Organic Waste Management for EBI in Quebec, Feedstock Analysis by Olivier Sylvestre Bachelor's Degree in Civil Engineering Universit6 de Sherbrooke, 2012 Submitted to the Department of Civil and Environmental Engineering Partial Fulfillment of the Requirements for the Degree of Master of Engineering in Civil and Environmental Engineering at the Massachusetts Institute of Technology NSTTE NSASUETTW ' June 2014 3BRARIES C2014 Olivier Sylvestre. All Rights Reserved. The author hereby grants to MIT permission to reproduce and distribute publicly paper and electronic copies of this thesis document in whole or in part in any medium now known or hereafter created. Signature of Author: Signature redacted Department of Civil and EnvironA1al Engineering May 9, 2014 Certified by: Signature redacted E. Eric Adams Senior Lecturer and Senior Research Engineer of Civil and Environmental Engineering Tbesis Supervisor Accepted by: Signature redacted Heidi M. kNepf Chair, Departmental Committee for Graduate Students Organic Waste Management for EBI in Quebec, Feedstock Analysis by Olivier Sylvestre Submitted to the Department of Civil and Environmental Engineering on May 9, 2014 in Partial Fulfillment of the Requirements for the Degree of Master of Engineering in Civil and Environmental Engineering at the Massachusetts Institute of Technology ABSTRACT EBI is a company located in the province of Quebec in Canada with the mission to integrate waste management. Great challenges in regards to organic waste management are faced and anaerobic digestion is considered by EBI as an innovative alternative to landfilling. The selection of the feedstock is a key success factor for an anaerobic digestion project. Based on an extended literature review, an investigation of organic waste available to EBI and a multi-criteria analysis, it is recommended to use a mix of food waste, dewatered septic systems sludge, poultry manure, wasted activated sludge, grease trap waste and liquid yeast as input for the anaerobic digester. Thesis Supervisor: E. Eric Adams Title: Senior Lecturer and Senior Research Engineer of Civil and Environmental Engineering EXECUTIVE SUMMARY The objective of this thesis is to recommend to the company EBI the optimal feedstock selection for anaerobic digestion. Initially, the company wants to invest less than one million dollars in a small-scale project which translates into an approximate capacity ranging between 1,000 and 2,000 tons per year. If it is successful, a large anaerobic digestion project may be envisioned as a subsequent step for EBI. Recommendations to EBI Table 1: Parameters Calculated for the Small-Scale Optimal Mix (Mix 14) Dry Matter (%) (%) Methane Production (x10 3 m3 in CH 4 /MT) C ya) CH4/year) Fee Quantity (MT/year) C/N Ratio (/N) pH 1,000 200 18 7.5 10 29.4-47.8 29.4-47.8 60,000 14 6.9 38 127.6 25.5 3,000 100 100 74 5.5 19 53.7 5.4 10,000 9 7.0 5 15.0 1.5 5,100 50 10-39 5.0 15 Liquid Yeast 50 4 5.7 18 63.2-77.9 97.2-145.8 3.2-3.9 4.9-7.3 3,750 2,800 Total Mix 14 1,500 20-21 6.2 14 46.5-60.9 69.8-91.4 84,650 Mix Food Waste Dewatered Septic Systems Sludge Poultry Manure Wasted Activated Sludge Grease Trap Waste * * * * * ($/year) Laboratory testing is strongly suggested in order to properly characterize each type of feedstock evaluated. Also, laboratory scale anaerobic digestion may be used to reduce uncertainties. The organic waste needs to be inserted gradually during startup phase. Bacteria from another anaerobic digester can also be seeded to accelerate the process. The full organic loading rate of the digester is reached when bacterial activity is stable and methane concentration in biogas is high enough which may take numerous weeks. Close monitoring is required at all times and adjustments need to be performed with the shortest reaction time possible to maximize efficiency. Growing energy crops is currently not recommended due to EBI's desire to start anaerobic digestion with limited investments, the high availability of organic waste, technological and climatic limitations, and ethical concerns over land use. From the quantities of food waste received in 2013 by EBI and the amounts potentially available, it is possible to scale the optimal mix by a factor of about 12.5. Table 2 describes the quantities, characteristics, methane production and fees generated by the probable large-scale mix. 5 Table 2: Parameters Calculated for the Large-Scale Optimal Mix (Mix 14) Mix(Tar) Food Waste Poultry Manure Wasted Activated Sludge Dewatered Septic Systems Sludge Grease Trap Waste Liquid Yeast Total Scaled Mix 14 * Quantity (MT/year) C/N Ratio Dry Matter pH (%) Methane Production (x103 m 3 3 (M CH/MT) CH4/year) Fee ($/year) 12,500 1,250 18 74 7.5 5.5 10 19 29.4-47.8 53.7 367.5-597.2 67.1 750,000 125,000 ,200 9 7.0 5 15.0 18.0 61,200 1,100 14 7.0 38 127.6 140.4 16,500 500 10-39 5.0 15 63.2-77.9 31.6-39.0 37,500 100 4 5.7 18 97.2-145.8 9.7-14.6 5,600 16,650 21-22 6.2 12 38.1-52.6 634.3-876.2 995,800 When possible, long-term waste treatment agreements with clients are valuable to secure delivery of organic waste and reduce risks related to feedstock availability. Developing an expertise in anaerobic digestion may represent an interesting regional first mover advantage for the company. Also, as a responsible corporate citizen of the world, EBI has the duty to contribute to the efforts against climate change and anaerobic digestion appears to be an innovative organic waste management alternative to landfilling. 6 ACKNOWLEDGEMENTS The support of many people was necessary to make this project possible. Special thanks are addressed to Pierre Sylvestre, Gilles Denis, Luc Turcotte, Maxim Sylvestre, Yvon Lafortune, Yves Rousseau, Eric Girard, Mario Brunelle and Alain Brunelle from EBI for their tremendous collaboration. Chapter 1 of this thesis is coauthored with Alexandre Bouaziz and Jaclyn Wilson. Their theses cover related subjects which are the design of the anaerobic digester and life cycle assessments of organic waste management methods respectively. Dr. Eric Adams is a very helpful advisor whose assistance was highly appreciated throughout the project. Susan from the MIT Writing and Communication Center also deserves gratitude for her exceptional contribution. Finally, thanks to Alexandre, Jaclyn, family members, friends, classmates and everyone else who supported the realization of this thesis. PROFESSIONAL RESPONSIBILITY All the advice from professors, advisors, other experts and client's representatives are given for academic purposes and do not involve their professional responsibility. 7 TABLE OF CONTENTS Abstract........................................................................................................................................... 3 Executive Sum m ary ........................................................................................................................ 5 A cknow ledgem ents......................................................................................................................... 7 Professional Responsibility ....................................................................................................... 7 List of Equations........................................................................................................................... 10 List of Figures ............................................................................................................................... 10 List of Tables ................................................................................................................................ 11 Abbreviations................................................................................................................................ 13 Chapter: 1 15 EBI and Organic Waste M anagem ent Options.................................................... 1.1 Introduction.................................................................................................................... 15 1.2 Inform ation on EBI ..................................................................................................... 16 1.3 Quebec's Specific Context.......................................................................................... 18 1.3.1 Environm ental Characteristics............................................................................. 18 1.3.2 Econom ic Characteristics ................................................................................... 18 1.3.3 Social Characteristics........................................................................................... 19 Organic W aste M anagem ent Options ........................................................................ 19 1.4 1.4.1 Landfilling .............................................................................................................. 19 1.4.2 A erobic D igestion (Com posting) ........................................................................ 21 1.4.3 A naerobic D igestion ............................................................................................ 25 1.5 Comparison of the Methods ........................................................................................ 30 1.6 A nalysis.......................................................................................................................... 31 1.6.1 U ncertainties ........................................................................................................ 31 1.6.2 Barriers to Success............................................................................................... 33 Recom m endations .......................................................................................................... 34 1.7 Chapter: 2 Feedstock Analysis ............................................................................................... 36 2.1 Introduction.................................................................................................................... 36 2.2 Objectives of EBI on Feedstock Selection.................................................................. 36 2.3 Literature Review ........................................................................................................... 37 2.3.1 Characteristics of Feedstock ............................................................................... 37 2.3.2 Origins of Feedstock............................................................................................. 40 2.3.3 Bacterial N eeds................................................................................................... 43 2.3.4 Feedstock Used in Anaerobic Digesters Worldwide .......................................... 46 8 2.4 Investigation................................................................................................................... 48 2.4.1 Procedure ................................................................................................................ 48 2.4.2 Organic Waste Currently M anaged by EBI........................................................ 48 2.4.3 Potential Feedstock ............................................................................................... 53 2.4.4 Com position of Organic W aste........................................................................... 55 2.5 Potential M ixes .............................................................................................................. 60 2.5.1 Total Capacity......................................................................................................... 60 2.5.2 Calculation of Param eters.................................................................................... 61 2.5.3 Form ation of the M ixes......................................................................................... 63 2.5.4 D escriptions of M ixes.......................................................................................... 64 M ulti-Criteria A nalysis (M CA ).................................................................................. 67 2.6.1 Before Treatm ent ................................................................................................. 68 2.6.2 During Treatm ent.................................................................................................. 76 2.6.3 Cumulative A nalysis............................................................................................. 84 Risk M anagem ent Analysis ........................................................................................ 89 2.6 2.7 2.7.1 Strategic Issues ................................................................................................... 89 2.7.2 Stakeholders............................................................................................................ 89 2.7.3 Tolerance Levels.................................................................................................. 90 2.7.4 Sources of Risk and their Criticality.................................................................... 92 Recom m endations...................................................................................................... 98 2.8.1 O n the Current Project ........................................................................................ 98 2.8.2 O n a G lobal Perspective ....................................................................................... 101 2.8 Bibliography ............................................................................................................................... 105 A ppendix A : Characteristics of som e Biogas Feedstock............................................................ 109 A ppendix B : Organic Waste M anaged by EBI in 2013.............................................................. 111 A ppendix C : O ther Potential Organic W aste.............................................................................. Appendix D: Partial Chemical Composition of some Types of Organic Waste ........................ 113 Appendix E: D etailed Description of the M ixes......................................................................... 115 Appendix F: Scores and V alues of the MCA ............................................................................. 119 9 114 LIST OF EQUATIONS Equation 1: Calculation of C/N Ratio of Multiple Substrates ................................................... Equation 2: Calculation of Dry Matter Fraction of Multiple Substrates ................................... Equation 3: Definition of the pH .............................................................................................. Equation 4: Calculation of H+ Ions Concentration of Multiple Substrates............................... Equation 5: Calculation of pH from H+ Ions Concentration of Multiple Substrates................. Equation 6: Conversion of Methane Yield per Volatile Dry Matter to Methane Production M ass .............................................................................................................................................. Equation 7: Calculation of Methane Production per Mass of Multiple Substrates ................... Equation 8: Calculation of Methane Production per Time of Multiple Substrates ................... 61 61 62 62 62 by 62 62 63 LIST OF FIGURES Figure 1: Schematic Diagram of the Existing Infrastructure at EBI.......................................... 17 Figure 2: Average Price of Electricity for Residential Customers in North American Cities ( /k Wh)......................................................................................................................................... 19 Figure 3: Diagram of Compost Pile Ventilation........................................................................... 22 Figure 4: Schematic Diagram of the Projected Anaerobic Digester and the Existing Infrastructure at E B I ............................................................................................................................................ 34 Figure 5: Potential Sources of Biogas Production in Germany (Total Energy Potential of 417 P J/Y ear) ........................................................................................................................................ 47 Figure 6: Feedstock Used in some Anaerobic Digesters in Japan............................................. 47 Figure 7: Pile of Food W aste ..................................................................................................... 50 Figure 8: Pretreated Leaves Stored Before Being Composted ................................................. 51 Figure 9: Effluents from Septic Systems Sludge Treatment Plant in 2012 ............................... 52 Figure 10: Initial Investment over Annual Capacity for Anaerobic Digestion Projects............ 60 Figure 11: Annual Quantities of Organic Waste in each Mix ................................................... 65 Figure 12: Total Value of the Mixes Based on the MCA.......................................................... 88 10 LIST OF TABLES Table 1: Parameters Calculated for the Small-Scale Optimal Mix (Mix 14) .............................. 5 Table 2: Parameters Calculated for the Large-Scale Optimal Mix (Mix 14) .............................. 6 Table 3: Food Waste Composting Facilities in the US............................................................. 25 Table 4: Anaerobic Digesters Processing Municipal Solid Waste in European Countries in 2006 28 ...................................................................................................................................................... Table 5: Quantified Aspects of Composting and Anaerobic Digestion.................................... 30 Table 6: Digestibility of Different Feedstock Compounds under Anaerobic Conditions ...... 39 Table 7: Concentrations of Minerals Potentially Inhibiting Bacteria in Anaerobic Digestion..... 40 41 Table 8: Methane Yield of Common Energy Crops ................................................................. 42 Table 9: Experimental Methane Yields of Algal Biomass ........................................................ Table 10: Description and Quantity of Microbial Groups in Anaerobic Digestion.................. 43 44 Table 11: Optimal Ratios of Organic Compounds in the Feedstock ........................................ 45 .............................................................. of Bacterial Cells Table 12: Theoretical Composition Table 13: Minimum Recommended Quantities of the Main Nutrients in Anaerobic Digestion.. 46 49 Table 14: Quantities of Organic Waste Managed by EBI in 2013 ............................................ Table 15: Quantities of Organic Waste Unsorted or Managed by Other Companies................ 53 57 Table 16: Composition of Organic W aste (1 of 2) ................................................................... 58 Table 17: Composition of Organic W aste (2 of 2) ................................................................... Table 18: Fee, Current Treatment, Current and Projected Transportation and Pretreatment Costs 59 of Organic W aste .......................................................................................................................... 66 Table 19: Param eters Calculated for the M ixes........................................................................ 67 Table 20: Score Scale of the M CA ............................................................................................ 67 Table 21: Abbreviations of the Types of Waste for the MCA.................................................. 68 .............................................................. of Fee Criterion on the Table 22: Score of the Mixes Table 23: Score of the Mixes on the Criterion of Diversion of Waste Specific to Treatment ..... 70 Table 24: Score of the Mixes on the Criterion of Diversion of Waste Specific to Transportation 71 ...................................................................................................................................................... Table 25: Average Score of the Mixes on the Criterion of Diversion of Waste........................ 72 73 Table 26: Score of the Mixes on the Criterion of Availability ................................................. 74 Table 27: Score of the Mixes on the Criterion of Odor............................................................. 75 Table 28: Score of the Mixes on the Criterion of Purity .......................................................... Table 29: Score of the Mixes on the Criterion of Suitability Specific to C/N Ratio................ 77 78 Table 30: Score of the Mixes on the Criterion of Suitability Specific to pH ............................ 79 Table 31: Average Score of the Mixes on the Criterion of Suitability...................................... 80 ...................... Basis on a Mass of Digestibility Table 32: Score of the Mixes on the Criterion Table 33: Score of the Mixes on the Criterion of Digestibility on a Time Basis ...................... 81 82 Table 34: Average Score of the Mixes on the Criterion of Digestibility.................................. 83 Table 35: Score of the Mixes on the Criterion of Inhibitors...................................................... 84 Table 36: Summary of the Criteria Before Treatment for the Mixes (1 of 2) .......................... 85 Table 37: Summary of the Criteria Before Treatment for the Mixes (2 of 2) .......................... 86 Table 38: Summary of the Criteria During Treatment for the Mixes........................................ 87 Table 39: W eight of the Criteria Used in the M CA.................................................................. Table 40: Tolerance Levels of the Stakeholders Related to the Strategic Issues ...................... 90 93 Table 41: Criticality of the Sources of Risk on the Strategic Issues......................................... 11 Table 42: Composition of the Optimal Feedstock Mixes.......................................................... Table 43: Evaluation of the Scalability of the Types of Waste in Mix 14 ................................. Table 44: Parameters Calculated for the Scaled Mix 14 ............................................................ 12 99 102 103 ABBREVIATIONS $: Cent $: Canadian Dollar BOD: Biochemical Oxygen Demand C/N Ratio: Carbon to Nitrogen Ratio CAD: Canadian Dollar COD: Chemical Oxygen Demand CSTR: Completely Mixed Tank Reactor DSSS: Dewatered Septic Systems Sludge FPOW: Food Processing Organic Waste FW: Food Waste GTW: Grease Trap Waste H+: Positively charged hydrogen kg: Kilogram km: Kilometer kWh: Kilowatt Hour L: Liter MCA: Multi-Criteria Analysis mg: Milligram MT: Metric Ton (1,000 kg) MW: Megawatt N: Nitrogen P: Phosphorus PJ: Petajoule (1015 Joules) PM: Poultry Manure QTY: Quantity RWFPI: Rinsing Water from Food Processing Industry Ton: Metric Ton (1,000 kg) US: United States USD: US Dollar VDM: Volatile Dry Matter VS: Volatile Solids WAS: Wasted Activated Sludge 13 14 Chapter: 1 1.1 EBI AND ORGANIC WASTE MANAGEMENT OPTIONS INTRODUCTION Covering almost 1.4 billion square kilometers,' Quebec is the largest province of Canada located in the eastern part of the country. Its land area is the equivalent of about seventy times the size of Massachusetts, 2 but the population is only over 8 million people.3 Quebec faces challenges similar to those of the rest of North America in terms of consumption lifestyle resulting in high production of waste per capita - 746 kilograms per capita and a total of 5.4 million tons of waste needed to be eliminated from the entire province in 2011.4 The provincial government is aware of the problem and has set up regulations to reduce the quantity of eliminated material. One of the objectives of the regulations is relatively ambitious: landfill of putrescible organic matter will be prohibited by 2020.5 However, as of 2012 only about 5% of the households have access to organic waste collection and very few services exist for institutional, commercial and industrial sectors.6 Two main solutions are envisioned to fulfill the future regulation: composting and anaerobic digestion. In Chapter 1, the company EBI is initially described with an evaluation of the environmental, economic and social constraints specific to Quebec. Then, the three organic waste management options competing in the province are covered which are landfilling, composting and anaerobic digestion. The overview includes a description of the processes, the factors of influence, a historic review and current facilities in operation. Based on the information provided, the organic waste management methods are compared and analyzed. The chapter concludes with recommendations on the optimal option. Chapter 2 emphasizes feedstock selection in anaerobic digestion. First, EBI's objectives specific to this aspect are detailed. Next, an extensive literature review is presented about the influence of the inputs on the treatment followed by an investigation of the organic material available to EBI for anaerobic digestion. Subsequently, Statistics Canada, 2012a World Atlas, "Population, World Atlas, United States." 3 "Population by Year, by Province and Territory." 4 Recyc-Qu~bec, Bilan 2010-2011 de la gestion des matibres r6siduelles au Qu6bec, 14-15. 5 Direction des matieres r6siduelles et des lieux contamin6s, Service des matieres r6siduelles, Banissement des matieres organiques de l'61imination au Qu6bec: 6tat des lieux et prospectives, VII. 6 Ibid., VIII-IX. 2 15 potential combinations of organic waste are compared and analyzed and a risk management analysis related to feedstock is performed. Finally, recommendations are formulated with regards to EBI's objectives. Note that Chapter 1 of this thesis is coauthored with Alexandre Bouaziz and Jaclyn Wilson. Their theses cover in greater detail the design of the anaerobic digester7 and life cycle assessments of organic waste management methods8 respectively. 1.2 INFORMATION ON EBI EBI is a family business founded in 1960 in Canada with the mission to integrate waste management. The company collects and transports all the waste of municipal, institutional, commercial and industrial sectors, sorts them and disposes of them in the best possible manner using efficient and up to date infrastructure. 7 Bouaziz, "Design of an Anaerobic Digester in Quebec, Canada." 8 Wilson, "Life Cycle Analysis of Waste Management Options for EBI in Quebec." 16 Waste iiiiiiiiiiililllll IP Biogas Purification Plant - -- BioSas LandfillOrgan Leachatei N t ra G s Eldetiudity Cogeneration Plant Wastewater f rat Treatment Plant Solid Waste Septic Systems Sludge Liquid Waste Treatment Plant Se ptic Systems Composst Sludge Wast+e Composting Platform + Limestone MFertilizer II Figure 1: Schematic Diagram of the Existing Infrastructure at EBI As illustrated in Figure 1, EBI's site contains many interconnected plants such as a landfill, a wastewater treatment plant, a composting platform, a biogas purification plant and more. Therefore, increasing capabilities to treat organic waste can enable the company to push integration of waste management further. In order for such a project to be interesting for the company, the investment and operating costs have to be as low as possible combined with the highest potential revenues. Deeper analysis is necessary to take the optimal decision in this complex scheme.9 9 Groupe EBI, 2010 17 1.3 QUEBEC'S SPECIFIC CONTEXT The province of Quebec has several particularities needing consideration in the evaluation of the management of organic waste. These elements are split in environmental, economic and social aspects and explained below. 1.3.1 Environmental Characteristics Quebec's territory is distinct; it is very large but most of the population lives in the South portion of it, mostly along the Saint-Lawrence River. The largest city is Montreal which has the territorial constraint of being located on an island. The entire metropolitan area counts over 3.5 million people.' 0 Quebec is a Northern region where the climate on most of the territory is cold, without dry season and a warm to cold summer.' 1 Temperature may vary from 30 C during summer to -30 C during winter. It is an important component to incorporate in the analysis of the management of organic waste. Just like in a refrigerator, the bacteria responsible for the transformation of matter stop working at cold temperatures. Heating has to be planned if a plant operating all year is desired. 1.3.2 Economic Characteristics The province has a unique economic landscape. In the 1960s, the provincial government decided to develop hydroelectricity in the northern part of the territory where many rivers flow and few people live. As a result, 96% of the electricity currently comes from hydropower which is a renewable energy. In addition, electricity produced in large hydropower plants has a significantly low cost making Quebec the place where electricity is the cheapest in North America.' 3 Moreover, electricity production, transmission and distribution are a monopoly owned by Hydro-Quebec which has the government of Quebec as its only shareholder. Figure 2 illustrates a comparison of the price of electricity in various cities in North America. 10 Population by Aboriginal group, by census metropolitan area (2006 Census", Statistics Canada, http://www.statcan.gc.ca/tables-tableaux/sum-som/101/cst01/demo64a-eng.htm, viewed on 10/20/2013. " Peel, Finlayson, and McMahon, "Updated World Map of the K6ppen-Geiger Climate Classification," 1636-1639. 12 "Electricity Generation", Hydro-Qudbec, http://www.hydroquebec.com/about-hydro-quebec/ourenergy/hydropower/pdf/presentation-generation-comments-june-2013-en.pdf, viewed on 10/30/2013, p. 11. 13 Hydro-Quebec, "Electricity Generation," 15. 18 Monthly billings for a typical consumption of 1,000 kWh (Rates in effect on Apnil 1,2012) 6.76 MONTREAL WINNIPEG 7A6 8.17 SEATTLE VANCOUVER .78 12.90 EDMONTON 13.14 OTTAWA 13.57 TORONTO 15.01 HAUFAX 1GAS BOSTON 22.26 SAN FRANCISCO 22.57 NEW YORK 0 S 15 10 20 25 Figure 2: Average Price of Electricity for Residential Customers in North American Cities 4 (0/kWh) Social Characteristics 1.3.3 As shown by the political decisions of the Quebec government, the population is getting more concerned about the environment. The province aspires to reduce its ecological impact on the planet and the proper management of organic waste is one way to reach this goal.' 5 However, its implementation has to be done with respect to people in order to make it successful. 1.4 ORGANIC WASTE MANAGEMENT OPTIONS 1.4.1 1.4.1.1 Landfilling Process Landfills can be used as the sole waste treatment option, or used in conjunction with other options as discussed later. It is the method commonly used in Quebec for organic waste disposal. Anaerobic processes, a result of the depletion of oxygen in pockets of the waste, are the primary form of waste degradation in landfills. Organic waste breaks down to release methane and carbon dioxide, while inorganic waste breaks down more variably. For instance, sulfate produces " "Electricity Generation", Hydro-Qu6bec, http://www.hydroquebec.com/about-hydro-quebec/our2 energy/hydropower/pdf/presentation-generation-comments-june- 013-en.pdf, viewed on 10/30/2013, p. 15. Ministbre du D&veloppement durable, Environnement et Parcs du Qu6bec. Banissement des matieres organiques de l'6limination au Qu6bec : 6tat des lieux et prospectives, 2012, Direction des matibres r6siduelles et des lieux contamin6s, Service des matieres r6siduelles, p. VII. 15 16 Harrison, 1995, p. 51. 19 a metal sulfide, which can then produce hydrogen sulfide under acidic conditions, a hazardous material. Liners, both natural and synthetic, are used in landfills to prevent the escape of hazardous materials.' 7 Leachate and landfill gas are two byproducts of concern. Leachate is collected via these liners and must be treated. Landfill gas, also known as biogas, is produced from the anaerobic processes and must be controlled to avoid health and environmental risks.' 8 Biogas has to be collected and burned or used for energy production. 1.4.1.2 Factors Influencing the Process The major factor influencing waste degradation in a landfill is the type of waste that is deposited in it. While the aerobic aspect is influenced by the amount of oxygen, the anaerobic processes are responsible for most of the degradation. Generally, the factors influencing a landfill are similar to those impacting anaerobic digestion, which is discussed in depth later. 1.4.1.3 Historic Review Though disposal via landfill has been the primary waste management method since humans' beginnings, formal landfills have come into play in the past two hundred years. " Until the 1970s, the concept of "dilute and attenuate" was used, allowing the leachate to be diluted by groundwater and attenuated as it travels down the layers of the landfill.20 Since this time, the objective is to focus on containment, in which leachate is collected and treated. Currently, landfills are designed to anticipate an eventual failure and implementing measures to limit the risk of releasing leachate in the environment. Additionally, landfills are increasingly designed to be with other types of waste management as well as being linked with energy recovery. 1.4.1.4 Current Operations Landfills are in operation worldwide, being the oldest and most common method of waste management. The United States (US) alone has over 2,000 landfills in operation, with waste to 17 Harrison, 1995, p. 57. Harrison, 1995, p. 60. 19 Harrison, 1995, p. 43. 18 20 Harrison, 1995, p. 45. 2 Harrison, 1995, p. 48. 20 landfills consisting of over 50% of the waste generated, at least from 2008 and before. 22 EBI has four main cells of landfills on its land. BFI Canada has been in operation in Quebec as well for the past 25 years. Their landfills operate with energy recovery, much like EBI. Many other companies manage landfills all around Quebec. 1.4.2 1.4.2.1 Aerobic Digestion (Composting) Biological Process The process of composting is characterized by the degradation of organic matter by a consortium of microorganisms with oxygen. Its main environmental advantage is to produce carbon dioxide instead of methane, which contributes less to global warming. Feedstock may come from any of the agricultural, residential, commercial, institutional or industrial sectors. According to Luc Turcotte, General Manager of EBI Energie, maturation of the material takes up to six months. After that period, a material rich in nutrients like phosphorus, nitrogen and potassium is produced.2 4 It can be used in agriculture or gardening as a fertilizer. To ensure a proper content of several components like nutrients, trace elements and pathogens, the compost produced has to be analyzed. During the process, heavily contaminated wastewater is produced which has to be collected and treated before it is released in the environment. It may also be mixed with limestone to increase the typical low pH of the wastewater to facilitate its use as a fertilizer in agriculture. Considerable odor is also released when composting. Depending on the neighbors and the winds, measures to control odor may be necessary. 1.4.2.2 Factors Influencing the Process Aerobic digestion depends on numerous aspects, which mainly are the feedstock, temperature, pH, aeration and moisture content. 26 Feedstock, also called substrate, is fundamental to the digestion. Nutrient content and particle size dictate the process of aerobic digestion.27 A high 22 EPA, 2009 23 BFI Canada, n.d. Direction des matieres residuelles et des lieux contamin6s, Lignes directrices pour 1'encadrement des activit6s de compostage, 2. 25 Ibid., 3. 26 Diaz et al., Compost Science and Technology, 49-56. 24 27 Ibid., 49-50. 21 nutrient content with a high surface area fosters digestion by bacteria. Carbon, nitrogen, phosphorus and potassium are the principal elements processed by microorganisms.28 In addition, the ratio of organic carbon to nitrogen is important to calibrate because bacteria need specific quantities of both.2 9 Composting produces high quantities of heat. Temperature can increase up to 90'C in certain cases. Even if pathogens and viruses are mostly being eliminated at high temperature, very little digestion occurs above 70*C. The optimal temperature range for composting is between 30*C and 450C.O Some methods exist to monitor and control temperature in a composting process. Heat extracted can even be used in other infrastructures. The pH varies throughout digestion and is hard to control; nonetheless it remains an important factor. It tends to acidify at the beginning of the process because acid is produced and pH increases towards the end. The most efficient range is between 5.5 and 8.0, but in general bacteria prefer a neutral pH. 3 1 Prmmsre suctmn finishe moripW~ - 0aaea ftOdor Peiforated Porous base lifter plIe of cm lco os 9 Cordensale tap Figure 3: Diagram of Compost Pile Ventilation32 As initially mentioned, aerobic digestion is characterized by the presence of oxygen. Therefore, aeration needs to be provided to the system to prevent digestion from becoming anaerobic. Pile 28 Diaz et al., 2007, p. 50 29 Diaz et al., 2007, p. 51 30 Diaz et al., 2007, p. 53 3' Diaz et al., 2007, p. 54. 32 Clean Washington Center, "Will Composting Work for Us? A Decision Guide for Managers of Businesses, Institutions, Campuses, and Other Facilities." 22 turning is a direct but inefficient way to aerate; ventilation provides guaranteed results.3 3 A lot of research and development is done on this aspect to optimize systems; 34 a diagram of two different ventilation methods is illustrated on Figure 3. Ventilation can also provide temperature and moisture control. A positive correlation between temperature and oxygen demand exists.3 5 Balancing moisture content is crucial to the process. Indeed, microorganisms stop degrading organic matter under low humidity conditions. On the other hand, too high water content does not allow air to penetrate the substrate. 36 During transformation, it is possible to monitor moisture content and add water if needed. At the end of the degradation, humidity of the compost has to be lower, approximately at 30%, to make sure it is biologically stable. 37 1.4.2.3 Historic Review of Composting Prior to 1950, there was only a very basic understanding of the composting process, but no real large-scale practical application existed. 38 According to Golueke, Sir Albert Howard developed one of the first composting systems intended for hygiene purposes for sewage water in India in th 39 the early 20th century. During the 1950s and early 1960s, research investigated composting as a way to enhance the quality of soils and a pilot scale experiment was made at University of California. Research performed in Europe aimed more towards survival of pathogens and their potential impacts on health. During that period, high hopes existed that composting would be an economically viable waste management solution. However, poor implementation of the process brought results below expectations. 40 A significant increase in research on composting occurred in the 1970s.41 The process was well understood and further study was conducted on specific aspects. Still, its development was 33 Diaz et al., 2007, p. 55 34 Diaz et al., 2007, p. 54 36 37 Diaz et al., 2007, p. 55. Diaz et al., 2007, p. 56 Diaz et al., 2007, p. 57 Bertoldi, Golueke, 40 Golueke, 4' Bertoldi, 38 3 1996, p. 5 2009, p. 28 2009, p. 28 1996, p. 9 23 slowed by unfavorable economic returns. The 1980s saw three large-scale projects fail in the US mostly due to wrong location and incorrect design, which resulted in odor problems.4 2 1.4.2.4 Current Operating Composting Infrastructure Many composting infrastructures are in operation worldwide. The current section goes over EBI's facility before presenting a broad overview of the food waste composting plants in the US. Finally, specific facilities are described in Canada and the US. EBI currently operates a platform used to transform organic matter into compost. 4 3 Most of the inputs are leaves, grass, wood chips and several residues from food industries. Even though the facility is located in a low density area, odor is monitored and appropriate guidelines are usually met. However, the compost produced has a relatively poor quality due to the presence of nonorganic contaminants like plastic residues, which reduces its value. Another similar open-air composting facility is operated by the city of Guelph in Ontario, Canada where odor emissions became a problem.44 Due to complaints from neighbors, the plant had to stop receiving organic waste for a period of time and an odor management plan had to be developed before the plant was allowed to treat material again. 45 Table 3, retrieved from Levis et al. (2010), lists the food waste composting facilities in the different regions of the US. It is observed that very few large-scale treatment units exist and most food waste composting infrastructures use material originating from the industrial, commercial and institutional sectors. 46 Bertoldi, 1996, p. 10 43 D6p6t Rive-Nord, n.d. 44 City of Guelph, n.d. 42 45 46 Ibid. Levis et al., "Assessment of the State of Food Waste Treatment in the United States and Canada," 1488. 24 Table 3: Food Waste Composting Facilities in the US47 Region Total Capacity > 5,000 > 50,000 MT/year MT/year Commercial or Municipal Composters Residential Waste Accepted New England 51 9 2 16 8 Northeast/Mid-Atlantic 48 6 3 15 3 Southeast 18 4 2 11 3 Upper Midwest 48 13 3 17 10 Mountain 36 6 5 27 13 West 72 19 9 45 34 273 57 24 131 71 Entire US A covered plant is located in Brampton in Ontario, Canada. It appears to be successfully operating with a 60,000 tons per year capacity. 48 Moving to a larger scale, Edmonton, Alberta has a plant treating municipal organic waste along with sewage sludge with a capacity of 200,000 and 25,000 tons per year respectively. 4 9 Also with an annual capacity of over 200,000 tons, a privately owned composting plant is located in Wilmington, Delaware. The treatment is partially indoor and covered during outdoor maturing. 1.4.3 1.4.3.1 Anaerobic Digestion Biological Process Anaerobic digestion is the degradation of organic matter by a consortium of bacteria in absence of oxygen. Like composting, this process can be used to transform organic matter from virtually any sector. The main difference from composting is that methane is produced during the reaction, which has a good energy potential. This process is slow because the microorganisms 5 need a large amount of energy in the form of heat and nutrients to degrade organic matter. ' 47 Ibid. BioCycle, n.d. City of Edmonton, n.d. 50 Environmental Protection, "Waste Management Adds Largest Composting Facility in the Eastern U.S. to Network of Organics Processing Facilities." 5' Tchobanoglous, Burton, & Stensel, p. 571-572. 48 4 25 Degradation can be divided in four main steps: hydrolysis, acidogenesis, acetogenesis and methanogenesis. 52 They are briefly explained below. In simple terms, hydrolysis is the degradation of large molecules into smaller compounds, hydrogen, and acetic acid. During the second step, the acidogenesis, the smaller molecules from hydrolysis are transformed into volatile fatty acids, hydrogen, and acetic acid.53 Next, the acetogenesis involves the complete transformation of volatile fatty acids into carbon dioxide, hydrogen, and acetic acid. Finally, hydrogen and acetic acid are both converted into methane during the methanogenesis. 1.4.3.2 Factors Influencing the Process The quantity and quality of biogas produced depends on numerous factors including concentration of microorganisms, type of feedstock, specific surface area of material, reactor type and its operation, light, pH and temperature.55 Bacteria responsible for degrading organic matter have a time of generation ranging from under twenty minutes to sixteen days.56 For this reason, feedstock has to stay long enough in the digester to give time for microorganisms to be generated and degrade organic matter. A way to increase concentration of bacteria is to recycle biomass in the reactor. The type of feedstock used is fundamental to degradation. Microorganisms need various nutrients to pursue an efficient transformation. Lack of an element can compromise the process. Some feedstock can produce intermediate products like fatty acids that inhibit reaction.: Also, the form of the input is important to the rate of the reaction; a higher surface area facilitates degradation.58 Three main types of reactors exist and impact the process which are batch reactor, completely mixed tank reactor (CSTR) or plug flow reactor. 59. They differ in the continuity of the system and 52 Cheng, 2010, p. 154 53 Cheng, 2010, p. 154 5 Cheng, 2010, p. 154 5 56 Deublein Deublein Deublein Deublein 57 58 59 & Steinhauser, 2011, pp. 112-127 & Steinhauser, 2011, p. 113 & Steinhauser, 2011, p. 114 & Steinhauser, 2011, p. 115 "The biogas handbook", Edited by Arthur Wellinger et al., Woodhead Publishing Limited, United States, 2013, p. 196. 26 its mixing which influences retention time. More details on reactor types is found in Alexandre Bouaziz's thesis. 60 Light acts as an inhibiter for microorganisms doing the transformation so it has to be avoided. 61 Furthermore, the optimal pH range for the degradation of organic matter is between 6.5 and 8.2.62 Temperature determines the types of bacteria generated. The general principle is that higher temperature has an increased transformation rate. Psychrophilic digestion is in the range of 1 00 C to 25'C and is known as a cheap, but inefficient process. 63 Moderate temperatures of about 30'C to 37 0 C characterize the mesophilic process. This type of system is an interesting balance between rate of performance, initial investment, ease of implementation and stability. 64 Thermophilic digestion typically happens between 50'C and 65'C. The advantages of this degradation are the high rate of reaction and the removal of most pathogens and viruses. However, it is more sensitive to temperature variations, hard to start and requires high initial and operational costs. 1.4.3.3 65 Historic Review of Anaerobic Digesters The first anaerobic digester intended to produce energy was built in France in 1860. The first digestion unit in the US was made in 1926. As the cheap price of fossil fuels limited interest in the technology, North America and Europe did little work towards the development of anaerobic digesters. Nonetheless, the oil-crisis in the US in the 1970s gave a second burst to research in anaerobic digestion, but it only lasted during the crisis. 66 Today, interest in organic waste digestion has increased due to the high price of fossil fuels and increasing environmental concerns. It is reported by Cheng that over 4,000 anaerobic digestion 60 61 Bouaziz, "Design of an Anaerobic Digester in Quebec, Canada." Deublein & Steinhauser, 2011, p. 123 62 Speece, Anaerobic Biotechnology for Industrial Wastewaters, 58. 63 Cheng, 2010, p. 157 64 Cheng, 2010, p. 158 65 Cheng, 2010, p. 161 66 Cheng, 2010, pp. 152-153 27 plants were in operation in Europe in 2005 producing the equivalent of 2.3 million tons of petroleum annually.6 7 1.4.3.4 Current Operating Anaerobic Digesters Numerous plants are operational around the globe. This section initially presents the municipal solid waste anaerobic digesters in Europe. Next, a few specific facilities in North America are described. Levis et al. draws some interesting some interesting conclusions regarding anaerobic digestion facilities processing municipal solid waste in European countries in 2006 presented in Table 4. Even if such a feedstock contains a significant fraction of non-digestible material, the high cost of energy in Europe and political incentives make this process economically sustainable. 68 Table 4: A naerobic Digesters Processing Municipal Solid Waste in European Countries in 200669 Country Germany Spain Switzerland France Netherlands Belgium Italy Austria Sweden Portugal United Kingdom Denmark Poland Total Number of Plants 55 23 13 6 5 5 5 4 3 3 2 2 1 127 Total Capacity (MT/year) 1,250,000 1,800,000 130,000 400,000 300,000 200,000 160,000 70,000 35,000 100,000 100,000 40,000 20,000 4,605,000 A facility with 35,000 tons per year capacity is located in Oakland, California reporting operating costs of about 40 to 55 US dollars (USD) per ton. 70 Biogas is used to produce electricity to fulfill the plant's needs and the surplus is sold to the local utilities. Water is partially removed from the digestate which is either used as a fertilizer in agriculture or as a daily 67 Cheng,2010, p.153 68 Levis et al., "Assessment of the State of Food Waste Treatment in the United States and Canada," 1487. 69 Ibid. 70 ILSR, 2010, pp. 5-6. 28 cover in a local landfill. 7' The city of Toronto, Ontario owns two anaerobic digestion plants, newly renovated in one case and newly constructed in the other.72 Their summed capacity is 110,000 tons annually and the city plans to expand to 180,000 tons per year.7 3 They treat municipal organic waste collected through a large municipal initiative.74 Based on an analysis from the city of Toronto, operational costs used to be 90 Canadian dollars (CAD) per ton but are estimated to decrease to 69 CAD per ton with the new plants.75 Very recently, a large-scale organic waste digester started to operate in London, Ontario. 76 It has an annual capacity of about 65,000 tons and an electricity production of approximately 2.8 MW. The project is economically viable, but strict constraints have to be met. According to Alex MacFarlane from Harvest Power, the company owning the digester, electricity has to be sold at over 0.13 CAD per kWh and the company has to charge over 45 CAD per ton to collect the feedstock. The same company operates a large composting facility in Richmond, British Columbia where the first commercial high-solids anaerobic digester was installed in parallel to a composting facility. The anaerobic digester can transform 30,000 tons per year.77 Indeed, a large range in the capacities of the existing plants is observed. The factors influencing this crucial design parameter are discussed in Section 1.6.1. The province of Quebec generated over 4.4 million tons of organic waste in 2010 with a valorized fraction estimated to 20%.78 The Government of Quebec recently granted subventions to many cities for the construction of anaerobic digestion infrastructure; some of them are combined with composting. The city of St-Hyacinthe currently has the only anaerobic digester functioning in the province, but Rivibre-du-Loup, Quebec city, Rocher-Perc6, the Monteregie region, La Prairie, Beauharnois-Salaberry, and Rousillon all have projects on the drawing table.79 Moreover, the city of Montreal currently plans to have two indoor composting facilities and two 71 72 ILSR, 2010, p. 5 City of Toronto, n.d. 73 ILSR, 2010, p. 7 74 City of Toronto, n.d. ILSR, 2010, p. 8. 7 76 "Anaerobic Digest," 2013 Harvest Power, n.d. Recyc-Qu6bec, Bilan 2010-2011 de la gestion des mati&es r6siduelles au Qudbec, 8. 79 Gouvernement du Qudbec, "Programme de traitement des matieres organiques par biom6thanisation et compostage." 77 78 29 anaerobic digestion facilities located on its territory; three facilities are expected to be in operation by 2016 and the forth one is supposed to open in 2020.0 1.5 COMPARISON OF THE METHODS Once the organic waste treatments available to EBI are explained in light of the constraints that apply to Quebec, they can be compared in order to select the optimal option. Regarding landfilling, it is the cheapest and the most common option. However, the regulation prohibiting this landfilling of putrescible organic waste by 2020 in Quebec indicates to EBI that an alternative has to be sought. The two other realistic avenues are composting and anaerobic digestion. Table 5 is a brief summary of the main aspects involved in these organic waste treatments. Note that only indoor composting is considered. Table 5: Quantified Aspects of Composting and Anaerobic Digestion Aspects Investment Composting 450 CAD/MT" Anaerobic Digestion 300-900 CAD/MT12 Maturation Up to 6 months 15-60 days83 Operating cost ~% 80 CAD/MT8 4 45-70 CAD/MT 85 Low 86 High Output value It is important to note that the investment cost for composting solely comes from the facility in Edmonton and might not be representative of all composting plants. In the case of anaerobic digestion, a high variability is observed. In both methods, the investment needed is specific to every project and a realistic range of values is hard to provide. It is influenced by all the design factors explained previously. 80 Ville de Montreal, "Centres de traitement des matieres organiques." 81 Office of the City Auditor, Edmonton Composting Facility Review, Edmonton, 2003, p. 1. 82 Institute for Local Self-Reliance, Update on Anaerobic Digester Projects Using Food Wastes in North America, United States, 2010, Division of Sustainability City of Atlanta, Georgia, p. 8. 83 KHANAL, Samir Kumar. Anaerobic biotechnology for bioenergy production: principles and applications, WileyBlackwell, 2008, United States, p. 95. 84 CM Consulting, Measuring the benefits of composting source separated organics in the region of Niagara, Canada, 2007, The Region of Niagara, p. 2. 85 Institute for Local Self-Reliance, Update on Anaerobic Digester Projects Using Food Wastes in North America, United States, 2010, Division of Sustainability City of Atlanta, Georgia, p. 8. 86 Office of the City Auditor, Edmonton Composting Facility Review, Edmonton, 2003, 10-11. 30 There is a clear gap between maturation times for the two treatments. Anaerobic digestion is much faster. A composting plant needs a lot of storage to allow the material to mature during several months, which is costly. More details can be found on this aspect in Jaclyn Wilson's thesis. Again, operating costs are highly variable because they are specific to each project. The two methods are in the same order of magnitude and a clear difference cannot be established. The output value favors anaerobic digestion because of the methane production. Both methods produce fertilizer and heat which are valuable, but have limited applications. However, the methane produced by anaerobic digestion represents a remarkable asset with a wide range of possible uses. From the information summarized, there is no clear monetary advantage for either treatment process. However, maturation time and the value of the outputs of anaerobic digestion are superior to those of composting. 1.6 ANALYSIS The current analysis critiques the information previously covered by raising uncertainties observed and evaluating the barriers to success in the two methods. 1.6.1 Uncertainties The two different ways to treat organic matter rely on biological degradation done by different consortia of bacteria. They present numerous uncertainties which may substantially alter the economic viability of projects. In the two cases, feedstock has a major influence on the outputs. Although industrial food waste may be relatively constant over the course of a year, residential organic waste significantly changes from season to season which impacts the performance of the process. The quality of residential source-separated organic waste depends on the good will of people to sort properly their organic matter which is virtually impossible. Plastic bags or other non-organic contaminants are always found. Potential pretreatments are described in Chapter 2. Furthermore, anaerobic digestion's viability relies on the market price of energy from other sources which is barely predictable but has a direct impact on revenues. Competing against 31 natural gas is not simple because prices in North America are extremely low due to the extraction of shale gas in the US. If this trend continues, it can possibly reduce the interest in methane. On the economic side, the comparison presented before reflects the great range of investment and operating costs which cannot be used to determine if a method is preferable. The economics are specific to each project and are barely comparable. For this reason, no monetary advantage is considered for any treatment. Another uncertainty is the political position which can imply influential decisions. The renewable aspect of the two methods is definitely a great asset, but if it is too costly, odor is emitted or trucking causes problems, strict measures may be enforced. On a plant size perspective, it is hard to determine if one large plant is preferable to many smaller ones. The first option certainly presents economies of scale during construction and operation, but the second alternative brings flexibility. Instead of building a large treatment unit that will be used at full capacity after a long period, building smaller plants over time has the capability to adapt to demand. Economies of scale have to be balanced against flexibility to identify which option is superior for a given project. On the biological side, it appears that digestion at large scale presents greater uncertainties related to the imperfections of the treatment. It is more complex to obtain a complete homogeneity of the substrate during the entire process. From a technical point of view, it is hard to compare quantities of wastewater and heat produced by the two studied treatments. The amount of leachate depends on the difference of water content in the substrate between the beginning and the end of the treatment plus any water added to facilitate degradation. It may be assumed that open-air composting plants involve more wastewater treatment because of storm water. However, it is unclear whether more leachate is produced in a covered composting plant or in an anaerobic digestion. The same difficulty applies to production of heat. These two factors may be highly variable and specific to each project. 32 1.6.2 Barriers to Success Currently in Quebec, the main barriers to success to treat organic matter are the lack of infrastructure to collect it and to treat it. In order to achieve the ambitious goal of not landfilling organic waste by 2020, the government has to greatly incentivize cities and private companies to collaborate in the management of organic waste. The high competition the outputs face is an additional challenge. The fertilizer produced is on the same market as chemical fertilizers which are more expensive but more efficient. In the case of biogas, it competes against fossil fuels which are cheap and abundant sources of energy. Finally, Quebec has cheap and renewable electricity available, but, the monopoly situation in the electricity sector can be an obstacle by blocking competition. The fact that companies are only allowed to sell electricity to Hydro-Quebec limits the economic potential of electricity production from biogas. 33 1.7 RECOMMENDATIONS It is recommended that EBI favors anaerobic digestion over composting under certain conditions explained below. saste SC r Gs fiogas Purification Pmn Wl B.. Heat Leachate Wastewater Treatment Plant Solid Waste Biogas Waste Liquid Septic Systems Sludge C +Lnestionen obitDgete andnEtExitin oenoetener Digam Figurei4: Sceai (pndected Digestate Treatment Plant Septic Systems Sludge COprg Cmo nrstutr C r 2. astc "at Organic W/aste Composting Platform _ + Limestone I,,Friie Figure 4: Schematic Diagram of the Projected Anaerobic Digester and the Existing Infrastructure at EBI Given all the different facilities already owned by the company, constructing an anaerobic digester can enable the company to push integration of waste management further as displayed in Figure 4. To ensure the viability of an anaerobic digester, the company needs a strong market evaluation of feedstock availability with great quality and quantity in the area of the plant. Moreover, the initial capital expenses have to be within EBI's capabilities. Some non-organic contaminants in the substrate can have a considerable impact on methane production which may involve pretreatment. This specific concern is addressed in Chapter 2. 34 Unless a lucrative contract with Hydro-Quebec to produce electricity is possible, biogas, purified into natural gas or not, may preferably be used as a fuel for vehicles because it competes against gasoline and diesel instead of natural gas. As mentioned previously, the price of natural gas dropped in the past years, but gasoline and diesel remain relatively expensive. Still, this option presents the challenge of setting up infrastructure to fuel vehicles and fostering the conversion of vehicles to natural gas. In the case of corporate customers, it is possible to reach a sufficient number of vehicles quite rapidly, but the operation becomes significantly complex if targeted to the public. The use of biogas has to be properly planned in order to gain the maximum benefits out of it. Anaerobic digestion is favored over composting mostly because of the methane production. This project can help the company to increase the amount of biogas to its biogas purification plant which may represent an interesting source of revenue for the company. Even if the system is initially harder to set up, it brings a competitive advantage to EBI in a society with growing energy needs. 35 Chapter: 2 2.1 FEEDSTOCK ANALYSIS INTRODUCTION An athlete is unable to perform to his full potential without the proper diet. Similarly, the microorganisms found in anaerobic digestion have to receive the best nutrition to give their optimal yield. The current chapter aims to determine the best combination of organic waste to serve as input for the organic waste digester. A wide range of potential substrates exist which is a key success factor for the project. Initially, the objectives of EBI regarding feedstock are covered. In this Chapter, background information includes technical aspects, bacterial needs and biomass types used worldwide in anaerobic digestion. Next, Section 2.4 describes an investigation of organic material currently received by EBI and potential additional quantities. Then, feedstock combinations are compared and analyzed with a Multi-Criteria Analysis (MCA). A risk management analysis specifically on feedstock follows. Finally, recommendations addressed to EBI can be found related to both short-term and long-term perspectives. 2.2 OBJECTIVES OF EBI ON FEEDSTOCK SELECTION As mentioned in Chapter 1, EBI has been in the waste management industry for numerous decades. An objective of the company is to have the capability to treat organic matter while efficiently using its existing infrastructure. As anaerobic digestion is a practice with substantial uncertainties when performed at large scale, EBI remains careful about this avenue and desires to invest a maximum of one million dollars for all the additional infrastructure required. By building a smaller treatment unit, it is possible for the company to obtain practical experience and test the concept before deciding to enlarge capacity. It is a way for EBI to take limited risks while attempting to stay innovative in waste management. Certainly, the feedstock selection has to comply with several constraints. In terms of operations, the supply of the chosen organic matter has to be reliable and constant through the course of a year to justify the investment and ensure stable digestion. Additionally, the nutritional needs of the consortium of bacteria have to be readily fulfilled to result in an optimal methane yield and a 36 fast digestion. Regarding the economical aspect specific to feedstock, a high methane yield brings greater income. Also, a fee is charged to clients to collect and treat their waste which needs to be included in the project income. Expenses come from transportation, storage and pretreatment requirements. The aspect of the environmental footprint of the feedstock is important. It may have a positive impact if diversion from landfilling to anaerobic digestion is accomplished or if a certain waste is transported a reduced distance. Furthermore, minimizing odor emissions is the main social objective for EBI. Failure to address this concern can decrease the acceptability of the project in the surrounding community. These factors frame the analysis and recommendations on the optimal feedstock for the anaerobic digester. Moreover, some assets on site may be used to grow energy crops for additional anaerobic digestion. Phosphorus and nitrate are found at the septic systems sludge treatment plant; carbon dioxide and heat are released from the cogeneration plant; water flows out of the wastewater treatment plant. All these elements can possibly be used to grow crops for anaerobic digestion. EBI is interested to explore this innovation. However, it represents additional expenses and growing biomass aimed to anaerobic digestion tends to increase the environmental footprint of the project; such elements are considered in the analysis. 2.3 LITERATURE REVIEW The literature review specific to feedstock goes over the characteristics and origins of organic material, the bacterial needs and the inputs used in anaerobic digesters currently operating around the world. 2.3.1 Characteristics of Feedstock Feedstocks can be defined based on their intrinsic and extrinsic characteristics. The most important are suitability, availability, digestibility, impurities and inhibitors. Each one is described in greater detail in the following paragraphs. Suitability includes numerous internal characteristics related to a given feedstock that define the anaerobic digestion potential. The pH, carbon to nitrogen (C/N) ratio, dry matter content and particle size are the main ones.87 Appendix A presents a large number of feedstock with their 87 Wellinger, Murphy, & Baxter, 2013, p. 34 37 approximated suitability. Optimal conditions are found when pH ranges from 6.5 to 8.2, but it may still be acceptable at 6.0. Yet, this criterion depends on alkalinity and volatile fatty acid production. Speece reports that it is not recommended to neutralize sludge prior to digestion; problems like high alkalinity during treatment may be caused leading to an excessively basic pH. Commonly, the ideal C/N ratio may range between 20/1 and 30/1. Still, it can be viable at a lower ratio of 15/1 .89 Regarding the dry matter content, the digestion is considered wet when the fraction is at 10% to 15% where the substrate mostly has the behavior of a liquid. Dry digestion processes have dry matter content between 20% and 40%; the organic waste is not really dry despite the nomenclature but more like a thick sludge with relatively low water content. 90 Moreover, feedstock below 15% dry matter can usually be pumped, facilitating operations. 9 1 Smaller particle size enhances digestion by increasing surface area and allowing more contact between bacteria and substrate; optimal size is under 40 mm.92 Availability is defined as the accessibility of the feedstock for a specific anaerobic digestion plant. It depends on the quantity at the source and transportation needed to bring it on site. Also, some feedstocks have a seasonal variation, which needs to be considered. The behavior of feedstock in anaerobic digestion is known as digestibility. 93 It is a core criterion for methane production and retention time. The composition of the feedstock directly influences digestibility and Table 6 summarizes the digestion time of different compounds. Lipids have the highest methane yield, but a relatively long digestion time. Proteins degrade faster, yet present a smaller methane yield.94 Note that combining feedstock, called codigestion, may produce a global methane production greater than the simple addition of the single inputs explained by "synergistic activity." 95 Moreover, digestibility of a substrate can be enhanced by pretreatment. A wide range of techniques exists based on physical, biological or chemical processes.96 For 88 Speece, Anaerobic Biotechnology for Industrial Wastewaters, 58. 89 Puyuelo et al., "Determining C/N Ratios for Typical Organic Wastes Using Biodegradable Fractions," 653. 90 La M~thanisation - Rend Moletta, 93. 91 Steven Thomas Sell, "A Scale-up Procedure for Substrate Co-Digestion in Anaerobic Digesters through the Use of Substrate Characterization, BMPs, ATAs, and Sub Pilot-Scale Digesters," 21. 92 La M6thanisation - Rend Moletta, 93. 9 Wellinger, Murphy, & Baxter, 2013, p. 34 94 Weiland, 2010, p. 852 95 Long et al., "Anaerobic Co-Digestion of Fat, Oil, and Grease (FOG)," 239. 96 Wellinger, Murphy, and Baxter, The Biogas Handbook, 2013, 4. 38 economic purposes, feedstock is typically selected with a high methane yield and low retention time. Table 6: Digestibility of Different Feedstock Compounds under Anaerobic Conditions"7 Compound Digestion Time Low molecular weight carbohydrates, volatile fatty acids, alcohols Proteins, hemicellulose, lipids Cellulose Hours Days Weeks Purity of feedstock is determined as the quantity of undesired material entering the anaerobic digester. Impurities can disturb the process by causing sedimentation, foaming, floating layers or damage to equipment. Granular material, straw, wood, glass and metal are the typical unwanted elements. They are either not digestible or very slowly digestible and need to be avoided in anaerobic digestion. Additional impurities can be pathogens or other microorganisms, in which case the feedstock is required to be pasteurized or sterilized before being digested.98 An inhibitor is a compound with a negative effect on bacterial activity, with the potential to break the balance of the digester or stop the biological activity. 99 Inhibition depends, among other things, on concentration and feedstock type.1 00 Table 7 lists concentrations of major compounds that may inhibit bacteria responsible for the treatment. The effect is however highly variable and barely predictable partly because microorganisms have the capability to adapt to certain adverse environmental conditions.'01 These elements need to be monitored closely and avoided in order to have constant anaerobic digestion. 97 Wellinger, Murphy, & Baxter, 2013, p. 35 98 Weiland, 2010, p. 852 Wellinger, Murphy, & Baxter, 2013, p. 35 10 Deublein & Steinhauser, 2011, p. 130 101 Deublein & Steinhauser, 2011, pp. 130-131 99 39 Table 7: Concentrations of Minerals Potentially Inhibiting Bacteria in Anaerobic DigestionO2 Compound Moderate Inhibition Ammonia Calcium Chromium (III) Chromium (VI) Copper Magnesium Nickel Potassium Sodium Sulfur Zinc 2.3.2 (mg/L) 1,500-3,000 High Inhibition (mg/L) 3,000 8,000 180-420 (total) 3.0 (soluble), 200-600 (total) 0.5 (soluble), 50-70 (total) 3,000 2.0 (soluble), 30 (total) 12,000 8,000 200 1.0 (soluble) 2,500-4,500 1,000-1,500 2,500-4,500 3,500-5,500 200 Origins of Feedstock Another useful categorization of feedstock is by its provenance being agricultural, industrial, commercial or municipal. 0 3 Each sector is explored from a broad perspective in the current section. Agriculture is known to provide the most important biogas generation potential and is composed of manure, residues, by-products or, most recently, energy crops.104 Important quantities of manure are produced by livestock and it represents a suitable feedstock for anaerobic digestion. 5 Nonetheless, solid manure has a low methane yield and impurities like straw are usually found so it is preferable to combine it with other feedstock in order to have an economically viable operation. Residues and by-products commonly present low digestibility with high content of cellulose requiring pretreatment and digestion with other organic material.10 6 Energy crops are plants grown specifically for anaerobic digestion. Currently, they are crops without wood because the lignin it contains is not suitable in anaerobic digestion. The Moletta, Le traitement des d6chets, 477. Wellinger, Murphy, & Baxter, 2013, p. 20 104 Wellinger, Murphy, & Baxter, 2013, p. 22 15 Wellinger, Murphy, & Baxter, 2013, p. 23 106 Wellinger, Murphy, & Baxter, 2013, p. 24 102 03 40 main types of energy crops are maize, grassy plants, cereals and vegetables.107 A range of methane yields is shown in Table 8. Table 8: Methane Yield of Common Energy Crops'08 Energy Crop Methane Yield (i 3 CH 4/MT VS) Fodder beet Leaves Ryegrass Hemp Barley Alfalfa Triticale Grass Clover grass Potatoes Straw Oilseed rape Sugar beet Maize (whole crop) Sunflower Nettle 420-500 417-453 390-410 355-409 353-658 340-500 337-555 298-467 290-390 275-400 242-324 240-340 236-381 205-450 154-400 120-420 Marine feedstock can also be included in energy crops. It is a fairly new domain with high potential where most of the activities are at the research level.10 9 Algae grows faster, which brings a greater land use efficiency compared to conventional crops." 0 Macroalgae and microalgae are the two different types of marine crops."' Hamani Abdou, in an academic project partly funded by EBI in 2012, found the results summarized in Table 9. When compared to the methane yields listed in Appendix A, macroalgae's methane yield is an order of magnitude below most of the values. Regarding microalgae, methane yield is comparable to most of the other types of feedstock. Additionally, some algae may be pretreated to enhance methane 107 108 09 110 " Wellinger, Murphy, & Baxter, 2013, p. 25 Wellinger, Murphy, & Baxter, 2013, p. 25 Wellinger, Murphy, & Baxter, 2013, p. 32 Wiley, Campbell, & McKuin, -2011, p. 326 33 Wellinger, Murphy, & Baxter, 2013, p. 41 production by increasing dry matter fraction, reducing particle dimensionn2 or diminishing inhibitory salt concentrations in the case of seawater biomass." 3 On the negative side, growing energy crops involves additional costs and reduces environmental benefits due to the use of fertilizers and energy to harvest.' 1 4 Table 9: Experimental Methane Yields of Algal Biomass' 15 Methane Yield 3 C /M V) Type of Algae(i (M CH4/MT VS) 44-70 Macroalgae Freshwater Microalgae 258-430 Seawater Microalgae 235-419 The industrial sector produces a wide variety of by-products in terms of suitability and digestibility. These residues come from food, pharmaceuticals, biochemical cosmetics and pulp and paper industries. Usually, they are characterized by a high purity and a low variability. Some industrial feedstock with a significant biogas yield can be used as boosters for anaerobic digestion. 116 Feedstock coming from the commercial and municipal sectors is either organic waste or sewage sludge. Organic waste is collected from shops and households, ideally sorted at the source to reduce as much as possible the quantity of impurities." 8 It must be over 99.9% pure in order to avoid disturbance of the process.'" 9 However, source-sorted organic waste is usually composed of approximately 10% contaminants. 20 Typically, the material originating from the commercial sector contains a reduced fraction of contaminants, but pretreatment is required in either case. If well sorted, this type of feedstock presents great environmental benefits by diverting waste from 12 Hamani Abdou, "Anaerobic Digestibility of Microalgae: Fate and Limitations of Long Chain Fatty Acids in the Biodegradation of Lipids," 17-18. "3 Ibid., 42. 114 Wellinger, Murphy, & Baxter, 2013, p. 26 115 Hamani Abdou, "Anaerobic Digestibility of Microalgae: Fate and Limitations of Long Chain Fatty Acids in the Biodegradation of Lipids," 39-48. 116 Wellinger, Murphy, & Baxter, 2013, p. 27 117 Wellinger, Murphy, & Baxter, 2013, pp. 30-32 118 Wellinger, Murphy, & Baxter, 2013, p. 30 119 Wellinger, Murphy, & Baxter, 2013, p. 31 12 Levis et al., "Assessment of the State of Food Waste Treatment in the United States and Canada," 1490. 42 landfills.12 ' Sewage sludge is a very common feedstock worldwide; nonetheless, some pollutants found in it cause limitations for the use of the digestate as a fertilizer.122 2.3.3 Bacterial Needs The nutritional needs of the bacteria are fundamental in the selection of the feedstock; satisfying their them is required to have the optimal yield. First, the types of bacteria present in anaerobic digestion are identified. Second, macronutrients and micronutrients are covered in greater details. Some differences in the classification between the two categories exist in the literature, but the objective is to understand the overall nutritional requirements. Additionally, as discussed previously, the pH, temperature, inhibitors and purity are key factors. The pH has to be ideally neutral, temperature is a design parameter and inhibitors have to be avoided. Further, the highest purity is desired, otherwise pretreatment may be needed. The bacteria responsible for the anaerobic digestion process can be divided into five groups. Table 10 shows the microbial groups as well as their roles and relative quantities. The concentrations come from an experiment on an activated sludge anaerobic digester and provide an order of magnitude of relative concentrations. Table 10: Description and Quantity of Microbial Groups in Anaerobic Digestion 12 3 Role Hydrolytic bacteria Degrade polymers to monomers Ferment monomers to organic acids and alcohols Produce acetate from other organic acids and alcohols Produce methane from acetate 4 x 10" 7 x 108 Produce methane from hydrogen and carbon dioxide 1 Acidogenic bacteria Acetogenic bacteria Acetotrophic methanogens Hydrogenotrophic methanogens 121 122 1 Cell Concentration (per mL) Microbial Group Wellinger, Murphy, & Baxter, 2013, p. 30 Wellinger, Murphy, & Baxter, 2013, p. 32 Wang, Environmental Biotechnology, 31-32. 43 2 x 10" 5 x 108 x 108 Gerardi mentions the two main macronutrients: nitrogen (N) and phosphorus (P). They have to be present and available in sufficient quantities to avoid limiting growth.124 In addition to these two elements, Wang et al. lists carbon, hydrogen, oxygen, potassium, sodium, magnesium and calcium. 125 According to Gerardi, it is possible to measure the amount of macronutrients in the feedstock entering the anaerobic digester or the residual amount of macronutrients in the digestate to target the adequate quantities required. Contrarily to the usual practice in environmental engineering, the chemical oxygen demand (COD) is used instead of the biochemical oxygen demand (BOD) to determine the quantity of organic compounds in the feedstock. As explained by Gerardi, BOD tends to underestimate the value because the test is done in aerobic conditions which are not representative of the environment in an anaerobic digester.126 COD should preferably be above 2,000 mg/L. 2 7 Table 11 summarizes optimal ratios of macronutrients for the feedstock. These numbers are empirical estimates and serve as a useful tool to choose the feedstock. Table 11: Optimal Ratios of Organic Compounds in the Feedstock Organic Compound Ratio COD/N/P 350-1000/7/1 128 C/N129 20-30/1 The ratios originate from the empirical formula of cellular material which is C2H70 2N. Table 12 lists the main organic compounds forming bacteria and their respective fraction. This record is another way to verify if the substrate is suitable for optimal anaerobic digestion.' 3 0 Gerardi, The Microbiology of Anaerobic Digesters, 93. Wang, Environmental Biotechnology, 39. 126 Gerardi, The Microbiology of Anaerobic Digesters, 93-94. 127 Wang, Environmental Biotechnology, 409. 128 Gerardi, The Microbiology of Anaerobic Digesters, 94. 129 Wellinger, Murphy, and Baxter, The Biogas Handbook, 2013, 34. 130 Gerardi, The Microbiology of Anaerobic Digesters, 94-95. 124 125 44 Table 12: Theoretical Composition of Bacterial Cells131 Element Approximate Percent Composition (% Dry Weight) Carbon Oxygen Nitrogen Hydrogen Phosphorus Sulfur Potassium Others 50 20 12 8 2 1 1 6 If the second method is used which is to measure residual quantities of nutrients, Gerardi recommends 5 mg/L of NH 4+-N and 1 to 2 mg/L of NP0 4 --P. If these values are respected, it means that nutrients are present in good quantities in the digester and do not limit.132 In the case that a growth constraint is observed due to a lack of nitrogen or phosphorus, ammonium chloride, aqueous ammonia and urea can be added for the first element; phosphate salts and phosphoric acid have the potential to counter phosphorus scarcity.133 However, such measures have a cost and are not optimal from an economic perspective. Even if micronutrients are only needed in lesser quantities, they remain essential in anaerobic digestion. Gerardi highlights cobalt, iron, nickel and sulfur as the most important micronutrients because they are required by the acetotrophic methanogens to produce methane from acetate.' 3 4 A more comprehensive but still incomplete list includes barium, copper, manganese, molybdenum, nickel, selenium, tungsten, vanadium and zinc."5 These elements are commonly present in several types feedstock, but a lack of micronutrients can threaten the operation of the anaerobic digester. Thus, laboratory testing is necessary to certify that the right nutrients are found. Gerardi states that the addition of 1.5 kg/M3 of yeast may provide the appropriate micronutrients, as it is rich in amino acids, minerals and vitamins.'36 " Ibid., 95. 132 Ibid., 94. 133 Wang, Environmental Biotechnology, 410; Gerardi, The Microbiology of Anaerobic Digesters, 94-96. 134 Gerardi, The Microbiology of Anaerobic Digesters, 96. "3 Ibid.; Wang, Environmental Biotechnology, 39. 136 Gerardi, The Microbiology of Anaerobic Digesters, 96. 45 Table 13 is a list of the most important nutrients and their minimum fraction of COD recommended. Table 13: Minimum Recommended Quantities of the Main Nutrients in Anaerobic Digestion Nutrient 37 Minimum Fraction Recommended (Mass Nutrient x 10-3/Mass COD Loading) Cobalt Iron Nickel Nitrogen Phosphorus Sulfur 0.1 2 0.01 30-40 5-10 2 The optimal feedstock may be determined by evaluating the requirements covered in the current section. Good knowledge of bacterial needs is drawn and may enhance the feedstock selection. 2.3.4 Feedstock Used in Anaerobic Digesters Worldwide Originally, animal manure as well as sewage sludge were the feedstocks used in anaerobic digestion. Waste from industrial and municipal sectors became inputs in this process in the 1970s. In the 1990s certain European countries like Germany started to grow energy crops.' 38 As of 2011, Deublin and Steinhauser report that 3% of the primary energy carriers originate from biomass in developed countries while it is estimated to be 38% in emerging countries.' 3 9 These numbers are not restricted to anaerobic digestion but express the variability of biomass management across the globe. Some regions are studied below with a specific interest on the origin of biomass. 137 Ibid. 138 Wellinger, Murphy, & Baxter, 2013, p. 20 139 Deublein & Steinhauser, 2011, p. 39 46 Energy crops___ 59% /- Manure 24% Harvesting residues 3%/ Landfill 2% Landscape ( Wastewater Municipal wastes 50/ 3% Industrial wastes 2% Figure 5: Potential Sources of Biogas Production in Germany (Total Energy Potential of 417 PJ/Year)140 Figure 5 illustrates the energy potential of biogas in Germany. This country is among the most advanced nations in organic waste management. As presented in Figure 4, the majority of the energy potential comes from energy crops followed by animal manure. Note that this chart represents the potential, which should not be confounded with the current practice. / Food-Processing Wastewater 22% _,Food Waste 2% Food-Processing Residues 10% Night Soil Sludge 5% Livestock Manure 4% Figure 6: Feedstock Used in some Anaerobic Digesters in Japan14 1 140 141 Weiland, 2010, p. 853 Zhang, Itakura, & Matsuto, 2012, p. 14 47 Figure 6 breaks down the feedstock used in anaerobic digesters in Japan from a study conducted by Zhang et al. (2012) on 42 plants. The chart is based on a total of 1.8 million tons per year processed. Contrary to the previous observations in Germany, sewage sludge and foodprocessing waste contribute to almost 90% of the feedstock of these plants in Japan. However, it is important to mention that only a fraction of the operating anaerobic digestion infrastructure is shown and it does not represent the full picture. The plants located in North America covered in the initial overview also present a great feedstock variety. The facility in Oakland, California treats food waste from the commercial sector.142 The two anaerobic digesters owned by the city of Toronto, Ontario operate with commercial and residential organic waste sorted at the source.143 The feedstock of the plant in London, Ontario is composed of food waste from restaurants, grocery stores and food processing plants.144 Finally, the anaerobic digester located in Richmond, BC treats high-solids municipal and industrial organic waste.145 This overview brings into perspective the wide range of possibilities in anaerobic digestion. Numerous nations transform all kinds of biomass into energy. The selection of feedstock depends on the regional economic, environmental and social factors. 2.4 2.4.1 INVESTIGATION Procedure The investigation has two major steps which are to describe the organic waste EBI already manages and determine potential organic waste. Finally, a full picture is drawn in terms of sustainability, availability, digestibility, impurities and inhibitors. This section is not intended to recommend any type of organic material. 2.4.2 Organic Waste Currently Managed by EBI As an integrated waste management company, EBI already receives a lot of organic waste from numerous origins. Table 14 is a comprehensive summary of rounded quantities of organic waste 142 ILSR, 2010, p. 5 43 ILSR, 2010, p. 7 "Anaerobic Digest," 2013, p. 18 145 Harvest Power, n.d. 144 48 received in 2013 with the type of organic waste, the source and the current treatment. The quantities of organic waste from industrial sources are rounded values. A detailed version is provided in Appendix B where the precise quantities, the client and location can also be found. In most of the cases, the collection of organic waste has a seasonal variation. A description of each type is in the paragraphs below. Table 14: Quantities of Organic Waste Managed by EBI in 2013 Type of Waste a. Food waste Lawn Clippings Leaves Whey Permeate Wasted Activated Sludge f. Dewatered Septic Systems Sludge g. Grease Trap Waste b. c. d. e. h. Food Processing Organic Waste i. Liquid Yeast Source of Waste 13,010 Residential Commercial Institutional Residential Residential Industrial Sewage Septic Systems Current Treatment None 8,400 4,270 2,500 1,180 Composting Composting Fertilizer Landfilling 1,100 Landfilling Commercial Industrial Industrial 500 Composting 250 Composting Industrial 100 Composting 31,310 TOTAL a. Quantity of Organic Waste (MT/year) Food Waste Food waste is collected from residential, commercial and institutional sectors. Figure 7 illustrates a pile of this organic material where, among others, fruits, vegetables, dairy products, cereals and meat compose the mix. During summer, people mix some lawn clippings in this waste while leaves are found during fall. Indeed, a large quantity of contaminants is observed, mainly plastic bags implying the need for pretreatment of this waste prior to anaerobic digestion. Currently, EBI only piles this organic material and is unable to compost it due to its low purity. 49 Figure 7: Pile of Food Waste" b. Lawn Clippings Lawn clippings are collected in even larger amounts during the late spring and summer. They are initially in large plastic bags mechanically removed leading to a relatively pure organic matter. Based on EBI's experience, lawn clippings have to be composted no later than a few days after reception because strong odor can be emitted. Additionally, heat in the pile may become so high that the organic material is burned and not compostable anymore. Contrarily to the leaves, it is not possible to store lawn clippings for these reasons. c. Leaves Large quantities of leaves are collected every year. Even if the collection is only during fall, this feedstock is easily stored outside and used all year to produce compost. Similarly to lawn clippings, they are received in large plastic bags which are mechanically removed to obtain a significantly pure result shown in Figure 8. 146 Photo from site visit on 1/30/2014. 50 Figure 8: Pretreated Leaves Stored Before Being Composted"' d. Whey Permeate Whey permeate is an industrial waste from dairy products. It is mostly liquid with approximately 7% dry matter and it is currently thickened with wood chips twice to be composted. This is a costly and ineffective process. Anaerobic digestion may be an enhanced treatment for this type of feedstock. Whey permeate is irregularly delivered in trucks with a capacity of 30 M 3 . The number of loads depend on the production but may vary from one to five per week. e. Wasted Activated Sludge 48 Activated sludge is composed of aerobic microorganisms and organic solids from wastewater.1 A fraction is wasted periodically by wastewater treatment plants in the regional area which is brought to EBI's landfill usually once a week. The wasted activated sludge is fairly constant over the course of a year. f. Dewatered Septic Systems Sludge EBI has a treatment plant receiving septic systems sludge with about 2% dry matter. After the treatment, the sludge has nearly 40% dry matter. The wastewater is sent to the wastewater treatment plant and the dewatered sludge goes to the landfill. The dewatering process costs about $10 per ton, but a fee of $15 per ton is received; pretreatment represents about two thirds of the fee received. Figure 9 illustrates the quantities of effluent in 2012. Indeed, this feedstock is seasonal with peaks in spring and fall and a substantial drop during winter. 47 Photo from site visit on 1/30/2014. 148 Tchobanoglous, Wastewater Engineering: Treatment and Reuse, 661. 51 Wastewater 6000 Dewatered Sludge 5000 4000 3000 2000 1000 0 Jan Feb March April May June July Aug Sept Oct Nov Dec Figure 9: Effluents from Septic Systems Sludge Treatment Plant in 201249 g. Grease Trap Waste Grease traps are devices preventing cooking residues from going to the sewage system. These residues can come from a large number of sources and their composition depends on their origin. As of now, EBI thickens the material with wood chips to compost it, similarly to the process used for whey permeate. This type of organic waste is collected all year. Mario Brunelle, General Manager at Leveill6 Fosses Septiques, a septic systems sludge collection company owned by EBI, claims that many restaurants currently discharge their grease trap waste in sewage systems. Still according to him, some regulations may be adopted in the near future to prevent this practice which may increase significantly the quantities available. h. Food Processing Organic Waste EBI receives organic waste from food processing industries which is currently composted with a process similar to that used with whey permeate. This material is variable; it can be an expired batch of jam or dressing for instance. Still, it has a high purity which is a good advantage. Small quantities are constantly received in barrels at EBI's transshipment center in Montreal and workers with a forklift handle and empty each one of them which is considered as an expensive 14 9 EBI 52 pretreatment. Finally, the organic waste is sent to the composting platform when there is a full truck load once or twice every month. i. Liquid Yeast Liquid yeast is an industrial waste originating from a food processing industry. Gerardi mentions that yeast can be added if a scarcity in micronutrients exists. The suggested minimum quantity to add is 1.5 kg/m3. 15 0 In EBI's situation, this feedstock is available and a fee is charged to the client to treat it. However, EBI's client desires to minimize the amount of this end-product discarded which results in highly intermittent deliveries. For instance, 37 m 3 of liquid yeast were received in January 2014 and the next supply may be in one to twelve months according to Eric Girard, Sales Manager from EBI. Potential Feedstock 2.4.3 This section relates to unsorted feedstock that EBI may already collect, to feedstock that is currently managed by other companies and to energy crops. 2.4.3.1 Organic Waste Unsorted or Managed by Other Companies EBI has other potential options for obtaining organic waste to use in anaerobic digestion which are summarized in Table 15. Detailed information is provided in Appendix C. Each type of feedstock is described below Table 15. Table 15: Quantities of Organic Waste Unsorted or Managed by Other Compani, Quantity of Type of Waste a. Poultry Manure No Industrial Initial Quantity (MT/year) 8,000 b. Rinsing Water No Industrial 2,500 100 2,500 from Food Processing Industry c. Food waste Yes Restaurants Grocery Stores 1,200 65 780 d. Straw No Agricultural Unknown 100 - Source of Waste Organic Waste (MT/year) 8,000 11,280 TOTAL 150 Estimated Organic Fraction (%) 100 Managed by EBI Gerardi, The Microbiology of Anaerobic Digesters, 96. 53 a. Poultry Manure Poultry manure from a major chicken slaughterhouse is another interesting feedstock EBI can potentially treat. The facility is located less than 10 km away from EBI's site. Years ago, their manure was sent in the sewage system, but the government decided to prohibit this practice. Currently, the chicken slaughterhouse transports its organic waste more than 200 km to an anaerobic digester in Ontario. Based on EBI's past experiences composting such a waste, odor emissions are very strong explaining the decision to stop treating it. In contrast to EBI's open-air composting platform, an anaerobic digester is a closed process where odor may be managed more easily. Nonetheless, it is a major concern needing consideration if this feedstock is recommended. b. Rinsing Water from Food Processing Industry Regarding the industrial sector, a food processing company presently transports its rinsing water to a regional farm. As EBI is in charge of other organic wastes produced by this company, it may be possible to receive this additional feedstock which represents significant quantities. Rinsing water from their facility is delivered two or three times per week in large containers. c. Food Waste The potential of food waste from the commercial sector is currently not completely captured. As shown in Section 2.4.2, some restaurants and grocery stores already sort their organic material. However, a great number of them still discharges all their waste to the landfill. Table 15 details the quantities received in 2013 from such stores. Recyc-Quebec, a governmental organization managing recycling in the province of Quebec, reported that about 65% of the waste originating from restaurants and grocery stores is organic material. 5 1 This fraction is used to estimate the quantities of organic waste these commercial clients may produce. d. Straw Straw may also be available locally. EBI's site is located in an agricultural area where straw is either left in the fields or used as a litter for livestock by farmers. The exact quantities EBI may receive are unknown, but this material may be found locally. 151 Taillefer, Les matibres organiques Fiches informatives, 5. 54 2.4.3.2 Energy Crops This section is an overview of the potential to grow energy crops for EBI. At first glance, it seems like the perfect ingredients to harvest crops intended for anaerobic digestion are found at EBI's site. The company uses just over 10% of the heat generated at the cogeneration plant and releases to the atmosphere all of the carbon dioxide produced by the generators, rejects approximately 1,000 cubic meters of treated leachate daily, generates large quantities of compost, and has plenty of area available surrounding the existing infrastructure. Slade mentions that over 50% cost reduction is possible when carbon dioxide, nutrients and water are cheaply available which reflects EBI's situation. However, some major improvements are necessary along most of the supply chain to obtain a reasonable cost, a positive energy balance and low environmental impacts in a large-scale digestion unit. 5 2 Another concern related to growing energy crops is the climate in Quebec. It is not possible to achieve the high efficiencies of equatorial zones due to cold weather and the short growing period. In addition to the technological and climatic limitations, energy crops raise justified ethical concerns over the role of farmers in society and use of arable lands. The constantly growing population represents a great pressure on food needs around the globe. The areas used to grow energy crops instead of food crops limit land availability and create a scarcity which drives prices up. Even if this practice is presently done at many places around the world, it may be considered immoral to divert crops from food to energy.1 2.4.4 Composition of Organic Waste The parameters of interest for each type of organic waste are presented in this section. Initially, the internal composition is shown and discussed. Next, external factors that may have an influence in the further analysis are illustrated. The usual procedure is to pursue the analysis of samples of each source of organic waste and determine the fraction of dry matter, the nutrient content, as well as their digestibility and purity. EBI, its clients, and potential clients provided the data they have which is incomplete and the other values are from the literature. This method is considered an acceptable estimate for an early stage project. Table 16 and Table 17 summarize the characterization of the organic waste 152 1 Slade and Bauen, "Micro-Algae Cultivation for Biofuels," 29. Wellinger, Murphy, and Baxter, The Biogas Handbook, 2013, 24-27. 55 previously described. Moreover, Appendix D illustrates other partial data on the chemical composition of some types of organic waste. Due to the lack of laboratory analysis, some values are unfortunately missing and no conclusion can be drawn on the presence of inhibitors. 56 29.4-47.8 63.2-77.9 54.0-99.0 226.8-243.0 A. I." 1"4 EBI; Carucci et al., "Anaerobic Digestion of Food Industry Wastes," 1039.; Wellinger, Murphy, and Baxter, The Biogas Handbook, 2013, 22. 155 EBI's Client; "PlanET Biogaz France."; Cornell Waste Management Institute, "App. A Characteristics of Raw Materials Table A. ." 156 Zhao and Ruan, "Biogas Performance from Co-Digestion of Taihu Algae and Kitchen Wastes," 22.; Alkanok, Demirel, and Onay, "Determination of Biogas Generation Potential as a Renewable Energy Source from Supermarket Wastes," 136-139. 157 Long et al., "Anaerobic Co-Digestion of Fat, Oil, and Grease (FOG)," 234.; Silvestre et al., "Biomass Adaptation over Anaerobic Co-Digestion of Sewage Sludge and Trapped Grease Waste," 6831. 158 Wellinger, Murphy, and Baxter, The Biogas Handbook, 2013, 22.; "PlanET Biogaz France."; Cornell Waste Management Institute, "App. A Characteristics of Raw Materials Table A. L." 159 Wellinger, Murphy, and Baxter, The Biogas Handbook, 2013, 21-25.; Cornell Waste Management Institute, "App. A Characteristics of Raw Materials Table Methane Production (m CH 4/MT) (M CH 4/MT VS) 469.8 900 400 3 127.6 54 18 15 7.4 52.2 32 420-450 90 90 98 73.5 90 84 300-550 60 20 15 10 58 38 Dry Matter(%) Volatile Solids (% of Dry Matter) Volatile Solids (%) Methane Yield 430-530 4.1-5.9 - 5.0 7.5 4.5 6.9 pH Organic Content 400-650 40-80 9-25 10-39 18 4-28 C/N Ratio (/N) 14 3,200 COD (mg/L) Carbohydrates, lipids - Carbohydrates, lipids - fats, oils and grease 15,000 Carbohydrates, proteins, lipids - Leaves159 Lawn5 8 Clippings Grease Trap s15 Parameter Food waste156 Waste Type of Waste Food Processing Organic 5 Waste15 Carbohydrates, proteins, lipids 24,700 Dewatered Septic Systems Sludge' 54 Table 16: Composition of Organic Waste (1 of 2) 00 53.7 CH 4/MT)__________________________ 128.3 900 95 14.3 15 4.5 23 114.0-463.6 150-610 95 76 80 4.4 48-150 15.0 400 75 3.75 5 7.0 9 - Activat1e6 Sludge Wasted Whey 14.9-24.3 _____ 330-540 64 5 7 4.5 5 75-80% lactose, 20-25% protein - Permeate'6 5 162 EBI's Client; "PlanET Biogaz France." 163 Wellinger, Murphy, and Baxter, The Biogas Handbook, 2013, 21-25.; "PlanET Biogaz France."; Borgstr6m, Pretreatment Technologies to Increase the Methane Yields by Anaerobic Digestion in Relation to Cost Efficiency of Substrate Transportation.Cornell Waste Management Institute, "App. A Characteristics of Raw Materials Table A. L." 164 Perron and H6bert, "Caract6risation des boues d'6puration municipales Partie I: Parambtres agronomiques," 50. 165 EBI's Client; Wellinger, Murphy, and Baxter, The Biogas Handbook, 2013, 21.; Ykema et al., "Optimization of Lipid Production in the Oleaginous Yeast Apiotrichum-Curvatum in Whey-Permeate," 213.; Mwangi, Gatebe, and Ndung'u, "Impact of Nutritional (C," 138. 161 EBI's Potential Client; Wellinger, Murphy, and Baxter, The Biogas Handbook, 2013, 21. 160 EBI's Client; "PlanET Biogaz France."; Anderson et al., "Pilot- and Full-Scale Anaerobic Digestion for the Food and Drink Industry," 286. (in 3 Methane Production 97.2-145.8 300 CH 4/MT VS) 600-900 3 94.7 17.9 90 16.2 (M 19 18 Dry Matter(%) Volatile Solids (% of Dry Matter) Volatile Solids (%) Methane Yield 5.5 5.7 pH 74 Carbohydrates, lipids - Carbohydrates, proteins, lipids - Carbohydrates, proteins, lipids 188,190 50% proteins, 10 % trehaloses 6,700 4 Straw Processing Industry162 Manure161 Yeast6" 163 from Food Poultry Rinsing Water Type of Waste Liquid C/N Ratio (/N) COD (mg/L) Organic Content Parameter Table 17: Composition of Organic Waste (2 of 2) In addition to the internal composition of each feedstock, other aspects need to be covered. Table 18 is a summary of the fee received by EBI to treat the waste, the current treatment, the current and projected transportation, as well as the cost of pretreatment. Indeed, all the fees but the one for poultry manure are the current values and may be adjusted with further economic analysis. Note that the fee for poultry manure is an estimate and needs to be negotiated with the company operating the facility if the project occurs. It is set to a high price because the current treatment involves large transportation costs; EBI has leverage to charge a good fee to receive this feedstock. The cost of food waste pretreatment is a discounted estimate from a feasibility study for the anaerobic digestion project in Toronto. 6 6 The other pretreatment costs are provided by EBI. Table 18: Fee, Current Treatment, Current and Projected Transportation and Pretreatment Costs of Organic Waste Transportation (km) Fee ($/MT) Current Treatment 15.00 Landfilling 95.00 Composting Lawn Clippings Leaves Liquid Yeast 60.00 75.00 60.00 60.00 56.00 None Composting Composting Composting Composting Poultry Manure 100.00 Anaerobic Digestion Fertilizer Type of Waste Dewatered Septic Systems Sludge Food Processing Organic Waste Food Waste Grease Trap Waste Rinsing Water from Food Processing Industry 95.00 Straw None Wasted Activated Sludge Whey Permeate 51.00 95.00 Litter for imals Landfilling Fertilizer Current Projected Regional Collection 80 Regional Regional Regional Regional 90 >200 100 80 Collection Collection Collection Collection 90 10 Pretreatment for Anaerobic Digestion ($/MT) 10 30 20 12 37 - 80 Local Collection - Regional Collection 80 70 - Allen Kani Associates with Enviros RIS Ltd., WDO Study: Implications of Different Waste Feed Streams (Source-Separated Organics and Mixed Waste) On Collection Options and Anaerobic Digestion Processing Facility Design, Equipment and Costs, 30-31. 166 59 2.5 POTENTIAL MIXES Once all the ingredients available or potentially available to EBI are known, recipes have to be assembled. Various mixes of feedstock are set in order to analyze them. The current section initially defines the total capacity the infrastructure may have in order to respect EBI's constraints. Next, the equations to calculate the parameters of the mixes are defined. Finally, the probable feedstock combinations are formed and described. They are compared with a multicriteria analysis (MCA) in Section 2.6. 2.5.1 Total Capacity The main constraint influencing the capacity of the anaerobic digester for EBI is the desire to invest a maximum amount of $1 million. 50 45 Z 40 0 C (P 25 E 20 a~ 15 C 10 5 0 0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 CapaCity (X 103 MT/year) Figure 10: Initial Investment over Annual Capacity for Anaerobic Digestion Projects 67 Figure 10 can be used to estimate the annual capacity of the plant. Unfortunately, the graph presents much larger values than the scale EBI desires and it is hard to read a value for an initial 167 Laforest, "Facteurs de rentabilite des projets de biomethanisation," 14. 60 investment of $1 million. However, by assuming that approximately a $5 million initial investment is necessary for about 3,000 annual tons and assuming a linear relation on that portion of the graph, an estimate of $1,667 per ton can be made. By contrast, capital costs reported by the Institute for Local Self-Reliance for different sites in Toronto, Canada show a range of $300 to $900 per ton 16 which is a large contrast with Laforest's value. From these assumptions, EBI's anaerobic digester can have an annual capacity between 600 tons and 3,300 tons. Based on the existing infrastructure of the company on one side and on the desire to remain conservative on the other side, an annual capacity between 1,000 and 2,000 tons is judged reasonable and may become more precise in further phases of the project. 2.5.2 Calculation of Parameters The parameters used to evaluate the options are C/N ratio, dry matter fraction, pH and methane production. This section covers the calculations done to obtain each value. These are estimates to compare the combinations. The C/N ratio and dry matter fraction of a specific mix is obtained with a weighted average of the parameters of each component as shown in Equation 1 and Equation 2. Equation 1: Calculation of C/N Ratio of Multiple Substrates C'N al = C/Ni x Massi T Massi Equation 2: Calculation of Dry Matter Fraction of Multiple Substrates Dry MatterTotal Dry Matteri x Massi Z Massi The calculation of pH cannot be done in the same way because it is the negative logarithm of a concentration as illustrated in Equation 3. Therefore, the H+ ion concentrations is calculated for each component of a given mix and a weighted average is calculated from the ion concentrations. Finally, the negative logarithm of the total concentration is calculated to obtain the pH of a feedstock combination. Equation 4 and Equation 5 summarize the steps to obtain this value. This may not be an exact calculation as pH depends on a large number of factors and chemical 168 "Update on Anaerobic Digester Projects Using Food Wastes in North America," 8. 61 reactions may occur when the substrates are mixed. Nonetheless, this method is considered as an acceptable estimate in the context of an early project evaluation. Equation 3: Definition of the pH' 69 pH = -log[H+] Equation 4: Calculation of H+ Ions Concentration of Multiple Substrates [H+]Total SE[H+]i x Mass. Mas - E Massi Equation 5: Calculation of pH from H+ Ions Concentration of Multiple Substrates pHTotaL = -log[H+ota Using Equation 6, the methane yield is converted to methane production using the volatile dry matter fraction (VDM). Then, Equation 7 is a weighted average done to obtain the methane production of a combination. Finally, the annual methane production is calculated by multiplying the production per mass by the mass per year as shown in Equation 8. Equation 6: Conversion of Methane Yield per Volatile Dry Matter to Methane Production by Mass CH4 Production (Volume Volume Mass VDM Mass) = CH 4 Yield (Mass VDM) x VDM Mass ( Equation 7: Calculation of Methane Production per Mass of Multiple Substrates (Volume CH 4 ProductionTotai .(Volume E CH 4 Productioni MVolm ass e x Massi = (Mass Massi 169 Mihelcic, Fundamentals of Environmental Engineering 1st (first) Edition by Mihelcic, James R. Published by Wiley, 86. 62 Equation 8: Calculation of Methane Production per Time of Multiple Substrates (Volumes CH 4 Productionrotai Time Time Volume~ L Mass1 CH 4 ProductionTotalIVu Mass X Time As mentioned before, codigestion, the simultaneous treatment of different types of organic waste, can improve digestibility. However, this effect is ignored in the calculations for several reasons. Such a phenomenon is more likely to be observed in laboratory experiments than in large scale digesters probably because parameters tend to differ from the ideal reactions in the latter case.170 Moreover, it is hard to theoretically quantify this effect due to the fact that all the mixes proposed are unique and no data exist regarding the combination of these precise types of waste. It is considered that ignoring the potential for enhanced digestibility represents a conservative assumption and may not significantly impact the ranking of the mixes. 2.5.3 Formation of the Mixes This process is iterative, but presented as a whole. The objective is to create and compare the potential optimal mixes. To facilitate operations and ensure the mixes can be pumped, dry matter fraction is kept below 15%.'1' Additionally, pH is held over 6.0 to provide a suitable environment for microorganisms.172 All the mixes include liquid yeast because it is a good source of micronutrients which may enhance digestion.173 The quantity in each mix is set to 50 tons, but the exact amount to add may be optimized with laboratory experiments and field experience. The number of possibilities being very large, a first iteration is done with thirteen mixes where the organic wastes below 15% dry matter are not combined. From the initial results, Mix 14 and Mix 15 are then created; they are variations of the optimal solution of the first attempt. These two mixes are incorporated to the analysis presented in Section 2.6. Some wastes were excluded from the mixes for different reasons. Lawn clippings are not considered due to their high seasonality and the storage difficulties encountered by EBI. Straw is set aside due to its high lignin content which reduces methane yield; no economically viable Long et al., "Anaerobic Co-Digestion of Fat, Oil, and Grease (FOG)," 239. Steven Thomas Sell, "A Scale-up Procedure for Substrate Co-Digestion in Anaerobic Digesters through the Use of Substrate Characterization, BMPs, ATAs, and Sub Pilot-Scale Digesters," 21. 172 Speece, Anaerobic Biotechnology for Industrial Wastewaters, 58. 173 Gerardi, The Microbiology of Anaerobic Digesters, 96. 170 171 63 pretreatment currently exists.1 74 Whey permeate is not considered because it is not possible, with the feedstock available, to produce a mix solely with this waste as the liquid input and to obtain a dry matter fraction under 15% combined with a pH over 6.0. This type of organic waste is excessively acid which compromises its use as the only liquid feedstock. Still, a small amount of whey permeate is added to Mix 15 to assess its potential. 2.5.4 Descriptions of Mixes Fifteen feedstock combinations are formed respecting the range of capacity and parameters defined previously. Figure 11 lists the mixes with the annual quantity of each component based on pure content. This implies that losses due to pretreatment already occurred. The six initial mixes use wasted activated sludge as the main component while food waste is the principal ingredient in Mix 7 to Mix 13 and Mix 14 and 15 are created after the first iteration. The combinations exhibit minor variations with dewatered septic systems sludge, food processing organic waste, grease trap waste, leaves, poultry manure, rinsing water from the food processing industry, wasted activated sludge and whey permeate. The specific quantities of each input can be found in Appendix E. Risberg et al., "Biogas Production from Wheat Straw and Manure - Impact of Pretreatment and Process Operating Parameters," 232-237. 174 64 1,600 1,550 1.500 1,510 1,400 400 - -1-ft 1,300 ,27 5 _ 1 )00 1 20 0 , 1 0 Leaves 1,300 1,270 7 ' 1,200 I 1,400 m Rinsing Water from Food Processing Industry O 1,100 i 075 1,100 11A75 1,000 Poultry Manure * Food Processing Organic Waste -- 800 -- - * Grease Trap Waste O Dewatered Septic 600 Systems Sludge E Wasted Activated Sludge 400 N Food Waste 200 N Liquid Yeast 0 1 2 3 4 5 6 7 8 9 Mix 10 11 12 Figure 11: Annual Quantities of Organic Waste in each Mix 65 13 14 15 The technical parameters of the mixes are summarized in Table 19. Detailed values can be found in Appendix E. Table 19: Parameters Calculated for the Mixes Mix 1. Wasted Activated Sludge and Rinsing Water from Food Processing Industry 2. Wasted Activated Sludge and Grease Trap Waste 3. Wasted Activated Sludge, Poultry Manure and Grease Trap Waste 4. Wasted Activated Sludge, Dewatered Septic Systems Sludge and Grease Trap Waste 5. Wasted Activated Sludge and Food Processing Organic Waste 6. Wasted Activated Sludge, Grease Trap Waste and Leaves 7. Food Waste and Grease Trap Waste 8. Food Waste and Rinsing Water from Food Processing Industry 9. Food Waste, Poultry Manure and Grease Trap Waste 10. Food Waste, Dewatered Septic Systems Sludge and Grease Trap Waste 11. Food Waste, Dewatered Septic Systems Sludge, Poultry Manure and Grease Trap Waste pH 9 6.1 6 9 6.3 14-15 3 (x10 m CH 4/MT) 3 CH 4/year) ($/year) 20.4-22.4 26.1-28.5 66,375 6 20.0-22.5 26.0-29.2 67,750 6.1 7 22.4-24.7 31.4-34.6 77,750 10-12 6.1 15 49.8-52.3 77.2-81.1 67,300 9 6.2 6 25.4-27.3 32.3-34.7 65,900 9-11 5.7-6.4 7 23.8-26.5 28.6-31.8 62,275 17-18 6.2 11 34.0-53.6 37.4-59.0 66,550 17 6.1 10 34.9-54.2 37.5-58.3 65,175 22-23 6.1 11 35.7-53.6 42.8-64.3 76,550 17-18 6.3 15 48.4-65.0 62.9-84.5 69,550 21-22 6.2 15 48.8-64.2 68.3-89.9 79,550 6.1 11 42.8-62.1 46.0-66.8 65,175 18-19 5.7-6.4 12 37.7-57.4 41.5-63.1 66,175 20-21 6.2 14 46.5-60.9 69.8-91.4 84,650 20-21 6.1 14 46.3-60.7 70.0-91.6 85,600 ProcessingaOrganic Waste17-18 13. Food Waste, Grease Trap Waste and Leaves 14. Food Waste, Dewatered Septic Systems Sludge, Poultry Manure, Wasted Activated Sludge and Grease Trap Waste 15. Food Waste, Dewatered Septic Systems Sludge, Poultry Manure, Wasted Activated Sludge, Grease Trap Waste and Whey Permeate (%) Fee Methane Production Dry Matter C/N Ratio (/N) 66 (mn 2.6 MULTI-CRITERIA ANALYSIS (MCA) Due to the large number of parameters and feedstock mixes to evaluate, a multi-criteria analysis (MCA) is necessary to justify recommendations. Eight criteria are assessed in order to target the optimal solutions: fee, diversion of waste, availability, odor, purity, suitability, digestibility and inhibitors. The first five criteria are classified before treatment, while suitability, digestibility and inhibitors are criteria considered during treatment. Each of them is explained in the following sections and a performance note is attributed to every mix. Table 20 defines the score scale used in the MCA. In the case it is not possible to obtain five different scores, the low end of the scale is used such as with odor. Such procedure intentionally reduces the mathematical importance of criteria with less variation. Additionally, it is essential to mention that the MCA is used as a way to contrast the best mixes with the other mixes. The aim is not to precisely target the single best mix, but to draw some general conclusions regarding a complex engineering problem. Table 20: Score Scale of the MCA Definition Excellent Very good Good Sufficient Low Score 5 4 3 2 1 Table 21 establishes the abbreviations used in the MCA to streamline the other tables. Table 21: Abbreviations of the Types of Waste for the MCA Type of Waste Dewatered Septic Systems Sludge Food Processing Organic Waste Food Waste Grease Trap Waste Leaves Poultry Manure Rinsing Water from Food Processing Industry Wasted Activated Sludge Whey Permeate 67 Abbreviation DSSS FPOW FW GTW Leaves PM RWFPI WAS WP 2.6.1 Before Treatment The criteria before treatment include all operations required prior to anaerobic digestion from transportation to storing to pretreatment. Additionally, the fee as well as the environmental performance of the mixes are measured. 2.6.1.1 Fee The fee is the amount of money EBI receives for each feedstock it manages. It is typically paid on a mass basis. Table 22 illustrates the total fee of all the ingredients for each mix. The two mixes providing the highest fees, 15 and 14 respectively, deserve a "very good" score. Mixes 11, 3 and 9 gamer slightly lower fees giving them a score of "good" while Mix 6 has the lowest fee giving it a score of "low". The rest of the combinations are too close to be objectively sorted so they all have a "sufficient" score. Table 22: Score of the Mixes on the Criterion of Fee Mix Fear) 15. Food Waste, Dewatered Septic Systems Sludge, Poultry Manure, Wasted Activated Sludge, Grease Trap Waste and Whey Permeate 14. Food Waste, Dewatered Septic Systems Sludge, Poultry Manure, Wasted Activated Sludge and Grease Trap Waste 11. Food Waste, Dewatered Septic Systems Sludge, Poultry Manure and Grease Trap Waste 3. Wasted Activated Sludge, Poultry Manure and Grease Trap Waste 9. Food Waste, Poultry Manure and Grease Trap Waste 10. Food Waste, Dewatered Septic Systems Sludge and Grease Trap Waste 2. Wasted Activated Sludge and Grease Trap Waste 4. Wasted Activated Sludge, Dewatered Septic Systems Sludge and Grease Trap Waste 7. Food Waste and Grease Trap Waste 1. Wasted Activated Sludge and Rinsing Water from Food Processing Industry 13. Food Waste, Grease Trap Waste and Leaves 5. Wasted Activated Sludge and Food Processing Organic Waste 8. Food Waste and Rinsing Water from Food Processing Industry 12. Food Waste and Food Processing Organic Waste 6. Wasted Activated Sludge, Grease Trap Waste and Leaves 68 Score 85,600 4 84,650 79,550 77,750 3 76,550 69,550 67,750 67,300 66,550 66,375 2 66,175 65,900 65,175 65,175 62,275 1 2.6.1.2 Diversion of Waste Diversion of waste considers two main elements: treatment and transportation. The idea is to evaluate the ingredients in each combination that are diverted from which treatment and the difference in transportation requirements; this analysis is done in three steps. Initially, the combinations obtain individual scores on treatment and transportation. Finally, the two scores are averaged leading to an overall objective ranking of the mixes for the criterion of diversion of waste. As mentioned previously, all the mixes contain liquid yeast, diverted from composting which is an equal factor in all cases. Table 23 shows the score attributed to the mixes for their treatment diversion. Mix 4 has the best performance because it contains 1,400 annual tons of waste currently landfilled, which is the largest quantity among the combinations. Mixes 1, 2, 3, 5 and 6 are scored as "good" due to their 1,100 tons to 1,200 tons per year diverted from landfilling. With much smaller quantities of material heading to the landfill and the potential to find a viable treatment for food waste, mixes 10, 11, 14 and 15 are considered as "sufficient". The rest of the mixes all contain food waste as well, but it is combined with waste presently composted or used as a fertilizer; hence a "low" performance score is given. 69 Table 23: Score of the Mixes on the Criterion of Diversion of Waste Specific to Treatment Mix 4. Wasted Activated Sludge, Dewatered Septic Systems Sludge and Grease Trap Waste Diversion from Landfilling (WAS/DSSS) and Composting (GTW) 1. Wasted Activated Sludge and Rinsing Water from Food Processing Industry 2. Wasted Activated Sludge and Grease Trap Waste Diversion from Landfilling (WAS) and Fertilizing (RWFPI) Diversion from Landfilling (WAS) and Composting (GTW) 3. Wasted Activated Sludge, Poultry Manure and Grease Trap Waste Diversion from Landfilling (WAS) and from Composting (GTW) 5. Wasted Activated Sludge and Food Processing Organic Waste Diversion from Landfilling (WAS) and Composting (FPOW) 6. Wasted Activated Sludge, Grease Trap Waste and Leaves Diversion from Landfilling (WAS) and Composting (GTW/Leaves) 14. Food Waste, Dewatered Septic Systems Sludge, Poultry Manure, Wasted Activated Sludge and Grease Trap Waste 15. Food Waste, Dewatered Septic Systems Sludge, Poultry Manure, Wasted Activated Sludge, Grease Trap Waste and Whey Permeate 10. Food Waste, Dewatered Septic Systems Sludge and Grease Trap Waste New Treatment (FW) and Diversion from Landfilling (DSSS/WAS) and Composting (GTW) New Treatment (FW) and Diversion from Landfilling (DSSS/WAS), Composting (GTW) and Fertilizing (WP) New Treatment (FW) and Diversion from Landfilling (DSSS) and Composting (GTW) New Treatment (FW) and Diversion from Landfilling (DSSS) and Composting (GTW) New Treatment (FW) and Diversion from Composting (GTW) 11. Food Waste, Dewatered Septic Systems Sludge, Poultry Manure and Grease Trap Waste 7. Food Waste and Grease Trap Waste Diversion of waste (Treatment) 8. Food Waste and Rinsing Water from Food Processing Industry New Treatment (FW) and Diversion from Fertilizing (RWFPI) 9. Food Waste, Poultry Manure and Grease Trap Waste New Treatment (FW) and Diversion from Composting (GTW) 12. Food Waste and Food Processing Organic Waste New Treatment (FW) and Diversion from Composting (FPOW) 13. Food Waste, Grease Trap Waste and Leaves New Treatment (FW) and Diversion from Composting (GTW/Leaves) Score 3 2 Table 24 illustrates the scores related to the impact the project may have in terms of transportation. Mixes 3, 9, 11 and 14 obtain the highest score because they contain poultry manure which currently travels over 200 km to be treated in an anaerobic digester in Ontario, Canada and the chicken slaughterhouse is located only 10 km away from the projected location of EBI's anaerobic digester. Mix 15 receives a "good" grade, which is lower than the previous 70 mixes; it contains poultry manure as well, but transportation of whey permeate is going to increase by about 10 km. Judged as "sufficient", Mix 1 and Mix 8 imply approximately a 20 km reduction in the transportation of rinsing water from the food processing industry. Finally, the other mixes are ranked "low" because all the material is already shipped to EBI's site so the anaerobic digestion project has no impact on transportation of these wastes. Table 24: Score of the Mixes on the Criterion of Diversion of Waste Specific to Transportation Mix Diversion of waste (Transportation) 3. Wasted Activated Sludge, Poultry Manure and Grease Trap Waste 9. Food Waste, Poultry Manure and Grease Trap Waste 11. Food Waste, Dewatered Septic Systems Sludge, Poultry Manure and Grease Trap Waste 14. Food Waste, Dewatered Septic Systems Sludge, Poultry Manure, Wasted Activated Sludge and Grease Trap Waste 15. Food Waste, Dewatered Septic Systems Sludge, Poultry Manure, Wasted Activated Sludge, Grease Trap Waste and Whey Permeate 1. Wasted Activated Sludge and Rinsing Water from Food Processing Industry 8. Food Waste and Rinsing Water from Food Processing Industry 2. Wasted Activated Sludge and Grease Trap Waste 4. Wasted Activated Sludge, Dewatered Septic Systems Sludge and Grease Trap Waste 5. Wasted Activated Sludge and Food Processing Organic Waste 6. Wasted Activated Sludge, Grease Trap Waste and Leaves 7. Food Waste and Grease Trap Waste 10. Food Waste, Dewatered Septic Systems Sludge and Grease Trap Waste 12. Food Waste and Food Processing Organic Waste 13. Food Waste, Grease Trap Waste and Leaves High Reduction (PM) 71 High Reduction (PM) High Reduction (PM) Score 4 High Reduction (PM) High Reduction (PM), Low Increase (WP) Low Reduction (RWFPI) Low Reduction (RWFPI) No Effect No Effect No Effect No Effect No effect No effect No Effect No Effect 3 2 Following the individual analysis of treatment and transportation diversion, Table 25 represents the average score of the criterion. Mix 3 obtains the best performance on diversion of waste. Table 25: Average Score of the Mixes on the Criterion of Diversion of Waste Mix 3. Wasted Activated Sludge, Poultry Manure and Grease Trap Waste 11. Food Waste, Dewatered Septic Systems Sludge, Poultry Manure and Grease Trap Waste 14. Food Waste, Dewatered Septic Systems Sludge, Poultry Manure, Wasted Activated Sludge and Grease Trap Waste 1. Wasted Activated Sludge and Rinsing Water from Food Processing Industry 4. Wasted Activated Sludge, Dewatered Septic Systems Sludge and Grease Trap Waste 9. Food Waste, Poultry Manure and Grease Trap Waste 15. Food Waste, Dewatered Septic Systems Sludge, Poultry Manure, Wasted Activated Sludge, Grease Trap Waste and Whey Permeate 2. Wasted Activated Sludge and Grease Trap Waste 5. Wasted Activated Sludge and Food Processing Organic Waste 6. Wasted Activated Sludge, Grease Trap Waste and Leaves 8. Food Waste and Rinsing Water from Food Processing Industry 10. Food Waste, Dewatered Septic Systems Sludge and Grease Trap Waste 7. Food Waste and Grease Trap Waste 12. Food Waste and Food Processing Organic Waste 13. Food Waste, Grease Trap Waste and Leaves 2.6.1.3 Average Score 3.5 3.0 2.5 2.0 1.5 1.0 Availability Availability of the feedstock relates to the seasonal variations of the reception of each waste. This element has a direct influence on storage requirements. Distance of transportation is ignored in the current criterion because the vast majority of the waste originates from local and regional sources and only a few variations exist in this regard. Additionally, transportation is partly included in diversion of waste, the prior criterion. Table 26 displays the scores of the fifteen combinations. Rated as "very good", Mix 1 and Mix 8 contain waste received on a regular basis all year. Next, mixes 2, 3, 5, 7, 9, and 12 are relatively consistent over the course of a year with some minor variations on grease trap waste and food processing organic waste. Even though leaves are very seasonal, their storage is easy and inexpensive which justifies the "sufficient" 72 grade of Mix 6 and Mix 13. The other mixes, 4, 10, 11 14 and 15, obtain a "low" performance score due to the high seasonality of septic systems sludge. Table 26: Score of the Mixes on the Criterion of Availability Mix 1. Wasted Activated Sludge and Rinsing Water from Food Processing Industry 8. Food Waste and Rinsing Water from Food Processing Industry 2. Wasted Activated Sludge and Grease Trap Waste 3. Wasted Activated Sludge, Poultry Manure and Grease Trap Waste 5. Wasted Activated Sludge and Food Processing Organic Waste 7. Food Waste and Grease Trap Waste 9. Food Waste, Poultry Manure and Grease Trap Waste 12. Food Waste and Food Processing Organic Waste 6. Wasted Activated Sludge, Grease Trap Waste and Leaves Availability (Seasonality) All year 4 All year All year with minor variations (GTW) All year with minor variations (GTW) All year with minor variations (FPOW) All year with minor variations over year (GTW) All year with minor variations over year (GTW) All year with minor variations (FPOW) 3 Mostly Fall (Leaves) and minor variations over year (GTW) 13. Food Waste, Grease Trap Waste and Leaves Mostly Fall (Leaves) and minor variations over year (GTW) 4. Wasted Activated Sludge, Dewatered Septic Systems Sludge and Grease Trap Waste 10. Food Waste, Dewatered Septic Systems Sludge and Grease Trap Waste Mostly Summer for DSSS and minor variations over year (GTW) 11. Food Waste, Dewatered Septic Systems Sludge, Poultry Manure and Grease Trap Waste 14. Food Waste, Dewatered Septic Systems Sludge, Poultry Manure, Wasted Activated Sludge and Grease Trap Waste 15. Food Waste, Dewatered Septic Systems Sludge, Poultry Manure, Wasted Activated Sludge, Grease Trap Waste and Whey Permeate Mostly Summer for DSSS and minor variations over year (GTW) 2.6.1.4 Score 2 Mostly Summer for DSSS and minor variations over year (GTW) Mostly Summer for DSSS and minor variations over year (GTW) Mostly Summer for DSSS and minor variations over year (GTW) Odor Odor is considered as the main social constraint of the project. EBI particularly wishes to avoid odor spreading large distances to the neighbors. All wastes smell on a short distance, but it has a lesser importance in terms of social impact. Additionally, the odor emissions are directly 73 influenced by the weather conditions which vary significantly. However, parameters such as short range odor and weather conditions are considered equal in all the mixes. Based on the experience of Gilles Denis, General Manager at Dep6t Rive-Nord, a division of EBI in charge of the landfill, poultry manure is the waste with the worst odor emissions because they are intense, they last a long time and they are capable of spreading over long distances. No scientific evidence is considered for the current criterion, but field experience is judged reliable. As observed on Table 27, mixes 3, 9, 11, 14 and 15 are ranked "low" due to the presence of poultry manure. Specific measures may be required to control odor in these cases. The rest of the combinations are all judged equal with a "sufficient" score. Table 27: Score of the Mixes on the Criterion of Odor Mix 1. Wasted Activated Sludge and Rinsing Water from Food Processing Industry 2. Wasted Activated Sludge and Grease Trap Waste 4. Wasted Activated Sludge, Dewatered Septic Systems Sludge and Grease Trap Waste 5. Wasted Activated Sludge and Food Processing Organic Waste 6. Wasted Activated Sludge, Grease Trap Waste and Leaves 7. Food Waste and Grease Trap Waste 8. Food Waste and Rinsing Water from Food Processing Industry 10. Food Waste, Dewatered Septic Systems Sludge and Grease Trap Waste 12. Food Waste and Food Processing Organic Waste 13. Food Waste, Grease Trap Waste and Leaves 3. Wasted Activated Sludge, Poultry Manure and Grease Trap Waste 9. Food Waste, Poultry Manure and Grease Trap Waste 11. Food Waste, Dewatered Septic Systems Sludge, Poultry Manure and Grease Trap Waste 14. Food Waste, Dewatered Septic Systems Sludge, Poultry Manure, Wasted Activated Sludge and Grease Trap Waste 15. Food Waste, Dewatered Septic Systems Sludge, Poultry Manure, Wasted Activated Sludge, Grease Trap Waste and Whey Permeate 2.6.1.5 Odor Low Score Low Low Low Low Low Low Low 2 Low Low High for PM High for PM High for PM High for PM High for PM Purity Purity is affected by the amount of non-biodegradable material in the feedstock as it is received, which directly relates to pretreatment requirements. Leaves, septic systems sludge and food 74 processing organic waste are already pretreated as part of their current treatment so the data come from EBI. As described previously, food waste is a significantly contaminated feedstock and the numerical value of the cost of sorting the material is taken from the literature.1 75 Pretreatment necessities as well as performance scores for all the mixes appear in Table 28. None of the ingredients of mixes 1, 2 and 3 involve pretreatment, so a "high" score is attributed. Mixes 4, 5, and 6 all have a secondary ingredient necessitating pretreatment so they are graded as "good". The main constituent of mixes 7, 8 and 9 is food waste which requires pretreatment, but no other input needs to go through this operation. Thus, they are evaluated as "sufficient". Finally, mixes 10, 11, 12, 13, 14 and 15 include two components involving pretreatment justifying the "low" score. Table 28: Score of the Mixes on the Criterion of Purity Mix Mix 1. Wasted Activated Sludge and Rinsing Water from Food Processing Industry 2. Wasted Activated Sludge and Grease Trap Waste 3. Wasted Activated Sludge, Poultry Manure and Grease Trap Waste 4. Wasted Activated Sludge, Dewatered Septic Systems Sludge and Grease Trap Waste 5. Wasted Activated Sludge and Food Processing Organic Waste 6. Wasted Activated Sludge, Grease Trap Waste and Leaves 7. Food Waste and Grease Trap Waste 8. Food Waste and Rinsing Water from Food Processing Industry 9. Food Waste, Poultry Manure and Grease Trap Waste 10. Food Waste, Dewatered Septic Systems Sludge and Grease Trap Waste 11. Food Waste, Dewatered Septic Systems Sludge, Poultry Manure and Grease Trap Waste 12. Food Waste and Food Processing Organic Waste 13. Food Waste, Grease Trap Waste and Leaves 14. Food Waste, Dewatered Septic Systems Sludge, Poultry Manure, Wasted Activated Sludge and Grease Trap Waste 15. Food Waste, Dewatered Septic Systems Sludge, Poultry Manure, Wasted Activated Sludge, Grease Trap Waste and Whey Permeate PurityScr (Pretreatment) Score None None None $10/MT (DSSS) $30/MT $37/MT $20/MT $20/MT $20/MT $20/MT $10/MT $20/MT $10/MT $20/MT $30/MT $20/MT $37/MT $20/MT $10/MT $20/MT $10/MT (FPOW) (Leaves) (FW) (FW) (FW) (FW) and (DSSS) (FW) and (DSSS) (FW) and (FPOW) (FW) and (Leaves) (FW) and (DSSS) (FW) and (DSSS) 2 Allen Kani Associates with Enviros RIS Ltd., WDO Study: Implications of Different Waste Feed Streams (Source-Separated Organics and Mixed Waste) On Collection Options and Anaerobic Digestion Processing Facility Design, Equipment and Costs, 30-31. 175 75 2.6.2 During Treatment The criteria during treatment are vital to the project. Suitability, digestibility and inhibitors are three parameters directly related to the performance of the consortium of bacteria in the anaerobic digester. Each one of them is described and graded below. 2.6.2.1 Suitability Suitability considers the quality of the internal environment of the anaerobic digester. The two most common parameters used to evaluate this criterion are C/N ratio and pH. In practice, many other factors are monitored to ensure a proper suitability, but C/N ratio and pH are adequate to perform the current analysis due to the limited information available and the early stage of the project. Each factor is evaluated individually before being compiled to obtain a global score for suitability. Table 29 illustrates an approximation of the C/N ratio of the mixes. As mentioned previously, the optimal range is between 20/1 and 30/1 but lower values are acceptable. All the combinations are either at the inferior end of the preferred range or below. They are ranked from highest to lowest and graded accordingly. Mixes 9, 11, 14 and 15 have a C/N ratio between 20 and 30, so they obtain an "excellent" score. Mixes 13, 7, 10, 12 and 8 are just under the lower end of the desired range so a "very good" score is granted. Mix 3 and Mix 4 obtain a "good" and "sufficient" score respectively whereas the rest of the mixes, 6, 2, 1, and 5, are considered "low" due to their poor C/N ratio. 76 Table 29: Score of the Mixes on the Criterion of Suitability Specific to C/N Ratio Mix 9. Food Waste, Poultry Manure and Grease Trap Waste 11. Food Waste, Dewatered Septic Systems Sludge, Poultry Manure and Grease Trap Waste 14. Food Waste, Dewatered Septic Systems Sludge, Poultry Manure, Wasted Activated Sludge and Grease Trap Waste 15. Food Waste, Dewatered Septic Systems Sludge, Poultry Manure, Wasted Activated Sludge, Grease Trap Waste and Whey Permeate 13. Food Waste, Grease Trap Waste and Leaves Su11itabhilit .7 (C/N Ratio) 22-23 21-22 20-21 18-19 17-18 10. Food Waste, Dewatered Septic Systems Sludge and Grease Trap Waste 17-18 12. Food Waste and Food Processing Organic Waste 17-18 4. Wasted Activated Sludge, Dewatered Septic Systems Sludge and Grease Trap Waste 6. Wasted Activated Sludge, Grease Trap Waste and Leaves 2. Wasted Activated Sludge and Grease Trap Waste 1. Wasted Activated Sludge and Rinsing Water from Food Processing Industry 5. Wasted Activated Sludge and Food Processing Organic Waste 5 20-21 7. Food Waste and Grease Trap Waste 8. Food Waste and Rinsing Water from Food Processing Industry 3. Wasted Activated Sludge, Poultry Manure and Grease Trap Waste Score 4 17 14-15 3 10-12 2 9-11 9-10 9 1 9 The optimal pH reported by Speece is between 6.5 and 8.2, but it may be acceptable as low as 6.0. 76 The pH and performance score of the mixes on this parameter are found in Table 30. All the combinations tend to the acid limit of the range, so this factor may need to be closely examined in further tests. The mixes are sorted in descending order with Mix 2 and Mix 10 obtaining a "very good" score. Mixes 5, 7 and 11 have a "good" score with a pH estimated at 6.2. Next, mixes 1, 3, 4, 8, 9 and 12 have a pH of 6.1 which leads to a "sufficient" score. Finally, Mix 6 and Mix 13 get a "low" score because their approximated pH is highly variable and may be too acid for bacterial activity. 176 Speece, Anaerobic Biotechnology for Industrial Wastewaters, 58. 77 Table 30: Score of the Mixes on the Criterion of Suitability Specific to pH Mix 2. Wasted Activated Sludge and Grease Trap Waste 10. Food Waste, Dewatered Septic Systems Sludge and Grease Trap Waste 5. Wasted Activated Sludge and Food Processing Organic Waste 7. Food Waste and Grease Trap Waste 11. Food Waste, Dewatered Septic Systems Sludge, Poultry Manure and Grease Trap Waste 14. Food Waste, Dewatered Septic Systems Sludge, Poultry Manure, Wasted Activated Sludge and Grease Trap Waste 1. Wasted Activated Sludge and Rinsing Water from Food Processing Industry 3. Wasted Activated Sludge, Poultry Manure and Grease Trap Waste 4. Wasted Activated Sludge, Dewatered Septic Systems Sludge and Grease Trap Waste 8. Food Waste and Rinsing Water from Food Processing Industry 9. Food Waste, Poultry Manure and Grease Trap Waste 12. Food Waste and Food Processing Organic Waste 15. Food Waste, Dewatered Septic Systems Sludge, Poultry Manure, Wasted Activated Sludge, Grease Trap Waste and Whey Permeate 6. Wasted Activated Sludge, Grease Trap Waste and Leaves 13. Food Waste, Grease Trap Waste and Leaves Suitability (pH) 6.3 6.3 Score 4 6.2 6.2 6.2 3 6.2 6.1 6.1 6.1 6.1 2 6.1 6.1 6.1 5.7-6.4 5.7-6.4 1 Table 31 shows the average score of the mixes on the criterion of suitability. The average score enables the classification of the combinations by weighting their performance on the C/N ratio and pH. Mixes 10, 11 and 14 appear to be the most suitable options. 78 Table 31: Average Score of the Mixes on the Criterion of Suitability Average Score Mix 10. Food Waste, Dewatered Septic Systems Sludge and Grease Trap Waste 11. Food Waste, Dewatered Septic Systems Sludge, Poultry Manure and Grease Trap Waste 14. Food Waste, Dewatered Septic Systems Sludge, Poultry Manure, Wasted Activated Sludge and Grease Trap Waste 7. Food Waste and Grease Trap Waste 9. Food Waste, Poultry Manure and Grease Trap Waste 15. Food Waste, Dewatered Septic Systems Sludge, Poultry Manure, Wasted Activated Sludge, Grease Trap Waste and Whey Permeate 8. Food Waste and Rinsing Water from Food Processing Industry 12. Food Waste and Food Processing Organic Waste 2. Wasted Activated Sludge and Grease Trap Waste 3. Wasted Activated Sludge, Poultry Manure and Grease Trap Waste 13. Food Waste, Grease Trap Waste and Leaves 4. Wasted Activated Sludge, Dewatered Septic Systems Sludge and Grease Trap Waste 5. Wasted Activated Sludge and Food Processing Organic Waste 1. Wasted Activated Sludge and Rinsing Water from Food Processing Industry 6. Wasted Activated Sludge, Grease Trap Waste and Leaves 2.6.2.2 4.0 3.5 3.0 2.5 2.0 1.5 1.0 Digestibility Digestibility is defined as the quantity of methane produced during digestion. As covered previously, it depends on various parameters like temperature and retention time. This analysis is not intended to predict the exact quantities of methane produced but to rank the different combinations. Digestibility is considered on a mass basis as well as a time basis. The quantity of methane produced per ton is useful for scalability purposes. From the perspective that EBI eventually aims at a larger project, it may be critical to maximize the quantity of methane produced by mass. Additionally, this metric is not affected by the total quantity of feedstock in the combinations which varies and tends to give an advantage to the ones with more annual tons. The total methane production per year is useful to assess the current small-scale project. Table 32 lists digestibility per mass for all the combinations. As observed, some ranges overlap, but they are ranked on their potential maximum and minimum. Mix 11 and Mix 10 are judged as the best ones so they receive an "excellent" score whereas Mix 14 and Mix 15 are ranked right 79 after as "very good". Mix 4 has a small and relatively high range while Mix 12 has a wide range with a fairly low minimum and a very high maximum; they both obtain a "good" score. Mixes 13, 9, 8 and 7 have a "sufficient" performance because they have a large range with reasonable maximum values. Finally, the other options, 5, 6, 3, 2 and 1, have small ranges and low values which justify the "low" grading. Table 32: Score of the Mixes on the Criterion of Digestibility on a Mass Basis Mix 11. Food Waste, Dewatered Septic Systems Sludge, Poultry Manure and Grease Trap Waste 10. Food Waste, Dewatered Septic Systems Sludge and Grease Trap Waste 14. Food Waste, Dewatered Septic Systems Sludge, Poultry Manure, Wasted Activated Sludge and Grease Trap Waste 15. Food Waste, Dewatered Septic Systems Sludge, Poultry Manure, Wasted Activated Sludge, Grease Trap Waste and Whey Permeate 4. Wasted Activated Sludge, Dewatered Septic Systems Sludge and Grease Trap Waste 12. Food Waste and Food Processing Organic Waste 13. Food Waste, Grease Trap Waste and Leaves 9. Food Waste, Poultry Manure and Grease Trap Waste 8. Food Waste and Rinsing Water from Food Processing Industry 7. Food Waste and Grease Trap Waste 5. Wasted Activated Sludge and Food Processing Organic Waste 6. Wasted Activated Sludge, Grease Trap Waste and Leaves 3. Wasted Activated Sludge, Poultry Manure and Grease Trap Waste 2. Wasted Activated Sludge and Grease Trap Waste 1. Wasted Activated Sludge and Rinsing Water from Food Processing Industry 80 Digestibility per Mass 3 (M CH 4/MT) 49-64 4 48-65 Score 47-61 4 46-61 50-52 3 43-62 38-57 36-54 35-54 34-54 25-27 24-27 22-25 20-23 20-22 2 Digestibility on a time basis is used to assess the combinations. Found in Table 33, the ranges are weighted on their maximum and minimum estimated values. Mix 15 and Mix 14 get a "very good" score and mixes 4, 11 and 10 are ranked right after with a "good" score. Lower digestibility is observed for mixes 12, 9, 13, 8 and 7 explaining the "sufficient" grade. Mixes 5, 3, 6, 1 and 2 have a "low" score because they are the options with small ranges at the lower end of the distribution. Table 33: Score of the Mixes on the Criterion of Digestibility on a Time Basis per Time Digestibility 3 Mix (x 103 m CH 4/year) 15. Food Waste, Dewatered Septic Systems Sludge, Poultry Manure, Wasted Activated Sludge, Grease Trap Waste and Whey Permeate 14. Food Waste, Dewatered Septic Systems Sludge, Poultry Manure, Wasted Activated Sludge and Grease Trap Waste 4. Wasted Activated Sludge, Dewatered Septic Systems Sludge and Grease Trap Waste 11. Food Waste, Dewatered Septic Systems Sludge, Poultry Manure and Grease Trap Waste 10. Food Waste, Dewatered Septic Systems Sludge and Grease Trap Waste 12. Food Waste and Food Processing Organic Waste 9. Food Waste, Poultry Manure and Grease Trap Waste 13. Food Waste, Grease Trap Waste and Leaves 8. Food Waste and Rinsing Water from Food Processing Industry 7. Food Waste and Grease Trap Waste 5. Wasted Activated Sludge and Food Processing Organic Waste 3. Wasted Activated Sludge, Poultry Manure and Grease Trap Waste 6. Wasted Activated Sludge, Grease Trap Waste and Leaves 1. Wasted Activated Sludge and Rinsing Water from Food Processing Industry 2. Wasted Activated Sludge and Grease Trap Waste 81 Score 70.0-91.6 4 69.8-91.4 77.2-81.1 68.3-89.9 3 62.9-84.5 46.0-66.8 42.8-64.3 41.5-63.1 2 37.5-58.3 37.4-59.0 32.3-34.7 31.4-34.6 28.6-31.8 26.1-28.5 26.0-29.2 1 Table 34 results from the combination of the two individual analyses of digestibility. An average score is calculated for each mix. Mixes 10, 11, 14 and 15 are ranked at the top. Table 34: Average Score of the Mixes on the Criterion of Digestibility Average Score Mix 10. Food Waste, Dewatered Septic Systems Sludge and Grease Trap Waste 11. Food Waste, Dewatered Septic Systems Sludge, Poultry Manure and Grease Trap Waste 14. Food Waste, Dewatered Septic Systems Sludge, Poultry Manure, Wasted Activated Sludge and Grease Trap Waste 15. Food Waste, Dewatered Septic Systems Sludge, Poultry Manure, Wasted Activated Sludge, Grease Trap Waste and Whey Permeate 4. Wasted Activated Sludge, Dewatered Septic Systems Sludge and Grease Trap Waste 12. Food Waste and Food Processing Organic Waste 7. Food Waste and Grease Trap Waste 8. Food Waste and Rinsing Water from Food Processing Industry 9. Food Waste, Poultry Manure and Grease Trap Waste 13. Food Waste, Grease Trap Waste and Leaves 5. Wasted Activated Sludge and Food Processing Organic Waste 1. Wasted Activated Sludge and Rinsing Water from Food Processing Industry 2. Wasted Activated Sludge and Grease Trap Waste10 3. Wasted Activated Sludge, Poultry Manure and Grease Trap Waste 6. Wasted Activated Sludge, Grease Trap Waste and Leaves 82 4.0 3.0 2.5 2.0 2.6.2.3 Inhibitors The presence of inhibitors may lead to major problems in the anaerobic digester and has the potential to completely stop bacterial activity. Unfortunately, only limited data related to the feedstock constituting the mixes are found on this subject. From the current information, poultry manure and rinsing water from the food processing industry have sulfur and potassium and only potassium respectively that may be inhibitive at high concentrations. Thus, mixes 3, 9, 11, 14, 15, 1 and 8 which contain one of these two types of waste have a "low" performance score and the other combinations are judged as "sufficient" because they do not have known probable inhibitors. Table 35: Score of the Mixes on the Criterion of Inhibitors Mix Inhibitors 2. Wasted Activated Sludge and Grease Trap Waste 4. Wasted Activated Sludge, Dewatered Septic Systems Sludge and Grease Trap Waste 5. Wasted Activated Sludge and Food Processing Organic Waste 6. Wasted Activated Sludge, Grease Trap Waste and Leaves 7. Food Waste and Grease Trap Waste 10. Food Waste, Dewatered Septic Systems Sludge and Grease Trap Waste 12. Food Waste and Food Processing Organic Waste 13. Food Waste, Grease Trap Waste and Leaves 3. Wasted Activated Sludge, Poultry Manure and Grease Trap Waste 9. Food Waste, Poultry Manure and Grease Trap Waste 11. Food Waste, Dewatered Septic Systems Sludge, Poultry Manure and Grease Trap Waste 14. Food Waste, Dewatered Septic Systems Sludge, Poultry Manure, Wasted Activated Sludge and Grease Trap Waste 15. Food Waste, Dewatered Septic Systems Sludge, Poultry Manure, Wasted Activated Sludge, Grease Trap Waste and Whey Permeate 1. Wasted Activated Sludge and Rinsing Water from Food Processing Industry 8. Food Waste and Rinsing Water from Food Processing Industry 83 Score None known None known None known None known 2 None known None known None known None known Maybe Sulfur and Potassium (PM) Maybe Sulfur and Potassium (PM) Maybe Sulfur and Potassium (PM) Maybe Sulfur and Potassium (PM) 1 Maybe Sulfur and Potassium (PM) Maybe Potassium (RWFPI) Maybe Potassium (RWFPI) 2.6.3 Cumulative Analysis Following the individual scoring of criteria, a cumulative analysis is required to draw a global assessment of the options. The criteria before treatment specific to each mix are summarized in Table 36 and Table 37 and the criteria during treatment can be found in Table 38. These two tables summarize concisely all the criteria used in the MCA. Table 36: Summary of the Criteria Before Treatment for the Mixes (1 of 2) Mix 1. Wasted Activated Sludge and Rinsing Water from Food Processing Industry 2. Wasted Activated Sludge and Grease Trap Waste 3. Wasted Activated Sludge, Poultry Manure and Grease Trap Waste 4. Wasted Activated Sludge, Dewatered Septic Systems Sludge and Grease Trap Waste 5. Wasted Activated Sludge and Food Processing Organic Waste 6. Wasted Activated Sludge, Grease Trap Waste and Leaves 7. Food Waste and Grease Trap Waste 8. Food Waste and Rinsing Water from Food Processing Industry 9. Food Waste, Poultry Manure and Grease Trap Waste 10. Food Waste, Dewatered Septic Systems Sludge and Grease Trap Waste 11. Food Waste, Dewatered Septic Systems Sludge, Poultry Manure and Grease Trap Waste 12. Food Waste and Food Processing Organic Waste 13. Food Waste, Grease Trap Waste and Leaves 14. Food Waste, Dewatered Septic Systems Sludge, Poultry Manure, Wasted Activated Sludge and Grease Trap Waste 15. Food Waste, Dewatered Septic Systems Sludge, Poultry Manure, Wasted Activated Sludge, Grease Trap Waste and Whey Permeate Diversion of waste Treatment Fee ($/year) Transportation 66,375 Diversion from Landfilling (WAS) and Fertilizing (RWFPI) Low Reduction (RWFPI) 67,750 Landfilling (WAS) and Diversion from Composting (GTW) Landfilling (WAS) and Diversion from Composting (GTW) No Effect 67,300 Landfilling (WAS/DSSS) and Diversion from Composting (GTW) No Effect 65,900 Diversion from Landfilling (WAS) and Composting (FPOW) Landfilling (WAS) and Diversion from Composting (GTW/Leaves) New Treatment (FW) and Diversion from Composting (GTW) New Treatment (FW) and Diversion from Fertilizing (RWFPI) No Effect New Treatment (FW) and Diversion from Composting (GTW) New Treatment (FW), Diversion from Landfilling (DSSS) and Composting (GTW) New Treatment (FW), Diversion from Landfilling (DSSS) and Composting (GTW) New Treatment (FW) and Diversion from Composting (FPOW) New Treatment (FW) and Diversion from Composting (GTW/Leaves) New Treatment (FW) and Diversion from Landfilling (DSSS/WAS) and Composting (GTW) High Reduction (PM) No effect 77,750 62,275 66,550 65,175 76,550 69,550 79,550 65,175 66,175 84,650 85,600 New Treatment (FW) and Diversion from Landfilling (DSSS/WAS) and Composting (GTW) 84 High Reduction (PM) No Effect No effect Low Reduction (RWFPI) High Reduction (PM) No Effect No Effect High Reduction (PM) High Reduction (PM), Low Increase (WP) Table 37: Summary of the Criteria Before Treatment for the Mixes (2 of 2) Availability (Seasonality) All year Odor Low Purity (Pretreatment) None All year with minor variations (GTW) All year with minor variations (GTW) Mostly Summer for DSSS and minor variations over year (GTW) All year with minor variations (FPOW) Mostly Fall (Leaves) and minor variations over year (GTW) All year with minor variations over year (GTW) All year Low None High (PM) Low None Low $30/MT (FPOW) Low $37/MT (Leaves) Low $20/MT (FW) Low $20/MT (FW) All year with minor variations over year (GTW) Mostly Summer for DSSS and minor variations over year (GTW) Mostly Summer for DSSS and minor variations over year (GTW) All year with minor variations (FPOW) High (PM) $20/MT (FW) Low $20/MT (FW) and $10/MT (DSSS) High (PM) $20/MT (FW) and $10/MT (DSSS) Low 13. Food Waste, Grease Trap Waste and Leaves Mostly Fall (Leaves) and minor variations over year (GTW) Low $20/MT (FW) and $30/MT (FPOW) $20/MT (FW) and $37/MT (Leaves) 14. Food Waste, Dewatered Septic Systems Maure Wate Acivaed SlugePoutr Sludge, Poultry Manure, Wasted Activated Sludge and Grease Trap Waste 15. Food Waste, Dewatered Septic Systems Sludge, Poultry Manure, Wasted Activated Sludge, Grease Trap Waste and Whey Permeate Mostly Summer for DSSS and minor variations over year (GTW) Mostly Summer for DSSS and minor variations over year (GTW) High (PM) $20/MT (FW) and $ 10/MT (DSSS) High (PM) $20/MT (FW) and $1 0/MT (DSSS) Mix 1. Wasted Activated Sludge and Rinsing Water from Food Processing Industry 2. Wasted Activated Sludge and Grease Trap Waste 3. Wasted Activated Sludge, Poultry Manure and Grease Trap Waste 4. Wasted Activated Sludge, Dewatered Septic Systems Sludge and Grease Trap Waste 5. Wasted Activated Sludge and Food Processing Organic Waste 6. Wasted Activated Sludge, Grease Trap Waste and Leaves 7. Food Waste and Grease Trap Waste 8. Food Waste and Rinsing Water from Food Processing Industry 9. Food Waste, Poultry Manure and Grease Trap Waste 10. Food Waste, Dewatered Septic Systems Sludge and Grease Trap Waste 11. Food Waste, Dewatered Septic Systems Sludge, Poultry Manure and Grease Trap Waste 12. Food Waste and Food Processing Organic Waste 85 $10/MT (DSSS) Table 38: Summary of the Criteria During Treatment for the Mixes Suitability Mix Digestibility (x 103 m 3 CH 4/year) C/N Ratio pH Dry Matter 9 6.1 6 20-22 26.1-28.5 9-10 6.3 6 20-23 26.0-29.2 14-15 6.1 7 22-25 31.4-34.6 10-12 6.1 15 50-52 77.2-81.1 9 6.2 6 25-27 32.3-34.7 9-11 5.7-6.4 7 24-27 28.6-31.8 17-18 171 6.2 . 11 34-54 37.4-59.0 17 6.1 10 35-54 37.5-58.3 22-23 6.1 11 36-54 42.8-64.3 10. Food Waste, Dewatered Septic Systems Sludge and Grease Trap Waste 17-18 6.3 15 48-65 62.9-84.5 11. Food Waste, Dewatered Septic Systems Sludge, Poultry Manure and Grease Trap Waste 21-22 6.2 15 49-64 68.3-89.9 17-18 6.1 11 43-62 46.0-66.8 5.7-6.4 12 38-57 41.5-63.1 20-21 6.2 14 47-61 69.8-91.4 20-21 6.1 14 46-61 70.0-91.6 1. Wasted Activated Sludge and Rinsing Water from Food Processing Industry 2. Wasted Activated Sludge and Grease Trap Waste 3. Wasted Activated Sludge, Poultry Manure and Grease Trap Waste 4. Wasted Activated Sludge, Dewatered Septic Systems Sludge and Grease Trap Waste 5. Wasted Activated Sludge and Food Processing Organic Waste 6. Wasted Activated Sludge, Grease Trap Waste and Leaves 7. Food Waste and Grease Trap Waste 8. Food Waste and Rinsing Water from Food Processing Industry 9. Food Waste, Poultry Manure and Grease Trap Waste 12. Food Waste and Food Processing Organic Waste 13. Food Waste, Grease Trap WatLeaves evs18-19 n Waste and 14. Food Waste, Dewatered Septic Systems Sludge, Poultry Manure, Wasted Activated Sludge and Grease Trap Waste 15. Food Waste, Dewatered Septic Systems Sludge, Poultry Manure, Wasted Activated Sludge, Grease Trap Waste and Whey Permeate (i 3 CH 4/MT) 13.-90 86 Inhibitors Maybe Potassium (RWFPI) None known Maybe Sulfur and Potassium (PM) None non None known None known None known Maybe Potassium (RWFPI) Maybe Sulfur and Potassium (PM) None known Maybe Sulfur and Potassium (PM) None known None knw known Maybe Sulfur and Potassium (PM) Maybe M a Sulfur and Potassium (PM) To compare the performance of the mixes on all the parameters, it is necessary to evaluate their relative importance. Table 39 lists the weight allocated to each criterion previously described. The levels of importance reflect EBI's objectives with regards to the feedstock. The values are recommended following discussions with EBI and the prior literature review. The most important parameter is suitability because it is vital to the entire process. The analysis only includes suitable mixes, but some of them are more suitable than others. The other very important criteria are the fee, odor, digestibility and inhibitors. This grading reflects a feedstock bringing significant revenues with reduced odor and a good behavior in the anaerobic digester. Availability and purity are evaluated as important because they are not crucial to the success of the project but they remain reasonably influential. If the feedstock is not available all year, it is possible to store it and if it is not pure, it may be sorted. These two solutions can potentially be expensive, but they are resolvable problems. Finally, diversion of waste is considered as moderately important because it does not have a direct impact on the project. Table 39: Weight of the Criteria Used in the MCA Criterion Bfre t Treatment During Treatment Weight Fee Diversion of waste Availability Oo 3 1 2 Odor 3 Purity 2 Suitability Digestibility Inhibitors 4 3 3 Legend 4 3 2 1 Critical Very important Important Moderately important 87 - 55-51.5 Inhibitors 45.5 45.5 .43 42.5 0 Digestibility 40 34 - 35 l Suitability 30 0 Purity 25 H Odor 20 MAvailability 5 Diversion of waste E Fee 5 0 14 10 15 11 7 9 2 8 12 Mix 3 4 5 1 13 6 Figure 12: Total Value of the Mixes Based on the MCA To perform a global MCA and obtain a total value for all the mixes, the score in each criterion is multiplied by its respective weight to obtain the value of the mix for a given criterion. Then, all the values are summed to get the total value. The individual values of all the combinations as well as their total value appear in Figure 12 and detailed scores and values can be found in Appendix F. Mixes 14, 10, 15 and 11, respectively, obtain the highest total value which greatly influences recommendations. They are all composed of food waste, grease trap waste and liquid yeast with variations of poultry manure, dewatered septic systems sludge, wasted activated sludge and whey permeate. 88 2.7 RISK MANAGEMENT ANALYSIS Any engineering project involves a certain degree of risk. Indeed, it is important to identify and analyze these risks in order to face them accordingly. A risk management analysis is pursued with an emphasis on feedstock. It remains qualitative as the main objective is to recognize the critical sources of risk that need to be addressed. Initially, the potential strategic issues related to feedstock management are described which are broad criteria to classify the impacts of risks. Next, the various stakeholders involved are identified along with the strategic issues they relate to. Then, the tolerance of the stakeholders regarding each issue is evaluated. Lastly, potential events involving risk are identified and their criticality is weighted based on the strategic issues. 2.7.1 Strategic Issues The four major strategic issues of the current analysis are economy, environment, function and society which are comprehensive but slightly different than the criteria used in the MCA. These issues enable the identification of the interests of the stakeholders and the risks connected with each issue. The economic aspect regarding feedstock is related to profitability and costs. Contamination of the environment and environmental impact are the two subjects associated with environment where the first is more related to precise events in time and the second issue is focused on a long-term perspective. The availability of feedstock and its quality are linked to the functional aspect. Finally, the social criterion is identified as the perception of the project by the community. 2.7.2 Stakeholders Various stakeholders are interested in the strategic issues associated with the feedstock. The main stakeholder is EBI which is the company in charge of the project. The Government of Quebec and the cities providing organic waste to EBI are two stakeholders from the public sector. As mentioned previously, the Government of Quebec wants to prohibit landfilling of organic matter by 2020 which brings this entity in line with the orientation of the project. Meanwhile, the cities are responsible for the management of their waste and they are clients of EBI. The other stakeholders are the clients from the institutional, commercial and industrial sectors. 89 2.7.3 Tolerance Levels The tolerance level is the level of flexibility a given stakeholder has on a specific strategic issue. Low tolerance implies that the interested party categorically desires to avoid risks linked to this issue whereas a stakeholder with high tolerance on a strategic issue may accept certain events. Table 40 presents the tolerance levels of the stakeholders in regard to each strategic issue. The following paragraphs describe the strategic issues. Table 40: Tolerance Levels of the Stakeholders Related to the Strategic Issues Strategic Issue Government of Quebec Stakeholder . Institutional, Commercial Cities and Industrial Clients a. Profitability 3 3 3 b. Costs 3 2 2 c. d. Contamination Economic Environmental e. Functional (Practical) f. g. Environmental Impact Quality of Feedstock Availability of Feedstock Perception by the community 2 3 3 3 3 3 3 2 2 2 Legend 3 High Tolerance 2 Medium Tolerance Low Tolerance No Tolerance a. Profitability For EBI, a main concern is profitability which is translated into a low tolerance towards this strategic issue. For the project to be sustainable in the long-term, it has to be profitable. The other stakeholders show a high tolerance because they are not in charge of the project and do not directly benefit economically from it. 90 b. Costs EBI has a low tolerance for the costs because high feedstock costs may compromise the economic viability of the project. The cities and the commercial, institutional and industrial clients illustrate a medium tolerance; they have contracts with EBI and high costs may impact their fee. However, they have the possibility to pursue another treatment for their waste if it happens to be cheaper. Finally, the Government of Quebec is only indirectly related to the economics of this specific project which explains its high tolerance. c. Contamination Unanimously, all stakeholders do not tolerate any environmental contamination. It is not in the benefit of anyone to have a spill or leakage of any sort. Highly organically charged material is handled and it has to be appropriately contained at all times. d. Environmental Impact The digestion of the feedstock should aim to reduce the environmental impact of the substrate treated. EBI's mission, to integrate waste management, demonstrates its commitment towards the environment. Thus, the company has a low tolerance on the environmental impact of the project. From a broader perspective, the public sector has a high desire to reduce its environmental footprint and the project may help accordingly. Indeed, the Government of Quebec and the cities have a low tolerance on this strategic issue. The medium tolerance of the commercial, institutional and industrial clients is ekplained by the wide range of commitments the companies have on this strategic issue. Some companies may accept paying a premium to have their organic wastes diverted from the landfill while some others constantly seek the cheapest option possible. e. Quality of Feedstock The criteria defining the quality of the feedstock are described in the literature review: suitability, availability, digestibility, purity and inhibitors. Availability of the feedstock is considered separately because it leads to fairly different tolerance levels and risks. Indeed, EBI may be highly impacted by the quality of the feedstock; the company is identified with a low tolerance on this issue. The other stakeholders are considered to have a high tolerance on the quality of the feedstock because they are not directly impacted by a feedstock with a low quality. 91 f. Availability of Feedstock EBI has no tolerance on the availability of organic waste; the lack of feedstock simply compromises the entire project. A high tolerance is exhibited by the other stakeholders as they generate the substrate and it is in their interest to make it available to EBI to treat it by anaerobic digestion which diverts waste from the landfill. However, they are not necessarily bound to this project and they may seek alternative treatment if it is too difficult to make their organic waste available to EBI. Perception by the Community g. From EBI's perspective, the project must be perceived positively by the community which justifies the low tolerance of the company on this issue. The other stakeholders may all benefit from a positive opinion of the population regarding the project but have less to lose if it turns out to be viewed negatively. 2.7.4 Sources of Risk and their Criticality The main sources of risk related to feedstock are listed in Table 41. The criticality of these issues is identified specifically for each strategic issue. The importance of a given risk is based on the probability of occurrence and the damages incurred. Thus, a dramatic event with an infinitesimal possibility of happening may be considered of lesser importance than a risk with a high likelihood of occurrence and minor damages. An analysis of each source of risk is found in the following paragraphs. 92 j. High competition k. Lower efficiency of energy crops coverage media i. Negative h. Increased storage costs 1/ 1 N/A N/A N/A 2 2 ______ N/A N/A N/A N/A N/A N/A N/A 2 2 N/A 2 2 2 1 1 N/A N/A 1 N/A 2 1 2 2 N/A Environmental Environmental Impact Contamination 2 1 2 1 costs 2 environment g. Increased transportation 2 2 Costs Economic Profitability e.Oo .112 emission f. Spill in the b. Contaminated feedstock c. Feedstock with low digestibility d. Presence of2N/ available a. Feedstock not Sources of Risk (Events) Strategic Issues Table 41: Criticality of the Sources of Risk on the Strategic Issues N/A N/A N/A N/A N/A N/A 2 2 Social N/A 1 2 2 N/A N/A 2 1 2 1 N/A_2 N/A 1NA N/A N/A 1 1 2 g Perception by the community 2 Functional (Practical) Quality of Availability of Feedstock Feedstock Medium Risk Low Risk Not applicable 2 1 N/A High Risk Le end a. Feedstock Not Available Shortage of feedstock implies important consequences for the project in relation to most of the strategic issues. However, it has a very limited chance of happening; EBI is an established player in the waste management industry. This event may occur with specific feedstock, but broadly this risk is judged as medium for profitability, quality of feedstock, availability of feedstock and perception by the community. Having infrastructure not used to their full potential also slightly increases the environmental impact of the project. So this event represents a low risk for the strategic issue of environmental impact. b. Contaminated Feedstock Contaminated feedstock may be considered the most critical event. It is very likely to happen, especially if food waste is used as input, because it requires pretreatment of the material. Pretreatment is a proven practice done elsewhere, but it is expensive and avoiding this step potentially represents benefits. The risk is ranked as high for the strategic issues of profitability, costs and quality of the feedstock. As pretreatment increases energy usage, this event is evaluated as a low risk for the environmental impact of the project. Additionally, the availability of the feedstock can possibly be affected by this source of risk because it can create some pressure on other pure feedstock resulting in scarcity. Still, this is a low risk in regards to the availability of the feedstock. c. Feedstock with Low Digestibility A medium risk for profitability, costs and quality of the feedstock is evaluated if EBI attempts to digest feedstock with low digestibility. With the proper engineering, it is relatively unlikely to happen, but uncertainties exist in this biological process. Substrate with low digestibility has the potential to significantly harm the project in the economical and functional aspects. Similarly to the risk of contaminated feedstock, a low risk is identified in relation to the environmental impact of the project because the infrastructure would not be used to its full potential. Again, the low risk for the availability of the feedstock originates from the fact that a shortage of the more desirable feedstock may be created. d. Presence of Inhibitors Inhibitors are hard to predict and to find in case of occurrence. An event with inhibitors in the anaerobic digester may compromise the profitability of the project which is a high risk regarding 94 this strategic issue. Moreover, a similar risk is assessed for quality of feedstock because this is the source of inhibitors. Costs may be incurred to find the reason for inhibition and to prevent it, explaining the medium risk associated with this strategic issue. The usage of a specific feedstock may need to cease due to inhibitive concentrations of compounds which is judged as a low risk for availability of feedstock. The reduced efficiency of the project occasioned by such an event is a low risk for the environmental impact. e. Odor Emission Odor emission is an event EBI already experienced in the past, and it resulted in terminating the reception of malodorous waste like poultry manure. The previous attempts to compost this substrate were done outdoors whereas anaerobic digestion is contained and odor management is facilitated. Note also that odor propagation is influenced by meteorological conditions which are out of EBI's control. This source of risk represents a high risk to the perception by the community because the viability of the project can be compromised. Additionally, odor emission are a form of environmental contamination and increase the impact of the project on the environment; the risk is medium regarding these strategic issues. Furthermore, dealing with odor emissions increases expenses which is a low risk for profitability and costs. f. Spill in the Environment Even if the material handled is mostly organic, a spill in the environment may highly threaten profitability, contamination in the environment, the environmental impact of the project and the perception by the community. Meanwhile, large cleanup costs can be engendered. Due to the low probability of occurrence, this risk is judged as a medium risk for the strategic issues previously listed. Increased Transportation Costs g. In the event that transportation costs increase, profitability and costs can be negatively impacted. Still, this source of risk is evaluated as low for these strategic issues because the landfill and composting platform are located at the same place as the projected anaerobic digester which means that most of the waste is likely to be transported to EBI's site in any case. Although some clients may search for nearer places to treat their waste, the targeted feedstock originates from the same region which reduces this event as a low risk for the availability of the feedstock. 95 h. Increased Storage Costs The seasonal variation of most of the feedstock identified in the investigation brings the need for storage. When possible, outdoor storage is preferable and very cheap. However, feedstocks that are mostly liquid or that emit odor have to be kept in closed containers where ventilation is cautiously controlled. This type of storage is more expensive and potential rising costs of this operation can compromise profitability. The evaluation of this event for profitability and costs leads to a medium risk because indoor storage is probably needed and costs may increase. This source of risk is identified as a medium risk for the availability of the feedstock as well; in addition, seasonal waste may not be available all year due to the costs of storage. i. Negative Media Coverage If negative coverage by the media happens, the perception by the community is the strategic issue mostly impacted. Some groups or individuals tend to be against waste management companies in general which makes negative media coverage probable even if the project is operated responsibly. Still, some of the other sources of risk like a spill in the environment or odor emissions may lead to legitimate negative media coverage. This event is likely to be the consequence of the occurrence of other sources of risk. It is judged as a medium risk for the perception by the community. The risk is considered as low for profitability and availability of the feedstock because negative media coverage may discourage some clients from treating their organic waste with anaerobic digestion at EBI. Nonetheless, this probability is of lesser importance due to the regional location of the clients. j. High Competition Competition already exists in the waste management industry and EBI is used to this dynamic. The risk of a higher competition in the organic waste industry is probable, especially with the regulations coming in Quebec in 2020. This event poses a medium risk to the availability of feedstock explained by clients opting for a potentially cheaper competitor. High competition also represents a medium risk for profitability because it may force EBI to cut fees, reducing incomes. Finally, the loss of organic waste to competitors negatively influences costs and quality of the feedstock, creating scarcity in some types of feedstock or increasing storage requirements. These impacts are expected to be lesser important so this event is rated as a low risk for these two strategic issues. 96 k. Lower Efficiency of Energy Crops If EBI takes the decision to exploit energy crops there is a risk of lower efficiency than anticipated. Indeed, depending on the type of crops, the risk is variable but it is a fairly new activity in a cold climate; significant uncertainties exist. The lower quantities of organic material impact profitability and availability of the feedstock to a level judged as medium. Other organic material is treated in the digester and may balance the lack of the energy crops. Having the same energy spent, but producing less organic material, is also a medium risk for costs. Lower efficiency of energy crops is a high risk for the environmental impact of the project because additional energy is used to grow the crops and a lower efficiency may seriously undermine environmental benefits. A low risk is identified for the perception by the community explained as a consequence of the increased environmental impact of the project with this event. The risk management analysis constitutes a strong basis to formulate recommendations which can be found in the next section. 97 2.8 RECOMMENDATIONS Numerous recommendations emerge from the current thesis. The literature review, the investigation and the analysis represent a foundation guiding recommendations. The current section initially considers the small-scale project EBI targets in the short-term. Next, a global approach is taken to offer broad recommendations to EBI on anaerobic digestion. 2.8.1 On the Current Project As stated in EBI's objectives, the company desires to make a controlled investment of less than 1 million dollars in anaerobic digestion. By comparing with similar projects, a reasonable annual capacity corresponding to this initial investment roughly ranges from 1,000 to 2,000 tons. From the fifteen feedstock combinations compared in the MCA, many have a relatively high score but the four mixes shown in Table 42 stand out. They are all formed with a base recipe of food waste, dewatered septic systems sludge, liquid yeast and grease trap waste. Mixes 11, 14 and 15 include small amounts of other ingredients such as poultry manure, wasted activated sludge and whey permeate. The annual capacity of these combinations varies from 1,100 tons per year to 1,510 tons per year. The detailed composition of all the mixes as well as the other criteria evaluated can be found in Appendix E. 98 Table 42: Composition of the Optimal Feedstock Mixes Type of Feedstock Mix Food Waste 10. Food Waste, Dewatered Septic Systems Sludge and Grease Trap Waste 14. Food Waste, Dewatered Septic Systems Sludge, Poultry Manure, Wasted Activated Sludge and Grease Trap Waste 15. Food Waste, Dewatered Septic Systems Sludge, Poultry Manure, Wasted Activated Sludge, Grease Trap Waste and Whey Permeate 1,000 200 Dewatered Septic Systems Sludge Grease Trap Waste Liquid Yeast Total Mix 10 50 50 1,300 Food Waste 1,000 Dewatered Septic Systems Sludge 11. Food Waste, Dewatered Septic Systems Sludge, Poultry Manure and Grease Trap Waste (uty 200 100 Poultr M e Poultry Manure Grease Trap Waste Liquid Yeast Total Mix 11 50 50 1,400 Food Waste 1,000 Dewatered Septic Systems Sludge 200 Poultry Manure Wasted Activated Sludge Grease Trap Waste 100 100 Liquid Yeast Total Mix 14 50 50 1,500 Food Waste 1,000 Dewatered Septic Systems Sludge 200 Poultry Manure Wasted Activated Sludge Grease Trap Waste Liquid Yeast 100 100 Whey Permeate Total Mix 15 50 50 10 1,510 Based on the criteria observed and the MCA performed, the mix appearing as optimal is number 14. This combination generates high fees joined with high suitability and digestibility. It performs well in EBI's key parameters which justifies its selection. The quantity of food waste is based on pure feedstock; approximately 10% more waste is needed to account for non-organic material removed during pretreatment so an estimate of 1,100 tons per year of raw food waste is used.1 77 Nonetheless, Mix 14 has disadvantages worth mentioning. This recommendation is based on the fact that pretreatment of contaminated food waste may be efficient and 177 Levis et al., "Assessment of the State of Food Waste Treatment in the United States and Canada," 1490. 99 economically viable for EBI. This assumption needs to be tested and validated. In order to implement this choice, EBI also has to obtain a deal with the company operating the chicken slaughterhouse to treat some of their poultry manure. As mentioned previously, the facility annually produces about 8,000 tons and the recommended combination necessitates only 100 tons. In addition to this constraint, the large number of inputs, six, with different delivery schedules and pretreatment requirements may contribute to complicate operations. Yet, if Mix 14 is too hard to apply in practice, variations of this combination also seem interesting and a simpler version can reasonably be envisioned if pretreatment of food waste is successful. Prior to further phases of the project, laboratory testing is essential to properly characterize all the types of organic waste available to EBI. The data obtained may be used to reformulate mixes and detect potential inhibitors. Next, additional laboratory experiments where all the combinations are anaerobically digested are crucial to assess the behavior of the combinations in a situation close to the real operating conditions. Particular attention should be paid to pH on the acid end of the desired spectrum. The influence of codigestion on methane production can also be weighted by laboratory-scale anaerobic digestion. The information obtained can serve to perform an MCA similar to the one previously done to accurately identify the optimal mixes. The startup of the anaerobic digester is worth covering. Treatment of the organic waste is done by a consortium of bacteria but none are present when feedstock is initially inserted in the digester. According to Gerardi, the startup operation has to be done gradually and may have a duration of approximately a month for a well-designed treatment unit. Monitoring and control of pH and alkalinity are very important; pH has to range between 6.8 and 7.2 during that period. It is also possible, but optional, to seed bacteria in the digester to accelerate the startup. Gerardi suggests primary wastewater sludge or cow manure that both present strong bacterial assets. This initiating process is completed when the biogas produced contains an acceptable fraction of methane and the conditions in the anaerobic digester are stable.178 Once the startup of the facility is finished, a close monitoring of the internal environment is still necessary. Regular measurements of numerous parameters are useful to understand and control efficiently the operations: temperature; pH; alkalinity; total solids; volatile solids; C/N ratio; the evolution of COD during digestion; secondary products like volatile fatty acids, hydrogen and 178 Gerardi, The Microbiology of Anaerobic Digesters, 81-84. 100 ammonia; metals and biogas production and composition. 7 9 Indeed, analyses have a cost, but the capacity to continuously optimize the anaerobic digester represents a great potential. To implement such an optimization, a proper framework is needed to understand the internal environment of the treatment unit and perform adjustments on a continuous basis. Even if EBI presents a favorable case for energy crops, several reasons justify the recommendation to avoid this path for the moment. First, energy crops require additional infrastructure making them less suitable with the company's desire to do a limited investment in the current project. Second, technological deficiencies need to be improved to ensure reduced costs and environmental impacts as well as a positive energy balance of the system. Finally, EBI already has large quantities of organic waste available regionally and should aim toward the treatment of this material instead of growing new biomass. Managing organic waste is in line with the company's mission to integrate waste management, and sound from an ethical point of view. The current small-scale project is a good way for EBI to verify the concept before investing in large infrastructure. Experience gained on an anaerobic digester with a limited capacity may benefit the company and avoid costly mistakes on a major project. Also, the ability to efficiently perform pretreatment is vital to the project, especially in the case food waste is selected. The potential risks with a small project are more acceptable for EBI due to the lesser investments at stake. In this situation, when high-risk events occur, such as contaminated feedstock, presence of inhibitors or odor emissions, and they are more costly than expected to address, at least the company goes through a very important learning process. These risks may be mitigated more efficiently in a larger project when practical experience is obtained from a small-scale facility. 2.8.2 On a Global Perspective The potential to scale the selected mix is an important element to evaluate. Table 43 compares the recommended quantity of each feedstock in Mix 14 with the quantity received by EBI in 2013 and potential additional quantities before calculating a scalability factor. This factor is obtained by dividing the quantity available of a given feedstock by the quantity recommended in Mix 14. At first sight, the limiting ingredient appears to be liquid yeast with a scalability factor 179 Wellinger, Murphy, and Baxter, The Biogas Handbook, 2013, 231. 101 of 2; this type of feedstock may be added to fulfill micronutrient requirements and Gerardi recommends a minimum of 1.5 kg/m 3 which is far below the recommended 50 tons per year in a mix of 1,500 annual tons.180 If the density of water of 1 ton per cubic meter is used to convert the tons of feedstock to volume, the annual volume is 1,500 M3 which is a conservative assumption because it overestimates the volume of substrate. Therefore, the minimum quantity stated by Gerardi for the recommended combination is 2.25 tons of yeast per year which theoretically brings the scalability factor of liquid yeast to over 44. Dewatered septic systems sludge is the other feedstock with a low potential for scalability. A lower ratio of this feedstock, or none as in Mix 9, still appears to be acceptable and might not have a major impact on the treatment. The same principle applies to grease trap waste and wasted activated sludge which are complementary; a reduced fraction may be viable. The main limiting type of waste is food waste with a scalability factor of 12.5. This is the core ingredient in the mix which limits scalability potential. The quantity of food waste received in 2013 found in Table 45 is on a pure basis which is estimated to be 90% of the total mass collected.' 8' Table 43: Evaluation of the Scalability of the Types of Waste in Mix 14 Recommended Type of Waste Quantity (MT/year) Food Waste Dewatered Septic Systems Sludge Poultry Manure Quantity Received in 2013 (MT) Potential Quantity (MT) Scalability (QTY Available /Recommended QTY) 1,000 11,700 800 12.5 200 1,100 - 5.5 100 100 1,200 Grease Trap Waste 50 500 Liquid Yeast 50 100 Wasted Activated 8,000 - 80.0 12.0 - 10.0 Sludge 2.0 Mix 14 with the maximum quantities available to EBI as of 2013 is shown in Table 44 with the main parameters of the mix. The different fractions of liquid yeast, dewatered septic systems sludge and grease trap waste do not seem to affect the global performance of the combination. The other concerns related to scalability are the large-scale pretreatment of food waste, Gerardi, The Microbiology of Anaerobic Digesters, 96. 181 Levis et al., "Assessment of the State of Food Waste Treatment in the United States and Canada," 1490. 180 102 homogeneity of the substrate throughout the treatment, and the storage of dewatered septic systems sludge, grease trap waste and liquid yeast. Nonetheless, the recommended mix appears to be scalable by a factor of 12.5 if the practical elements raised are addressed. Table 44: Parameters Calculated for the Scaled Mix 14 Mix Food Waste Poultry Manure Wasted Activated Sludge Dewatered Septic Systems Sludge Quantity (TVI/year) C/N Ratio (/N) Methane Production 3 Dry DH Matter (%) (X10 (in 3 CHIMi) M Fee 3 CH 4 /year) ($/year) 12,500 1,250 18 74 7.5 5.5 10 19 29.4-47.8 53.7 367.5-597.2 67.1 ,200 9 7.0 5 15.0 18.0 61,200 1,100 14 7.0 38 127.6 140.4 16,500 Grease Trap Waste 500 10-39 5.0 15 63.2-77.9 Liquid Yeast 100 4 5.7 18 97.2-145.8 31.6-39.0 9.7-14.6 37,500 5,600 16,650 21-22 6.2 12 38.1-52.6 634.3-876.2 995,800 Total Scaled Mix 14 750,000 125,000 To reduce the risks associated with availability, EBI may obtain long-term waste treatment agreements when possible. Clients from the public sector are bound to public tenders which typically last for less than five years. Most of the food waste and wasted activated sludge originates from such entities. Nonetheless, it is possible to sign contracts with private companies to guarantee reception of feedstock over a longer period of time. It may be particularly convenient for EBI to bond with the owner of the poultry slaughterhouse. Additionally, the client providing the liquid yeast has two years left to its contract, so this feedstock needs to be secured. Grease trap waste and septic systems sludge are both coming from aggregates of numerous companies and individuals which complicates the situation. The septic systems collection company owned by EBI, L6veill6 Fosses Septiques, delivers the major fraction of these two types of waste; this is a recognized company in the regional market and it can rely on a certain loyalty from its clients. The rest of the grease trap waste and septic systems sludge is delivered by independent brokers. As large-scale anaerobic digestion of organic waste is relatively new in Quebec, there may be a regional first mover advantage for EBI. This waste treatment has a smaller environmental footprint than landfill and may attract companies concerned by their impact on environment and their image. However, as mentioned previously, many projects are expected in the near future 103 meaning this competitive advantage might only exist for a few years. Note that only about 20% of the 4.4 million tons of organic waste generated in the province in 2010 were valorized which is a market with a tremendous potential for expansion where a large number of treatment facilities may coexist.1 82 Being a well-known member in the waste management industry in Quebec, EBI has to lead in innovating practices such as anaerobic digestion and ensure a strategic position while competition is low. It is clear that an anaerobic digestion project managed by EBI can have a positive impact on the regional and provincial waste management landscape especially with the new regulations coming in Quebec in 2020 prohibiting landfilling of putrescible organic waste.' 83 However, this project has to be set in a broader perspective; EBI is a corporate citizen of the world, with its rights and duties like any other entity. The company thrived with a continuous growth over the past decades and wishes to sustain a responsible development. Such a desire may be fulfilled with an awareness and leadership in the context of climate change. The planet faces countless global environmental problems, caused by humans, like global warming, sea level rise,' 4 ocean acidification' 8 5 and so on. These long-term consequences are mostly caused by massive combustion of fossil fuels.' 86 Indeed, energy is a necessity for the high consumption lifestyle adopted in developed countries. As tiny as it may appear, EBI can have a positive impact on a global scale by establishing more responsible waste management practices regionally. This anaerobic digestion project is a potential innovation that may set the standards for the future and contribute to preserving the Earth for generations to come. 182 Recyc-Qu6bec, Bilan 2010-2011 de la gestion des matibres r6siduelles au Qu6bec, 8. 183 Direction des mati&es r6siduelles et des lieux contamin6s, Service des matibres r6siduelles, Banissement des matibres organiques de 1'elimination au Qu6bec: dtat des lieux et prospectives, VII. 184 Tester, Sustainable Energy, 204. 185 Stephens, "Ocean Acidification," 1065. 186 Cheng, Biomass to Renewable Energy Processes., 2. 104 BIBLIOGRAPHY Alkanok, Gizem, Burak Demirel, and Turgut T. Onay. "Determination of Biogas Generation Potential as a Renewable Energy Source from Supermarket Wastes." Waste Management 34, no. 1 (January 2014): 134-40. doi:10.1016/j.wasman.2013.09.015. 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Energy Conversion and Management 75 (November 2013): 21-24. doi:10.1016/j.enconman.2013.05.037. 108 187 Organic Content 44.2 460 9.6 80 12 4 Carbohydrates, proteins, lipids Stomach/intestine content, pig 150-350 200-500 300-550 250-500 80-90 90 90 75 70-90 60-70 20-25 15-20 90 125 18 35 Wellinger, Murphy, and Baxter, The Biogas Handbook, 2013, 21-22. (Continuedon next page) Plant wastes and by-products Carbohydrates, lipids Straw Carbohydrates, lipids Garden wastes Carbohydrates, lipids Grass Carbohydrates, lipids Fruit wastes 38.4 400 9.6 80 12 4 Carbohydrates, proteins, lipids Stomach/intestine content, cattle 48.0 300 16.0 80 20 Carbohydrates, proteins, lipids 12.6 300 4.0 80 5 Poultry manure, solid 7 Carbohydrates, proteins, lipids Poultry droppings 32.0 200 16.0 80 20 Carbohydrates, proteins, lipids 12.8 200 6.4 80 8 Cattle manure, solid 13 Carbohydrates, proteins, lipids 48.0 300 16.0 80 20 Cattle slurry 12.0 Methane Production 3 3 (M CH 4/m ) 300 Methane Yield 3 CH4 /MT VS) ( 4.0 Volatile Solids (%) 80 Volatile Solids (% of Dry Matter) 5 (%) Dry Matter Carbohydrates, proteins, lipids 7 C/N Ratio Pig manure, solid Animal Wastes and by-products Carbohydrates, Pig slurry proteins, lipids Type of Feedstock 187 APPENDIX A: CHARACTERISTICS OF SOME BIOGAS FEEDSTOCK Carbohydrates 90 30-50% lipids 90% vegetable oil 40% alcohol *Fish oil *Soya oil/margarine *Alcohol 20 Brewers spent grains Energy crops *indicates methane booster Food remains 10 10 Concentrated wastewater sludge 5 Wastewater sludge Sewage sludge Fodder beet silage Maize silage Grass silage 15-40 24 Olive pulp *Glycerine 98 40 *Bleach clay 17 8.5 95 91 12.6 Thin silage (grain) 80 75 75 90 90 96 40 95 90 90 86 90 1-5 80 90 90 Volatile Solids (% of Dry Matter) Fermentation slop Whole silage (grain) 7 65-70% lactose, 30-35% lipids Flotation sludge 5 10 75-80% lactose, 20-25% protein (%) Dry Matter Concentrated whey C/ Ratio 5 Organic Content Organic wastes from industries Whey 75-80% lactose, 20-25% protein Type of Feedstock (Continuedfrom previous page) 7.5 3.75 18.0 23.0 39.2 38.0 85.5 81.0 7.3 11.5 4.0 9.0 4.5 (%) Volatile Solids 500-600 400 400 <450 330 180 800 400 800 800 500 470 350-780 540 540 330 (m Methane Yield (ml CH4/MT VS) 30.0 15.0 59.4 41.4 313.6 152.0 684.0 648.0 36.5 53.9 21.6 31.5 15.0 Methane Production 3 CH 4/m 3) APPENDIX B: ORGANIC WASTE MANAGED BY EBI IN 2013 Quantities (Mtyer Client Location Sources Types Multiple Multiple Septic Systems Kraft Montreal Industrial Multiple Multiple Residential Metro Beaulieu Ste-Julienne Berthierville Grocery Store Dewatered Septic Systems Sludge Food Processing Organic Waste Food waste Food waste Joliette Sorel-Tracy Cafeteria St-Charles-Borromee Joliette Joliette Restaurant St-Charles-Borromee Joliette Restaurant Berthierville St-Esprit Restaurant St-Felix Ste-Julienne Ste-Julienne Restaurant St-Jacques St-Esprit Cafeteria St-Hubert Firestone St-Hubert Jardin D'Aphrodite Annexe i Rolland Brulerie du Roy Rotisserie Benny Holcim Rotisserie Benny Rotisserie Benny Rotisserie Benny Camp N-D des Petits Lemire Fruits et LUgumes College Esther-Blondin CPE Bout en Train+OMH Multiple Restaurant Restaurant Cafeteria Restaurant Cafeteria Restaurant Cafeteria Grocery Store Cafeteria Multiple Joliette Berthierville (MT/year) Food waste Food waste Food waste Food waste Food waste Food waste 3.3 Food waste Food waste Grease trap 1.6 Cafeteria Grease trap Ville de Repentigny Repentigny City Centre Nouveau Regard Notre-Dame-de-Lourdes Notre-Dame-des-Prairies Cafeteria Joliette Berthierville Grocery Store Berthierville Berthierville Industrial Grease Grease Grease Grease Grease Grease Centre Jeunesse Joliette Youth Center COOP Profid'Or Joliette Rawdon Lavaltrie L'Assomption Agriculture IGA Fromagerie Domaine Feodal Olymel Harvey's CPE Rawdon Club de Golf Lavaltrie Ville de L'Assomption Grocery Store Cheese Restaurant (Continued on next page) 111 14.2 14.2 10.6 4.1 3.3 1.7 1.7 1.6 299.1 64.4 40.8 10.3 18.4 trap trap trap trap trap trap 9.3 9.0 Grease trap Grease trap Grease trap 4.5 Restaurant Grease trap Grease trap City Grease trap Kindergarten 35.4 7.1 Comission Scolaire IGA 53.1 49.5 42.5 Food waste Food waste Food waste Restaurant Chez Henri Restaurant 12,744.7 17.7 St-Charles-Borromee Rawdon Club de Golf Berthier Bakery 251.2 Food waste Food waste Food waste Food waste Grease trap Grease trap Grease trap Signature & Passion 1,096.0 7.3 7.2 7.1 6.0 4.1 3.6 3.3 2.8 1.5 (Continuedfrom previous page) Client Location Source of Waste Multiple Multiple Residential Lawn Clippings 8,398.7 Multiple Multiple Residential Leaves 4,265.9 Fleischmann Montreal Industrial Liquid Yeast Multiple Multiple Sewage Kraft Montreal Industrial Wasted Activated Sludge Whey Permeate TOTAL Type of Waste (Mtyr) M/er 100.0 1,181.5 2,500.0 31,298.1 112 TOTAL 11,281.0 100 Unknown Agricultural Multiple No Multiple Farmers 2,500.0 Industrial Montreal No Kraft 100 Poultry Manure Rinsing Water from Food Processing Industry Straw Industrial Berthierville No Olymel 2,500.0 Food waste Grocery Store St-Michel-des-Saints Yes Provigo 39.4 Food waste Food waste Food waste Grocery Store Restaurant Grocery Store Rawdon Yamachiche Louiseville Yes Yes Yes IGA Porte de la Mauricie IGA 8,000.0 57.5 56.7 54.6 65 65 65 88.4 87.3 84.0 65 61.1 65 94.0 Restaurant Yes 100 122.9 73.3 65 65 189.1 112.8 Food waste Food waste Food waste Grocery Store Grocery Store Yes Yes IGA Crevier Metro Vercheres Henri 60.6 130.8 65 201.2 Food waste Grocery Store Notre-Dame-desPrairies Repentigny Verch&es St-Charles Borromee Yes IGA 8000.0 184.7 65 284.1 Food waste Grocery Store Sorel-Tracy Waste Quantity of Organic Waste (MT/year) Estimated Organic Fraction (%) Initial Quantity Q ani (MT/year) Yes Location Type of Waste aste IGA Managed by EBI C: OTHER POTENTIAL ORGANIC WASTE Client APPENDIX Element (mg/kg) 6.5 25 - Sludge' 8 8 Wasted Activated - - 350 - - - - - waste 9 0 Grease Geae trap 114,500 < 0.01 4,770 4,500 - Wate Food waste' 8 9 879,450 < 3.3 31,307 7,974 922 4,674 Manure Poultry 191 Type of Waste 1,573 < 15 22,500 0.2 482 6,930 58 - Systems Sludge 9 Dewatered Septic Se s 499,000 5 0.2 22,000 4,000 2,960 - Organic Waste 9 Food Processing Prgc PARTIAL CHEMICAL COMPOSITION OF SOME TYPES OF ORGANIC WASTE Carbon Cobalt Iron Nickel Nitrogen Phosphorus Potassium Sulfur D: 188 Perron and H6bert, "Caracterisation des boues d'6puration municipales Partie II : EI6ments traces mdtalliques," 44. 189 Zhao and Ruan, "Biogas Performance from Co-Digestion of Taihu Algae and Kitchen Wastes," 22.; Alkanok, Demirel, and Onay, "Determination of Biogas Generation Potential as a Renewable Energy Source from Supermarket Wastes," 136-139. 90 Silvestre et al., "Biomass Adaptation over Anaerobic Co-Digestion of Sewage Sludge and Trapped Grease Waste," 6831. 191 EBI's Potential Client 192 EBI 193 Carucci et al., "Anaerobic Digestion of Food Industry Wastes," 1038. APPENDIX 2,800 67,750 61,200 51.00 26.0-29.2 18.0 6.3-7.8 4.9-7.3 77.2-81.1 20.0-22.5 15.0 53.7 63.2-77.9 63.2-77.9 97.2-145.8 49.8-52.3 6 5 19 15 18 7 5 38 15 18 15 5.5 1.0 32 100 20 7.4 1.0 1.3 100 20 8.1 6.3 7.0 5.5 5.0 5.7 6.1 7.0 6.9 5.0 5.7 6.1 9 9 74 10-39 4 14-15 9 14 10 4 10-12 1,300 1,200 100 50 50 1,400 1,000 400 100 50 1,550 Wasted Activated Sludge Poultry Manure Grease Trap Waste Liquid Yeast Total Mix 3 Wasted Activated Sludge Dewatered Septic Systems Sludge Grease Trap Waste Total Mix 2 56.00 52.12 4.9-7.3 97.2-145.8 18 20 Liquid Yeast Total Mix 4 75.00 56.00 43.42 7,500 2,800 67,300 6,000 51,000 51.00 15.0 15.0 15.00 2,800 77,750 56.00 55.54 4.9-7.3 31.4-34.6 97.2-145.8 22.4-24.7 51.0 3,750 75.00 127.6 10,000 100.00 5.4 3.2-3.9 3,750 5.7 75.00 5 15 1.0 100 1,200 50 50 Wasted Activated Sludge Grease Trap Waste Liquid Yeast 7.0 5.0 6.1 9 1,275 Total Mix 1 9 10-39 4 66,375 61,200 52.06 51.00 26.1-28.5 18.0 3.2-3.9 61,200 2,800 2,375 51.00 56.00 20.4-22.4 15.0 63.2-77.9 4.5 23 25 Processing Industry (Continued on next page) Trap Waste 4. Wasted Activated Sludge, Dewatered Septic Systems 3. Wasted Activated Sludge, Poultry Manure and Grease Trap Waste 2. Wasted Activated Sludge and Grease $/er 95.00 18.0 4.9-7.3 15.0 97.2-145.8 ($M) Fee ($/MT)e ($/year) 3.2 CH 4Iyear) ethan PrO Methane Production (nC4M) 3 6 320 5 18 1.0 20 (%) Matter (X 0 7) 7.9 Sludge and Rinsing 9 4 7.0 5.7 C/NDry pH (/N) Ratio 128.3 Rinsing Water from Food 1. Wasted Activated 1,200 50 Quantiy Quany (Tya) 15 Wasted Activated Sludge Liquid Yeast from Food WaterWaterfromFood Processing Industry Type of Feedstock Mix APPENDIX E: DETAILED DESCRIPTION OF THE MIXES 18 4 23 17 1,000 50 25 1,075 1,000 100 50 50 1,200 Food Waste Liquid Yeast Rinsing Water from Food Processing Industry Total Mix 8 Food Waste Poultry Manure Grease Trap Waste Liquid Yeast Total Mix 9 4 22-23 18 74 10-39 4 17-18 50 1,100 Liquid Yeast Total Mix 7 (Continued on next page) 9. Food Waste, Poultry Manure and Grease Trap Waste 8. Food Waste and Rinsing Water from Food Processing Industry 7. Food Waste and Grease Trap Waste 4 50 10-39 40 9-11 18 10-39 9 1,100 9 25 25 1,200 1,000 50 6. Wasted Activated 1,270 5.7 6.1 7.5 5.5 5.0 6.1 4.5 20 7.9 32 100 0.32 8.6 320 18 11 19 15 10 10 15 97.2-145.8 35.7-53.6 53.7 63.2-77.9 29.4-47.8 34.9-54.2 128.3 56.00 63.79 75.00 3.2-3.9 4.9-7.3 42.8-64.3 100.00 60.00 60.63 95.00 5.4 29.4-47.8 37.5-58.3 3.2 2,800 76,550 3,750 10,000 60,000 65,175 2,375 60,000 2,800 60.00 56.00 29.4-47.8 4.9-7.3 29.4-47.8 97.2-145.8 10 18 0.32 20 7.5 5.7 2,800 66,550 56.00 60.50 4.9-7.3 37.4-59.0 97.2-145.8 34.0-53.6 18 11 20 5.7 5.7 6.2 1,875 1,500 62,275 60,000 2,800 56,100 65,900 1,900 3,750 56.00 51.00 51.89 95.00 75.00 60.00 51.90 60.00 75.00 4.9-7.3 16.5 32.3-34.7 9.4 1.6-1.9 5.7-6.1 28.6-31.8 29.4-47.8 3.2-3.9 97.2-145.8 15.0 25.4-27.3 469.8 63.2-77.9 226.8-243.0 23.8-26.5 29.4-47.8 63.2-77.9 18 5 6 15 60 7 10 15 20 1.0 6.7 1.00 13-790 4.1-20 0.32 1.00 5.0 4.1-5.9 5.7-6.4 7.5 5.0 5.7 7.0 6.2 58 4-28 20 320 2,800 56.00 4.9-7.3 97.2-145.8 18 20 5.7 4 50 4.5 61,200 ($/year) 51.00 ($/MT) Fee 18.0 Methane Production CH 4[MT) (X10 3 M 3 CH 4/year) 15.0 3 5 (x 1.0 Dry Matter 7.0 [H+] (x10) 9 C/N Ratio pH (/N)T(%) 1,200 Quantity (MT/year) Grease Trap Waste Leaves Total Mix 6 Food Waste Grease Trap Waste Wasted Activated Sludge Liquid Yeast Trap Waste and Leaves Liquid Yeast Food Processing Organic Waste Total Mix 5 Wasted Activated Sludge Type of Feedstock 5. Wasted Activated Sludge and Food Processing Organic Waste Mix (Continuedfrom previous page) 3,750 2,800 69,550 60,000 75.00 56.00 53.50 60.00 3.2-3.9 4.9-7.3 62.9-84.5 29.4-47.8 25.5 63.2-77.9 97.2-145.8 48.4-65.0 29.4-47.8 127.6 15 18 15 10 100 20 5.1 0.32 5.0 5.7 6.3 7.5 6.9 18 14 1,000 60 12 226.8-243.0 37.7-57.4 1,500 66,175 13-790 3.8-22 60.00 60.16 4.1-5.9 5.7-6.4 5.7-6.1 41.5-63.1 40-80 18-19 75.00 1.6-1.9 25 1,100 1,875 56.00 4.9-7.3 97.2-145.8 63.2-77.9 18 15 Leaves Total Mix 13 60,000 60.00 29.4-47.8 29.4-47.8 10 0.32 20 100 7.5 5.7 5.0 18 4 10-39 1,000 50 25 Food Waste Liquid Yeast Grease Trap Waste 2,800 65,175 60.63 2,375 46.0-66.8 95.00 42.8-62.1 11.7 11 469.8 8.6 58 6.1 320 3,750 10,000 17-18 4.5 75.00 1,075 4 100.00 5.4 3.2-3.9 Total Mix 12 (Continued on next page) Leaves Waste and 13. Food Waste, Grease Trap Organic Waste Processing 25 2,800 56.00 4.9-7.3 12. Food Waste and Food Organic Waste 60,000 60.00 29.4-47.8 29.4-47.8 97.2-145.8 10 18 0.32 20 7.5 5.7 18 4 1,000 50 Food Waste Liquid Yeast Food Processing 2,800 79,550 56.00 56.82 4.9-7.3 68.3-89.9 97.2-145.8 48.8-64.2 18 15 20 6.9 5.7 6.2 4 21-22 19 15 53.7 63.2-77.9 50 1,400 32 100 3,000 Liquid Yeast Total Mix 11 5.5 5.0 15.00 Grease Trap Waste 74 10-39 38 100 50 1.3 200 ewatered D 11. Food Waste, Systems Sludge Poultry Manure Grease Trap Waste 3,000 Septic Systems Sludge, Poultry Manure and 15.00 Food Waste DwtrdSpi ewatered Septic 25.5 60,000 60.00 10-39 4 17-18 127.6 29.4-47.8 50 50 1,300 38 1.3 29.4-47.8 Grease Trap Waste Liquid Yeast Total Mix 10 7.5 6.9 18 14 ($/year) ($/MT) Sludge and Grease Trap Waste 1,000 200 pH Ratio (/N) Systems Sludge Fee Septic Systems 10 CH 4/year) Methane Production (m CH 4/MT) (X103 M Food Waste Dewatered Septic 0.32 (%) Dry Matter [H+] (x104) 10. Food Waste, Dewatered (M/ea) C/N Type of Feedstock ntity Qua Mix (Continuedfrom previouspage) 00 Dewatered SepticS Systems Sludge, Poultry Manure, Wasted Activated Sludge, Grease Trap Waste and Whey Permeate 14. Food Waste, Dewatered Septic Systems Sludge, Poultry Manure, Wasted Activated Sludge and Grease Trap Waste Mix 4 17-18 50 1,500 1,000 Food Waste Poultry Manure Wasted Activated Sludge Grease Trap Waste Liquid Yeast Whey Permeate Total Mix 15 10-39 50 5.0 5.7 4.5 6.1 74 9 10-39 4 5 21-22 50 50 10 1,510 5.5 7.0 7.5 5.7 6.2 100 100 18 5.5 7.0 74 9 100 100 5.0 6.9 14 200 Dewatered Septic Systems Sludge Poultry Manure Wasted Activated Sludge Grease Trap Waste Liquid Yeast Total Mix 14 pH 7.5 C/N Ratio 18 1,000 Quantity (MT/year) Food Waste Feedstock Type of (Continuedfrom previouspage) [Hi] 3,750 2,800 950 85,600 56.00 95.00 56.69 4.9-7.3 0.1-0.2 70.0-91.6 97.2-145.8 14.9-24.3 46.3-60.7 18 7 14 20 320 8.6 5,100 10,000 75.00 51.00 100.00 60,000 2,800 84,650 3,750 5,100 3.2-3.9 1.5 5.4 60.00 56.00 56.43 75.00 51.00 63.2-77.9 15.0 53.7 29.4-47.8 4.9-7.3 69.8-91.4 3.2-3.9 1.5 15 5 19 29.4-47.8 97.2-145.8 46.5-60.9 18 14 10 63.2-77.9 15 15.0 100 1.0 32 0.32 20 6.6 100 5 1.0 10,000 100.00 5.4 53.7 19 32 3,000 15.00 25.5 127.6 38 60,000 ($/year) 60.00 ($/MT) Fee 29.4-47.8 1.3 Methane Production 3 CH4MT) C 4 e ) 29.4-47.8 Dry Matter 10 0.32 (X10-7) 3 3 2 12 12 2 6 14 16 3.5 14 14 2.5 10 2 2 2 4 2 4 4 8 3 3 2 6 1 3 2 6 2 1 2 2 3 6 3 6 3 6 1.5 2.5 2.5 3 1 1 2.5 2.5 2 2 6 4 12 3 9 2 6 3 9 2 6 Value Score Value Score Value Score Value Score Value Score Value 7. Food Waste and Grease Trap Waste 9. Food Waste, Poultry Manure and Grease Trap Waste 2. Wasted Activated Sludge and Grease Trap Waste (Continued on next page) 3 1 4 3.5 2 1 6 1 1 1.5 1 1 2 1 1 3.5 6 1 3 2 4 6 3 2 1 6 1 6 12 16 4 2 4 3 4 12 16 2 2 3 Score 2 1 3 4 4 1 12 14. Food Waste, Dewatered Septic Systems Sludge, Poultry Manure, Wasted Activated Sludge and Grease Trap Waste 10. Food Waste, Dewatered Septic Systems Sludge and Grease Trap Waste 15. Food Waste, Dewatered Septic Systems Sludge, Poultry Manure, Wasted Activated Sludge, Grease Trap Waste and Whey Permeate 11. Food Waste, Dewatered Septic Systems Sludge, Poultry Manure and Grease Trap Waste Value 3 3 4 2 3 1 2 1 1 3 3 4 Inhibitors Digestibility Suitability Purity Odor During Treatment Availability Criterion Weight Score Fe Diversion of waste Before Treatment F: SCORES AND VALUES OF THE MCA Mix APPENDIX 47 47.5 49 50 50.5 51.5 53 TOTAL VALUE 2 6 1 3 2 6 2 6 1 3 1 3 2 6 1 3 2 8 1.5 6 2.5 10 1 4 6 4 8 1 2 3 6 6 2 6 2 6 2 6 6 4 8 2 4 2 4 2 2.5 2.5 1 1 2 2 6 2 6 2 6 1 3 Value Score Value Score Value Score Value 13. Food Waste, Grease Trap Waste and Leaves 6. Wasted Activated Sludge, Grease Trap Waste and Leaves 6 3 9 2 2 8 3 3 6 2 2 6 3 2 2 2 Score 2.5 1 5. Wasted Activated Sludge and Food Processing Organic Waste 1. Wasted Activated Sludge and Rinsing Water from Food Processing Industry 6 Value 2.5 3 3 10 8 3 6 3.5 9 Value 2 1 1 2.5 4 1 3 3.5 3 Score 3. Wasted Activated Sludge, Poultry Manure and Grease Trap Waste Score 2 2.5 7.5 3 12 1 2 2 6 3 6 1 1 2 6 Score Value 12. Food Waste and Food Processing Organic Waste 4. Wasted Activated Sludge, Dewatered Septic Systems Sludge and Grease Trap Waste 3 6 12 4 6 8 1.5 6 Value 6 1 3 2 3 3 4 Inhibitors 2 2 Digestibility 2 3 Suitability 2 4 Purity 1 1.5 Odor 3 2 Availability During Treatment Weight Score Diversion Before Treatment Criterion 8. Food Waste and Rinsing Water from Food Processing Industry Mix (Continuedfrom previous page) 34 41 42.5 43 45.5 45.5 46.5 46.5 TOTAL VALUE