KNOWLEDGE PAPERS Decision Maker’s Guides for Solid Waste Management Technologies KNOWLEDGE PAPERS Decision Maker’s Guides for Solid Waste Management Technologies Silpa Kaza and Perinaz Bhada-Tata September 2018 Urban Development Series Produced by the World Bank’s Social, Urban, Rural & Resilience Global Practice, the Urban Development Series discusses the challenge of urbanization and what it will mean for developing countries in the decades ahead. The Series aims to explore and delve more substantively into the core issues framed by the World Bank’s 2009 Urban Strategy Systems of Cities: Harnessing Urbanization for Growth and Poverty Alleviation. Across the five domains of the Urban Strategy, the Series provides a focal point for publications that seek to foster a better understanding of (i) the core elements of the city system, (ii) pro-poor policies, (iii) city economies, (iv) urban land and housing markets, (v) sustainable urban environment, and other urban issues germane to the urban development agenda for sustainable cities and communities. Copyright © 2016 The International Bank for Reconstruction and Development/THE WORLD BANK 1818 H Street, N.W. Washington, D.C. 20433, U.S.A. All rights reserved Manufactured in the United States of America The findings, interpretations, and conclusions expressed in this paper are entirely those of the author(s) and should not be attributed in any manner to the World Bank, to its affiliated organizations, or to members of its Board of Executive Directors or the countries they represent. The World Bank does not guarantee the accuracy of the data included in this publication and accepts no responsibility for any consequence of their use. The boundaries, colors, denominations, and other information shown on any map in this volume do not imply on the part of the World Bank Group any judgment on the legal status of any territory or the endorsement or acceptance of such boundaries. The material in this publication is copyrighted. Request for permission to reproduce portions of it should be sent to the Urban Development Division at the address in the copyright notice above. The World Bank encourages dissemination of its work and will normally give permission promptly and, when reproduction is for noncommercial purposes, without asking a fee. Photo credits: All photos used with permission. Further permission required for reuse. Cover, © Farouk Banna / World Bank; Page 11, © Alan Levine / Flickr; Page 17, Government of Prince Edward Island / Flickr; Page 19, © Imging/ Shutterstock; Page 19, © Karen Ashby/Global Composting Solutions Ltd; Page 23, © Keith Murray / Flickr; Page 29, © Roland Zh / Wikimedia; Page 36, © Duke Energy / Flickr; Back cover, © Alan Levine / Flickr; Back cover, © MPCA Photo / Flickr Design: Navajeet Khatri, based on previous work by miki@ultradesigns.com Table of Contents ACKNOWLEDGMENTS INTRODUCTION 1. WHAT MAYORS SHOULD KNOW 2. COMPARISON OF SOLID WASTE MANAGEMENT TECHNOLOGIES 3. SANITARY LANDFILLS 4. COMPOSTING 5. ANAEROBIC DIGESTION 6. INCINERATION WITH ENERGY RECOVERY 7. PYROLYSIS AND GASIFICATION Acknowledgements This report was prepared by Silpa Kaza (Task-Team Leader) and Perinaz Bhada-Tata. The team thanks Stephen Hammer, Adviser to the World Bank’s Climate Change Cross-Cutting Solution Area, for his guidance throughout the development of the report. The team appreciates the early comments and review provided by Farouk Banna and Yewande Awe to shape the guidance notes. James Michelsen and Frank Van Woerden provided critical insights and guidance for the costs. The study was prepared under the guidance of Ede Ijjasz- Vasquez, Senior Director of the Social, Urban, Rural and Resilience Global Practice; Sameh Wahba, Director of Urban and Territorial Development, Disaster Risk Management, and Resilience; and Senait Assefa, Practice Manager. Internal and external peer reviewers provided critical expert comments. The team thanks Daniel Hoornweg, Professor and Research Chair at the University of Ontario Institute of Technology; Fabien Mainguy, Senior Project Manager at Suez Environnement; and David Lerpiniere, Head of Waste, Resources and Development at Resource Futures. Introduction The Decision Maker’s Guides for Solid Waste Management Technologies were created to help mayors and decision mak- ers understand the various technologies and when they would be appropriate based on local circumstances. Mayors are often approached by different solid waste management technology vendors and these guides aim to provide objective guidance and critical considerations. They offer insights into implement- ing environmentally sound treatment and disposal solutions. The guides include: • A basic description of what each technology is and how it works • Key considerations when thinking about pursuing a specific technology • Financial implications and suggestions for reducing and recovering costs • Examples of where the technology has succeeded and failed • Questions to ask the solid waste vendor to assess appropriateness of the technology and vendor for the local context This is a compilation of guidance documents that are stand- alone and can be utilized independently as required. The doc- uments included entail the following: • Summary of key insights for decision makers to keep in mind for each technology • Comparison table on key metrics for solid waste management technologies • Guidance notes for sanitary landfills, composting, anaerobic digestion, incineration with energy recovery, and pyrolysis and gasification. Decision Maker’s Guides for Solid Waste Management Technologies What Mayors Should Know Sanitary • Regardless of other waste disposal solutions, landfills are necessary for safe disposal of wastes that Landfill cannot be recovered/recycled and for residues from other treatment processes • If a landfill is not properly sited and constructed (with appropriate liner), maintained (monitoring surface and ground water and landfill gas generated) and operated (waste compacted and covered daily), it will quickly turn into a dumpsite and have significant adverse environmental and social impacts. • Financing for the entire landfill life, including post-closure monitoring (at least 30 years), should be accounted for from the beginning • Collecting and harnessing landfill gas before and after landfill closure can generate revenue and minimize greenhouse gas emissions • The organic fraction of waste can only be used once whether it is for landfill gas-to-energy, composting, or anaerobic digestion. Composting • Composting is a relatively low-cost option to convert organic waste into a fertilizer-like product while generating employment opportunities and environmental benefits • Uncontaminated organic waste (e.g. restaurant, vegetable market, or source-segregated waste) is necessary to produce a marketable product • Compost from separated household waste is unlikely to have high marketability but could be considered for other purposes (landscaping, landfill cover, residents’ gardens) • In order to obtain revenues from compost sales, there needs to be a market or end use. A certification system could help build market confidence by demonstrating the quality of compost produced • Composting facilities can be operationally self-sufficient but tend to require support for capital costs Anaerobic • An anaerobic digester requires a largely uncontaminated organic waste stream (e.g. restaurant, Digestion vegetable market, or source segregated waste) at a consistent and sufficient volume to function properly. The process produces biogas and a liquid or, after drying, a solid fertilizer. The biogas can be used to generate heat and/or electricity • Large scale anaerobic digesters are high in capital and operating costs and require a high level of technical capacity to operate • Income can be generated by distributing the biogas directly to end-users, selling electricity generated from the biogas, and potentially selling the fertilizer to farms Incineration • Incineration requires a consistently high volume of dry, high energy content waste (i.e. <50% of organics and high proportions of combustible materials) and electricity price to operate cost- effectively • Incineration is typically used in contexts where there are land constraints, high tipping fees at landfills, high electricity prices, strong technical capacity, relatively high energy content waste, and robust environmental regulations • To date, incineration has not been widely used for treating municipal solid waste treatment in low- income countries • An incineration facility has high capital and operating costs and normally requires a long-term (25-30 year) contractual commitment from a municipality Pyrolysis and • Pyrolysis and gasification are emerging technologies that have not yet been demonstrated at large- Gasification scale for treating municipal solid waste • Both technologies require high capital and operating costs and technical capacity • They can generate a range of products, mostly a synthetic gas (that can be condensed to a liquid fuel) and a soil amendment Decision Maker’s Guides for Solid Waste Management Technologies Comparison of Solid Waste Technologies Sanitary Landfill Composting Anaerobic Digestion Incineration Basic Process Disposal Biological treatment Biological treatment Thermal treatment Ideal Types of Municipal solid Food waste Food waste Mixed municipal solid Waste waste, construction (including wastes (including wastes waste, medical waste, and demolition from households, from households, demolition wood, auto waste, wastewater restaurants and restaurants and shredder residue, dried sludge, non- markets), fats/ markets), fats/ sewage sludge, and hazardous industrial oils/ grease, paper oils/grease, some industrial solid wastes and cardboard, slaughterhouse wastes landscaping and waste (depending garden waste (e.g. local regulations), hedge-clippings, and garden waste leaves) Waste to Avoid Medical Non-biodegradable Non-biodegradable Yard leaves or source- wastes (plastic, wastes (plastic, separated food waste glass, metal, inerts) glass, metal, inerts), tree clippings Waste composition -- High as possible >50% <50% threshold for organic fraction or moisture content (%) Mass Reduction of -- 50% 50% 80-85% Waste (%) Land Requirement Generally large 0.065 – 10.8 1.61 – 6.45 Much smaller than that (m2/tonne) for landfill but ash must be disposed Proven Technology/ +++ ++ ++ ++ Market Maturity Operational Requires specialized Proper training Proper training Technically complex, complexity training, careful required required requires highly skilled maintenance, and training and careful post-closure care maintenance Pre-processing of No Preferred Yes Yes Feedstock Average Range of 50-10,000 2.5 - 300 0.5 - 500 5 – 1000 (common Waste Throughput range is 200 – 700) (tonnes/day) Primary output Landfill gas (where Compost Methane, digestate Air and ash recovered), leachate Secondary output Electricity and/or -- Electricity and/or Heat and sometimes heat (where landfill heat; liquid or solid electricity gas is recovered) fertilizer Energy conversion 65 (landfill gas) -- 165 - 245 500 - 600 efficiency (kWh/ tonne of municipal solid waste) (continued) Decision Maker’s Guides for Solid Waste Management Technologies Comparison of Solid Waste Technologies (continued) Sanitary Landfill Composting Anaerobic Digestion Incineration Capital costs (US$/ 5 - 52 (US$/tonne 30 - 400 220 - 660 190 – 1000 annual tonne) over lifetime) Operating costs 7 – 30 (but can be as 12 - 100 22 - 57 12- 55 (US$/tonne) high as 120) Greenhouse Gas Significant; can be Reduced Significant; captured Considered renewable Emissions captured by landfill and used to or climate-neutral gas recovery generate energy Carbon Finance Yes (where landfill Yes Yes (where biogas is Yes (where energy is potential gas is recovered) recovered) recovered) CDM (Carbon AMS-III.G. AMS-III.F. AMS-III.A.O. AMS-III.E. finance AMS-III.AF. methodology) References Aracdis 2009. Assessment of the Options to Improve the management of Bio-Waste in the European Union. European Commission Directorate-General Environment, Brussels, Belgium. Arup. 2014. Building California's Organics Diversion Infrastructure: Evaluating Technology Options To Increase Diversion, Reduce GHG Emissions. In the proceedings: Biocycle 28th Annual West Coast Conference: Refor14West, San Diego, CA. Kaza, Silpa, Lisa C. Yao, Perinaz Bhada-Tata, and Frank Van Woerden. 2018. What a Waste 2.0: A Global Snapshot of Solid Waste Management to 2050. Urban Development Working Series. Washington, DC: World Bank. https://openknowledge.worldbank.org/handle/10986/30317. Ministry of Urban Development. Energy Recovery from Municipal Solid Waste. Government of India. Available at http://urbanindia.nic.in/publicinfo/swm/chap15.pdf Themelis, N. and S. Reshadi. 2009. Potential for Reducing the Capital Costs of WTE Facilities. Proceedings of the 17th Annual North American Waste-to-Energy Conference (NAWTEC), Chantilly, Virginia, May 18-20, 2009. World Bank. 2011. Viability of Current and Emerging Technologies for Domestic Solid Waste Treatment and Disposal: Implications on Dioxin and Furan Emissions. World Bank, Washington, DC, USA. SANITARY LANDFILLS Decision Maker’s Guides for Solid Waste Management Technologies SANITARY LANDFILLS Landfills are an important part of any urban waste management system—regardless of other waste disposal solutions used. Even cities that recycle much of their waste or are heavily reliant on incineration need to landfill residual ash, wastes that cannot be recycled or combusted, and waste from other waste facilities when other disposal systems are not operating. Around the world, nearly 40% of all waste discarded ends up in some type of a landfill. The rate is even higher in upper-middle income countries at 54%. Together with open dumping at 33%, landfills make up the most common form of waste disposal. Landfills require engineered design (as opposed to open dumps) and must be constructed and operated with care to ensure that they do not create problems that threaten human or eco-system health. Sanitary landfills are a mature and proven waste management technique. Nevertheless, they are still fairly uncommon in low- and some middle-income countries due to the costs involved in infrastructure and operation and inadequate regulatory oversight. In these areas, it is more common to find uncontrolled or open dumps that lack basic environmental controls, putting public health and safety at risk. LANDFILLING – THE BASICS A properly designed sanitary landfill includes land area with properly managed landfill, waste is compacted to conserve an impermeable liner at the bottom. The liner prevents liq- space; a cover material is applied over the waste on a regular uid contaminants (leachate) from coming into contact with basis to control odor, blowing litter, and other nuisances; and groundwater (aquifers) and seeping into the soil. Leachate gas control systems are used to capture flammable landfill forms from moisture in the waste, or from rainwater that flows gas that forms as organic waste material decomposes within into the landfill and should be collected and treated. At a the landfill. WHAT TO THINK ABOUT WHEN PURSUING A LANDFILL STRATEGY? PRE-CONSTRUCTION ed site should be consulted to understand and address their Landfill capacity: Landfills are usually built to last approxi- concerns before the facility begins operation. Some commu- mately 30 years; however, they should be sized to account nities may need to be resettled once a site is selected, and for anticipated changes in local waste generation levels as they should be compensated for any loss of land, livelihood, the population grows or household income levels rise. Op- or cultural identity caused by the facility. timally, the plan should be to create and fill a cell every 18 Recovery of valuable recyclable or reusable materials: months – 2 years before it is closed and utilized for landfill Landfill life can be extended if recyclable and organic mate- gas to energy. rials are removed or recovered before waste arrives at the Siting: A landfill is ideally geographically isolated from resi- landfill and will also likely result in lower costs. This could dential areas, airports, and drinking water aquifers. Depend- either be done at the community level, at a materials recov- ing on the area served by the landfill, proximity to rail lines ery facility, or at the landfill site itself. Landfill operators could or roads capable of handling heavy truck loads or volume benefit from partnering with waste pickers at the landfill site may be necessary. The selected site should be assessed to ensure that these materials can be diverted and should by engineers and geologists to ensure low risk for flooding, ensure livelihoods are not displaced without making alterna- earthquakes, and landslides. Access to a regular supply of tive provision for them. cover material is also critical. Communities near the select- 12 - SANITARY LANDFILLS Decision Maker’s Guides for Solid Waste Management Technologies Illustration adapted from original by Rich Bishop Electricity generated at methane facility Leachate pond Leachate collection pipes Working face of cell Filled garbage layers Methane facility Soil layer Methane wells & collection pipes Pea gravel Geotextile mat Polyethylene liner Compacted clay Groundwater Schematic diagram of a sanitary landfill CONSTRUCTION AND OPERATIONS Liner: The liner is an impermeable barrier (made of a low ab- sorbing soil material such as clay and/or a synthetic material such as plastic) installed at the bottom of a landfill to prevent leachate from seeping into the groundwater or nearby wa- terways. CLIMATE-PROOFING YOUR LANDFILL: Leachate monitoring, collection, and treatment: The landfill • Landfills in rainy regions are subject to should be designed with a network of pipes and synthetic erosion and landslides so the stability of material (drainage net) to collect the leachate from the bot- steep slopes will have to be monitored. tom of the landfill. It can then be treated in a wastewater Heavy rains may also create the need for treatment plant or managed onsite in an evaporation pond. larger leachate fields to handle the extra Landfill gas collection: A landfill gas recovery system needs water flow. Some equipment, including to be installed to capture the combustible gas resulting from weighbridges, may need to be elevated for the organic waste decomposition. If the landfill gas is not cap- year-round use. tured, there is a risk of explosion at the site. There is the sec- • Landfills should be sited away from ondary benefit of reducing greenhouse gas emissions. waterways to ensure that flooding does not Storm water management: A proper drainage system to di- affect the facility. vert water from landfills needs to be included in situations • High temperatures and droughts could of excessive precipitation. A properly designed storm water increase the risk of fire so proper covering management system reduces the quantity of leachate gener- is essential. ated and, thus, the cost to treat the leachate. Waste compaction: Waste should be compacted daily with specialized equipment to maximize the space available for disposal. SANITARY LANDFILLS - 13 Decision Maker’s Guides for Solid Waste Management Technologies Cover: Landfills should be covered at the end of each day to CLOSURE AND POST-CLOSURE prevent fires, scavengers, disease breeding, and litter. Typi- Final cover: Landfill caps can be made with vegetative soil cally, this entails a 6-inch soil layer; however, alternative ma- (suited for dry climates) or have a sophisticated multi-layer terials can be used. These can include clean soil excavated system of soil and geosynthetic material to divert water from from construction projects, vegetation and leaves, removable entering the landfill (more appropriate for wet climates). A tarps, compost, mulch, construction and demolition waste, topsoil layer could be placed on top of any synthetic covers shredded tires, or spray-on slurry. Advantages of using alter- to support vegetative growth and to create opportunities for native materials include saving landfill space, reducing costs subsequent uses of the land. of procuring, excavating, and transporting soil to the landfill, Monitoring: Landfills must be monitored post-closure for providing equal or better protection against odors and ver- methane gas formation and release, leachate problems, and min than a 6-inch layer 400of soil, and slowing down the move- to ensure the integrity of the landfill cover. ment of landfill gas and leachate. 350 Amount Disposed (millions tons/year) Post-closure use: Closed landfills pose some environmental Monitoring: Monitoring 300wells should be installed nearby to and health risks, mainly from the potential escape of form guard against groundwater contamination and landfill gas 250 of landfill gas; however, if planned and monitored properly, leakage. Every facility should have an environmental mon- itoring plan that covers 200 all phases of a landfill’s life prior to closed landfills can provide valuable space for recreation or even industrial use (including waste management, such as commencing construction and operations. 150 recycling or composting activities). Whatever the post-clo- 100 sure use, it is important the gas and leachate emissions are 50 monitored and the associated risks mitigated. 0 Landfill Recycled WTE Dump Compost Other Upfront Capital Operations and Maintenance Disposal Options Closure and Post-Closure Costs vary considerably by • Labor Post-closure costs can continue for size, region, regulations, design • Safety equipment up to 30 years after landfill closure sophistication, etc. • Final closure (e.g., landfill cap) • Machinery and vehicles (e.g., • Studies and design (e.g., site compactors) • Drainage system selection, topographic survey, social impact assessment) • Venting of gases and drainage, • Green cover and landscaping leachate treatment • Monitoring costs for landfill gas • Land acquisition • Monitoring equipment and groundwater contamination • Preparation of the site • Periodic changes to the site • Closure of open dumps (e.g., roads, cell development • Regulatory approval and closures, excavations) • Construction and equipment • Power, fuel c Up-front Outlays Operating Period Outlays Back-end Outlays Operating Costs (Fully reflects all life cycle outlays) $ 0 10 30 60 YEARS Pre-operational period of Operating Post-operating Period for Studies, Landfill Acquisition, Period Closure and Post-closure Care Constrcution, and Permitting Landfill life-cycle costs and outlays Source: US Environmental Protection Agency, 2014 14 - SANITARY LANDFILLS Decision Maker’s Guides for Solid Waste Management Technologies HOW MUCH WILL A LANDFILL COST? plemented for usage after closure (e.g. parking fees or entry The costs of sanitary landfills do not vary widely between fees for a recreational area) developed and developing countries as the technology re- Tipping fees: The landfill operator should charge a tipping fee quired is not labor intensive. However, poor site selection (fee charged per tonne of material delivered to the landfill), may drive up costs considerably. Landfills have huge econo- which serves as a revenue source for landfills to cover oper- mies of scale. Generally, landfills that receive 400 tonnes/day ational costs and encourage households and municipalities or less of waste will have under-utilized equipment. to decrease the amount of waste sent to landfills. Such fee Costs for landfills can be divided into three components: (1) systems require a weigh station at the entrance to the facility capital, (2) operations and maintenance, and (3) closure and as well as enforcement of fee collection (by securing the pe- post-closure. rimeter, proper record keeping, monitoring entry and exit, etc.). (1) Capital costs are typically 25-50% of the total lifetime cost Public-private partnerships: Municipalities should consider of a sanitary landfill. Total outlays could range from $1m to different models of public-private partnerships based on need. $50m for landfills with a processing capacity of 20,000 to For example, a build-own-operate model allows a municipal- 2,000,000 tonnes per year. A common industry benchmark ity to share costs with and leverage technical expertise from is $1m per hectare over the lifetime of the landfill. the private sector. A design-build-operate model would ensure (2) Operating costs typically fall in the range of $7-30/tonne, that the operator optimizes the landfill facility design and oper- and make up approximately 60-80% of landfill lifetime costs. ations for efficiency. The municipality could also procure con- (3) Post-closure costs for the final cap are typically $80,000- tracts for design and construction and take on the operations $500,000 per acre and closure/post-closure costs can make themselves. up 10-15% of the lifetime landfill costs. Post-closure requires WHERE IS A GOOD SANITARY LANDFILL AND WHAT monitoring and performing necessary corrective actions for HAVE WE LEARNED? up to 30 years and should be accounted for through the cre- Prior to 2000, the Northern West Bank was infamous for the ation of financial reserves set up while the facility is opera- poor quality of its waste collection system and improper dis- tional. posal of waste at more than 85 unsanitary dumpsites. Open IS YOUR LANDFILL FACILITY TOO EXPENSIVE? burning of waste was also a common practice. The local gov- THINK ABOUT… ernment had little financial and technical capacity to proper- Regional landfills: A landfill can be built and shared by sev- ly manage their solid waste. Between 2000 and 2009, the eral municipalities to take advantage of economies of scale. World Bank and other donors supported the closing of these Pooling or bundling landfills: If there are multiple landfills be- dumpsites and construction of a new Zahrat al Finjan sanitary ing designed nationally, then bundling the landfills together landfill in Jenin, West Bank to serve all municipal and village for financing could increase their attractiveness to investors. councils in the area. A joint council was established to coor- dinate solid waste management efforts across these commu- Carbon finance: Landfill gas (primarily consisting of methane) nities. To ensure financial sustainability of waste collection can be captured at landfills and converted into electricity and/ and disposal, a household solid waste fee was implemented or heat, thus creating a steady revenue source. Depending and collected with the assistance of the village and munic- on the size of the facility, it may be possible to access carbon ipal councils. Most of the municipalities and villages collect finance or general climate financing to help pay for the cost the fee as a surcharge on household electricity bills and pay of constructing the gas capture system. the joint council for the management of the disposal facility. Preferred tariffs for renewable energy: Governments may In contrast, in many low and middle income countries, while provide initiatives in the form of tax credits, preferential pric- there is an intention to operate a sanitary landfill, often the ing, discounts, or other benefits to encourage electricity from basic requirements (leachate management, landfill gas cap- renewable sources. This could be a potential revenue source ture, daily cover, fencing, record-keeping, and plan for waste if landfill gas is considered to be a renewable energy source pickers) are not met. As a result, landfills end up being used in your jurisdiction. as dumpsites and have an adverse social and environmental Sale of byproducts or services: Landfill gas could be sold to impact. Open fires are common across these sites, posing power generators if a grid connection is available, recycla- health risks to the waste pickers who operate there and the bles could be sold if a market exists, and fees could be im- surrounding communities. SANITARY LANDFILLS - 15 Decision Maker’s Guides for Solid Waste Management Technologies MAYOR’S CORNER: QUESTIONS TO ASK YOUR SOLID WASTE MANAGERS OR VENDORS WHO WANT TO CONSTRUCT AND OPERATE YOUR LANDFILL 1. Where would the landfill be sited? Do these areas meet siting requirements (e.g., geology, hydrology, seismology, storm water and groundwater impacts)? 2. What is your strategy to maximize the recovery of valuable recyclable commodities before they are buried in our landfill? 3. What would the disposal tipping fee be and does the fee fully cover our operating costs and enable you to deal with post-closure considerations? What other cost recovery mechanisms are you considering, if any? 4. How many local jobs will the facility create? 5. What is our health and safety strategy to protect workers at the landfill and minimize other nuisances (odors, fires, etc.)? What are you doing to ensure that the facility does not threaten local water supply aquifers, reduce the amount of landfill gas being vented into the atmosphere, and account for other environmental considerations? 6. Do you fully understand the waste disposal needs including the anticipated waste generation to determine the land area needed and the expected lifespan of the landfill? 7. How will climate change affect this landfill site, and what can you do to prepare for that? References Cointreau, Sandra. 2008. “Landfill ER Revenue vs Landfill Costs.” World Bank Presentation. Washington, DC: World Bank. http://siteresources.worldbank.org/INTUWM/Resources/340232-1208964677407/Cointreau.pdf FRTR. “4.26 Landfill Cap”. Remediation Technologies Screening Matrix and Reference Guide, Version 4.0. Frtr.gov http://www.frtr.gov/matrix2/section4/4-27.html. Integrated Skills Consulting Services. 2013. Electricity Generation from MSW, Jenin. Final Report for Islamic Development Bank. Washington, DC: IFC. Jaramillo, Jorge. 2003. Guidelines for the design, construction and operation of manual sanitary landfills. Translated from Spanish by Representative Offices of Guyana, Trinidad and Tobago, and Jamaica. Colombia: PAHO/WHO. whqlibdoc.who.int/paho/2003/a85640.pdf Kaza, Silpa, Lisa C. Yao, Perinaz Bhada-Tata, and Frank Van Woerden. 2018. What a Waste 2.0: A Global Snapshot of Solid Waste Management to 2050. Urban Development Working Series. Washington, DC: World Bank. https://openknowledge.worldbank.org/handle/10986/30317 Langmore, Kathleen, ed. 1998. “Minimum Requirements for Waste Disposal by Landfill. 2nd ed.” Waste Management Series. Pretoria: Department of Water Affairs and Forestry. http:// sawic.environment.gov.za/documents/266.PDF Maryland Department of the Environment. 2015. “Estimated Costs of Landfill Closure.” Fact Sheet- Solid Waste Management. http://www.mde.state.md.us/programs/ResearchCenter/FactSheets/Documents/SWP_Capping_Costs_FS.pdf Moore, Adrian and Geoffrey Segal. 2000. “Privatizing Landfills: Market Solutions for Solid Waste Disposal.” Reason Public Policy Institute Policy Study 267. http://reason.org/news/show/privatizing-landfills UNEP. “Sound Practices – Landfills.” In International Source Book on Environmentally Sound Technologies (ESTs) for Municipal Solid Waste Management. http://www.unep.or.jp/ietc/estdir/pub/msw/sp/sp6/SP6_5.asp US EPA. 2012. “Landfill Gas Energy – A Guide to Developing and Implementing Greenhouse Gas Reduction Programs.” Local Government Climate and Energy Strategy Guides. Washington, DC: US EPA. https://www.epa.gov/sites/production/files/2015-08/documents/landfill_methane_utilization.pdf US EPA. 2014. “Municipal Solid Waste Landfills: Economic Impact Analysis for the Proposed New Subpart to the New Source Performance Standards.” https://www3.epa.gov/ttnecas1/regdata/EIAs/LandfillsNSPSProposalEIA.pdf World Bank. 2001. Operational Manual – OP4.12: Involuntary Resettlement. Washington, DC: World Bank. https://policies.worldbank.org/sites/ppf3/PPFDocuments/090224b0822f89db.pdf 16 - SANITARY LANDFILLS COMPOSTING Decision Maker’s Guides for Solid Waste Management Technologies COMPOSTING Composting is a process that optimizes the natural decomposition of food, garden, and agricultural wastes into a fertilizer-like product, called compost. It is a relatively low-cost strategy for converting the organic portion of the waste stream into a valuable material that can enrich the soil on farms, in parks and in household gardens. 44% of the municipal solid waste stream globally and 56% of waste in low-income countries could be readily composted, but less than 6%2 of total waste generated worldwide is composted at present. Municipal composting is often not profitable unless capital expenditures are undertaken by another party such a government or an international organization. Composting on a municipal scale requires segregating the organic waste from other waste materials to ensure a high-quality end product. Composting differs from the natural decaying process because levels of oxygen, moisture, temperature, nutrients and the chemical environment are monitored and controlled at a facility. These conditions play a significant role in accelerating the decomposition process and determining the quality of the finished compost. COMPOSTING - THE BASICS The process of composting involves the breaking down of Another method is in-vessel composting, which is a mechanical organic matter by microorganisms in the presence of oxygen. solution that drastically speeds up the natural decomposition The volume of the organic waste can decrease by 60-90% process by closely controlling the temperature and oxygen as a result. levels in a composting chamber. These systems generally Various composting methods are available depending on include a mechanism to grind the waste into smaller pieces the amount of available land, the volume of organic material as well as to turn or agitate the material at periodic intervals to be composted, a community’s available budget, and the to speed up the breakdown of waste. Once the organic technical ability of those working at the facility. Windrow material is processed, it must sit outside of the vessel to composting is the cheapest and simplest process for allow completion of the decomposition process. This municipal systems, where organic waste is placed in a large maturation stage can take a few days or weeks depending pile or row (known as a windrow) and periodically turned. The on the system. Enclosed systems are much more expensive mixing process introduces oxygen into the pile to promote than windrow systems, but they require less land because microbial activity. Specialized equipment known as windrow of the faster processing time. If managed poorly, both types turners can be used for this purpose, but front-end loader of systems can create odor problems that are a nuisance to tractors can suffice. More sophisticated windrow systems neighbors of the facility. insert a perforated pipe into the middle of the compost pile and force air through the pile to promote increased microbial activity. 18 - COMPOSTING Decision Maker’s Guides for Solid Waste Management Technologies Windrow/Static Piles In-Vessel Scale of operation Large/ regional/ municipal Small/ neighborhood/ community Processing capacity (tonnes per 1 – 1,000 20 – 350 day) Space/land requirement High Small, can increase for windrow drying or maturing of compost Time required Several weeks Few days to weeks depending on the specifications of the unit. However, the compost might need to sit an additional 2-4 weeks prior to use Odor Can be significant if not well Air purification system confines odor to the aerated vessel Leachate production Low Minimal Sensitivity to weather If feedstock freezes, the Functions in all climates decomposition process stalls Capital cost (US$/tonne) 40-60 300-500 Operating cost (US$/tonne) 12 130 WHAT TO THINK ABOUT WHEN YOU ESTABLISH THE wetter, nitrogen-rich waste material (grass, food waste) with COMPOSTING FACILITY carbon-rich waste material (leaves, shredded wood, etc.). Quality of input: The quality of the compost, and therefore Clean paper and cardboard can also be composted if there its marketability, depends primarily on the quality of the feed- are no good recycling options in a community. stock. A single stream of organic waste, such as yard or gar- Siting: Because of the odor potential, the question of where den waste, organic waste from produce markets or agricul- to site the facility is critical. Enclosed facilities can install a tural waste, rather than mixed municipal solid waste (MSW), filtration system to eliminate most of the odor problems, but creates higher quality compost and reduces the likelihood of this adds to the system cost. Another option is to isolate the contamination by chemical compounds. It is not advisable to facility from residential or commercial areas or to co-locate attempt to produce a high quality marketable compost out the operation at a landfill or wastewater treatment site. Com- of MSW, even if the waste contains a high volume of organic posting facilities should not be located in flood-prone areas material. In order to make MSW-based compost marketable, as floodwaters will ruin the quality of the final compost. Prox- there needs to be a strong source separation to minimize imity to the feedstock material is very important, since waste contaminants and build consumer confidence. A mechani- transportation can easily drive up system costs. Alternatively, cal biological treatment (MBT) facility where organic waste is if composting is only being used for reduced disposal vol- separated from MSW is likely to lead to compromised com- ume, it could occur at the landfill facility. post quality. Facility size: The size of the facility depends on the quanti- Types of input: The composting process occurs most rapid- ty of feedstock expected, the composting method selected, ly if the material being composted has a carbon-to-nitrogen and the size of the compost market. An in-vessel composting ratio of 30:1. Achieving this ratio generally involves balancing operation typically requires a fraction of the space needed Windrow/Static Piles In-vessel composting COMPOSTING - 19 Decision Maker’s Guides for Solid Waste Management Technologies for windrow composting, but it still requires land where the compost can mature once the active in-vessel composting CLIMATE-PROOFING COMPOSTING: phase is complete. Regardless of the type of system select- ed, there should be sufficient space to accommodate at least • Select a site away from waterways to prevent contaminated runoff from polluting waters during four months of composted material. More space may be re- storms quired for storage if the market for the finished compost is highly seasonal. • Ensure facility is sheltered from rain and extreme weather Storm water and leachate management: Leachate is liquid produced from the decomposing waste that could be poten- CLIMATE-BENEFITS OF COMPOSTING: tially hazardous. It will be generated even in well-run facili- ties. Outdoor sites (without protective roofing) will generate • Composting avoids the generation of methane, large volumes of leachate when it rains. Paved flooring and a which would have occurred if the organic waste drainage system leading to a leachate tank or a wastewater had been landfilled instead treatment system can lessen this problem but they can dra- • Use of compost reduces the need for synthetic matically increase the capital costs of a facility. Leachate can fertilizers (made from fossil fuels) and reduces the be reused on-site to maintain an appropriate moisture level amount of water needed for irrigation (thus saving in the pile or windrow. Poor leachate or storm water manage- water as well as energy needed to pump and filter ment can lead to water pollution, cause odors, and create a the water). breeding ground for mosquitoes and other insects or pests. Sensitivity to weather: During optimal composting, the de- THINK YOU’RE SPENDING TOO MUCH ON YOUR composition process generates heat within the compost pile ORGANIC WASTE MANAGEMENT PROGRAM? or chamber ranging from 30° to 60°C. Surrounding air tem- peratures do not affect the composting process as long as Think in total system terms: The composting process reduc- the ideal internal temperature range is maintained. Lower es the volume of the waste by 60 to 90%, elongating your temperatures may slow down the decomposition process, landfill life and often creating a new revenue source for your while higher temperatures can kill the bacteria aiding the de- program. High quality compost can be used on local farm- composition process. land, increasing the productivity of the land, or reducing mu- nicipal expenses for beautification efforts in parks or public Speed of composting process: Reducing the size of waste spaces around the city. by chopping or grinding and frequently aerating will help break down waste more quickly and speed up the compost- Charge a fee for private sector access to your composting ing process. facility: Some cities ban organic waste from their landfill as a methane-prevention strategy, forcing private firms that col- Market for compost and product certification: Common con- lect food waste (or landscaping waste) from hotels or other sumers include farmers, landscapers and municipalities who commercial establishments to find a composting facility to can use the compost for agriculture, parks, schools, and pub- accept this material. A small tipping (disposal) fee can be as- lic areas. Municipalities are the customers with the greatest sessed on private businesses that bring organic waste to a control. Other small, high-end markets can also potentially municipal facility. exist. While no one will buy low-quality compost, good quality compost is not enough to guarantee a market. Attempting to Offer related services: Composting facilities with self-suffi- sell poor quality compost can undermine attempts to create cient operations often offer related services such a recycling a market so it is important that careful consideration is given or waste vocational training program. to quality control and marketing. Decision makers should be Find a partner: Farmers or landscapers can also be the op- aware of negative attitudes towards compost produced from erator of composting plants, using the product for their own municipal solid waste because it is bulky and perceived as businesses. In such cases, some or all of the costs of com- waste material or because the economic benefits to agricul- posting can be amortized by the partnering business. ture and sustainable land management are not well-known. Share a regional facility: A composting facility can be built Many operators offer compost quality assurance by having and shared by several municipalities in close proximity to one a third-party vendor or review system test the quality of the another to take advantage of economies of scale. product and certify it to build trust. 20 - COMPOSTING Decision Maker’s Guides for Solid Waste Management Technologies Pool or bundle facilities: If there are multiple composting fa- organic material for composting and maximizing the amount cilities being designed nationally, then bundling the facilities of waste diverted from landfills. Site managers, who receive together for financing could increase their attractiveness to training, are motivated to get a high-quality input and main- investors. tain the facilities to create compost of market value. Facili- Carbon finance: Composting avoids the generation of meth- ties that receive only yard and landscaping waste produce ane that would otherwise have formed in landfills. Compost- better quality compost than those that accept mixed munic- ing facilities may be eligible for carbon finance, where “cred- ipal waste; regardless of the differences in quality, all sites its” from the reduction of emissions of greenhouse gases can are able to sell their compost to the local market (nurseries, be sold to offset the costs of a compost facility. households, landscapers). Encourage on-site composting: Home and business owners A successful small-scale composting example involves small can be encouraged to compost material on their own proper- cities in Indonesia that adopted a two-pronged approach: ty, cutting the need for municipal collection of organic waste enhancing the role of waste pickers by training them in com- and reducing the size of facility required. To support this posting techniques while stimulating the market by training strategy, many cities give away or sell “backyard” compost- intermediate buyers of compost to understand the physical ing bins at low cost to the public. and commercial benefits of compost. Offering training and support to a variety of stakeholders can benefit the overall Try a targeted approach: Many cities start their composting community in the long run, and create an enduring market program by targeting high volume, uncontaminated organic for the product. waste generators (produce markets, restaurants, hotels, pri- vate landscaping firms), and build a program around these In cases where municipal composting has not been suc- sources. This cuts collection costs, and is logistically much cessful, reasons include poor quality feedstock due to use easier than trying to collect source-separated organic waste of mixed MSW, failure to enforce guidelines, or poor estima- from every household or business on Day 1 of the program. tion of revenue potential. The poor quality feedstock led to low-quality compost that farmers or other users rejected and WHERE IS COMPOSTING BEING USED AND potentially even harmed the environment with leaching of WHAT HAVE WE LEARNED? heavy metals into the ground. Improving waste separation and implementing strict guidelines for compost quality would South Africa is focusing on establishing an uncontaminat- mitigate the problem of low quality compost generation. A ed source of organic waste for composting and has met market study combined with the financing recommendations with success across several cities. Public awareness en- above could lead to a sustainable plan. ables these cities to separate waste properly, enabling pure MAYOR’S CORNER: QUESTIONS TO ASK YOUR SOLID WASTE MANAGERS OR VENDORS WHO WANT TO OPERATE YOUR COMPOSTING PROGRAM 1. How much feedstock is available and what are the waste generation projections over the next 20-30 years? What is the seasonal variation of the feedstock as well as the moisture and carbon content? Does the size of the proposed composting facility make sense given the availability of the feedstock? 2. What systems are in place to ensure the quality as well as guaranteed supply of the feedstock? 3. What are the siting requirements for such a facility and have they been met? Have relevant site studies been conducted to make sure the facility will meet local and national regulations? What steps are planned to minimize any community opposition? 4. What’s your odor strategy? Who else has relied on this strategy and what were the results? What is the plan to train the staff to ensure odor problems do not arise? 5. How many local jobs will the facility create? COMPOSTING - 21 Decision Maker’s Guides for Solid Waste Management Technologies MAYOR’S CORNER (CONTINUED) 6. What is the local market outlook for compost? What factors will influence what users are willing to pay (if anything)? What can the city do to build market demand and trust for locally-produced compost? 7. What are we doing to maximize the revenue potential and minimize costs from our composting program? 8. Can the facility access or benefit from carbon finance or other incentive programs? 9. How else is waste being treated? Are there complementary or competing disposal incentives in place? 10. How will climate change affect the composting site, and what can we do now to prepare? References Babu, M. PPP in Waste Management in India: Opportunities, Barrier and Way Ahead. IL&FS Waste Management and Urban Services Ltd. Available at http://sustainabledevelopment.un.org/ content/dsd/susdevtopics/sdt_pdfs/meetings2010/icm0310/2g_Manesh_Babu.pdf. Bogner, J., M. Abdelrafie Ahmed, C. Diaz, A. Faaij, Q. Gao, S. Hashimoto, K. Mareckova, R. Pipatti, T. Zhang. 2007. “Waste Management.” In Climate Change 2007: Mitigation. Contribution of Working Group III to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change, ed. B. Metz, O.R. Davidson, P.R. Bosch, R. Dave, L.A. Meyer, 585-618. Cambridge, UK and New York, USA: Cambridge University Press. Composting Council of Canada. n.d. “Composting Process Technologies.” Accessed April 9, 2018. http://www.compost.org/pdf/compost_proc_tech_eng.pdf. Ekelund, L. and K. Nyström. 2007. “Composting of Municipal Waste in South Africa – Sustainability Aspects.” Degree Project, Uppsala University. http://www.utn.uu.se/sts/cms/ filarea/0602_kristinanystromlottenekelund.pdf. Hoornweg, Danial, Laura Thomas, Lambert Otten. 2000. “Composting and its applicability in developing countries.” Working Paper Series, Urban Development Division. Washington DC: World Bank. http://documents.worldbank.org/curated/en/483421468740129529/pdf/multi0page.pdf Kaza, Silpa; Yao, Lisa; Stowell, Andrea. 2016. Sustainable Financing and Policy Models for Municipal Composting. Urban Development Knowledge Series. Washington, DC: World Bank. https://openknowledge.worldbank.org/handle/10986/26286. Kaza, Silpa, Lisa C. Yao, Perinaz Bhada-Tata, and Frank Van Woerden. 2018. What a Waste 2.0: A Global Snapshot of Solid Waste Management to 2050. Urban Development Working Series. Washington, DC: World Bank. https://openknowledge.worldbank.org/handle/10986/30317. King, Mark A., and George M. MacDonald. Commercially Available In-Vessel Compost Systems for Organics. Maine Department of Environmental Protection. Available at http://www.mrra. net/wp-content/uploads/2013-Mark-King-InVessel-Talk.pdf. New South Wales Department of Urban Affairs and Planning. 1996. “Composting and Related Facilities – EIS Guideline.” New South Wales, Australia: Department of Urban Affairs and Planning. http://www.planning.nsw.gov.au/rdaguidelines/documents/Section_E_Composting.pdf. Richard, T. L. 1992. “Municipal Yard Waste Composting: A series of ten fact sheets.” Ithaca, NY: Cornell Resource Center. Available at http://compost.css.cornell.edu/Factsheets/FactsheetTOC.html. Richard, T.L. 1993. “Municipal Solid Waste Composting: Biological Processing.” Ithaca, NY: Cornell Waste Management Institute, Cornell University. http://compost.css.cornell.edu/ MSWFactSheets/msw.fs2.html . UNDESA. No date. Waste Concern: Public/Private partnership and community based composting in Dhaka, Bangladesh. Sustainable Development Knowledge Platform. Available at http:// sustainabledevelopment.un.org/index.php?page=view&type=1006&menu=1348&nr=2200. UNEP. “Municipal Solid Waste Management. Newsletter and Technical Publications.” UNEP.or.jp. Accessed April 9, 2018. http://www.unep.or.jp/Ietc/ESTdir/Pub/MSW/index.asp. US Composting Council. 2012. “USCC Position Statement: Keeping Organics Out of Landfills.” Accessed April 9, 2018. http://compostingcouncil.org/admin/wp-content/uploads/2011/11/ Keeping-Organics-Out-of-Landfills-Position-Paper.pdf. US EPA. 1995. Decision-Makers’ Guide to Solid Waste Management. Volume II. EPA530-R-95-023. US EPA. “Composting at Home.” EPA.gov. Accessed April 9, 2018. https://www.epa.gov/recycle/composting-home van Haaren, Rob. 2009. “Large scale aerobic composting of source-separated organic wastes: A comparative study of environmental impacts, costs, and contextual effects,” master’s thesis. Earth Engineering Center, Columbia University. Worrell, William A., and P. Aarne Vesilind. 2012. Solid Waste Engineering, 2nd ed. Stamford, Connecticut: Cengage Learning. 22 - COMPOSTING ANAEROBIC DIGESTION Decision Maker’s Guides for Solid Waste Management Technologies ANAEROBIC DIGESTION Anaerobic digestion (AD) refers to the biological process of converting food and outdoor green waste into two useable products — semi-solid fertilizer and biogas. The fertilizer can be used for landscaping or agricultural purposes and the biogas (primarily consisting of methane) can be used to generate electricity and/or heat. AD is a proven technology that has been used for many years to treat animal waste and municipal and industrial wastewater. More recently, it is being used to convert the organic content of municipal solid waste (MSW) to useable products. Developing countries commonly use AD to treat waste from farms, while in Europe, the technology has been used to treat the organic fraction of MSW for over 20 years. The technology can break down any biodegradable matter and is most cost-effective when uncontaminated waste is readily available. Anaerobic Digestion (AD) ANAEROBIC DIGESTION - THE BASICS Process flow diagram Anaerobic digestion occurs when naturally occurring microorganisms break down waste in the absence of Organic waste reception oxygen (unlike composting which requires oxygen) and emit gases that are captured to generate electricity and heat. The fertilizer produced from anaerobic digestion is significantly moister than compost. It can be used directly or dried into a more solid form. As with composting, the solid residue may require some time outdoors in piles to Cooking fuel Pre-treatment finish the natural decomposition process. The anaerobic digestion process typically decreases the solids content by 50-60% while conserving nutrients for soil and killing up to 95% of any disease-causing Vehicle fuel organisms. The fertilizer produced is a stable, low odor, Digestion high nutrient product that is suitable for land application. Storage and treatment Biogas The biogas created in this process can be used to generate electricity or can be refined and supplied to natural gas utilities. The typical amount of biogas generation is Liquid and solid bio-fertiliser 100-200m3 of total gas per tonne of organic MSW digested. Generator Anaerobic digestion models can vary based on 1) percent Organic Food production Agriculture of solid content in the waste (low-solids waste has less waste and consumption /gardens than 20% solid concentration and high-solids waste has Cooling and heating greater than 20%, ideally 20-50%), 2) preference of batch Electricity or continuous process, and Technology 3) preference for a single or overview AD is the natural decomposition (digestion) of organic waste in an oxy- multi-stage process. gen-free (anaerobic) environment. The process generates a biogas, com- prised of approximately 60% methane and 40% carbon dioxide. This bio- gas Schematic of fertilizer can be burned and energy to generate generation combined from heat organic and power MSW in AD (CHP) or the biogas can be upgraded (scrubbed) to biomethane for use as a vehicle fuel. A solid and liquid digestate is also generated from the process that can 24 - ANAEROBIC DIGESTION be used as an organic fertilizer for soil improvement. Ideal calorific value of waste (MJ/kg) N/A Decision Maker’s Guides for Solid Waste Management Technologies A batch process (loading all organic waste at once) is lower cost, simpler to use, and requires less water than a continuous process (loading waste continuously as needed). Beyond that, the comparison of the remaining choices to be made are included in the table: Single-stage Multi-stage Low-solids waste • Simple to design & operate • Higher waste loading rates • Less capital than multi-stage • Higher methane production • Longer process • Higher capital costs • More sensitive • More stable High-solids waste • Biogas generation rate comparable to or • Higher waste loading rates greater than low-solids systems • Higher methane production • Minimal pre-treatment (system tolerant • Minimal pre-treatment of contaminants) • High capital costs & operating costs • Low water needs • Low water needs • High capital costs • More expensive equipment WHAT TO KEEP IN MIND WHEN PURSUING ANAEROBIC DIGESTION CLIMATE-PROOFING AN ANAEROBIC DIGESTER: Infrastructure: Digestion has to occur in a fully sealed vessel, in order to exclude oxygen and maintain optimal moisture • May require a storm water management system and temperature levels. to protect fertilizer from heavy runoff (if placed outdoors) Feedstock: The waste should either be a purely organic • Site away from waterways to prevent leachate waste stream or, if sourced from MSW, it needs to be well- contamination separated organic material that is free from contaminants. If the input contains other materials, such as plastic, metal, and CLIMATE-BENEFITS: glass, that are not removed beforehand, then the digesters • Will result in reduced greenhouse gas emissions run the risk of getting blocked and becoming inefficient. The through capture and utilization of methane contaminants will also reduce the fertilizer quality. Therefore, an effective source separation program is required if household organic waste is being considered. Biogas production: To maximize biogas production, the MECHANICAL BIOLOGICAL TREATMENT SYSTEM: feedstock should be entirely biodegradable, and the • A Mechanical Biological Treatment System (MBT) is conditions in the digester should be moist (often achieved by a Materials Recovery Facility, where sorting of waste adding water or wastewater) and maintained at a sufficiently occurs, that is combined with a biological treatment high temperature as microorganisms are very sensitive to method such as composting or AD changes in these parameters. Note that the large quantity of biogas could be safety issue if not properly secured. • MBTs are used for processing mixed household Biogas uses: Most anaerobic digestion plant, even small • Generally, the quality of output from composting and units, should generate sufficient biogas to be used as a fuel, AD are lower from an MBT facility than when organics either for creating heat (e.g. for heating or cooking) or to are sourced directly from restaurants, hotels, and generate electricity using a generator. Excess biogas should markets due to contaminants be stored in a storage tank or balloon, or burnt (flared). ANAEROBIC DIGESTION - 25 Decision Maker’s Guides for Solid Waste Management Technologies Cleaning of the biogas: A highly corrosive gas (hydrogen Capital and operating costs in Europe and the United States sulfide) is generated during AD and can be removed by are estimated in the table below: two methods: 1) adding oxygen directly into the digester or Anaerobic Digestion storage tank, or 2) running the biogas through iron particles. Less cleanup is need for heat and electricity-use onsite than Capital Expenditures Operational (US$/annual tonne) Expenditures when the biogas is used for transport fuel or as a replacement (1) (US$/tonne) for natural gas. Europe $345-600 $31-57 HOW MUCH WILL AN ANAEROBIC DIGESTION United States $220-660 $22-55 SYSTEM COST? A financial analysis of using organic waste in an AD plant (1) Annual tonne is the capital cost of the facility divided by the annual processing capacity versus landfill should include the transportation cost of moving the organic waste to the AD plant as well as the IS YOUR ANAEROBIC DIGESTION SYSTEM TOO transport of the resulting fertilizer to its destination. EXPENSIVE? THINK ABOUT… Total system terms: AD reduces the volume of the waste by • In resource-constrained communities, it may make 50-60%, elongates your landfill life and often creates a new sense to co-digest food waste and wastewater revenue source for your program. High quality fertilizer can because the combination produces more biogas be used on local farmland, increasing the productivity of the than stand-alone digestion, and one capital land, or reduce municipal expenses for beautification efforts investment can manage both food waste and in parks or public spaces around the city. wastewater Tipping fees: Like other waste disposal facilities, AD facilities also charge tipping fees per tonne of waste brought to the Capital costs facility, which offset operational costs and sometimes even • Purchase/lease price of • Connection to the capital costs. the land and equipment grid (for electricity Sale of fertilizer: The fertilizer that is produced can be sold • Design and construction generation) and would benefit from laboratory testing to provide product costs of the facility and • Permits and licensing quality assurance. related systems • Training for operators Sale of biogas as an energy source: The biogas generated from the AD process could be used to generate electricity Capital costs: Capital costs can range from approximately and/or heat and could be sold to nearby industries or to the $2,800 to $6,400 per kW of installed capacity. For AD plants grid, thus bringing in revenue. It could also be used on-site to accepting food waste, the biggest costs involve biomass reduce operating costs. feedstock preparation and handling and the converter system (to convert the gas into heat or electricity). Preferred tariffs for renewable energy: Governments may provide initiatives in the form of tax credits, preferential Operating costs: Generally, 20% of the income generated pricing, discounts, or other benefits to encourage electricity from an AD plant should be sufficient to cover maintenance from renewable sources. and repairs. Operation and maintenance costs generally have two components: fixed and variable: Carbon finance: AD captures the methane that would otherwise have formed in landfills, and is thus a possible Fixed O&M costs Variable O&M costs • Include labor, • Include non-biomass fuel, source for carbon finance, where “credits” from the reduction maintenance, unplanned maintenance of emissions of greenhouse gases can be sold to offset the routine equipment and equipment costs of the facility. replacement, etc. replacement Public-private partnership: AD plants are specialized • Usually calculated as a • Vary based on the output of systems that are more difficult to design, construct and percentage of capital the system and are usually operate than landfills or traditional composting facilities. costs expressed as a value per unit of output (e.g., $/kWh) Municipalities normally work with a private sector developer • Range from 2.1 to 7% for proper design, construction and operation of an AD plant of installed cost of AD • Approximately $4.2/MWh to share costs and reduce operational risk systems on average 26 - ANAEROBIC DIGESTION Decision Maker’s Guides for Solid Waste Management Technologies WHERE IS ANAEROBIC DIGESTION BEING USED AND WHAT HAVE WE LEARNED? AD of MSW is commonplace in Europe and is increasingly the quality and quantity of waste diverted, but still needs economically attractive due to the widespread source greater volume of waste and purer organic waste. separation of waste, high landfill tipping fees, and favorable AD facilities have also faced problems, some to a point where energy prices. AD of other organic waste such as agricultural they have had to shut down. Mechanical problems related waste and wastewater is common throughout the developing to temperature control, mixing of the feedstock, appropriate world. Small-scale digestion of agricultural waste (e.g., liquid content; biological problems such as continuing manure) has been occurring in rural areas in China, India, and viability of seed bacteria; and over-production of gases such throughout the world, for hundreds of years. In Ningbo, China, as ammonia have been known to occur. Nevertheless, these there is an AD facility that primary processes restaurant waste. issues can be alleviated with proper expertise, monitoring, Recently, the government began including source-separated and training. It is also important to remember that not only organic waste from households and is focusing on ensuring is financing important, but also siting and permitting issues, that incoming waste is uncontaminated. The municipality is which have sometimes been the cause of halting projects. providing a financial incentive to neighborhoods based on MAYOR’S CORNER: QUESTIONS TO ASK SOLID WASTE MANAGERS OR VENDORS WHO WANT TO OPERATE THE ANAEROBIC DIGESTION FACILITY 1. How much feedstock is available and what are the waste generation projections over the next 20-30 years? Does the size of the proposed AD facility make sense given the availability of the feedstock? 2. What systems are in place to ensure the quality as well as guaranteed supply of the feedstock? 3. What is the market for the fertilizer and energy (electricity and/or heat) generated and the related costs for selling and transporting both? Can an AD facility be developed in conjunction with, or adjacent to, a factory that can use the energy (or produces organic waste which can be used in the AD process)? 4. Are there any other by-products that cannot be beneficially used? How would you dispose/treat them (whether solid, liquid, or gas)? 5. What are the siting requirements for the AD facility and have they been met? Have relevant site studies been conducted to make sure the facility will meet local and national regulations? 6. How many local jobs will the facility create? 7. What training and maintenance will be provided over the lifetime of the facility by the private developer? How can local capacity be fostered over time? 8. Can the facility access or benefit from feed-in tariffs, carbon finance, renewable energy tariff incentives, and other incentive programs? 9. Do you have a commercial facility like this in operation already? Where? What are the references? 10. How will climate change affect the facility, and what are you doing now to prepare for it? ANAEROBIC DIGESTION - 27 Decision Maker’s Guides for Solid Waste Management Technologies References Abbasi Tasneem, S. M. Tauseef, and S. A. Abbasi. 2012. “A Brief History of Anaerobic Digestion and “Biogas”.” In Biogas Energy, SpringerBriefs in Environmental Science 2. New York, NY: Springer. DOI 10.1007/978-1-4614-1040-9_2. http://www.springer.com/cda/content/document/cda_ downloaddocument/9781461410393-c1.pdf?SGWID=0-0-45-1277160-p174133368 Aracdis 2009. Assessment of the Options to Improve the management of Bio-Waste in the European Union. European Commission Directorate- General Environment, Brussels, Belgium. De Baere, Luc and Bruno Mattheeuws. 2012. “Anaerobic Digestion of the Organic Fraction of Municipal Solid Waste in Europe - Status, Experience and Prospects.” In Waste Management, Vol. 3: Recycling and Recovery, ed. Karl J. Thomé-Kozmiensky and Stephanie Thiel, 517-526. Neuruppin: TK Verlag Karl Thomé-Kozmiensky. IRENA. 2012. “Biomasss for Power Generation.” Renewable Energy Technologies: Cost Analysis Series, Volume 1: Power Generation. Abu Dhabi: IRENA https://www.irena.org/DocumentDownloads/Publications/RE_Technologies_Cost_Analysis-BIOMASS.pdf Verma, Shefali. 2002. “Anaerobic digestion of biodegradable organics in municipal solid wastes,” master’s thesis. Earth Engineering Centre, Columbia University. https://pdfs.semanticscholar.org/27d6/b00d657e3fca72e6317e3f4b369dd900765a.pdf 28 - ANAEROBIC DIGESTION INCINERATION WITH ENERGY RECOVERY Decision Maker’s Guides for Solid Waste Management Technologies INCINERATION WITH ENERGY RECOVERY Incineration with energy recovery refers to the combustion of waste under controlled conditions to generate electricity and/or heat. The technology produces energy and heat, reduces the volume of municipal solid waste (MSW) that must be handled and destroys harmful substances, provided that the process includes highly advanced air pollution control (APC) equipment. The energy generated is considered to be partially renewable, due to the biogenic (plant-based) content of the waste, such as food and other organic waste, cardboard and wood. The fossil-fuel sourced components of the waste (e.g. plastic materials) are non-renewable. Incineration was often historically applied without energy recovery, but that is increasingly rare given the potential for the technology to be a source of energy in addition to a waste management solution. Although incineration technology has matured over the last few decades, it is still relatively expensive, and thus primarily used in high-income countries. Incineration has been implemented successfully in jurisdictions with land (or landfill) scarcity, high technical capacity, significant financial resources, strong environmental regulations and typically a low or separated organic waste fraction. It is widely used in Japan where 80% of MSW was combusted in 2015. Around the world, approximately 11% of MSW is combusted, although the technology is most prevalent in high-income countries. Incineration INCINERATION - THE BASICS Process flow diagram Modern incineration facilities consist of a storage area to sort Electricity Steam and store the incoming waste, a crane for lifting the waste Generator from the storage area into the combustion chamber, a heat recovery system that uses the heat from incineration to produce steam in a boiler for electricity generation, an ash handling system to capture non-toxic bottom ash (ash that collects at the bottom of the system), and an APC system, Scrubber which captures toxic particles that rise with the gaseous emissions (fly ash) and treats harmful gasses prior to release into the air. The operational capacity of incineration facilities can range from 5 to over 1,000 tonnes per day of MSW; Incinerator however, most facilities are in the range of 200 to 700 tonnes per day. Particulate The main difference between incineration and open or Grabber collects waste Ash and materials removal system uncontrolled burning is that the combustion in incineration occurs at a very high temperature in a contained plant which reduces the generation of harmful air pollutants. An incinerator can also capture and utilize heat and steam for electricity. Open burning occurs at a much lower temperature Chimney while exposed to the atmosphere. Schematic diagram of incineration facility Technology overview Incineration (i.e. mass burn) is one of the most common forms of thermal 30 - INCINERATION waste treatment technology. It involves the combustion of waste materials in a chamber that contains excess air. There are two main types of inciner- ators: moving grate incinerators and fluidized bed incinerators. In a moving Decision Maker’s Guides for Solid Waste Management Technologies Comparison of incineration and open burning Incineration Open burning Control of burning Strict controls on volume and types of waste No control included as well as temperature of furnace Energy Recovery Electricity and/or heat potential No potential Toxic Emissions Low due to high temperature combustion, Can be 45 times higher than emissions Pollution advanced APC equipment and typically strict from incineration. They are not captured but government emission regulations rather released into the atmosphere WHAT TO KEEP IN MIND WHEN PURSUING INCINERATION Feedstock requirements: The MSW should contain a sufficient Electricity and heat generation: A feedstock with suitable amount of dry, combustible waste (paper, unrecyclable characteristics would generate net electricity of 500-600 plastics, etc.), and be available at a consistent volume, that kWh/tonne of MSW. In the European Union, it is common for varies by less than 20%, to enable effective combustion and both electricity (500 kWh/tonne) and heat (1000 kWh/tonne) a minimum level of electricity and/or heat generation. Waste to be generated, with the latter used in providing industrial with a low organics fraction (<50%) is easier for combustion. or district heating. This approach is termed ‘co-generation’. The feedstock does not need to be homogenous and can Public perception: The lingering criticism of local incinerators include municipal, medical and hazardous waste. Waste that from the 1960s and ‘70s makes incineration a highly should be avoided includes those with high sulfur or chlorine contentious subject among many communities. Decision contents, organic salts, or radioactive materials. makers need to include the public in the decision-making Siting: Assuming multiple sites are available close to the process, by providing accurate information, and siting municipality, siting close to industrial plants would benefit facilities away from residential areas. both parties by reducing the cost of transportation of waste Contract duration: Due to the very high capital costs of these to the incinerator as well as the distribution cost of electricity plants, contracts for incineration are normally 25-30 years and/or heat. If the ash is to be landfilled, siting the facility near in duration. This is the typical time-period that allows the a landfill would reduce transportation costs. developer (and its financial backers) to recoup the substantial Air pollution control: The APC system is a sophisticated investment made in the capital equipment. It is important and key part of the incineration plant. It ensures that air to properly assess possible changes in waste quantities, emissions are kept below harmful levels. The APC system composition and other related factors over the long term so normally comprises a bag filter system in the flue (chimney) as to ensure that the municipality is not bound into a contract to capture the fine particles of the toxic fly ash and also a that prevents waste prevention or discourages recycling or chemical-based system to capture other harmful gaseous composting initiatives to be developed. compounds in the flue gas. Emissions are typically monitored Contractual requirements for waste quantities and continuously for regulatory compliance. Monitoring data is composition: Successful incineration plants require a often made publicly available to demonstrate that emissions consistent flow of waste feedstock and a consistent are below harmful limits. composition, with a calorific value between defined levels. Ash disposal: The non-toxic bottom ash normally comprises The developer and operator of an incinerator will typically 10-25% by weight of the MSW processed. It can be treated insist on a minimum quantity and composition of waste as and recycled as construction material or used in the part of any waste treatment contract with a municipality. Small production of cement. If such use is not possible, it must be waste quantities are likely to make the facility too costly due disposed of in a landfill. Toxic fly ash (ranges from 3-5% by to the high upfront capital investments. If the agreed quantity weight) is a hazardous material due to an often high content and composition of waste is not provided by the municipality of heavy metals. It can be disposed of in a hazardous waste then the incinerator operator will normally apply a financial landfill (common in Europe) or can be mixed with bottom ash penalty to compensate for the effect that the lower quantity (common in the US) to be disposed of in a sanitary landfill or or change in composition will have on the plant’s operation. used as landfill cover. INCINERATION - 31 Decision Maker’s Guides for Solid Waste Management Technologies Informal waste pickers: the contractual requirements of an an integrated waste management strategy to integrate waste incinerator-based waste treatment contract could result in pickers as part of the new system. pressure to collect as much waste as possible for delivery Integrated solid waste policy: An incineration facility should to the incinerator. In cities where there are major waste be planned as part of an integrated, long-term strategy picking activities, waste pickers and informal recyclers that also considers waste prevention, reuse, and recycling may lose access to waste materials, their main source of and composting activities. Recycling and incineration can income. It is essential to consider the issues carefully before complement each other if there is sufficient waste volume and engaging in an incinerator-based waste treatment contract. the interactions between different initiatives are assessed in A social assessment must be done with measures in place to detail. mitigate these risks. Policies could be developed as part of HOW MUCH WILL AN INCINERATION FACILITY COST? • Costs vary by facility according to the combustion tech- • The high costs of incineration facilities can be heavily off- nology chosen since each has unique design character- set by revenues earned from operations, as long as the istics, variations in equipment costs, capacity, site-specific facilities are operated at full processing capacity and op- waste characteristics, space requirements, and regulatory timized technically. requirements. • APC equipment costs are roughly equal to that of the rest • On a per tonne basis, capital costs for incineration plants of the facility. Thus, the costs and importance of APC tech- range from US$190-1000 per annual tonne, while operat- nology should be clearly understood. ing costs range from US$12-55/tonne. This makes inciner- • There are significant potential economies of scale for in- ation generally more expensive than landfilling, compost- cineration, especially when the cost of APC equipment is ing, and anaerobic digestion, but cheaper than pyrolysis factored in. Hence, if there is sufficient demand for waste and gasification. treatment or if a plant can serve a whole region, there may be a clear financial benefit. • Below are a few examples of operational expenditures • In general, maintenance and other consumable costs are and capital expenditures for incineration facilities (per estimated to be 3% and 1%, respectively, of capital costs. tonne of waste processed): Incineration Expenditures Capital Costs Capital Expenditures (1) Operational • Land and buildings • Approvals and (US$/annual tonne) (2) Expenditures (3) acquisitions licensing (US$/tonne) (4) • Design and construction of the • Machinery and Europe $600-1000 $25-30 facility and related systems equipment United (steam turbine, APC, etc.) • Training and $600-830 $44-55 States • Environmental and social monitoring China $190-400 $12-22 impact assessments equipment (1) In Europe and US, predominantly mass-burn/moving grate technology is used for waste incinerator with energy recovery (waste-to-energy). In China many incinerators use circulating fluidized bed (CFB) technology REVENUE OPPORTUNITY which reflects the lower end of investment cost although moving grate incinerators are also becoming more common. Revenues can be obtained from tipping fees, sale of (2) Annual tonne is the capital cost of the facility divided by the annual electricity, metals recovery, and carbon finance. processing capacity of the facility (3) Operating costs without accounting for revenues range between $100-200/tonne. The figures presented in the table are typical operating Costs are sometimes also calculated based on the per kilo-watt genera- costs (net gate fees) taking into account revenues for electricity and/ tion electricity from the facility. Comparative costs of thermal treatment or heat sales and other revenues. In the EU, also including subsidies to options are shown below ($/kW for a 15 MW output) energy from waste in some countries, these revenues are typically about $100/tonne, hence the resulting operating costs. In US feed-in tariffs for Incineration with energy recovery $7,000-10,000 electricity are typically lower, below $50/MWh. (4) Mixed waste in the US and the EU is relatively low in organics and Gasification (conventional) $7,500-11,000 water content and hence high in calorific value. As a consequence, oper- ating costs for waste with high organics often seen in lower income coun- Gasification (plasma arc) $8,000-11,500 tries could substantially increase operating costs due to lower revenues Pyrolysis $8,000-11,500 32 - INCINERATION Decision Maker’s Guides for Solid Waste Management Technologies HOW TO RECOVER COSTS OF IMPLEMENTING THESE TECHNOLOGIES Think in total system terms: Incineration reduces the volume Preferred tariffs for renewable energy: Governments may of the waste, elongating your landfill life and often creating a provide incentives in the form of tax credits, preferential new revenue source for your program. The average lifespan pricing, discounts, or other benefits to encourage electricity of incineration facilities is about 25 years. from renewable sources. In the US and Europe, incineration Tipping fees: A major source of income at an incineration is considered to be a renewable source of energy because facility is tipping fees, which is the fee charged to waste the major portion of carbon in the waste does not increase haulers or the municipality per tonne of waste brought to the the total amount of atmospheric carbon facility. This can offset capital and operating costs. Larger Carbon finance: Incineration facilities can be possible facilities would have slightly lower tipping fees due to small candidates for carbon finance where “credits” from the economies of scale. reduction of emissions of greenhouse gases can be sold to Sale of electricity and/or heat generated: The electricity offset costs. Incineration facilities prevent the generation of and/or heat generated that is not used in running the facility methane in landfills that could have occurred, and generate itself could be sold to nearby industries, to the electric grid, or electricity and/or heat that might otherwise have been to district heating systems. generated from fossil fuels. Generation efficiency: Incinerators that generate both heat Materials recovery: The separation of recyclables, particularly and electricity are significant more energy-efficient (in terms high-value metals, prior to combustion can be a significant of the using the energy context of the waste feedstock) than source of revenue for incineration facilities. those that generate electricity only. Generating electricity is a common challenge and should not be solely relied on. Locating an incinerator adjacent to, or as part of, an industrial facility/area that can use the heat is an effective way of maximizing the use of the available energy. Alternatively, a district heating system can be developed in conjunction with an incinerator. WHERE IS INCINERATION BEING USED AND WHAT HAVE WE LEARNED? Incineration facilities have been successful in places like quality feedstock, inefficient incineration, and high levels of Japan and the European Union where space for landfilling is air pollution. The facilities were not profitable due to lack diminishing and the costs of landfilling are increasing. Other of revenue generation from electricity, and instead resulted factors that have driven the growth of incineration include in strong public opposition to the technology due to the improved pollution and emissions controls, legally-binding resulting high costs and pollution. regulations mandating energy generation from renewable sources, targets for reduction in greenhouse gas emissions, and eligibility for carbon credits and other financial and tax CLIMATE CONSIDERATIONS: incentives. Decision makers and incineration operators • Combusting one tonne of waste in an incineration have succeeded in gaining public acceptance by including plant prevents one tonne of CO2e from being incineration as a key part of their environmental and waste emitted through alternative waste treatment strategies, encouraging recycling, and using waste as a methods source of energy. • Incineration offsets fossil fuels by generating Incineration has been challenged in some low and middle- sustainable energy income countries where facilities built decades ago without proper waste characterization studies and lack of air pollution control equipment resulted in insufficient and low- 4 Assuming 5-year average conversion rate of 1.5139 USD per British pound and 1.18 USD per Euro INCINERATION - 33 Decision Maker’s Guides for Solid Waste Management Technologies MAYOR’S CORNER: QUESTIONS TO ASK YOUR SOLID WASTE MANAGER OR VENDOR WHO WANT TO CONSTRUCT AND OPERATE THE INCINERATION FACILITY 1. Is the technology appropriate given the local waste composition (organics should be <50% unless government is willing to procure extra treatment equipment), quantity generated, and seasonal variation? What are the waste generation projections over the next 20-30 years? Does the size of the proposed incineration facility make sense given the availability of the feedstock? 2. What systems are in place to ensure the quality as well as a guaranteed supply of the feedstock? 3. Is it financially sustainable? What will the tipping cost be and what cost recovery mechanisms will be put in place? 4. Is there a market for the sale of electricity and/or heat generated from the incineration facility? Is there preferential pricing for waste-derived electricity? Can the incinerator be developed in conjunction with an industrial or residential development or be connected to a grid that can use the electricity and heat? 5. Can land for the facility be readily obtained? What are the siting requirements for such a facility and have they been met? Have relevant site studies been conducted to make sure the facility will meet local and national regulations? 6. How many local jobs will the facility create? 7. What training and maintenance will be provided over the life of the facility by the private devel- oper? How can local capacity be fostered over time? 8. Does the project developer have prior experience in undertaking complex technical and finan- cial projects with sufficient technical knowledge? 9. Does the technology provider already have an existing facility in operation, operating at a sim- ilar scale, with a similar feedstock? Can the vendor provide operational and performance data, including emissions and costs, for at least several months, if not longer, of continuous operation? 10. Does the vendor have proof of adhering to the local standards set by solid waste and air pollu- tion regulations? 11. What opportunities exist to put the physical by-products of incineration (e.g., bottom ash) to productive use, such as in road construction or as a component of cement? INCINERATION - 34 Decision Maker’s Guides for Solid Waste Management Technologies References Aracdis 2009. Assessment of the Options to Improve the management of Bio-Waste in the European Union. European Commission Directorate- General Environment, Brussels, Belgium Energy Recovery Council. 2016. “2016 Directory of Waste-To-Energy Facilities.”. http://energyrecoverycouncil.org/wp-content/uploads/2016/06/ERC-2016-directory.pdf European Commission, Directorate General Environment. 2003. Refuse derived fuel, current practice and perspectives (B4-3040/2000/306517/MAR/ E3). Final Report, UK. http://ec.europa.eu/environment/waste/studies/pdf/rdf.pdf Fendel, Ansgar and Henning Friege. 2011. “Competition of Different Methods for Recovering Energy from Waste Leading to Overcapacities.” Waste Management & Resources 29: 30-38. https://doi.org/10.1177/0734242X11413955 Hogg, Dominic. n.d. “Costs for Municipal Waste Management in the EU - Final Report to Directorate General Environment, European Commission.” Eunomia Research and Consulting. Kaza, Silpa, Lisa C. Yao, Perinaz Bhada-Tata, and Frank Van Woerden. 2018. What a Waste 2.0: A Global Snapshot of Solid Waste Management to 2050. Urban Development Working Series. Washington, DC: World Bank. https://openknowledge.worldbank.org/handle/10986/30317 Qiu, Ling. 2002. “Analysis of the Economics of Waste-to-Energy Plants in China,” master’s thesis, Columbia University. http://www.seas.columbia.edu/earth/wtert/sofos/Qiu_thesis.pdf Renewable Energy Association. 2011. Energy from Waste – A Guide for Decision-Makers. UK: Renewable Energy Association. https://www.r-e-a.net/pdf/energy-from-waste-guide-for-decision-makers.pdf Ricardo-AEA. 2013. “Waste to Energy Background Paper.” http://www.zerowaste.sa.gov.au/upload/resource-centre/publications/waste-to-energy/ waste%20to%20energy%20background%20paper%20final.pdf Schneider, D.R., D. Lončar and Ž Bogdan. 2010. “Cost analysis of waste-to-energy plant.” Strojarstvo 52: 369-378 Stringfellow, T. and R. Witherell. 2014. “An Independent Engineering Evaluation of Waste-to-Energy Technologies.” Renewable Energy World. http://www.renewableenergyworld.com/rea/news/article/2014/01/an-independent-engineering-evaluation-of-waste-to-energy-technologies Tang, Jiao. 2012. “A Cost‐Benefit Analysis of Waste Incineration with Advanced Bottom Ash Separation Technology for a Chinese Municipality – Guanghan,” master’s thesis. Vienna School of International Studies: Vienna. http://www.seas.columbia.edu/earth/wtert/sofos/PubDat_210340.pdf Themelis, Nickolas J. and Charles Mussche. 2013. “Municipal Solid Waste Management and Waste to Energy in the United States, China and Japan”. Paper presented at the 2nd International Academic Symposium on Enhanced Landfill Mining, Belgium, October 4-16. https://pdfs.semanticscholar.org/bfdb/859fb02ede97bdfed221674521369f4bf5e5.pdf UK Department for Environment Food & Rural Affairs.2013. Incineration of Municipal Solid Waste. Waste Technology Briefs. London: UK DEFRA. http:// www.wtert.co.uk/content/Defra%20report.pdf Waste-to-Energy Research and Technology Council. “Answers to Frequently Asked Questions Regarding Waste-to-Energy.” http://www.seas.columbia. edu/earth/wtert/faq.html World Bank. 2011. Viability of Current and Emerging Technologies for Domestic Solid Waste Treatment and Disposal: Implications on Dioxin and Furan Emissions. World Bank, Washington, DC, USA. World Energy Council. 2013. World Energy Resources: Waste to Energy. London: World Energy Council. https://www.worldenergy.org/wp-content/uploads/2013/09/Complete_WER_2013_Survey.pdf 35 - INCINERATION SECTION TITLE HERE PYROLYSIS AND GASIFICATION Decision Maker’s Guides for Solid Waste Management Technologies PYROLYSIS AND GASIFICATION Pyrolysis and gasification, two technologies referred to as Advanced Thermal Treatment (ATT) technologies, convert waste primarily into a synthetic gas or fuel. ATT technologies have been widely applied to industrial and hazardous waste streams for a number of years but only recently been applied to the treatment of municipal solid waste, mainly in Japan. Both ATT technologies burn waste in a zero- or low-oxygen environment and provide several waste management benefits: (1) quick and large reduction in mass and volume of waste, thus prolonging landfill life; (2) destruction of toxic substances; and (3) energy production. Unlike incineration, where the energy is used on-site to create electricity and/ or heat, pyrolysis and gasification generate fuel that can be transported for use at other locations. PYROLYSIS AND GASIFICATION - THE BASICS Pyrolysis involves heating the waste to high temperatures in an enclosed container without oxygen, producing (1) a synthetic gas (syngas) that can be used as liquid fuel, (2) tar, and (3) char, a solid material consisting of the remaining burned waste that can be used as a soil amendment. The temperature at which the waste is burned affects the composition of the output: higher temperatures (>760°C) Plasma arc is a heating method that can be used with lead to more gas production, while lower temperatures (450- both technologies. For gasification, it treats waste 730°C) favor the production of both liquid fuel and gas. with very high heat (1,000-1,500°C), producing syngas Gasification involves heating the waste at high temperatures and a glass-like inert material that may be reused or (typically above 700°C) with some oxygen but less than the safely disposed. amount required for incineration, producing syngas and char. Most pyrolysis and gasification plants follow four basic stages: 1. PRE-TREATMENT 2. HEATING 3. ‘SCRUBBING’ 4. GENERATE ELEC- OF WASTE REMAINING WASTE THE SYNGAS TRICITY AND/ OR HEAT • Dry • Mainly organic waste • Clean syngas to • Use ‘scrubbed’ • Sterilize • Produce syngas, remove particles, gas to generate solids soluble substances electricity and/or • Separate out heat recyclables recyclables • Produce a ‘clean’ gas 37 - PYROLYSIS AND GASIFICATION Decision Maker’s Guides for Solid Waste Management Technologies Pyrolysis Gasification Incineration with energy recovery Air Supply Total absence of oxygen Low oxygen Significant oxygen Temperature Range 300-800 >750 >850 (°C) External heat source Required Required Not required Pre-treatment of Required (removal of glass, Required (removal of glass, Not required unless waste Feedstock metals, inerts) metals, inerts) has organic fraction to be dried Products Syngas, char, tar Syngas, char, ash Steam, gas, ash Outputs Syngas converted to liquid Syngas converted to liquid Heat, electricity fuel to produce electricity, fuel to produce electricity, heat, or use in a gas engine heat, or use in a gas engine or as a chemical feedstock or as a chemical feedstock Scale of application Range from small scale Range from small scale Generally large scale (30,000 tonnes/year) to large (30,000 tonnes/year) to large (73,000+ tonnes/year) scale (500,000 tonnes/year) scale (500,000 tonnes/year) Efficiency of energy 10-20% 10-20% 19-24% conversion to a steam boiler Table 1: Comparison of gasification, pyrolysis, and incineration WHAT TO THINK ABOUT WHEN PURSUING PYROLYSIS AND GASIFICATION Energy: ATT technologies require high amounts of energy for Siting: Locate ATT facilities in areas that are planned for operations due to the need for external heating and to clean industrial activities or near recycling stations and landfills to the syngas. If the gasification process uses pure oxygen, as transport the residual wastes. The electricity and/or heat opposed to air, more energy would be required. In plasma generated can be used by neighboring industrial plants, arc gasification, the process is viewed more as a waste thus reducing the cost to both parties. Residential areas are disposal option rather than as a fuel source option, because generally avoided but if appropriate, communities should be a considerable amount of the energy generated from the involved in the decision-making process to avoid opposition. process is consumed to operate the plasma torches. Enclosed facility: Dust and odor are possible issues and can Feedstock: The feedstock can be heterogeneous, but both the be controlled within an enclosed building. Waste facilities are amount of energy required to run the facility and the amount generally designed to operate under negative pressure, which generated would depend on 1) the moisture of the waste (if too minimizes the dust and odor that leaves the building. high, waste would need to be dried in advance), 2) the reactor Residual waste disposal: If the waste is sorted to remove temperature (higher temperature requires more energy), and recyclables at the ATT facility, the recyclables could be sent for 3) quantity of air introduced. Upstream separation of waste is further processing. Residual waste should be sent to a landfill recommended to secure a constant waste composition. for final disposal. An integrated plan should be established Controlled facility: The facility needs to contain the syngas during the design phase. because the gas itself is toxic and explosive. Syngas is also costly to clean and prepare for use as an energy source. Air pollution control: An air pollution control system is essential to monitor and prevent harmful emissions from entering the air. Flexible capacity: Generally, the ATT technology plants are modular and made up of small units that can be added or removed as waste generation changes, making them more flexible than incineration facilities. They can also be operational in the span of a few months. 38 - PYROLYSIS AND GASIFICATION Decision Maker’s Guides for Solid Waste Management Technologies HOW MUCH WILL PYROLYSIS AND GASIFICATION THINK YOUR PYROLYSIS OR GASIFICATION FACILITY COST? IS TOO EXPENSIVE? CONSIDER… Capital costs for ATT technologies range between $15-80 Think in total system terms: The ATT technologies reduce million for facilities that receive 25-100 kilo-tonnes per an- the volume of the waste, elongating your landfill life and often num of MSW. Cost estimates are difficult given the limited creating a new revenue source for your program. The aver- number of full-scale operations. Cost data should be treated age lifespan of ATT facilities is approximately 30 years. with a high degree of caution as prices may vary dramatically Sale of electricity and/or heat generated: The electricity among technology vendors and may not be fully inclusive. and/or heat generated that is not used in running the facility Costs for pyrolysis and gasification average at $699/tonne itself could be sold to nearby industries or to the electric grid for capital expenditures and $6.6 million for annual opera- or district heating system. tions and maintenance expenses. These costs assume an Tipping fees: Facilities can be paid a fee per tonne of waste average electricity generation of 8MW. accepted from waste haulers/municipalities. Fees are typical- Air pollution control costs are generally lower for ATT tech- ly considered to be the main source of revenue for ATT tech- nologies than incineration due to the lower volume of air and nology facilities. Larger facilities would have slightly lower energy required for the process. tipping fees due to small economies of scale. Sale of recyclables: Facilities that segregate recyclables can Capital Costs earn revenues from the sale of metals, plastic, and other re- • Land acquisition • Approvals and cyclables • Design and construction licensing Renewable energy credits: Governments may provide in- of the facility and related • Machinery and centives in the form of tax credits, preferential pricing, dis- systems equipment counts, or other benefits to encourage electricity from renew- • Environmental and social • Training and monitoring able sources impact assessments equipment Carbon finance: ATT could be a possible candidate for car- bon finance, where “credits” from the reduction of emissions Operating costs can vary from $3-3.7 million (roughly $35/ of greenhouse gases can be sold to offset the costs of the tonne) for a 100,000 tonne/year facility. These generally have facility. a lower impact on the overall costs of the facility as compared to capital costs and are mainly a function of the amount of Private sector partnership: A way to overcome the lack of waste processed. capacity to operate and finance could be to work with the private sector under a public-private partnership. A de- sign-build-operate model could be considered with the cave- Operating Costs at that there is a higher financial risk to the municipality and • Repair and maintenance • Sorting/pre-processing less for the developer. • Labor (salaries, • Taxes insurance) • Facility operations • Insurance for the facility CLIMATE BENEFITS OF ADVANCED THERMAL TREATMENT TECHNOLOGIES: • ATT avoids the generation of methane by diverting waste from landfills • Char benefits soil fertility and long-term carbon sequestration • Compared to landfilling, gasification reduces CO2- eq emissions by 0.3-0.6 tonnes per tonne of MSW; the reduction for pyrolysis is 0.15-0.25 tonnes CO2- eq per tonne of MSW (WMW 2012) 39 - PYROLYSIS AND GASIFICATION Decision Maker’s Guides for Solid Waste Management Technologies WHERE ARE PYROLYSIS AND GASIFICATION BEING USED AND WHAT HAVE WE LEARNED? Given the relative newness of applying these technologies for renewable fuels (with a willingness to pay higher prices). to MSW treatment, the need for advanced technical knowl- The stringent environmental regulations have encouraged edge, and the expense required, there are only a handful improvements in air pollution control technology to such an of full-scale operations in Europe and Japan. Most facilities extent that emissions into the atmosphere are significantly were constructed in the late 1990’s or early 2000’s. A num- lower than emission standards, thus gaining public accep- ber of these facilities handle relatively homogeneous and dry tance for these technologies. These are in combination with waste, thus more research is required on whether pyrolysis high recyclable content with high caloric value, strong local and gasification would be suited for all kinds of MSW. technical capacity, and the ability to fund significant capital Europe, in particular, provides a number of enabling condi- investments and operations and maintenance costs. Finally, tions through government regulations and public support the lack of space for landfills provides motivation to advance that encourage the development of ATT technologies. There technologies that reduce the amount of final waste that are regulations that support the generation of electricity and needs to be disposed. heat from renewable energy sources as well as a market MAYOR’S CORNER: QUESTIONS TO ASK YOUR SOLID WASTE MANAGER OR VENDOR WHO WANT TO OPERATE THE PYROLYSIS OR GASIFICATION FACILITY 1. Is the technology appropriate given the local waste composition and quantity generated? What systems are in place to ensure the quality as well as guaranteed supply of the feedstock? 2. Does the municipality have prior experience in undertaking complex technical and financial projects with sufficient technical knowledge? 3. Is sustainable financing possible? What cost recovery mechanisms will be put in place? Is there a market for the end products? 4. Is there preferential pricing for waste-derived electricity, or at least an easy mechanism by which to sell electricity to the electric grid or heat to neighboring industries? 5. Can land for the facility be readily obtained? What are the siting requirements for such a facility and have they been met? Have relevant site studies been conducted to make sure the facility will meet local and national regulations? 6. What are the local or national air pollution regulations applicable for ATTs? Does the vendor have proof of adhering to the local standards set by solid waste and air pollution regulations in past projects? 7. Does the technology provider already have an existing facility in operation, operating at a sim- ilar scale, with a similar feedstock? Can the vendor provide operational and performance data, including emissions and costs, for at least several months, if not longer, of continuous opera- tion? If syngas is to be used as an electricity source, does the vendor have the syngas already operating on an electricity production device (engine, turbine, etc.)? 8. How many local jobs will the facility create? 9. What training and maintenance will be provided over the life of the facility by the private devel- oper? How can local capacity be fostered over time? 10. Is there a local source of expertise to operate the likely imported ATT technology or a private firm that has the technical and operational capabilities? 40 - PYROLYSIS AND GASIFICATION Decision Maker’s Guides for Solid Waste Management Technologies References Arena, Umberto. 2012.“Process and Technological Aspects of Municipal Solid Waste Gasification. A Review.” Waste Management 32, no. 4 625–639. DOI: 10.1016/j.wasman.2011.09.025 California Integrated Waste Management Board. 2007. New and emerging conversion technologies: Report to the legislature. California: California Environmental Protection Agency. http://www.calrecycle.ca.gov/publications/Documents/Organics/44205016.pdf California Integrated Waste Management Board. 2013. Municipal Solid Waste Thermal Technologies. California: California Environmental Protection Agency. https://www.arb.ca.gov/cc/waste/msw_thermal.pdf Chester Mikhail, Richard Plevin, and Deepak Rajagopal. 2007. Biopower and waste conversion technologies for Santa Barbara County, California. Report for the Community Environmental Council. Chapter 5: Biopower and waste conversion technologies. Berkeley: University of California. https://www.researchgate.net/publication/242780848_Biopower_and_Waste_Conversion_Technologies_for_Santa_Barbara_County_California Fichtner Consulting. 2004. The Viability of Advanced Thermal Treatment of MSW in the UK. Environmental Services Training and Education Trust. London: ESTET. http://www.esauk.org/reports_press_releases/esa_reports/thermal_treatment_report.pdf Michelsen J. 2013. Senior Industry Specialist, International Finance Corporation. Personal communication. Mountouris, Antonious, Epaminondas Voutsas, and Dimitrios P. Tassios. 2008. “Plasma Gasification of Sewage Sludge: Process Development and Energy Optimization.” Energy Conversion and Management 49, no.8: 2264–2271. DOI:10.1016/j.enconman.2008.01.025 Ricardo-AEA. 2013. Waste to Energy Background Paper. Final Report for Zero Waste SA. http://www.zerowaste.sa.gov.au/upload/resource-centre/ publications/waste-to-energy/waste%20to%20energy%20background%20paper%20final.pdf UK Department for Environment Food & Rural Affairs.2013. Incineration of Municipal Solid Waste. Waste Technology Briefs. London: UK DEFRA. http://www.wtert.co.uk/content/Defra%20report.pdf UK Department for Environment Food & Rural Affairs. 2013. Advanced Thermal Treatment of Municipal Solid Waste. London: UK DEFRA https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/221035/pb13888-thermal-treatment-waste.pdf. 41 - PYROLYSIS AND GASIFICATION Previous knowledge papers in this series Lessons and Experiences from Mainstreaming HIV/AIDS into Urban/Water (AFTU1 & AFTU2) Projects Nina Schuler, Alicia Casalis, Sylvie Debomy, Christianna Johnnides, and Kate Kuper, September 2005, No. 1 Occupational and Environmental Health Issues of Solid Waste Management: Special Emphasis on Middle and Lower-Income Countries Sandra Cointreau, July 2006, No. 2 A Review of Urban Development Issues in Poverty Reduction Strategies Judy L. Baker and Iwona Reichardt, June 2007, No. 3 Urban Poverty in Ethiopia: A Multi-Faceted and Spatial Perspective Elisa Muzzini, January 2008, No. 4 Urban Poverty: A Global View Judy L. Baker, January 2008, No. 5 Preparing Surveys for Urban Upgrading Interventions: Prototype Survey Instrument and User Guide Ana Goicoechea, April 2008, No. 6 Exploring Urban Growth Management: Insights from Three Cities Mila Freire, Douglas Webster, and Christopher Rose, June 2008, No. 7 Private Sector Initiatives in Slum Upgrading Judy L. Baker and Kim McClain, May 2009, No. 8 The Urban Rehabilitation of the Medinas: The World Bank Experience in the Middle East and North Africa Anthony G. Bigio and Guido Licciardi, May 2010, No. 9 Cities and Climate Change: An Urgent Agenda Daniel Hoornweg, December 2010, No. 10 Memo to the Mayor: Improving Access to Urban Land for All Residents – Fulfilling the Promise Barbara Lipman, with Robin Rajack, June 2011, No. 11 Conserving the Past as a Foundation for the Future: China-World Bank Partnership on Cultural Heritage Conservation Katrinka Ebbe, Guido Licciardi and Axel Baeumler, September 2011, No. 12 Guidebook on Capital Investment Planning for Local Governments Olga Kaganova, October 2011, No. 13 Financing the Urban Expansion in Tanzania Zara Sarzin and Uri Raich, January 2012, No. 14 What a Waste: A Global Review of Solid Waste Management Daniel Hoornweg and Perinaz Bhada-Tata, March 2012, No. 15 Investment in Urban Heritage: Economic Impacts of Cultural Heritage Projects in FYR Macedonia and Georgia David Throsby, Macquarie University, Sydney, September 2012, No. 16 Building Sustainability in an Urbanizing World: A Partnership Report Daniel Hoornweg, Mila Freire, Julianne Baker-Gallegos and Artessa Saldivar- Sali, eds., July 2013, No. 17 Urban Agriculture: Findings from Four City Case Studies July 2013, No. 18 Climate-resilient, Climate-friendly World Heritage Cities Anthony Gad Bigio, Maria Catalina Ochoa, Rana Amirtahmasebi, June 2014, No. 19 Results-Based Financing for Municipal Solid Waste July 2014, No. 20 On the Engagement of Excluded Groups in Inclusive Cities: Highlighting Good Practices and Key Challenges in the Global South Diana Mitlin and David Satterthwaite, February 2016, No. 21 Results-Based Financing for Municipal Solid Waste Mona Serageldin, with Sheelah Gobar, Warren Hagist, and Maren Larsen, February 2016, No. 22 Financing Landfill Gas Projects in Developing Countries Claire Markgraf and Silpa Kaza, September 2016, No. 23 Sustainable Financing and Policy Models for Municipal Composting Silpa Kaza, Lisa Yao, and Andrea Stowell, September 2016, No. 24 KNOWLEDGE PAPERS For more information about the Urban Development Series, contact: Global Programs Unit Social, Urban, Rural & Resilience Global Practice World Bank 1818 H Street, NW Washington, DC 20433 USA Email: gpsurrkl@worldbank.org Website: http://www.worldbank.org/urban September 2018, No. 25