Technical Document on Municipal Solid Waste Organics Processing Technical Document on Municipal Solid Waste Organics Processing
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Technical Document on Municipal Solid Waste Organics Processing Technical Document on Municipal Solid Waste Organics Processing. Cat. No.: En14-83/2013E ISBN: 978-1-100-21707-9 Information contained in this publication or product may be reproduced, in part or in whole, and by any means, for personal or public non-commercial purposes, without charge or further permission, unless otherwise specified. You are asked to: Exercise due diligence in ensuring the accuracy of the materials reproduced; Indicate both the complete title of the materials reproduced, as well as the author organization; and Indicate that the reproduction is a copy of an official work that is published by the Government of Canada and that the reproduction has not been produced in affiliation with or with the endorsement of the Government of Canada. Commercial reproduction and distribution is prohibited except with written permission from the Government of Canada’s copyright administrator, Public Works and Government Services of Canada (PWGSC). For more information, please contact PWGSC at 613-996-6886 or at [email protected]. © Her Majesty the Queen in Right of Canada, represented by the Minister of the Environment, 2013 Aussi disponible en français sous le titre : Document technique sur la gestion des matières organiques municipales Preface Solid waste management is unquestionably an essential service that local governments provide their citizens. They have an important responsibility to make decisions regarding collection services, disposal infrastructure, waste diversion and recycling programs that are cost-effective and respond to their communities’ needs. Even in communities with long-established programs and infrastructure, the management of waste continues to evolve and require informed decisions that take into consideration a complex set of environmental, social, technological, and financial factors. Communities are considering options for processing organic waste and need more detailed, objective technical guidance and reliable information on the available processing technologies. In recent years, there has been increasing attention to managing the organic fraction of the municipal waste stream. Biodegradable material such as food waste constitutes approximately 40% of the residential waste stream, therefore diversion of organic materials is essential to reach high diversion targets. The environmental benefits of diverting organic materials from landfill include reduced methane emissions (a potent greenhouse gas), and decreased leachate quantities from landfills. From a life-cycle perspective, other benefits, such as the production of valuable compost and renewable energy, can also be derived from the diversion of organic materials from disposal depending on the processing method selected. While the science of processing leaf and yard waste at open windrow sites is well understood, and facilities are successfully operating at numerous sites across the country, the knowledge and experience of processing food waste in Canada is less well established. Opinions differ on the effectiveness of various technologies for the processing of organics. Canadian experience has been a mix of successes and setbacks. It is important that lessons learned be shared. Objective and reliable technical information is needed so that local governments choosing an approach to the processing of organics are doing so in a well-informed way that best meets their local needs. Optimization of resource allocation and the economic value of waste materials are important aspects of the sustainability of integrated waste management. This Technical Document on Municipal Solid Waste Organics Processing was developed to meet this need by providing science-based, objective and user-friendly information on the various aspects of organic waste management planning and operation for organics processing of different capacities and in different locations. The most applicable and relevant proven composting and anaerobic digestion treatment approaches for implementation in Canada and the considerations applicable to their implementation are also discussed. Treatment technologies still at the research level, that are not yet commercially available, or that have not fully demonstrated technical feasibility in the Canadian context are not covered in this Technical Document. i Preface As many municipalities across Canada are considering options for processing organic wastes, this document can be used as a resource by government officials and stakeholders as they engage with consulting firms and service and technology providers to discuss and assess potential options, prepare tender documents, and evaluate proposals. Users are encouraged to carefully read and interpret the information based on their specific local conditions and regulatory requirements. This document draws on lessons learned and expert knowledge of professionals, practitioners and academics in the field of organics management across North America. The extensive and varied experience of all contributors and reviewers is brought together in 18 comprehensive chapters describing the technical aspects and key considerations involved in processing organic wastes. The document covers a wide range of topics from the science and principles of composting and anaerobic digestion, to the description of proven processing technologies, biogas utilization, facility design, odor control, and compost quality, as well as other related issues such as procurement approaches and system selection. It is hoped that readers will benefit from this compendium of knowledge and lessons learned to support further efforts to reduce greenhouse gas emissions and optimize the value of municipal solid waste organics under an integrated waste management approach. ii Contents Preface . i Acknowledgements . ix Acronyms and Abbreviations . x 1 . Introduction to Municipal Solid Waste Organics . 1-1 1.1 Composition of MSW Organics .............................................1-1 1.1.1 Food Waste .....................................................1-1 1.1.2 Leaf and Yard Waste ..............................................1-2 1.2 Estimating the Quantities of MSW Organics ...................................1-3 1.3 Common Issues and Challenges ............................................1-4 2. Benefits of Organic Waste Diversion . 2-1 2.1 Environmental Benefits ...................................................2-1 2.1.1 Greenhouse Gas Reduction .........................................2-1 2.1.2 Compost Products Uses ............................................2-2 2.2 Social Benefits ..........................................................2-3 2.3 Economic Benefits .......................................................2-4 3 . Science and Principles of Aerobic Processing (Composting) . 3-1 3.1 Steps of the Composting Process ...........................................3-1 3.2 Compost Microbiology ....................................................3-5 3.2.1 Bacteria ........................................................3-6 3.2.2 Fungi ...........................................................3-6 3.2.3 Actinomycetes ...................................................3-6 3.3 Key Process Management Parameters .......................................3-7 3.3.1 Oxygen Concentration .............................................3-7 3.3.2 Free Air Space, and Particle Size and Structure ........................3-10 3.3.3 Carbon to Nitrogen Ratio .......................................... 3-11 3.3.4 Moisture Content ................................................3-12 3.3.5 Temperature ....................................................3-13 3.3.6 pH Level .......................................................3-15 iii Contents 4 . Science and Principles of Anaerobic Processing (Anaerobic digestion) . 4-1 4.1 Overview of the Anaerobic Digestion Process ..................................4-1 4.2 Typical Mass Balance. 4-5 4.3 Anaerobic Digestion Chemistry and Microbiology ...............................4-6 4.4 Key Process Management Parameters .......................................4-8 4.4.1 Moisture Content .................................................4-8 4.4.2 pH, Alkalinity, and Volatile Fatty Acids .................................4-9 4.4.3 Temperature .....................................................4-9 4.4.4 Solids Retention Time .............................................4-10 4.4.5 C:N Ratio and Ammonia Toxicity ....................................4-10 4.4.6 Sulphide Concentration ...........................................4-10 4.5 Digestate Characteristics, Quantities, and Processing .......................... 4-11 4.5.1 Digestate Characteristics and Processing ............................. 4-11 4.5.2 Digestate Quantities .............................................. 4-11 4.6 Biogas Characteristics and Quantities .......................................4-12 4.6.1 Biogas Characteristics ............................................4-12 4.6.2 Biogas Quantities ................................................4-13 4.6.3 Energy Potential of Biogas .........................................4-14 5 . Aerobic Processing Technologies . 5-1 5.1 General Feedstock Preparation Steps ........................................5-4 5.1.1 Particle Size Reduction ............................................5-4 5.1.2 Mixing and Blending ...............................................5-4 5.1.3 Ferrous Metal Removal ............................................5-4 5.1.4