1.2 KV1 ...... 28 4.1.3 Gärstad Verket ...... 28 4.1.4 FUDD ...... 29 4.1.5 Landfill Tax ...... 29 4.2 Flows and stocks of waste ...... 29 4.2.1 Estimation of flows between 1974‐1990 and outflows ...... 32 4.2.2 Waste flow history...... 33 4.3 Concentrations ...... 33 4.3.1 Ashes ...... 33 4.3.2 Construction and demolition waste ...... 35 4.3.3 Me‐OH Sludge...... 36 4.3.4 Household Waste ...... 36 4.3.5 Mixed Waste ...... 37 4.3.6 Others ...... 37 4.4 Accessibility Criteria ...... 37 5 Results ...... 39 5.1 Scrap metal ...... 40 5.2 Metal content in ashes ...... 40 5.3 Metal content in C&D waste ...... 41 5.4 Metal content in Metal hydroxide sludge ...... 42

5.5 Metal Content in Household Waste ...... 42 5.6 Metal Content by Areas ...... 43 5.7 Accessibility and Hotspots ...... 44 6 Discussion ...... 47 6.1 Method ...... 47 6.2 Data ...... 47 6.3 Comparing concentrations with mining ...... 48 6.4 Comparing LFM with modern mining ...... 48 6.5 Value ...... 50 6.6 National Numbers ...... 50 6.6.1 Gärstad landfill as a source of material ...... 51 7 Conclusion ...... 53 7.1 Recommendations for the company ...... 53 8 Bibliography ...... 55 Appendix A: Inflows of the landfill per year ...... 59 Appendix B: Metal amounts in different types of ash ...... 65

List of Figures Figure 1: Location of Gärstad landfill, 3 Km northeast of Linköping, Sweden...... 18 Figure 2: The life cycle of a product; the disposal stage includes all the material inside a landfill...... 19 Figure 3: Closing the loop; instead of disposing of material, they are reinserted into the life cycle. Own illustration based on Frosch & Gallopoulos (1989) ...... 19 Figure 4: Diagram of the two methods used in the study. The left one was used for estimating amounts of landfilled waste and metal and the right for verifying the amount of waste and allocating the metal...... 24 Figure 5: The different areas of Gärstad landfill, each area used for different purposes, except for E which is a lake...... 27 Figure 6: Ashes in all forms (BA, FA and sludge) sent from each power plant for landfilling in Gärstad. The old incinerator was decommissioned in 1980 and thus no more ash was sent from there. Own illustration, based on data from all Gärstad landfill environmental reports and county administration permissions...... 29 Figure 7: Schematic view of the waste flows to and from the landfill (the oval shape) currently. The two circles are power plants that send their incineration residue to landfill which makes up around 85% of the total incoming waste...... 31 Figure 8: The landfilled amount of main types of wastes since landfill started operating, 1974 until now, 2011...... 33 Figure 9: Estimated amount of landfilled metals in all forms calculated from flows of waste...... 39 Figure 10: Estimated amount of different metals in all types of landfilled ash...... 41

List of Tables Table 1: generated and treated waste in Sweden in years 2004, 2006 and 2008 (dry weight) (Naturvårdverket, 2012). The landfilled mining waste is the landfilled waste generated from the mining industry and should not be confused with LFM...... 17 Table 2: Usage description of the landfill areas...... 27 Table 3: All identified waste flows of Gärstad; from which the interesting waste flows were selected for calculating metal amount in the landfill ...... 30 Table 4: Area, volume and waste content of each area until 2009 (Hammar, 2012)...... 32 Table 5: Identified outflows of ash from Gärstad landfill...... 33 Table 6: Estimated metal concentrations in bottom ash generated from different fuels (waste, coal and wood)...... 34 Table 7: Estimated metal concentrations in fly ash, generated from different fuels; and for wood from different filters...... 34 Table 8: Conversion factor used to obtain the amount of metals from their oxide form...... 35 Table 9: Estimated metal concentrations in C&D waste based on (Boverket, 1998)...... 35 Table 10: Concentrations of metal in me‐OH sludge from different studies (weight %)...... 36 Table 11: Estimated metal concentrations in household waste ...... 36 Table 12: Accessibility criteria applied to different areas of the landfill...... 38 Table 13: Estimated total amount of waste based on flows approach; and estimated amount of landfilled metals in all forms calculated from flows of waste and its ratio compared to total amount of waste...... 39

Table 14: Estimated total amount of waste based on volume approach; and estimated amount of metals using the rate from the flows approach...... 40 Table 15: Estimated total amount of scrap metal in the landfill, and its rate compared to the total amount of waste...... 40 Table 16: Estimated total amount of landfilled ash and the estimated amount of metals within...... 40 Table 17 : Iron and Aluminium in scrap form in bottom ash from waste incineration...... 41 Table 18: Total amount of landfilled C&D waste and the estimated amount of metals within...... 42 Table 19: Total amount of me‐OH waste and the estimated amount of metals within...... 42 Table 20: Total amount of Household waste and the estimated amount of metals within...... 43 Table 21: Estimated amount of metals in A0 ...... 43 Table 22: Estimated amount of metals in A1, underground ...... 43 Table 23: Estimated amount of metals in A1, above ground ...... 43 Table 24: Estimated amount of metals in A2, underground ...... 43 Table 25: Estimated amount of metals in A2 aboveground ...... 44 Table 26: Estimated amount of metals in FUDD cell ...... 44 Table 27: Estimated amount of metals in B ...... 44 Table 28: Estimated amount of metals in C ...... 44 Table 29: Estimated amount of metals in D ...... 44 Table 30: Estimated amount of metals in F ...... 44 Table 31: Estimated amount of metals in me‐OH cell...... 44 Table 32: Concentration of different metals in ores compared to those in ashes...... 48 Table 33: Concentrations of metals in ores compared to those in the landfill...... 48 Table 34: Estimated economic value of some metals in the landfill...... 50 Table 35: Deposited ashes in Sweden compared to those in Gärstad and the ratio between them. .. 50 Table 36: Total amount of metal in landfilled bottom ash in Sweden; then downscaled to Gärstad landfill and compared with results of this study. All units are in tonne...... 51 Table 37: Domestic material consumption of some metals in Sweden downscaled to Östergötland and compared with landfilled amount of metals in Gärstad landfill...... 51

Terms Anthropogenic stocks: Refers to the material in the technosphere that already has been extracted, processed, used, or discarded.

Ash: Is the non‐combustible residues of an incineration process.

Bottom Ash: Is the ash which is taken out from the bottom of an incinerator after burning the fuel.

Flue gas: Is the gas emitted to the atmosphere from an incineration process; which usually goes through a smokestack.

Fly ash: Is the ash that follows the flue gas.

Metal‐Hydroxide: Is any metal element which has formed a compound with hydroxide anion (OH‐), and thus shown with Me‐OH.

Metal‐Oxide: Is any metal element which has formed a chemical compound with oxygen anion (0‐‐).

Mixed Waste: Mixed waste is a mixture of household, industrial, ash and all other waste which used to be landfilled.

Natural Stock: Refers to the material available in natural sources (e.g. ores), where the elements have been gathered through geological processes.

Sludge: Refers to the fluid residue from cleaning flue gas and bottom ash with water.

Wastes: “are substances or objects which are disposed of or are intended to be disposed of or are required to be disposed of by the provisions of national law” (EIONET, 2009).

Abbreviation BA: Bottom Ash CHP: Combined Heat and Power CY: Cyclone Filter C&D: Construction and Demolition EL: Electrostatic Filter EPA: Environmental Protection Agency FA: Fly Ash FUDD: Funktionsanpassad Deponidesign [Landfill designed for specific function] KV: Kraftvärmeverket [CHP Plant] LFM: Landfill Mining Me‐OH: Metal Hydroxide MSW: Municipal Solid Waste MSWI: Municipal Solid Waste Incinerator WEEE: Waste from Electrical and Electronic Equipment

Number system Comma (,) is used as decimal separator and space ( ) is used as thousands separator. All the units are based on the International System of Units (SI).

1 Introduction All processes in society produce waste. In nature, the waste is normally used as a resource for another process, but in human societies waste is often discarded. These discarded materials end up in places for depositing waste known as landfills. The increase in population, and humans’ tendency to improve their quality of life, has led to an increase in consumption of material. More material consumption means generating more waste, and more waste means bigger landfills.

This thesis focuses on the valuable materials that are deposited in landfills. Since landfills are the most common way for waste disposal and exist all over the world (UNSD, 2011) . The landfills are becoming bigger, and represent different threats to society and the environment; for example numerous hazardous substances reside inside them which can pollute the water and the land (Baas, et al., 2011).

In order to tackle the waste problem, The EU Commission on environment has defined a waste hierarchy which sets priority on how the waste should be treated. From the highest priority to the lowest they are: prevention, re‐use, recycling, recovery and disposal (EU, 2008). Based on this definition, landfilling falls under the disposal step. Disposal of waste has the lowest priority and thus needs to be avoided as much as possible. A solution to this problem could be the emerging LFM (Landfill Mining) concept, which makes it possible to shift landfill from a disposal stage to a recycling or recovery stage. LFM means recovering the landfilled waste, and use the buried material for other purposes. There are many barriers for doing so, including economical, technical, legal, and health and safety (Baas, et al., 2011).

Just like a normal mining project, before you can extract material from a landfill you need to know what resides inside it and what kind of waste has been deposited; thus it could be argued that the first barrier is prospecting. After searching for other studies about waste composition inside landfills, we found out that most of them focus on the environmental impact of heavy metals and leachate (Cossu, et al., 1995; Rettenberger, 1995). A few pilot studies (Hogland, 2002; Hogland, et al., 2004) which prospect landfills in Sweden classify metals as a single category without any more details. This can also be seen in the review made by Krook et al (2012) where no papers about prospecting metals in landfills were identified. Previous research (Cossu, et al., 1995; Hogland, 2002) shows that the waste composition of landfills has large variations in physical and chemical characteristics. This makes the estimation of the content and thus determination of valuable resources or hazardous substances difficult.

Hence prospecting is a key challenge. Earlier studies have used sampling method for prospecting (Hogland, et al., 2004) which is expensive, time consuming and reflects only a fraction of the landfill and thus leads to an isolated understanding. In this study we will use another method called MFA (Material Flow Analysis) which maps all the waste that has entered and left the landfilled through time. By this means, we will be able to give a better picture of landfill and its content. The main objective of this thesis is to prospect for metals, not because of its environmental impacts but for its economic value; so it is intended to serve as a base for future feasibility studies.

1.1 Aim The main goal of the project is to prospect Gärstad landfill. Thereby the occurrence of different metals will be estimated, their location and distribution will be shown and the accessibility of these

15 metal stocks will be assessed. The secondary goal is to develop a generic method for prospecting landfills. The research questions that we try to answer are as follows:

1. How much different metals have been landfilled in Gärstad landfill over time? 2. Where is the metal located? 3. In what forms are the metal found? 4. What are the advantages and disadvantages of MFA compared to direct measurements when applied to prospecting landfills?

1.2 Limitation In this study we included the metals that we could find data for. For this decade more data was available, and twenty different kinds of metals were included: (Iron (Fe), Aluminium (Al), Arsenic (As), Boron (B), Barium (Ba), Cadmium (Cd), Cobalt (Co), Chromium (Cr), Copper (Cu), Mercury (Hg), Manganese (Mn), Molybdenum (Mo), Nickel (Ni), Lead (Pb), Antimony (Sb), Selenium (Se), Tin (Sn), Titanium (Ti), Vanadium (V), and Zinc (Zn)). For previous decades, where data couldn’t be found, we limited the metal types to ferrous and non‐ferrous. Also the study only considers the metals within the underground and above ground waste in Gärstad landfill area. None of the structures such as office buildings, processing facilities and transportation equipment are included in the prospecting. Also temporary flammable waste deposits which are stored for a short time are not included in the calculations, since they will be eventually used as fuel for the incinerators, and thus converted into ash in the future. Temporary non‐flammable waste will be considered as landfill by law only if it is stored more than 3 years (Hammar, 2012), and the same concept was applied in the calculations.

1.3 Background Sweden’s waste management history starts in 1969 when the Environment Protection Act came in force and put new environmental obligations on waste treatment facilities. In the 1970s, the government emphasized that waste has to be seen as a resource. In the 1980s, the phase‐out or substitution of hazardous substances started. In 1992 the concept of “producer responsibility” was introduced which obliged certain producers to collect and dispose their products after being used. After Sweden joined EU in 1995, the waste management got greatly influenced by EU policies and regulatory frameworks like the Framework Directive on Waste, the Landfill Directive, and the Waste Incineration Directive. In 1997 the landfill bans were imposed which prohibited landfilling of flammable and organic waste; later in 2000, tax on landfilled waste started. These steps in waste management go on to this date (Swedish Environmental Protection Agency, 2005).

In 2008 about 98 million tonne of waste was generated in Sweden. Out of this, more than 70 million tonnes (72%) of waste was generated by the mining industry. Household waste was about 5 million tonnes (5%) and the rest belongs to other sectors. In table 1, the generated and treated waste in Sweden in years 2004, 2006, and 2008 can be seen. It is important to consider that the figures represent the dry weight (without water) of waste; thus the mining industry waste becomes 59 million tonnes instead of 70 million tonnes.

Table 1: generated and treated waste in Sweden in years 2004, 2006 and 2008 (dry weight) (Naturvårdverket, 2012). The landfilled mining waste is the landfilled waste generated from the mining industry and should not be confused with LFM.

hazardous waste non‐hazardous waste kton 2004 2006 2008 2004 2006 2008 household waste 373 489 349 4 459 4 643 4 044 industrial waste 981 2 288 1 715 113 482 116 093 80 061 mining industry waste 58 400 61 800 58 699 recycled waste 292 339 108 17 544 26 059 2 853 incinerated waste 382 312 187 10 773 18 598 8 311 landfilled waste 494 378 384 3 937 3 765 3 837 landfilled mining waste 58 400 61 800 58 699

Currently the Swedish waste management system tries to achieve maximum environmental and social benefits from the waste. This has been possible through the cooperation of different actors, business, municipality and people. The producers are responsible for some products in their end of life stage, municipalities are responsible for household waste and people are responsible for separating their waste. Actually as of 2011, 99% of the household waste was recycled for energy or material (Avfall Sverige, 2011).

The most important methods for waste treatment in Sweden include material recycling for packaging, paper, scrap, and WEEE (Waste Electrical and Electronic Equipment), biological treatment through digestion or composting of green and food (organic) waste, waste‐to‐energy of combustible waste (household), and finally landfilling for waste that cannot be recycled (Avfall Sverige, 2011).

Since this study is about landfills, we chose Tekniska Verken i Linköping AB (publ), a company which itself belongs to Linköping Municipality. This company is involved in different areas like electricity production, district heating, water and sewage treatment, waste treatment and biogas. The company also owns the Gärstad Landfill where waste is deposited. The Gärstad landfill falls under the energy division in the company (Tekniska Verken i Linköping AB (publ), 2010).

Currently the Landfill receives all kinds of waste from more than 30 municipalities in Östergötland County. Household waste and other flammable waste are incinerated for energy recovery. Other waste like C&D is deposited and some other like WEEE is sent to other facilities for treatment.

Gärstad landfill is located about 3 Km northeast of Linköping, Sweden. The map of the facility can be seen in figure 1.

Figure 1: Location of Gärstad landfill, 3 Km northeast of Linköping, Sweden.

2 Theoretical Framework All products that we use are made out of different materials like metals, plastics and etc. These materials are extracted from different sources that lay in the rigid outer part of the earth known as lithosphere. After being processed into different products they enter the anthroposphere, which is the regions of the surface of earth affected by humans, like cities and villages. Then the products start to be used in everyday applications. Materials inside different products that are in this phase are known as “stock in use”. Then the product is thrown away after being used. The life cycle of a product can be seen in figure 2.

Material Manufacture Distribution Usage Disposal Extraction

Figure 2: The life cycle of a product; the disposal stage includes all the material inside a landfill.

2.1 Industrial Ecology With the raise in awareness of environmental and economic issues such as mineral depletion and scarcity of mineral resources, it has been proposed (Frosch & Gallopoulos, 1989) that the material life cycle should be a closed loop, meaning that all the material that goes to waste should be reused or recycled, and that material in stock which is no longer used but not thrown away should be recovered to replace natural sources. For this purposes all the waste that normally goes to disposal should be instead send to one of the previous phases. It is even suggested that all the material that has been deposited already in the landfill should be extracted and reinserted into the cycle as shown in figure 3 (Frosch & Gallopoulos, 1989).

Material Extraction/ Recovery

Disposal / Manufacture Recolection

Usage Distribution

Figure 3: Closing the loop; instead of disposing of material, they are reinserted into the life cycle. Own illustration based on Frosch & Gallopoulos (1989)

The concept of closing the cycle is, however, much more complex to achieve in practice; because the different phases of one product are not independent from other products or materials, meaning each life cycle stage of a product may interact with a life cycle stage of another product or material

19 and the efficiency of these interactions will determine the amount of waste of the whole system. To optimize these interactions it is necessary to have a system approach in which the industry emulates the natural processes to maximize the efficiency of energy and resources use and to minimize waste. This concept was first introduced by Frosch and Gallopoulos (1989) and is known as Industrial Ecology.

To minimize the waste it is necessary that different industries interact with each other in the way that the waste of one process can be used as raw materials for another. The practice of this industrial symbiosis leads to reduced needs for extraction of virgin materials, reduced costs for companies, and less discarded waste. The success of this approach depends on the correlation between government, manufacturers and consumers; normally the interactions between industries appear naturally, but then the challenge appears when the materials leave the industrial level and are scattered in the rest of the society, and the recollection and recovery processes become much harder. Here the role of governments and consumers gains importance as it is their duty to facilitate the ways in which waste is treated and where the materials will reach their end of life (Frosch & Gallopoulos, 1989).

When materials reach their end of life stage, two things can happen: either they persist without being used or they are discarded in the form of waste. The first case is called material hibernation, where a material stays in the anthroposphere for years without being collected by any waste management process (UNEP, 2010). In the latter case, where materials are thrown away, they can be managed in several ways in order to return to the material cycle, but when it is not possible, they are discarded and generally end up in landfills.

2.2 Landfill Mining One of the biggest challenges for industrial ecology is how to deal with these growing hibernating stocks in the anthroposphere, and is has been suggested (UNEP, 2010) that mining them can be a solution to reintroduce material into the cycle and as a replacement for natural resource extraction. The process of extracting these materials and bring them back in the material cycle is called urban mining (UNEP, 2011). And more specifically if the extraction comes from a landfill the associated term is landfill mining. Landfill mining is defined by Krook et al (2011) as “a process for extracting minerals or other solid natural resources from waste materials that previously have been disposed of by burying them in the ground”.

According to previous studies (Hogland, 2002; Krook, et al., 2011), there are many additional benefits from landfill mining, which includes: conservation of landfill space, reduction of landfill area, expanding landfill lifetime, prevention and remediation of pollution and other sources of contamination like leachate1, material and energy recovery, reduction in management system costs, site redevelopment, and reclamation of land.

Landfill mining was first carried out in 1953 in order to obtain fertilizer for orchards (Krook, et al., 2011). Historically the attempts on landfill mining have been done for land reclamation and recovery of the soil, but not for material recovery.

1 A liquid material that drains from stockpiled material and contains environmentally harmful substances (wiki).

2.3 MFA (Material Flow Analysis) One of the tools used in industrial ecology is MFA. It allows the user to quantify the flows or stocks of certain material that goes into, through and, out of a system of interest. To make a MFA it is necessary to define a system boundary and a time scale. The system boundary is spatial boundary that confines a specific area (i.e. a factory, city or county). Defining a system boundary facilitates the data collection phase in a study. The time scale chosen is normally one year, because most of the data from governments, organizations and agencies are reported annually.

After defining the system boundary and time scale, the estimating method is defined. The standard methods for estimating a material stock are the bottom‐up, and top‐down (UNEP, 2010).

Bottom‐up: in this method the data about the level of stock is collected and used for estimating the amount of material stock. This can be shown with the below formula:

(1)

Where is stock of a material in time t, is the quantity of good i at time t, and is the material concentration of good i, and A is the number of different types of goods. This method depends on the stock data. This approach is used when there is not enough information about the flows of the system.

Top‐down: this method is used when the flows of a material into and out of a system are considered, and their cumulative difference shows the stock. This method can be shown as followed:

(2)

Where is stock of a material in time t, is the initial time step, T is current time step, and is the stock the material in the initial time step. This method depends on the inflow and outflow data.

Both methods have their advantages and disadvantages. And then in the study a mixture of both is used considering the availability of the data. The top‐down method uses the stocks’ flow rate, and thus shows the evolution of stock over time; and since it is done considering the flows and not the actual stock, it can be seen as a less accurate method compared to bottom‐up. On the other hand, the bottom‐up method can present a high level of uncertainty depending on the quality of the information about material concentrations, especially if the stock is mixed with other kind of material (UNEP, 2010).

For the specific case of metal stocks above the ground (such as landfills) and because of the non‐ homogeneous characteristics of waste, the methods presented before are not enough and should be use together with rough estimates made based on calculations of discard of end‐of‐life products combined with information on the amount of recycled metal used over time (UNEP, 2010).

3 Method In this study we will use case study as our research method in order to investigate the LFM concept in a real life context which is the Gärstad landfill. Since it is a case study, generalization of the results must be done with care, but the approach developed during the study might be useful for similar cases. In this case the system boundary is Gärstad landfill, and the time boundary is the time period in which the landfill has been operational.

The calculations are done based on the methods proposed in a UNEP report called “Metals Stocks in Society” (UNEP, 2010), In the case of data unavailability, assumptions will be made based on relevant data or similar studies.

In the study the current state of the landfill is described in order to know where the different waste goes and where it is landfilled. All the incoming and outgoing flows of different types of waste in the landfill are identified, and the amount of different types of waste inside the landfill is determined by using these flows.

To quantify the flows is necessary to gather the information given by Gärstad Landfill annual environmental reports, which cover the time period between 1990 and 2011. For estimating the flows during previous years, assumptions will be done based on environmental permissions given to Tekniska Verken by the Swedish EPA (Statens Naturvårdsverket) and other documents collected from the Municipality of Linköping (Linköpings kommun) and the Östergötland’s county administration (Östergötlands Länstyrelssen).

Equation 3 represents how the data will be used to quantify the amount of the different types of waste, from the periods from to .

∑ (3)

All flow units are given in tonne and the periods are defined depending on the available data and milestones, and are not necessarily equal.

In a parallel approach, the amount of waste in the landfill (Sw) is estimated by using the volumes (V) of the different areas (z) described for the landfill.

Sw ∑ ∗ (4)

The density of the waste ( are taken from results of geotechnical analysis done on Gärstad landfill by the Swedish Geotechnical Institute (Statens Geotekniska Institut). The information about the different areas of the landfill is obtained from Tekniska Verken annual environmental reports and from interviews and mail communication with the contact person (Magnus Hammar) and other staff of Tekniska Verken.

In order to estimate the total amount of waste based on the flows of the landfill (equation 3) it is required to identify all the flows over time. This approach requires more attention to details through the time period. When estimating the amount of waste based on volume (equation 4), it is only required to measure the dimensions of the waste deposits. This approach requires less data and thus less processing time compared to the flows approach. The flows approach gives detailed results about the composition of waste meanwhile the volume approach gives detailed results about the

23 allocation of waste, resulting in a detailed description of the waste in the landfill. The estimated total amount of waste is considered to be more precise by the flows approach compared to volume approach, since the latter highly depends on density of waste, which is influenced by several factors such as type of waste and the pressure on it.

Thereafter the concentrations of different metals in the different types of waste are established. Because of the non‐homogeneous characteristics of waste, the concentrations will be estimated based on studies performed for the same type of waste. Depending on the amount of the collected information, the concentrations will be given in a range obtained from statistical analysis of the data using a 95% confidence interval. Since the data about metal concentrations in waste depends on the type of waste, the estimated amount of each waste types obtained from the flow approach will be used to estimate the total amount of metals on each type of waste (equation 1), and then added up to estimate the total amount of metal in the landfill (equation 2).

By assuming a uniform distribution of waste and metal in the landfill, the rate between the estimated total amount of metals and the estimated total amount of waste will be used as the metal concentration in the whole landfill (using equation 1 as a basis). This rate is used as an approximation of metal concentration in mixed waste and also for estimating the amount of metals in area with mixed waste. A schematic view of the method can be seen in figure 4.

Define Boundaries: Gärstad Landfill: 1974- 2011

Identify Inflows Identify type of and outflows per waste in each year area

Determine density Exlude of each type of insignificant flows waste

Add all flows for Obtain volume of each type of waste waste in each (Eq 3) area

Add totals of different types of Determine amount waste of waste in each area (Eq 4)

Determine concentration of metals in each type of waste Add the amount of Compare Results waste in each area Determine amount of each metal per year in each type of waste (Eq 1)

Find the total amount of each metal in each type of waste (Eq 2)

Calculate the ratio Find the total of each metal to Calculate metal by amount of each total amount of area metal in the landfill waste Figure 4: Diagram of the two methods used in the study. The left one was used for estimating amounts of landfilled waste and metal and the right for verifying the amount of waste and allocating the metal.

Finally, all the information obtained will be analysed to determine the quantity, distribution, form and accessibility of the metal stocks in the landfill.

In order to determine the accessibility of the metal in waste, a few criteria are defined. Later the criteria are applied to each identified area of the landfill. The first criterion is if there is a construction or facility built above the area. It is considered that areas with such characteristic are not accessible and thus are not interesting for LFM. The second criterion is if the area is in use or has it been covered and closed. Since waste located in these areas are supposed to be hard to access physically. The third criterion is the type of waste, which gives an overview of the amount and forms of metal within each area, and determines the ease of accessibility and the required technology to extract the metal.

3.1 Assumptions When estimating the amount of flows, volumes and metal concentrations, due to lack of data it was necessary to make assumptions. All the assumptions can be found through chapter 4, especially sections 4.2 and 4.3 where flows and concentrations are shown respectively.

It is important to make assumptions where there is lack of data in order to show a more precise picture of the landfill use; thus the reliability of the results depend on the quality of the assumptions.

4 Collected Data and Estimations Gärstad landfill is approximately 0,6 km2. It consists of six areas, named from A to F. In these areas different activities are done which consist of receiving, treating, recovering, storing, and landfilling of waste. In figure 5, a map of the landfill can be seen.

Figure 5: The different areas of Gärstad landfill, each area used for different purposes, except for E which is a lake.

In the past all the areas (except E, which is not used) were used to landfill mixed industrial and household waste, filling existing holes up to ground level. After that each area has been used for a specific purpose. A description of the current use of each area can be seen in table 2 (Tekniska Verken, 2012):

Table 2: Usage description of the landfill areas.

Name Description of current usage Treatment of oil contaminated soil, and temporary storage of A 0 waste for incineration.

A1 Sorting and Landfilling of BA from MSWI, and organic residues.

A2 Storing and landfilling of BA from the different boilers. Fly ash cell (RGR‐cell, included in A2), covered and closed in FUDD Cell 2004. B Sorting and recycling of incoming waste, covered in 1994. Treatment and storage of different kinds of fuel (wood and C plastic); covered in 2009. Landfill of industrial waste, storing of MSW, operating since D 1992. Landfill for hazardous waste, storing of MSW. (Landfill of Metal‐ F OH in this area started in 2009)

4.1 Gärstad Landfill History It is important to consider the history of the landfill and its milestones, since it directly affects the waste composition and makes it possible to make better assumption where there is a lack of data. The history of different power plants in Linköping will also be stated, since all their incineration by‐ products go to the landfill.

4.1.1 The old Incinerator Everything started in 1958, when Tekniska Verken started to burn waste in the old incineration plant, known as “Sopförbränningsanläggningen”. Back then the ash from incineration was sent to another landfill which was on the verge of filling up (Tekniska Verken, 1999). In 1973 Tekniska Verken was granted permission from County Administration to landfill waste in the new landfill, Gärstad. Gärstad was a clay land, excavated by a local clay factory for producing bricks. This left the land with big holes in the ground, which was suitable for landfilling. The waste that was intended to be landfilled consisted of construction and demolition, inflammable waste, soil and excavated material, slaughterhouse waste, a small percentage of industrial and household waste, and finally the ash generated from burning the flammable waste. The incineration capacity of the incineration plant was 45 000 tons of household waste per year. The plant used to send its ash to the landfill from 1974 until 1980, when it was shut down (Tekniska Verken, 1999).

4.1.2 KV1 In 1962, the construction of Kraftvärmeverk (KV1) started, which is a CHP (Combined Heat and Power) plant. It got operational in 1964 with two oil boilers. Later in 1971 they added another oil boiler to it. In 1985 two of the oil boilers were converted to coal and wood boilers, which resulted in generation of bottom ash. Also, a flue gas cleaning system was installed, which resulted in generation of fly ash. From this date until 1992 the BA and the FA from the boilers were mixed together and then landfilled. In 1992 the boilers were renovated, which led to increase in ash generation (Tekniska

Verken, 1999). Also at the same year a NOx reduction and flue gas condensing system was installed on wood boiler in KV1 because of the new environmental regulations, introducing FA from the cyclone filter and Electrostatic filters into the landfill (Tekniska Verken, 2004). Due to its hazardousness, since 2005 the ashes collected from the electrostatic filter of wood incineration are sent to Norway for treatment.

4.1.3 Gärstad Verket In 1979 the construction of Gärstad Verket (GV) started. In 1981 the first phase started to work with waste and tree as fuels. In 1982 the second waste boiler started to work and thus reaching its full operational capacity. In 1985 a flue gas cleaning system was installed, and around x ton of fly ash was collected. Due to increased demand in power production, in 1993 and 1994 the boilers got fit for steam production which increased their incineration capacity.

In 2001 a contractor started to separate the ferrous metal from BA with a magnet. This resulted in less concentration of ferrous metal in the BA which was sent for construction. In 2005 the fourth boiler (KV60) was put into operation, which doubled the nominal incineration capacity of GV, and thus the ash generation increased. In 2006 the contractor started to recover non‐ferrous metal from BA, which resulted in less concentration of such metals in the final BA. In the same year, three of the boilers (KV50) were shut down for maintenance, which resulted in a reduction in ash generation. The ashes (BA, FA, and sludge) sent by all the power plants through time can be seen in figure 6.

90 000 80 000 70 000 60 000 50 000 Old Incinerator Tonne 40 000 KV1 30 000 Gärstadverket 20 000 10 000 0 1974 1976 1978 1980 1982 1984 1986 1988 1990 1992 1994 1996 1998 2000 2002 2004 2006 2008 2010

Figure 6: Ashes in all forms (BA, FA and sludge) sent from each power plant for landfilling in Gärstad. The old incinerator was decommissioned in 1980 and thus no more ash was sent from there. Own illustration, based on data from all Gärstad landfill environmental reports and county administration permissions.

4.1.4 FUDD In 1992 the FA from Gärstad Verket started to be landfilled in a special cell called FUDD (Funktionsanpassad deponidesign [Landfill designed for specific function]). Before this date all the FA from waste was mixed and landfilled with all the other ashes. This cell was decommissioned and covered in 2004. Since then the FA from waste is sent to Norway for treatment.

4.1.5 Landfill Tax In 2000 with the introduction of landfill tax, Tekniska Verken started to use BA as a construction material, and thus no more BA was officially landfilled. These stocks of ash that are used for construction are referred to as “hidden landfills”; and are considered as landfilled material in our calculations.

4.2 Flows and stocks of waste Gärstad landfill receive several types of waste, but nowadays many of them never reach the landfill itself, instead they are sent to other facilities to be treated (e.g. electronic waste, batteries and other hazardous substances) or recycled (e.g. asphalt, concrete or scrap metal). These wastes are mentioned in Gärstad landfill environmental reports but are excluded from the calculations since they are never landfilled. In Table 3 all different types of waste flows that have been sent to Gärstad over its history can be seen. In order to estimate the total amount of waste, all the flows except those who were not landfilled or excluded due to low amount are used. But to estimate the total amount of metal, only the flows mentioned in Table 3 as “included” are used. When estimating the total amount of waste, it is necessary to include as many flows as possible since it will affect the rate of metal to waste in the landfill. But flows such as leachate and dust will not affect the final results due to their very low amounts. Also, when estimating the total amount of metal, it is necessary to include as many flows as possible which contain metal. But flows such as sludge and asbestos can be excluded since their low metal content will not affect the final results. More details regarding these comments can be found further in the report.

Table 3: All identified waste flows of Gärstad. The flows except those that are not landfilled or excluded due to low amount are used to estimate total amount of waste. The flows marked as “included” are the ones used for estimating the total amount of metal.

Waste Waste subgroups Comments Bottom ash KV1 coal Included Fly ash KV1 coal Included Sludge KV1 Excluded due to low concentrations Bottom ash KV1 wood Included Ashes Fly ash KV1 wood Included Bottom ash Gärstad Included Fly ash Gärstad Included Sludge Gärstad Excluded due to low concentrations Wood Ash from other sources Included Construction and demolition Included Asphalt Excluded due to low concentrations Inert waste Asbestos Excluded due to low concentrations Concrete Not landfilled Excavated material Not landfilled Municipality waste water Excluded due to low concentrations Sludge from street gullies and industry Excluded due to low concentrations Industrial waste water Oil separated sludge Excluded due to low concentrations Slaughter waste Excluded due to low concentrations Commercial waste Metal Hydroxide sludge Included Forest Waste Not landfilled Contaminated soil Not landfilled Batteries, chemicals, acids, explosives, Hazardous Not landfilled electronic waste and etc. Latrine Excluded due to low concentrations Scrap metal Not Landfilled Glass Excluded due to low concentrations Other Not specific industrial waste Excluded due to low concentrations Household Waste Included Leachate Excluded due to low amount Dust Excluded due to low amount

Currently inside the landfill, the waste can be treated in three different ways: landfilled, recovered and stored.

Waste is landfilled when it is deposited in the area and currently has no more use. This category includes BA, FA, sludge from various sources, construction and demolition waste, asbestos, Industrial, and commercial waste. These wastes are the inflows of the landfill.

Waste is recovered when it is reused, recycled or sold. By this definition, metal scrap is recovered since it is separated from other waste and sold to other entities. Some waste can be recovered without being processed, for example BA and asphalt are recovered and used as construction or covering material, or sold to other landfills. The main outflows (scrap metal and a small amount BA) of the landfill come from this category.

Waste is stored when it is possible to be reused or recycled, but there is no immediate need for it. This means that there is no difference between the characteristics of recovered and stored waste, but stored waste may be more accessible. These kinds of waste are neither inflow nor outflow. In this study it is assumed that stored ash is the same as landfilled and stored C&D waste is sent outside the landfill.

The amount of landfilled and stored waste is easier to determine, because they are stated in the reports. For recovered waste, it is necessary to exclude the outflows. So it is necessary to determine how much was send outside to estimate the amount in stock. In most of the cases the outflows is bottom ash sold to other landfills used as covering material and coal bottom ash used for construction of roads. The remaining recovered material is used internally.

There are other types of waste which are sorted inside Gärstad landfill, such as hazardous waste and scrap metal. These types of waste come inside the landfill facilities, are sorted and leave. Thus they are not included in the calculations.

Figure 7: Schematic view of the waste flows to and from the landfill (the oval shape) currently. The two circles are power plants that send their incineration residue to landfill which makes up around 85% of the total incoming waste.

The volume is presented based on areas, from A to F. as it can be seen in table 4, there are two kind of volumes; underground volume and above surface volume. Underground volume is the volume of waste from below the surface to ground level and above surface volume is the volume of waste from ground level to above. The reason for this separation is that most of the underground waste is mixed waste with its own characteristics and above surface waste are mostly ashes and a small amount of C&D.

Table 4: Area, volume and waste content of each area until 2009 (Hammar, 2012).

Average Area Underground Underground Surface volume Name Above surface content height (m2) volume (m³) content (m3)

A0 ‐ 50 000 250 000 Mixed waste BA from Waste, Ash from A1 +6 m 61 500 307 500 Mixed Waste 369 500 coal and wood BA from Waste, Ash from A2 +7 54 500 272 500 Mixed Waste 381 500 coal and wood FUDD +9 5 600 n/a n/a 50 400 FA from waste B 0 45 000 225 000 Mixed waste 0 n/a C 0 87 000 435 000 Mixed waste 0 n/a D 0 75 500 377 500 Industrial Waste n/a C&D Asbestos and industrial F +4 45 000 225 000 Industrial Waste 180 000 Waste

The amount of waste in stock is calculated using a density of 1 tonne/m³ for waste and 1,4 tonne/m³ for ashes (Statens Geotekniska Institut, 1999).

4.2.1 Estimation of flows between 1974‐1990 and outflows From 1990 to 2011 the flows are presented in the environmental reports on a yearly basis, but to identify and quantify the flows for previous years, permissions given by country administration were used. Since there was no specific values for material flows for each year, previous years were divided into groups (1985‐1989, 1982‐1984, 1980‐1981, 1974‐1979). These groups are based on different milestones and changes in the landfill and its related facilities, such as opening of a new incinerator. These groups are explained in the following.

Since the date of the permission to use Gärstad as a landfill was given in the end of 1973, year 1974 was considered as the starting point. For the period between 1974 and 1979 the permit given by Naturvårdsverket which describes the future use of the land (Statens Naturvårdsverk, 1973) is used for estimating the flows. The amount for different waste are given in m3 and in order to convert the values into tonne, a density of 1 tonne/m3 is used for all waste, and 1,5 tonne/m3 for ashes (Statens Geotekniska Institut, 1999).

In 1980 construction permission for Gärstad Verket is given, which describes that the old incinerator will be decommissioned that year and predicts that Gärstad Verket incinerators will reach their full capacity in 5 years, and for the period between, the amount of incinerated waste will be reduced, and the rest will be landfilled (Statens Naturvårdsverk, 1980). Alas it was found that in 1982 one of the boilers becomes fully operational (Tekniska Verken, 1999), and thus it was assumed that all the Gärstad Verket incinerators were fully operational in 1982.

The flows during years 1982‐1989 are taken from the description of the new facilities (Statens Naturvårdsverk, 1981), and the introduction of the coal and wood boilers in KV1 (Tekniska Verken, 1999).

It is also assumed that the landfilled amounts of waste during each period (group of years) are constant before 1990. Their yearly amount until 1990 is taken from the assumptions made above.

As mentioned in section 4.2. The main outflow is bottom ash. But as it can be seen in table 5, there is no specific pattern for these flows. Thus it is assumed that the occurrences of the outflows are random. The outflows will be considered zero unless it is clearly documented. And since for 1974‐ 1989 such documents were not found, it is assumed that there are no outflows during this period.

Table 5: Identified outflows of ash from Gärstad landfill.

Usage Year amount unit Type Construction of Parking Space 2010 6300 ton bottom ash from coal Sold to other landfills 2010 4700 ton bottom ash from waste Sold to other landfills 2009 6 000 ton bottom ash from waste Sold to other landfills 2008 4000 ton bottom ash from waste Sold to other landfills 2007 1700 ton bottom ash from waste Construction (expanding) 2002 17000 m3 All bottom ash Construction (Road to Ekängen) 2001 4500 ton Bottom ash from coal Send away (Stenugnssund) 1990 4000 ton Bottom ash from coal

There are other outflows from GA which are mainly emissions to water in form of leachate and emissions to air in form of exhaust gases, and dust. The amount of lost mass in these emissions is assumed to be insignificant compared to the amounts inside the landfill; thus they are excluded from the calculations.

4.2.2 Waste flow history Using the information collected from Gärstad Landfill’s environmental reports from 1990 to 2011, and the estimations of the use of the landfill collected from the different permissions given to Tekniska Verken by the environmental authorities. The annual landfilled amount can be seen on figure 8. More detailed information can be found in appendix A.

Landfilled amount of waste 120 000 100 000 Ash 80 000 C&D Tonne 60 000 40 000 Household 20 000 Other 0 1974 1976 1978 1980 1982 1984 1986 1988 1990 1992 1994 1996 1998 2000 2002 2004 2006 2008 2010

Figure 8: The landfilled amount of main types of wastes since landfill started operating, 1974 until now, 2011.

4.3 Concentrations The next step after estimating the amount of different waste in stock is to find the concentration of different metals in them. Then the amount of each type of waste is multiplied by its metal concentration, and then summed up in order to find the total amount of each metal.

4.3.1 Ashes The generated ashes have been analysed in Gärstad facilities in order to determine the amount of hazardous material, most of them are the metals considered for this study. After comparing these measurements with data from ALLASKA database, and seeing similar results, it was assumed that data about missing metals (iron and aluminium) in Gärstad reports could be derived from these databases (värmeforsk, 2011; Vägverket, 2000). Since these metals are not hazardous, they do not appear on the Tekniska Verken analysis, but must be included due to their importance in society.

Tables 6 and 7 show the concentration range of different metals in ashes, calculated from measurements done by Tekniska Verken since 2000.

Table 6: Estimated metal concentrations in bottom ash generated from different fuels (waste, coal and wood).

Estimated Concentrations Minimum Maximum Waste (untreated / Waste (untreated / mg/kg Coal Wood Coal Wood treated) treated) Iron 69 997B 45 150A 10 585A 90 178B 82 150A ‐ 13 458A Aluminium 54 389 B 25 890A 33 744 8 163 56 911B 27 506A 57 614 12 237 Arsenic 28 0 22 38 31 138 Boron 90 ‐ 184A 252A ‐ 234A Barium 1 138 5 628 794 1 745 26 532 1 976 Cadmium 10 0 0 16 1 5 Cobalt 25 70 8 54 123 21 Chromium 309 189 129 484 392 334 Copper 3 255 272 314 4 611 767 976 Mercury 0 0 0 0 1 1 Manganese 911 993 1 450 1 125 1 435 1 737 Molybdenum 18 9 4 29 27 9 Nickel 186 115 27 310 244 78 Lead 894 69 308 2 531 251 672 Antimony 101 ‐ 0A 163A ‐ 12 A Selenium 4 ‐ ‐ 7 ‐ ‐ Tin 250 ‐ 22 A 552 A ‐ 33* Titanium 3 473 ‐ 1 252 A 3 542 A ‐ 3 325 A Vanadium 28 59 15 33 119 43 Zinc 4 460 1 972 848 5 523 3 333 2 564 ATaken from Allaska database B Calculated from SGI (Statens Geotekniska Institut, 1999)

Table 7: Estimated metal concentrations in fly ash, generated from different fuels; and for wood from different filters.

Estimated Concentrations Minimum Maximum mg/kg Waste Coal Wood Wood CY C Wood EL D Waste Coal Wood Wood CY C Wood EL D Iron 14 694 A 29 147 A 12 210 A 12 210 B 12 210 B 26 322 A 49 611 A 15 662 A 15 662 B 15 662 B Aluminium 27 401 A 54 310 A 23 447 A 23 447 B 23 447 B 39 021 A 66 939 A 32 219 A 32 219 B 32 219 B Arsenic 76 10 344 77 751 191 20 465 143 955 Boron 155 A 292 A 292 B 292 B 175 A 357 A 357 B 357 B Barium 817 370 1 533 1 586 1 453 2 189 605 2 561 2 964 1 947 Cadmium 65 5 28 3 66 103 7 39 5 91 Cobalt 31 169 12 12 12 50 236 21 24 17 Chromium 674 42 135 116 164 964 70 332 358 291 Copper 703 271 275 180 421 941 304 415 340 529 Mercury 0 0 2 0 4 0 1 3 0 9 Manganese 759 A 700 2 183 1 061 3 893 1 490 A 2 401 A 2 635 1 729 4 017 Molybdenum 29 5 4 4 4 54 14 17 9 30 Nickel 123 21 ‐443 30 ‐1 165 177 64 1 394 73 3 407 Lead 2 454 234 1 543 288 3 454 4 703 501 3 062 666 6 713 Antimony 872 40 107 28 227 2 085 87 204 48 441 Selenium 0 A 10 13 13 13 6 A 14 16 18 14 Tin 237 0 A 17 A 17B 17 B 580 16 A 29 A 29 B 29 B Titanium 6 096 A 2 390 A 2 846 A 2 846 B 2 846 B 9 975 A 3 336 A 4 864 A 4 864 B 4 864 B Vanadium 41 46 A 38 A 38 B 38 B 54 115 A 52 A 52 B 52 B Zinc 17 947 19 730 8 032 ‐1 620 22 741 28 331 42 470 21 154 13 923 32 174 A Taken from Allaska Database B No data available, concentration assumed to be the same as Fly ash from wood concentration C CY: fly ash collected from the cyclone filters. D EL: fly ash collected from electrostatic filter.

When no values are found in the measurements by Tekniska Verken, tables 5 and 6 were completed using the Allaska database. The search criteria were waste, coal and wood as fuels for incineration, and grate furnace as the boiler type for waste incineration.

All the recent measures for BA from waste incineration were taken after metal separation, so in order to identify changes in concentration a study done by SGI in 1999 was used. The only relevant changes were identified for Iron and Aluminium, so the concentration values in this report are used for the BA flows before 2000 and 2005 respectively.

In some cases, the generated ashes are not separated, and only the total amount is given. In these cases the concentration of metals is calculated based on the average ratio of generated BA and FA. It was calculated that ashes from waste incineration has 87% BA – 13% FA, coal incineration 35% BA – 65% FA, wood incineration 75% BA – 25% FA, and FA from wood incineration 40% EL – 60% CY.

There are elements which are found in oxidized form, and some metal concentration values given in Allaska database are in oxidized form, so to obtain the concentration of the element, it was needed to use the conversion factors shown in table 8 (British Columbia Ministry of Energy and Mines, 2011).

Table 8: Conversion factor used to obtain the amount of metals from their oxide form.

Original form To Obtain Divide By Al2O3 Aluminium 1,8895 Fe2O3 Iron 1,4297 MnO Manganese 1,2912 TiO2 Titanium 1,6681

Elements such as Iron and aluminium can be found mainly in oxidized form, because the scrap form is separated. Nevertheless older ashes still contain metal in both oxidized and scrap form. Comparing the concentrations of metal before and after metal recovery, it is estimated that approximately 45‐ 55% of the iron and 52‐54% of the aluminium in the ashes prior to separation are in scrap form. For other metals there is no significant difference between the concentration after and before metal separation.

4.3.2 Construction and demolition waste Based on the visual inspection by Tekniska Verken in years 2005, 2006, 2007 and 2009, the waste has approximately 3% metal. They contain mainly copper, aluminium and iron.

A study published by Boverket (1998), measured the materials used for construction and the generated waste after renovation processes, the results can be seen in table 9.

Table 9: Estimated metal concentrations in C&D waste based on (Boverket, 1998).

Total waste per year Ferrous metals Others Metals Aluminium Copper in Sweden (Kt) ratio (Iron) (unclassified) Construction waste 419 0,50% 73% 0% 27% 0% Renovation and demolition waste 195 8% 75% 2% 5% 18% Estimated total amounts 614 3% 2,15% 0,05% 0,22% 0,46%

After comparing the study with the visual inspection, it is possible to assume that the concentrations are in the same range for both cases.

4.3.3 Me‐OH Sludge Metal Hydroxide is any metal element which has formed a compound with hydroxide anion (OH), and thus shown with Me‐OH. Me‐OH sludge is the sediment left after filtering the wash water used in different industries. The Me‐OH received at Gärstad comes mainly from different surface treatment industries, such as painting, galvanizing, electroplating, etc. The metal concentration in the sludge is very high, but varies depending on the industry; but regardless the industry, the main component is Iron. The sludge also contains high concentrations of other metals such as chrome, copper, nickel, and zinc. Table 10 shows the most common results:

Table 10: Concentrations of metal in me‐OH sludge from different studies (weight %).

Iron Aluminium Zinc Chromium Manganese Copper Source 26,42 0,36 21,37 2,5 0,21 n/a (Sılvia C.R. Santos, 2008) 15 1,5 0,3 1 n/a 2 (S. Netpradita, 2003) It can be seen that it is an important source of valuable metals. However, as the name indicates, the metals here are basically in hydroxide form, which are highly unstable and are difficult to treat (Dulski, 1996).

4.3.4 Household Waste Although household waste is not currently being landfilled in Gärstad, a considerable amount of this type of waste was deposited in the 70s. The amount of metals in household waste is calculated from the concentration of metals in ash from waste incineration. It was seen from collected data that around 25% of waste mass remains after incineration as ashes. so in order to find the metal concentration in waste before incineration, the metal concentration in ashes are multiplied by 25%, assuming there has been no losses in metal during the incineration process. In table 11 the calculated concentrations can be seen.

Table 11: Estimated metal concentrations in household waste

Household Concentration (mg/kg) Waste Min Max Iron 15702 20469 Aluminium 12720 13646 Arsenic 9 14 Boron 25 61 Barium 274 451 Cadmium 4 7 Cobalt 7 13 Chromium 89 137 Copper 731 1034 Mercury 0 0 Manganese 223 293 Molybdenum 5 8 Nickel 44 73 Lead 274 703 Antimony 50 103 Selenium 1 2 Tin 62 139 Titanium 953 1095 Vanadium 7 9 Zinc 1553 2122

4.3.5 Mixed Waste The landfilled waste in the past is hard to characterize, because there are no measurements about its composition. In order to tackle this problem this old waste was named ‘mixed waste’ and its metal concentration is a combination of the metal concentrations of the different types of waste present in the landfill. The concentrations are calculated as the rate between the total amount of estimated metal and the total amount of estimated waste in the landfill.

These concentrations are used to give an overview of the metal concentration if a uniform distribution of waste is assumed over the landfill. In addition, these concentrations are used to estimate the amount of metals by volume, in the areas where the waste is presented in a mixed state.

4.3.6 Others The focus of this study is the flows that have a relevant content of metal. So the flows whose metal concentration are too little or have no metal has been omitted from the results. This includes flows such as latrine, municipality waste water and slaughter waste which are not included due to being organic compounds, and their recovery being important for other applications such as decomposition, gasification, composting.

The metal concentration of leachate has a unit ratio of less than 1 mg/kg (Tekniska Verken, 2012) and all together (Cr, Ni, Zn, Cu, Pb, Cd, and As) adds up to around 20 kg per year. The exception is Iron (Fe) and Manganese (Mn) which have a concentration unit of mg/kg but because of the small flows they are assumed to be insignificant compared to metal content of the ashes and landfilled waste, and thus not included in the calculations.

Industrial waste sludge has high amount of toxic metals like lead, mercury, and cadmium. These metals are phased out, and thus are not interesting for recovery. Asbestos is a family of carcinogenic minerals; their composition may include iron, aluminium or magnesium in complex forms, but in very low concentration.

To simplify calculations, it is assumed that the metal concentrations in such flows presented above are zero.

4.4 Accessibility Criteria Since the beginning, different types of waste have been deposited separately. But when new layers of waste appear, the landfilling is done without considering the previous use. For this reason the waste inside each area is considered as mixed waste, unless the area has been specified for a particular type of waste. Table 12 brings an overview of the characteristics of the different areas of the landfill. As it can be seen, type of waste is categorized as above and under ground. The reason is that the information about waste above ground is more detailed compared to the underground. Also, the waste above ground is easier to access physically.

Table 12: Accessibility criteria applied to different areas of the landfill.

Construction Type of waste Type of waste Final coverage above (aboveground) (underground) A0 No Yes n/a Mixed A1 No No Mixed ashes Mixed A2 No No Mixed ashes Mixed FUDD (in A2) No Yes FA A n/a B Yes Yes n/a Mixed C Partly Partly n/a Mixed D No No Mixed B Mixed F No No Mixed Mixed metal‐OH cell No Yes Metal‐oh n/a (old) Metal‐OH cell No No Metal‐oh n/a (new, in F) A Fly ash only from waste incineration B Without ashes

5 Results The figure bellow shows the estimated total amount of the most common metals in the whole landfill based on the flow approach. The total amount of waste in the landfill is the sum of the different types of waste, including those whose metal concentration is assumed to be zero which adds up to 4 million tonne. And the total amount of metal is the sum of the estimated amount of metal in each type of waste, described in section 5.2 to 5.5.

Metals in Landfill 200 000

150 000

Ton 100 000

50 000

0 Iron Aluminium Copper Zinc Others

Figure 9: Estimated amount of landfilled metals in all forms calculated from flows of waste.

As it can be seen in figure 9, iron and aluminium have the largest amounts in the landfill. Copper and zinc are also found in considerable amounts. The values used for the figure above are shown in table 13, which also shows the rate of estimated total metal to estimated total landfilled waste. This rate is later used to estimate the amount of metal in areas where the landfill consists of mixed waste.

Table 13: Estimated total amount of waste based on flows approach; and estimated amount of landfilled metals in all forms calculated from flows of waste and its ratio compared to total amount of waste.

Amount (ton) Rate (%) Min Max Min Max Total waste 4 000 000 100 Iron 127 015 180 283 3,18 4,51 Aluminium 98 075 110 912 2,45 2,77 Copper 7 388 9 392 0,18 0,23 Zinc 16 126 27 069 0,40 0,68 Others 22 633 33 714 0,57 0,84

In table 14 the total amount of waste calculated based on the volume approach can be seen. Since there is no detailed data about the metal contents within each area of the landfill, the total amount of each metal is calculated based on the rates presented in table 13.

Table 14: Estimated total amount of waste based on volume approach; and estimated amount of metals using the rate from the flows approach.

Amount (ton) Total Min Max Total Waste 3 553 000 Iron 118200 159500 Aluminum 96120 108600 Copper 6720 8600 Zinc 15700 26200 Others 20800 31700

Since the amount of waste calculated from volume, depends greatly on the used values for density of each type of waste, it is considered that the results given by the flows approach are more accurate, and is used for showing the metal content in the following sections. Nevertheless, the results from both approaches are in the same order of magnitude and only vary around 10%. This shows that both approaches are valid for estimating the amount of waste in a landfill.

5.1 Scrap metal Scrap metal is mainly found in C&D waste, bottom ash and household waste. While the biggest share of scrap metal is found in bottom ashes, and specifically in ash deposits that belong to the period of time before 2000 for ferrous, and 2005 for non‐ferrous. Since after these dates, the metal has been sorted out from the bottom ash. These values are obtained after assuming that all the metal in C&D and household waste are in scrap form, and oxidizing process for scrap metal is not happening.

Table 15: Estimated total amount of scrap metal in the landfill, and its rate compared to the total amount of waste.

Scrap (tonne) Rate (%)

min max min max Iron 48 700 67 000 1,22 1,68 Aluminium 35 300 38 200 0,88 0,96 Copper 2010 2180 0,05 0,05 Other Metals 5909 6834 0,15 0,17

As it can be seen in table 15, the biggest amount of scrap metal is iron and aluminium. Scrap metal add up to around 2,5 % of the landfill and 30% of the total amount of metal.

5.2 Metal content in ashes Table 16 shows the estimated total amount of ashes and the concentrations of some of the most common metals. It can be seen that more than half of the landfilled waste consists of ash, which shows the influence of ash on the final results.

Table 16: Estimated total amount of landfilled ash and the estimated amount of metals within.

Concentration (%) Total (tonne) Min Max Min Max Waste 100 2 298 656 Iron 4,26 6,37 97915 146383 Aluminium 3,92 4,43 90039 101856 Copper 0,23 0,29 5278 6612 Zinc 0,62 0,99 14155 22679 others 0,72 1,13 16496 25971

Figure 10 shows the total amount of metal in ashes, in logarithmic scale (to see the order of magnitude of the results). More detailed information can be found in appendix B.

1 000 000

100 000

10 000 Ton 1 000

100

10 Tin Zinc Iron Lead Boron Nickel Cobalt Barium Copper Arsenic Mercury Titanium Selenium Cadmium Antimony Vanadium Chromium Aluminium Manganese Molybdenum

Figure 10: Estimated amount of different metals in all types of landfilled ash.

As it can be seen in figure 10, the biggest amounts of metals belong to iron, aluminium and Zinc. All other metals except for mercury can be found in considerable amounts. This shows that ashes from incineration are a good source of different metals.

In order to find the amount of scrap metal in ashes, the difference between metal concentrations before and after recovery was used. It is assumed that all scrap metal is recovered. The ferrous and non‐ferrous scrap metal inside bottom ash from waste incineration has been recovered since 2000 and 2005 respectively. After comparing the concentration of different metals after and before these dates, it was found that only iron and aluminium concentrations changed significantly. Table 17 shows the estimated amount of metal in scrap form in the landfill, which can be found in the underground mixed waste, and the first layers of areas A1 and A2.

Table 17 : Iron and Aluminium in scrap form in bottom ash from waste incineration.

Landfilled amount before Landfilled amount of scrap Rate of scrap in total Year of recovery (tonne) (tonne) ashes (%) Recovery min max min max min max Iron 2000 54 489 70 460 22 799 38 359 0,99 1,66 Aluminium 2005 53 440 56 220 27 343 29 742 1,18 1,29

As seen in table 17, around half of the landfilled iron and aluminium was in scrap form. Scrap metal makes up around 2, 5% of the total landfilled ashes.

5.3 Metal content in C&D waste It is assumed that all metals in this type of waste are in scrap form. C&D waste is generated mostly from the construction and renovation industry. The main metal used in Swedish constructions is steel (iron and zinc), used in pipes, covering and structures. It is possible also to find small amounts of

41 aluminium and copper (Boverket, 1998). In total, it is estimated that there is approximately 360 000 tonnes of C&D waste in the landfill.

The metal concentrations in table 18 are based on several studies made by Boverket, and from visual inspection done in the Weigh Bridge in Gärstad facilities.

Table 18: Total amount of landfilled C&D waste and the estimated amount of metals within.

C&D waste Concentration (%) Total (tonne) (tonne) Waste 100 777 468 Iron 2,2 17 100 Aluminium 0,1 800 Copper 0,2 1 600 Other Metals 0,5 3 900

5.4 Metal content in Metal hydroxide sludge Around 5000 tonne of Metal Hydroxide can be found in a special cell in area C, which has been covered. The technical barriers are similar to the ones of the FUDD cell. Around 16000 tonne of Metal‐OH is landfilled in a special cell in area F. Table 19 shows the estimated amount of metal within these areas.

Table 19: Total amount of me‐OH waste and the estimated amount of metals within.

Me‐OH sludge Concentration (%) Total (tonne) (tonne) Min Max Min Max Waste 100 21 000 Iron 15 25 3 200 5 300 Aluminium 0,5 3 100 600 Copper 0,5 3 100 600 Others Metals 5,00 10,00 1 100 2 100 Zinc 5,00 15,00 1 100 3 200

Even though the amount of Me‐OH is small, it has a very high concentration of metals. Around 40% of this area is made out of metals, but in hydroxide form.

5.5 Metal Content in Household Waste There is a considerable amount of household waste landfilled in the earlier stages of Gärstad. Due to the characteristics of the data collected for this period, the total amount of landfilled household waste includes a great uncertainty. Moreover this type of waste is expected to be in the deepest parts of the landfill only. Table 20 shows the total amount of estimated waste and the amount of metal within.

Table 20: Total amount of Household waste and the estimated amount of metals within.

Concentration (mg/kg) Total (tonne) Household Min Max Min Max Waste 100 561 000 Iron 15702 20469 8800 11500 Aluminium 12720 13646 7136 7656 Arsenic 9 14 5 8 Boron 25 61 14 34 Barium 274 451 154 253 Cadmium 4 7 2 4 Cobalt 7 13 4 7 Chromium 89 137 50 77 Copper 731 1034 410 580 Mercury 0 0 0 0 Manganese 223 293 125 164 Molybdenum 5 8 3 5 Nickel 44 73 25 41 Lead 274 703 154 395 Antimony 50 103 28 58 Selenium 1 2 1 1 Tin 62 139 35 78 Titanium 953 1095 535 614 Vanadium 7 9 4 5 Zinc 1553 2122 871 1190

5.6 Metal Content by Areas All the areas of the landfill have mixed waste below ground level; they contain a mixture of all the different types of waste received by the landfill. Tables 21 to 31 shows the estimated amount of metals by area, calculated using equation 4. And the concentrations used for underground waste (all areas) are taken form the total results shown in the beginning of section 5, in table 13.

Table 21: Estimated amount of metals in A0 Table 23: Estimated amount of metals in A1, above ground

Concentration (%) Amount (ton) Concentration (%) Amount (ton) A0 A1 A Min Max Min Max Min Max Min Max Total waste 100 250 000 Total waste 100 553 500 Iron 3,18 4,51 7900 11300 Iron 4,20 6,29 23200 34800 Aluminium 2,45 2,77 6100 6900 Aluminium 3,87 4,38 21400 24300 Copper 0,18 0,23 500 600 Copper 0,23 0,28 1300 1600 Zinc 0,40 0,68 1000 1700 Zinc 0,63 1,01 3500 5600 Others 0,57 0,84 1400 2100 Others 0,72 1,13 4000 6200

Table 22: Estimated amount of metals in A1, underground Table 24: Estimated amount of metals in A2, underground

Concentration (%) Amount (ton) Concentration (%) Amount (ton) A1 U A2 U Min Max Min Max Min Max Min Max Total waste 100 307 500 Total waste 100 272 500 Iron 3,18 4,51 17600 13900 Iron 3,18 4,51 8700 12300 Aluminium 2,45 2,77 13600 15300 Aluminium 2,45 2,77 6700 7600 Copper 0,18 0,23 1000 1300 Copper 0,18 0,23 500 600 Zinc 0,40 0,68 2200 3700 Zinc 0,40 0,68 1100 1800 Others 0,57 0,84 3100 4700 Others 0,57 0,84 1500 2300

Table 25: Estimated amount of metals in A2 aboveground Table 28: Estimated amount of metals in C

Concentration (%) Amount (ton) Concentration (%) Amount (ton) A2 A C Min Max Min Max Min Max Min Max Total waste 100 572 250 Total waste 100 435 000 Iron 4,20 6,29 24200 36200 Iron 3,18 4,51 13800 19600 Aluminium 3,87 4,38 22300 25200 Aluminium 2,45 2,77 10700 12100 Copper 0,23 0,28 1300 1600 Copper 0,18 0,23 800 1000 Zinc 0,63 1,01 3500 5600 Zinc 0,40 0,68 1800 2900 Others 0,72 1,13 4100 6400 Others 0,57 0,84 2500 3700

Table 26: Estimated amount of metals in FUDD cell Table 29: Estimated amount of metals in D

Concentration (%) Amount (ton) Concentration (%) Amount (ton) FUDD D Min Max Min Max Min Max Min Max Total waste 100 75 600 Total waste 100 377 500 Iron 1,47 2,63 1100 2000 Iron 3,18 4,51 12000 17000 Aluminium 2,74 3,90 2100 2900 Aluminium 2,45 2,77 9300 10500 Copper 0,07 0,09 100 100 Copper 0,18 0,23 700 900 Zinc 1,79 2,83 1400 2100 Zinc 0,40 0,68 1500 2600 Others 1,24 2,28 900 1700 Others 0,57 0,84 2100 3200

Table 27: Estimated amount of metals in B Table 30: Estimated amount of metals in F

Concentration (%) Amount (ton) Concentration (%) Amount (ton) B F Min Max Min Max Min Max Min Max Total waste 100 300 000 Total waste 100 405 000 Iron 3,18 4,51 9500 13500 Iron 3,18 4,51 12900 18300 Aluminium 2,45 2,77 7400 8300 Aluminium 2,45 2,77 9900 11200 Copper 0,18 0,23 600 700 Copper 0,18 0,23 700 1000 Zinc 0,40 0,68 1200 2000 Zinc 0,40 0,68 1600 2700 Others 0,57 0,84 1700 2500 Others 0,57 0,84 2300 3400

Table 31: Estimated amount of metals in me‐OH cell

Concentration (%) Amount (ton) Me‐OH Min Max Min Max Total waste 100 4 000 Iron 15,00 25,00 600 1000 Aluminium 0,50 3,00 20 100 Copper 0,50 3,00 20 100 Zinc 5,00 15,00 200 600 Others 5,00 10,00 200 400

It can be seen that the largest deposit of metal are in A1 and A2, which is a consequence of having the largest amount of waste in those areas. The smallest amounts of metals are found in the special cells, the FUDD cell and the Me‐OH cell.

5.7 Accessibility and Hotspots In this section first the areas will be ranked from least accessible to most accessible, considering the accessibility criteria described in section 4.4 and shown in table 12. The least accessible area is B, because it has built facilities above, making the underground mixed waste there unreachable. Then it is area C, which has been partially used for constructions above it. The underground mixed waste in this area is totally covered and closed. After that, come areas A0, FUDD cell, and Me‐OH cell, which

44 are also covered and closed. Then it come areas D, F, A1 and A2 which have no construction above them and are open, and based on these criteria they have the same accessibility conditions. To compare these areas, the third criterion, type of waste, is used. The type of waste determines the concentration of different metals. Based on the results about scrap metal content in the mixed waste and in ashes, areas A1 and A2 are considered to be more accessible than D and F.

By considering the factors for accessibility and the amount of metals, areas A1 and A2 become the hotspot for metal recovery.

6 Discussion

6.1 Method The method that was used in this report has a couple of advantages. The first is that it is a quit cheap and fast process for estimating the metal stock, or any other kind of stock in a landfill, compared to traditional methods such as drilling and sampling. Of course in this study, the composition analysis of previous studies done by the company was used, but there was no need for any new sampling or measuring.

Of course there are some disadvantages to this method. First of all, it only works if there is any previous data available. In case of a landfill which no measuring has been done, it is impossible to apply this method. Second, it is not as precise as direct sampling, in the sense that this method shows the amount of flows which has entered or left the landfill, but it doesn’t say where it is landfilled, unless a systematic way for depositing the waste has been applied.

After comparing the concentrations obtained by direct measuring in Gärstad landfill with the concentrations given by Allaska database, it can be seen that databases can be used in cases where there is no direct data available, and the results can be still relevant.

Two approaches were used in the method. The flows approach and the volume approach. The flows approach is useful for quantifying the types of flows, and specific information about them can be derived such as metal concentration and density. This approach mostly works on the boundaries of the defined system, but can not be used to track the flows inside the boundaries. Thus waste and its metal content can not be allocated precisely with this approach. Also, this approach requires extensive data and background information. On the other hand, the volume approach needs less data and information, and can be performed faster. It also can give the location of landfilled waste but can not be used for analysing the content of the waste stocks. Thus these two methods are complementary and should be used together in order to get a better understanding of the system, which in this case is Gärstad landfill.

6.2 Data When observing the data obtained from several measurements with more detail, there may be some inconsistences, like extreme values or ranges which include negative numbers. This reminds of the possibility of errors in measurement. Nevertheless, these exotic values were not modified to keep the validity of the method used.

There are factors that can influence in great way the values used in the study (metal concentrations), more precisely when considering the different fuels used for incineration. All the incinerators use a mixture of different materials as fuel (waste‐wood; coal‐rubber) which are a result of the needs of the moment, these combinations do not follow any pattern, so the values used are expected to represent all the possibilities.

All the documents were in Swedish, and language barrier became another limit; this could have led to some misunderstanding during the translation phase and thus some of our assumptions which were based on those translations might have been imprecise or even wrong.

6.3 Comparing concentrations with mining In order to decide if it is profitable to do more research about recovering metals from landfill, it is good to compare the concentration of metal in the landfill with the concentration of natural body ores used for mining. Tables 32 and 33 show the concentrations of some of the metals in the landfill. The presented concentrations are the median value obtained from the statistical analysis of the data, and it is given in mg/kg because several metals are found in very low concentrations which are hard to show in percentage.

Table 32: Concentration of different metals in ores compared to those in ashes.

Bottom ash (median) Fly ash (median) mg/kg Metal Ore Waste (Before/after Coal Wood Waste Coal Wood Wood Cy Wood el metal recovery) Iron 60000 74100 40428 n/a 12230 16017 35672 11191 11191 11191 Aluminium 50000‐60000 55600 26047 45309 10200 31754 60175 20005 14000 37000 Chromium 1 to 3000 385 203 284 887 56 238 230 250 Copper 6000 3400 437 725 774 285 340 254 470 Mercury 1000 – 2500 0 ‐ 0 0 1 2 0 6 Manganese 4400 1140 1330 1500 864 1200 2409 1395 3955 Nickel 3000 170 141 45 138 48 47 52 39 Lead 30000‐100000 1200 120 500 3820 310 2627 545 5800 Antimony 3 115 39 1 1085 61 137 36 290 Tin 150 212 ‐ 24 396 5 20 20 20 Vanadium 1200 30 89 29 44 70 33 28 87 Zinc 50000‐150000 4400 2990 1250 23250 27550 13286 2450 29800

Table 33: Concentrations of metals in ores compared to those in the landfill.

Metal Ore (%) In Landfill (%) Iron 6,0 2,7 3,9 Aluminium 5,0 6,0 2,2 2,5 Copper 0,6 0,1 0,2 Zinc 5,0 15,0 0,4 0,7

It can be seen that the biggest potential for the more interesting metals can be found in the metal hydroxide sludge, only limited by the available technologies. But is also important to mention that the iron, aluminium and copper in C&D waste is in scrap form, which is expected to be easier to recover.

In the case of ashes, it can be seen that the potential varies depending on the metal. It is important to mention that the iron ores contain mainly iron oxide, which is the same form in which appears in ashes, which leads to the possibility of applying traditional mining techniques. This is not the case for aluminium, in which, despite the fact that it is found naturally in oxidized form, it is mined from bauxite, and also because separating from the oxide is not yet cost‐effective. For other metals, though the concentrations are lower, they can be found already separated, reducing the processes needed for separation.

6.4 Comparing LFM with modern mining Even though based on our results the metal concentrations in the landfill are less then commercial mines, there are other factors that makes LFM financially attractive. There are five stages in modern mining, prospecting, exploration, development, exploitation, and reclamation. Prospecting is the

48 search for metal ores or other minerals and exploration determines the size and value of the ore or mineral deposit.

Based on Hartman (2002) the cost for prospecting is 1, 3 – 65 million SEK (0, 33 – 7, 15 SEK/tonne)2. This cost includes searching and studying geological reports and maps, conduct and study aerial and satellite photographs, establishing base of operations and ground units, conduct geo surveys and analysing the findings. This stage takes between 1 – 3 years. The exploration stage costs 6,5 – 98 million SEK (1,43 – 10,73 SEK/tonne) and takes 2 ‐5 years. This stage includes sampling (drilling or excavation), estimating tonnage and concentration, and deposit valuation. This stage determines to whether develop the project further or terminate it.

On the other hand, in LFM, the prospecting stage is much shorter and cheaper since the locations of most landfills are already known. There is no need for searching for a landfill, especially if it is an active one. So in reality the cost and time spent for this stage can be skipped or reduced significantly. As for the exploration stage, in our case 4 million tonne of waste was examined with no cost in 6 months by two students, of course the cost of used manpower (supervisor, contact person), used utilities (university rooms, computers), previous reports and samplings are not considered; still compared to a similar prospecting‐exploration project, which will cost around 7 – 71 million SEK and take 3 – 8 years, LFM is much cheaper and faster. It can be argued that that our results are not as concrete as a mining project, neither as detailed or statistically proven; but by establishing a standard method for prospecting‐exploring landfills, this problem can be resolved.

Development is preparation necessary to bring a mine into full operation. It includes planning, design, and construction. Before the development stage can start, a few factors must be considered (Howard L. Hartman, Jan M. Mutmansky, 2002). The first one is the locational factors; this includes transportation of mineral products and supplies, availability of labour and support services, operational impacts on environment, and employees’ satisfaction with their lifestyle. Almost none of these factors are an issue in LFM. All active landfills have already access roads, and are close to population centres, thus labour is available. Since landfill itself is a threat to the environment, mining it helps to mitigate the undesirable environmental impacts. Still, employees’ satisfaction might be an issue since landfills smell bad. The other factor is geological factors that include topography, dimension of the ore body, geologic consideration, chemical and metallurgical properties of ore. This factor is the same in LFM, but instead of ore body, we have waste. The other mentioned factor is a social‐economic‐political‐environmental factor that is out of the scope of this study.

Exploitation is the recovering of minerals from the mine and delivering it to other facilities. There are many factors that affect the mining method (Hartman, 2002). For LFM, these factors and available technologies can be found in a thesis done by Shojai (2012).

The final stage in mining is reclamation where the mine is closed and the land is restored. This stage takes 1 – 10 years with a cost of 6,5 – 130 million SEK (1,43 – 29 SEK/tonne). In LFM, reclamation stage is becomes a part of the exploitation stage since the waste is being removed or reduced in the exploitation stage. So unlike modern mining, as the exploitation reaches its end, the less waste and land there is to cover and restore.

2 The prices are originally in U.S. $, the used conversion rate is 1 $=6,5 SEK.

6.5 Value Based on the recent price of several metals that can be attractive for the market, we calculated the approximate value of the metals landfilled; Iron, Aluminium, Copper and Zinc are estimated using the total previously presented, other metals are shown only based on the amounts expected in ashes.

Table 34: Estimated economic value of some metals in the landfill.

3 4 Amount (ton) Price Estimated Value (Msek) Min Max (USD/kg) Min Max Iron 127 015 180 283 0,14 116 164 Aluminium 98 075 110 912 2,13 1358 1536 Cobalt A 100 161 27 17 28 Molybdenum A 40 62 27 7 11 Nickel A 319 676 18,86 39 83 Copper 7 388 9 392 7,97 383 487 Lead A 2 442 4 726 2 32 61 Tin A 476 1 031 21,93 68 147 Titanium A 7 959 9 648 8 414 502 Zinc 16 §126 27 069 1,9 199 334 A Amount in ashes only

It can be seen in table 34 that there is great economic value in metals, adding up to around 3 billion Swedish kronor, being aluminium the most interesting metal in the study worthy around 1,4 billion Swedish kronor. In addition, metals such as Copper, Titanium and Zinc represent relatively high values. On the downside, the most abundant metal in the landfill, iron, is not as valuable because of its low price, being less valuable than the metals presented before, but reaching however an important value.

However, since separation process and technological barriers can bring extraordinary costs, the ideal way of LFM to increase the profitability would be to find a direct use of the landfilled waste.

6.6 National Numbers In order to verify our results we compared them with an unpublished paper (Krook, et al., 2012), in which the metal amount in Swedish waste incineration ashes has been assessed. The study includes the BA and FA deposited for the period 1985 to 2010. In table 35, the generated ashes in Sweden and Gärstad has been compared.

Table 35: Deposited ashes in Sweden compared to those in Gärstad and the ratio between them.

Period BA (tonne) FA (tonne) Total (tonne) Krook, et al. 1985‐2010 11,780,000 3,000,000 14,730,000 Our study 1985‐2010 1,810,000 203,000 2,076,000 Ratio (%) 15 7 14

This shows that for the past 25 years, on average 14% of the generated ashes has been deposited in Gärstad landfill. Now we will apply this percentage on the metal amount of ashes from the study and

3 Prices taken from (Index Mundi, 2012) after calculating the average price from October 2011 to April 2012 4 The prices are originally in U.S. $, the used conversion rate is 1 $=6,5 SEK.

50 compare with our results, as shown in table 36. In case of Fe and Al the scrap form has been excluded, thus only the elemental from are being shown. It can be seen that numbers are not the same; this goes back to the fact that MFA is not a very precise method. But the important thing is they all have the same order of magnitude and it can be concluded that our numbers agree with the previous study (Krook, et al., 2012).

Table 36: Total amount of metal in landfilled bottom ash in Sweden; then downscaled to Gärstad landfill and compared with results of this study. All units are in tonne.

Sweden (Krook, et al., median (min‐max) based Gärstad (14%) 2012) on this study Al 500000 70000 66000(62000‐74000) Fe 400000 56000 69000 (67000‐116000) Ti 100000 14000 7100 (7000‐8500) Zn 80000 11200 16500 (14000‐23000) Cu 70000 9800 5500 (5200‐6600)

By downscaling the results of Krook’s (2012) study about bottom ash to the level of bottom ash in Gärstad landfill, and comparing them with this study’s result, it can be seen that the figures are in same order of magnitude. This suggests that national studies about discarded metal can be used as an additional approach to estimate the metal stocks in a region.

6.6.1 Gärstad landfill as a source of material In order to estimate the potential of Gärstad landfill as a source for raw materials, it can be seen in table 37 a comparison between the material consumption in 2005 in Sweden and Östergötland with the estimated amount of some metals landfilled in Gärstadverket (Statistika Centralbyrån, 2009).

Table 37: Domestic material consumption of some metals in Sweden downscaled to Östergötland and compared with landfilled amount of metals in Gärstad landfill.

Landfilled in Gärstad DMC in 2005 (kton) (kton)

Sweden Östergötland B Min Max Iron 4460 202 127 180 Copper 532 24 7,4 9,4 Nickel A 31 1 0,3 0,7 Lead A ‐21 ‐1 2,4 4,7 Zinc 35 2 16,1 27,1 Tin A 1 0,05 0,5 1,0 Aluminium 236 11 98,1 110,9 A Amount in ashes only B Considering Östergötland as 5% of Sweden consumption, based on population ratio

It can be seen that the amount of metals in the landfill is enough to fulfil the consumption of metals (Production + Import ‐ Export) in Östergötland for metals such as Zinc, Tin, and Aluminium for several years.

The difference between the consumption and the landfilled amount of metals may lead to the conclusion that landfill mining is not a reliable source of materials for the Östergötland area; however this can be explained as a result of the recycling policies that have been implemented in recent years which have resulted in low concentrations of metals in waste.

Nevertheless, in other countries with less strict policies about waste management, is expected that landfills have a great potential as a source of raw materials.

7 Conclusion Though there is a considerable amount of metals in this specific landfill, it appears that is not yet an attractive source of metals compared to a normal mine. But if other advantages of LFM like waste deposit space reduction, mitigation of environmental impacts (leachate) and others are considered, it might be economically and at the same time environmentally interesting to carry out LFM. Especially if the landfill runs out of space and expanding it becomes needed. Then a cost‐benefit analysis must be done to determine whether expanding the landfill or implementing LFM is more justifiable, economically and environmentally.

As for the applied method, MFA, it was shown that it is possible to prospect and explore the amount of metals in a landfill by analysing the background of the landfill, resulting in a faster and cheaper but not as accurate process as direct measuring, leaving the technological barriers as the principal limitation for landfill mining.

7.1 Recommendations for the company This study has shown that it may be interesting to consider in the near future the possibility of recovering metals from landfills; however, some additional procedures can be implemented to facilitate future explorations.

A systematic way for depositing waste can be implemented; or a more detailed record on how and where the different types of waste are being deposited all over the landfill can be made.

Considering the large amounts of waste that are deposited monthly, and sampling is done on a regular basis, the analysis of the ashes could include some more metals, based not only on environmental impact, but also on value, like iron, aluminium, and titanium.

Nevertheless, the reason why ashes are hazardous and then landfilled is the metal contamination. Since metals are not combustible it seems as a waste of energy and space to have them inside the incinerators, so the possibility to use metal extraction technologies for waste before incineration should be considered.

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Appendix A: Inflows of the landfill per year

Inflows 2007‐2011

Tonne 2011 2010 2009 2008 2007 Waste subgroups Landfilled Recovered Stored Landfilled Recovered Stored Landfilled Recovered Stored Landfilled Recovered Stored Landfilled Recovered Stored Bottom ash KV1 coal 6300 ‐3200 400 3800 3300 3100 3600 Fly ash KV1 coal 5500 7100 8500 7300 8800 Wet ash and sludge KV1 220 60 240 470 530 Bottom ash KV1 wood 11400 1200 10200 6400 3600 1400 9300 8800 Fly ash KV1 wood 2200 1700 1700 2600 1400 Bottom ash Garstad 92300 ‐11900 71300 7100 100 59300 10600 54400 17500 43400 25500 Fly ash Garstad Wet and sludge Garstad 1010 180 120 40 20 Wood Ash from other sources 150 110 200

Construction and demolition 10200 4260 9900 4260 9000 4210 11300 3780 10400 4480 Asphalt 340 Asbestos 3050 590 640 950 530 Concrete Excavated material

Municipality waste water 20 30 20 100 200

Sludge from street gullies and industry 2500 900 2000 Oil separated sludge 200

slaughter waste Metal Hydroxide sludge 1900 1550 1490 2570 1400 Forest Waste

Latrine 410 30 30 30 30 Scrap metal 8500 6400 9700 8800 9200 Glass Not specific industrial waste Household Waste

Inflows 2002‐2006

Tonne 2006 2005 2004 2003 2002 Waste subgroups Landfilled Recovered Stored Landfilled Recovered Stored Landfilled Recovered Stored Landfilled Recovered Stored Landfilled Recovered Stored Bottom ash KV1 coal 5500 2500 3100 300 1500 1100 2900 200 5100 Fly ash KV1 coal 11900 6000 6100 1500 4700 6700 Wet ash and sludge KV1 1600 1210 1180 700 1000 Bottom ash KV1 wood 9400 9500 3100 13200 8600 3400 14500 22200 Fly ash KV1 wood 1600 2200 3500 3600 Bottom ash Garstad 38800 10900 9700 60700 8700 1800 44100 ‐2100 3200 42100 ‐1700 30000 13400 Fly ash Garstad 6600 6400 5900 Wet and sludge Garstad 20 60 70 240 380 Wood Ash from other sources 280 600 140 1090 500 590

Construction and demolition 9500 3110 10200 13700 12200 13200 Asphalt 1480 30 5400 4600 Asbestos 490 420 450 530 380 Concrete Excavated material

Municipality waste water 100 100 200 100 3800

Sludge from street gullies and industry 2000 500 700 900 1200 Oil separated sludge 2400 2300 2700 3600

slaughter waste 40 140 220 Metal Hydroxide sludge 2490 2890 2570 340 230 Forest Waste

Latrine 50 320 830 900 540 Scrap metal 5700 9000 6600 5700 6700 Glass Not specific industrial waste Household Waste

Inflows 1997‐2001

Tonne 2001 2000 1999 1998 1997 Waste subgroups Landfilled Recovered Stored Landfilled Recovered Stored Landfilled Recovered Stored Landfilled Recovered Stored Landfilled Recovered Stored Bottom ash KV1 coal 300 3070 1340 4850 1000 6140 14344 13200 Fly ash KV1 coal 4800 5900 7087 Wet ash and sludge KV1 860 710 792 1273 Bottom ash KV1 wood 12700 8100 9000 5700 19244 20846 21877 Fly ash KV1 wood Bottom ash Garstad 400 39900 7500 44700 6900 57240 49942 49673 Fly ash Garstad 5300 5200 4414 7462 7422 Wet and sludge Garstad 220 560 378 1277 Wood Ash from other sources 430 1050 1878 1745

Construction and demolition 20500 16700 10999 9507 6722 Asphalt 7800 12 7360 9851 Asbestos 400 370 278 297 Concrete 1846 976 Excavated material 2212 1717 1410

Municipality waste water 11400 770 19675 6708 7126

Sludge from street gullies and industry 1380 1460 654 773 567 Oil separated sludge 4610 4830

slaughter waste 110 110 8476 7102 700 Metal Hydroxide sludge 330 560 499 539 381 Forest Waste 119464

Latrine 380 190 283 237 1099 Scrap metal 6200 4140 1180 3764 949 1704 238 2546 Glass 17 Not specific industrial waste ? Household Waste

Inflows 1992‐1996

Tonne 1996 1995 1994 1993 1992 Waste subgroups Landfilled Recovered Stored Landfilled Recovered Stored Landfilled Recovered Stored Landfilled Recovered Stored Landfilled Recovered Stored Bottom ash KV1 coal 21229 17458 20148 10971 10632 Fly ash KV1 coal Wet ash and sludge KV1 Bottom ash KV1 wood 20848 19693 18191 16679 15337 Fly ash KV1 wood Bottom ash Garstad 51330 42873 34253 37816 38246 Fly ash Garstad 7670 6406 5118 5650 5714 Wet and sludge Garstad Wood Ash from other sources

Construction and demolition 12622 8657 19219 Asphalt 3835 12585 14163 9456 6098 Asbestos 389 267 396 403 414 Concrete 1750 1445 2925 8411 Excavated material 1330 4643

Municipality waste water 17661 428

Sludge from street gullies and industry 106 5649 5528 4671 5320 Oil separated sludge 70 402 497

slaughter waste 7822 2167 Metal Hydroxide sludge 295 317 244 264 278 Forest Waste 141373

Latrine 579 197 2478 3422 2698 Scrap metal 3833 1997 4875 2783 2576 Glass 385 1173 1330 972 380 Not specific industrial waste 6539 8512 Household Waste

Inflows 1974‐1991

Tonne 1991 1990 1985‐1989 1982‐1984 1980‐1981 1974‐1979 Waste subgroups Landfilled Landfilled Landfilled Landfilled Landfilled Landfilled Bottom ash KV1 coal 8170 6300 5544 Fly ash KV1 coal 3600 3168 Wet ash and sludge KV1 Bottom ash KV1 wood 9446 8100 7128 Fly ash KV1 wood Bottom ash Garstad 43588 38000 38000 33060 5600 10500 Fly ash Garstad Wet and sludge Garstad Wood Ash from other sources

Construction and demolition 21942 13000 30000 30000 3000 47000 Asphalt Asbestos 434 450 Concrete Excavated material

Municipality waste water 569

Sludge from street gullies and industry 6991 6150 Oil separated sludge 662

slaughter waste 646 7200 Metal Hydroxide sludge 330 Forest Waste

Latrine 48 3130 200 Scrap metal Glass Not specific industrial waste 2000 2000 2000 3050 Household Waste 16500 88000

Appendix B: Metal amounts in different types of ash Estimated Median Values

Tonne Total Fe Al As B Ba Cd Co Cr Cu Hg Ma Mo Ni Pb Sb Se Sn Ti V Z Ash from Waste 271 588 18 074 14 258 12 37 492 5 8 122 831 0 300 6 45 418 65 1 64 1 125 9 1 861 Incineration (BA + FA) Bottom ash 594 656 42 047 31 768 20 77 1 077 6 18 237 2 104 0 671 13 110 807 69 2 135 2 086 18 2 620 from WI Bottom ash 564 974 22 841 20 826 16 73 558 6 21 159 1 868 0 642 11 100 623 62 3 121 1 982 16 2 649 from WI Bottom ash 85 500 3 457 2 989 3 11 127 1 3 37 332 0 97 2 19 103 11 0 18 300 2 451 from WI Fly ash 80 350 1 227 2 354 8 13 106 6 3 62 59 0 65 3 10 245 78 0 25 570 3 1 627 from WI Ash from Coal 159 712 3 703 8 780 2 4 214 1 25 17 54 0 199 1 13 39 9 2 0 305 12 3 027 Inineration (BA + FA) Bottom ash from Coal 12 940 0 586 0 1 39 0 1 3 6 0 17 0 2 2 1 0 0 0 1 39 Incineration Bottom ash from Coal 14 820 0 671 0 1 44 0 1 3 6 0 20 0 2 2 1 0 0 0 1 44 Incineration Bottom ash from Coal 24 140 0 1 094 0 2 72 0 2 5 11 0 32 0 3 3 1 0 0 0 2 72 Incineration Fly ash from Coal 93 987 3 353 5 656 1 0 42 1 18 5 27 0 113 1 4 29 6 1 0 276 7 2 607 Incineration Fly ash from Coal 1 500 54 90 0 0 1 0 0 0 0 0 2 0 0 0 0 0 0 4 0 41 Incineration Ash from Wood 245 619 2 943 3 083 33 54 388 2 3 67 155 0 422 2 11 248 8 1 6 292 7 1 017 Incineration (BA + FA) Ash from Wood 20 100 241 252 3 4 32 0 0 5 13 0 35 0 1 20 1 0 0 24 1 83 Incineration (BA + FA) Ash from Wood 5 700 68 72 1 1 9 0 0 2 4 0 10 0 0 6 0 0 0 7 0 24 Incineration (BA + FA) Bottom ash from Wood 39 490 483 403 2 8 57 0 0 11 29 0 59 0 2 20 0 0 1 38 1 49 Inineration Bottom ash from Wood 63 080 771 643 3 12 91 0 1 18 46 0 95 0 3 32 0 0 1 61 2 79 Inineration Fly ash from wood 17 400 195 314 6 5 36 0 0 4 5 0 36 0 1 34 2 0 0 33 1 170 Incineration (Cyclone) Fly ash from wood 3 100 35 115 3 1 5 0 0 1 1 0 12 0 0 18 1 0 0 6 0 92 Incineration (Elfilter) Total 2 298 656 99 490 93 955 111 305 3 390 28 107 758 5 550 1 2 826 40 327 2 649 313 11 372 7 108 84 16 553 Landfilled Recovered Stored

Estimated Minimum Values

Tonne Total Fe Al As B Ba Cd Co Cr Cu Hg Ma Mo Ni Pb Sb Se Sn Ti V Z Ash from Waste 271 588 17 058 13 819 9 27 298 5 7 97 794 0 242 5 48 298 55 1 68 1 036 8 1 687 Incineration (BA + FA) Bottom ash 594 656 40 136 31 102 17 54 728 6 15 197 2 026 0 545 11 118 643 61 3 156 2 067 17 2 652 from WI Bottom ash 564 974 25 508 20 521 16 51 532 6 20 159 1 868 0 523 10 100 623 61 3 142 1 962 16 2 649 from WI Bottom ash 85 500 3 860 2 949 3 8 122 1 3 37 332 0 79 2 19 103 11 0 21 297 2 451 from WI Fly ash 80 350 1 181 2 202 6 12 66 5 2 54 56 0 61 2 10 197 70 0 19 490 3 1 442 from WI Ash from Coal 159 712 3 026 7 524 1 0 353 0 21 15 43 0 128 1 9 28 4 1 0 248 8 2 158 Inineration (BA + FA) Bottom ash from 12 940 0 437 0 0 73 0 1 2 4 0 13 0 1 1 0 0 0 0 1 26 Coal Incineration Bottom ash from 14 820 0 500 0 0 83 0 1 3 4 0 15 0 2 1 0 0 0 0 1 29 Coal Incineration Bottom ash from 24 140 0 815 0 0 136 0 2 5 7 0 24 0 3 2 0 0 0 0 1 48 Coal Incineration Fly ash from Coal 93 987 2 739 5 104 1 0 35 0 16 4 25 0 66 0 2 22 4 1 0 225 4 1 940 Incineration Fly ash from Coal 1 500 44 81 0 0 1 0 0 0 0 0 1 0 0 0 0 0 0 4 0 30 Incineration Ash from Wood 245 619 2 740 3 319 33 54 259 2 2 32 74 0 419 1 ‐34 182 9 1 5 445 6 826 Incineration (BA + FA) Ash from Wood 20 100 224 272 3 4 21 0 0 3 6 0 34 0 ‐3 15 1 0 0 36 0 68 Incineration (BA + FA) Ash from Wood 5 700 64 77 1 1 6 0 0 1 2 0 10 0 ‐1 4 0 0 0 10 0 19 Incineration (BA + FA) Bottom ash from 39 490 418 322 1 7 31 0 0 5 12 0 57 0 1 12 0 0 1 49 1 33 Wood Inineration Bottom ash from 63 080 668 515 1 12 50 0 0 8 20 0 91 0 2 19 0 0 1 79 1 54 Wood Inineration Fly ash from wood Incineration 17 400 212 408 1 5 28 0 0 2 3 0 18 0 1 5 0 0 0 50 1 ‐28 (Cyclone) Fly ash from wood 3 100 38 73 2 1 5 0 0 1 1 0 12 0 ‐4 11 1 0 0 9 0 70 Incineration (Elfilter) Total 2 298 656 97 915 90 039 96 237 2 825 27 93 623 5 278 1 2 340 35 274 2 168 277 10 414 7 006 71 14 155 Landfilled Recovered Stored

Estimated Maximum Values

Tonne Total Fe Al As B Ba Cd Co Cr Cu Hg Ma Mo Ni Pb Sb Se Sn Ti V Z Ash from Waste 119 588 22 237 14 825 16 66 490 7 15 148 1 123 0 318 9 80 764 112 2 151 1 189 10 2 305 Incineration (BA + FA) Bottom ash 470 436 53 144 32 489 23 150 1 053 9 31 290 2 752 0 663 18 185 1 519 97 4 321 2 105 20 3 221 from WI Bottom ash 564 974 46 413 21 610 16 143 556 6 25 159 1 868 0 634 11 100 623 64 4 311 2 001 17 2 649 from WI Bottom ash 85 500 7 024 3 110 3 22 126 1 4 37 332 0 96 2 19 103 11 1 47 303 3 451 from WI Fly ash 80 350 2 115 3 135 15 14 176 8 4 77 76 0 120 4 14 378 168 0 47 801 4 2 276 from WI Ash from Coal 124 864 5 150 10 170 4 0 1 546 1 31 29 74 0 329 3 20 66 9 1 2 346 19 4 595 Inineration (BA + FA) Bottom ash from 12 940 0 746 0 0 343 0 2 5 10 0 19 0 3 3 0 0 0 0 2 43 Coal Incineration Bottom ash from 14 820 0 854 0 0 393 0 2 6 11 0 21 0 4 4 0 0 0 0 2 49 Coal Incineration Bottom ash from 24 140 0 1 391 1 0 640 0 3 9 19 0 35 1 6 6 0 0 0 0 3 80 Coal Incineration Fly ash from Coal 93 987 4 663 6 291 2 0 55 1 22 6 28 0 226 1 6 45 8 1 2 314 11 3 878 Incineration Fly ash from Coal 1 500 74 100 0 0 1 0 0 0 0 0 4 0 0 1 0 0 0 5 0 64 Incineration Ash from Wood 217 107 3 495 4 723 62 68 536 4 5 82 192 0 504 3 132 371 19 1 8 949 11 2 228 Incineration (BA + FA) Ash from Wood 20 100 286 387 5 6 44 0 0 7 16 0 41 0 11 30 2 0 1 78 1 182 Incineration (BA + FA) Ash from Wood 5 700 81 110 1 2 12 0 0 2 4 0 12 0 3 9 0 0 0 22 0 52 Incineration (BA + FA) Bottom ash from 39 490 531 483 5 9 78 0 1 13 39 0 69 0 3 27 0 0 1 131 2 101 Wood Inineration Bottom ash from 63 080 849 772 9 15 125 0 1 21 62 0 110 1 5 42 1 0 2 210 3 162 Wood Inineration Fly ash from wood Incineration 17 400 273 561 2 6 52 0 0 6 6 0 30 0 1 12 1 0 1 85 1 242 (Cyclone) Fly ash from wood 3 100 49 100 3 1 6 0 0 1 2 0 12 0 11 21 1 0 0 15 0 100 Incineration (Elfilter) Total 2 298 656 146 383 101 856 168 501 6 232 39 147 900 6 612 1 3 241 54 602 4 023 494 16 892 8 553 108 22 679 Landfilled Recovered Stored