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CGE Training Materials National Greenhouse Gas Inventories

CGE Training Materials National Greenhouse Gas Inventories. Waste Sector Version 2, April 2012. Target Audience and Objective from Training Materials.

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CGE Training Materials National Greenhouse Gas Inventories

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  1. CGE Training MaterialsNational Greenhouse Gas Inventories Waste Sector Version 2, April 2012 Consultative Group of Experts (CGE)

  2. Target Audience and Objective from Training Materials • These training materials are suitable for people with beginner to intermediate level knowledge of national greenhouse (GHG) inventory development. • After having read this Presentation, in combination with the related documentation, the reader should: • Have an overview of how emissions inventories are developed for the waste sector; • Have a general understanding of the UNFCCC and IPCC guidelines; • Be able to determine which methods suits their country’s situation best; • know where to find more detailed information on the topic discussed. • These training materials have been developed primarily on the basis ofmethodologies developed by the IPCC; hence the reader is always encouraged to refer to the original documents to obtain further detailed information on a particular issue. 2 Consultative Group of Experts (CGE) Training Materials for National Greenhouse Gas Inventories

  3. Acronyms • BOD Biochemical oxygen demand • DOC Degradable Organic Carbon • EFDB IPCC Emission Factor Database • GHG Greenhouse Gas • GPG Good Practice Guidance • MSW Municipal Solid Waste • SWDS Solid Waste Disposal Site 3 Consultative Group of Experts (CGE) Training Materials for National Greenhouse Gas Inventories

  4. Outline of course – Waste Sector • Introduction (slide 5) • Definitions (slide 7) • Revised 1996 IPCC Guidelines (slide 29) • Good Practice Guidance and Uncertainty Management in National Greenhouse Gas Inventories (slide 46) 4 Consultative Group of Experts (CGE) Training Materials for National Greenhouse Gas Inventories

  5. Introduction • GHG inventories for the biological sectors, such as waste, are characterized by: • Methodological limitations • Lack of data or low reliability of existing data • High uncertainty. • This presentation aims to assist non-Annex I (NAI) Parties in preparing GHG inventories using the Revised 1996 IPCC Guidelines, particularly in the context of UNFCCC decision 17/CP.8, focusing on: • The need to shift to the IPCC good practice guidance (2000) and higher tiers/methods to reduce uncertainty • Complete overview of the tools and methods • Use of UNFCCC inventory software and EFDB • Review of activity data and emission factors and options to reduce uncertainty • Use of key sources, methodologies and decision trees. 5 Consultative Group of Experts (CGE) Training Materials for National Greenhouse Gas Inventories

  6. NAI Party examples • Examination of national communications • GHG inventories show that the waste sector may be significant in NAI countries • Commonly a significant source of CH4 • In some cases, a significant source of N2O • Solid waste disposal sites (SWDS) frequently a key source of CH4 emissions. 6 Consultative Group of Experts (CGE) Training Materials for National Greenhouse Gas Inventories

  7. Definitions • Waste emissions – Includes GHG emissions resulting from waste management activities (solid and liquid waste management, excepting CO2 from organic matter incinerated and/or used for energy purposes). • Source – Any process or activity that releases a GHG (such as CO2, N2O, CH4) into the atmosphere. 7 Consultative Group of Experts (CGE) Training Materials for National Greenhouse Gas Inventories

  8. Definitions (cont.) • Activity Data – Data on the magnitude of human activity, resulting in emissions during a given period of time (e.g. data on waste quantity, management systems and incinerated waste). • Emission Factor – A coefficient that relates activity data to the amount of chemical compound that is the source of later emissions. Emission factors are often based on a sample of measurement data, averaged to develop a representative rate of emission for a given activity level under a given set of operating conditions. 8 Consultative Group of Experts (CGE) Training Materials for National Greenhouse Gas Inventories

  9. Revised 1996 IPCC Guidelines andIPCC good practice guidance (2000) Approach and steps 9 Consultative Group of Experts (CGE)

  10. Emissions from Waste Management • Decomposition of organic matter in wastes (carbon and nitrogen) • Waste incineration (these emissions are not reported when waste is used to generate energy). 10 Consultative Group of Experts (CGE) Training Materials for National Greenhouse Gas Inventories

  11. Decomposition of Waste • Anaerobic decomposition of man-made waste by methanogenic bacteria • Solid waste • Land disposal sites • Liquid waste • Human sewage • Industrial waste water. • Nitrous oxide emissions from waste-water are also produced from protein decomposition. 11 Consultative Group of Experts (CGE) Training Materials for National Greenhouse Gas Inventories

  12. Land Disposal Sites • Major form of solid waste disposal in developed world • Produces mainly methane at a diminishing rate, taking many years for waste to decompose completely • Also carbon dioxide and volatile organic compounds produced • Carbon dioxide from biomass not accounted or reported elsewhere. 12 Consultative Group of Experts (CGE) Training Materials for National Greenhouse Gas Inventories

  13. Decomposition Process • Organic matter into small soluble molecules (including sugars) • Broken down to hydrogen, carbon dioxide and different acids • Acids are converted to acetic acid • Acetic acid with hydrogen and carbon dioxide are substrate for methanogenic bacteria. 13 Consultative Group of Experts (CGE) Training Materials for National Greenhouse Gas Inventories

  14. Methane from Land Disposal • Volumes • Estimates from landfills: 20–70 Tg/yr • Total human methane emissions: 360 Tg/yr • From 6% to 20% of total. • Other impacts • Vegetation damage • Odours • May form explosive mixtures. 14 Consultative Group of Experts (CGE) Training Materials for National Greenhouse Gas Inventories

  15. Characteristics of the Methanogenic Process • Highly heterogeneous • However, relevant factors to consider: • Waste management practices • Waste composition • Physical factors. 15 Consultative Group of Experts (CGE) Training Materials for National Greenhouse Gas Inventories

  16. Waste Management Practices Aerobic waste treatment • Produces compost that may increase soil carbon • No methane. Open dumping • Common in developing regions • Shallow, open piles, loosely compacted • No control for pollutants, scavenging frequent • Anecdotal evidence of methane production • An arbitrary factor, 50% of sanitary land filling, is used. 16 Consultative Group of Experts (CGE) Training Materials for National Greenhouse Gas Inventories

  17. Waste Management Practices (cont.) Sanitary landfills • Specially designed • Gas and leakage control • Scale economy • Continued methane production. 17 Consultative Group of Experts (CGE) Training Materials for National Greenhouse Gas Inventories

  18. Waste Composition • Degradable organic matter can vary: • Highly putrescible in developing countries • In developed countries, due to higher paper and card content, less putrescible. • This affects stabilization and methane production: • Developing countries: 10–15 years • Developed countries: more than 20 years. 18 Consultative Group of Experts (CGE) Training Materials for National Greenhouse Gas Inventories

  19. Physical Factors Moisture essential for bacterial metabolism: • Factors: initial moisture content, infiltration from surface and groundwater, as well as decomposition processes. Temperature: 25–40°C required for a good methane production. 19 Consultative Group of Experts (CGE) Training Materials for National Greenhouse Gas Inventories

  20. Physical Factors (cont.) Chemical conditions • Optimal pH for methane production: 6.8 to 7.2 • Sharp decrease of methane production below 6.5 pH • Acidity may delay the onset of methane production. Conclusion • Data availability is too poor to use these factors for national or global methane emissions estimates. 20 Consultative Group of Experts (CGE) Training Materials for National Greenhouse Gas Inventories

  21. Methane Emissions • Depend on several factors • Open dumps require other approaches • Availability and quality of relevant data. 21 Consultative Group of Experts (CGE) Training Materials for National Greenhouse Gas Inventories

  22. Wastewater Treatment • Produces methane, nitrous oxide and non-methane volatile organic compounds • May lead to storage of carbon through eutrophication. 22 Consultative Group of Experts (CGE) Training Materials for National Greenhouse Gas Inventories

  23. Methane Emissions from Wastewater Treatment • From anaerobic processes without methane recovery • Volumes • 30–40 Tg/yr • About 8%–11% of anthropogenic methane emissions • Industrial emissions estimated at 26–40 Tg/yr • Domestic and commercial estimated at 2 Tg/yr. 23 Consultative Group of Experts (CGE) Training Materials for National Greenhouse Gas Inventories

  24. Factors for Methane Emissions • Biochemical oxygen demand (BOD) (+/+) • Temperature ( >15°C) • Retention time • Lagoon maintenance: • Depth of lagoon ( >2.5 m, pure anaerobic; less than 1 m, not expected to be significant, most common facultative 1.2 to 2.5 m – 20% to 30% BOD anaerobically). 24 Consultative Group of Experts (CGE) Training Materials for National Greenhouse Gas Inventories

  25. Biochemical Oxygen Demand • Is the organic content of wastewater (“loading”) • Represents oxygen consumed by waste water during decomposition (expressed in mg/l) • Standardized measurement is the “5-day test” denoted as BOD5 • Examples of BOD5: • Municipal waste water 110–400 mg/l • Food processing 10 000–100 000 mg/l. 25 Consultative Group of Experts (CGE) Training Materials for National Greenhouse Gas Inventories

  26. Main Industrial Sources • Food processing: • Processing plants (fruit, sugar, meat, etc.) • Creameries • Breweries • Others. • Pulp and paper. 26 Consultative Group of Experts (CGE) Training Materials for National Greenhouse Gas Inventories

  27. Waste Incineration • Waste incineration can produce: • Carbon dioxide, methane, carbon monoxide, nitrogen oxides, nitrous oxides and non-methane volatile organic compounds • Nevertheless, it accounts for a small percentage of GHG output from the waste sector. 27 Consultative Group of Experts (CGE) Training Materials for National Greenhouse Gas Inventories

  28. Emissions from Waste Incineration • Only the fossil-based portion of waste to be considered for carbon dioxide • Other gases difficult to estimate: • Nitrous oxide mainly from sludge incineration. 28 Consultative Group of Experts (CGE) Training Materials for National Greenhouse Gas Inventories

  29. Revised 1996 IPCC Guidelines • Basis of inventory methodology for waste sector is: • Organic matter decomposition • Incineration of fossil origin organic material • Does not include concrete calculations for the latter • Organic matter decomposition covers: • Methane from organic matter in both liquid and solid wastes • Nitrous oxide from protein in human sewage • Emissions of non-methane volatile organic compounds are not covered. 29 Consultative Group of Experts (CGE) Training Materials for National Greenhouse Gas Inventories

  30. IPCC Default Categories • Methane Emissions from Solid Waste Disposal Sites • Methane Emissions from Wastewater treatment: • Domestic and Commercial Wastewater • Industrial Wastewater and Sludge Streams • Nitrous oxide from Human Sewage. 30 Consultative Group of Experts (CGE) Training Materials for National Greenhouse Gas Inventories

  31. Inventory Preparation using Revised 1996 IPCC Guidelines • Step 1: Conduct key source category analysis for waste sector where: • Sector is compared to other source sectors such as energy, agriculture, LULUCF, etc. • Estimate waste sector’s share of national GHG inventory • Key source sector identification adopted by Parties that have already prepared an initial national communication, have inventory estimates • Parties that have not prepared an initial national communication can use inventories prepared under other programmes/projects • Parties that have not prepared any inventory, may not be able to carry out the key source sector analysis. • Step 2:Select the categories 31 Consultative Group of Experts (CGE) Training Materials for National Greenhouse Gas Inventories

  32. Inventory Preparation using Revised 1996 IPCC Guidelines (cont.) • Step 3: Assemble required activity data depending on tier selected from local, regional, national and global databases, including EFDB • Step 4: Collect emission/removal factors depending on tier level selected from local/regional/national/global databases, including EFDB • Step 5: Select method of estimation based on tier level and quantify emissions/removals for each category • Step 6: Estimate uncertainty involved • Step 7: Adopt quality assurance/control procedures and report results • Step 8: Report GHG emissions • Step 9: Report all procedures, equations and sources of data adopted for GHG inventory estimation. 32 Consultative Group of Experts (CGE) Training Materials for National Greenhouse Gas Inventories

  33. Calculation of Methane from Solid Waste Disposal • For sanitary landfills there are several methods: • Mass balance and theoretical gas yield • Theoretical first order kinetics methodologies • Regression approach. • Complex models not applicable for regions or countries. • Open dumps considered to emit 50%, but should be reported separately. 33 Consultative Group of Experts (CGE) Training Materials for National Greenhouse Gas Inventories

  34. Mass Balance and Theoretical Gas Yield • No time factors • Immediate release of methane • Produces reasonable estimates if amount and composition of waste have been constant or slowly varying, otherwise biased trends • How to calculate: • Using empirical formulae • Using degradable organic content. 34 Consultative Group of Experts (CGE) Training Materials for National Greenhouse Gas Inventories

  35. Empirical Formulae • Assumes 53% of carbon content is converted to methane • If microbial biomass is discounted it reduces the amount emitted • 234 m3 of methane per tonne of wet municipal solid waste. 35 Consultative Group of Experts (CGE) Training Materials for National Greenhouse Gas Inventories

  36. Using Degradable Organic Content (Basis for Tier 1) • Calculated from the weighted average of the carbon content of various components of the waste stream • Requires knowledge of: • Carbon content of the fractions • Composition of the fractions in the waste stream • This method is the basis for the Tier I calculation approach. 36 Consultative Group of Experts (CGE) Training Materials for National Greenhouse Gas Inventories

  37. Equation • Methane emissions = Total municipal solid waste (MSW) generated (Gg/yr) x Fraction landfilled x Fraction degradable organic carbon (DOC) in MSW x Fraction dissimilated DOC x 0.5 g C as CH4/g C as biogas x Conversion ratio (16/12) ) – Recovered CH4 37 Consultative Group of Experts (CGE) Training Materials for National Greenhouse Gas Inventories

  38. Assumptions • Only urban populations in developing countries need be considered; rural areas produce no significant amount of emissions. • Fraction dissimilated was assumed from a theoretical model that varies with temperature: 0.014T + 0.28, considering a constant 35°C for the anaerobic zone of a landfill, this gives 0.77 dissimilated DOC. • No oxidation or aerobic process included. 38 Consultative Group of Experts (CGE) Training Materials for National Greenhouse Gas Inventories

  39. Example • Waste generated 235 Gg/yr • % landfilled 80 • % DOC 21 • % DOC dissimilated 77 • Recovered 1.5 Gg/yr • Methane =(235*0.80*0.21*0.77*0.5*16/12) – 1.5 =19 Gg/yr 39 Consultative Group of Experts (CGE) Training Materials for National Greenhouse Gas Inventories

  40. Limitations • Main: • No time factor • No oxidation considered • DOC dissimilated too high • Delayed release of methane under increasing waste landfilled conditions leads to significant overestimations of emissions • Oxidation factor may reach up to 50% according to some authors, a 10% reduction is to be accounted. 40 Consultative Group of Experts (CGE) Training Materials for National Greenhouse Gas Inventories

  41. Default Method – Tier 1 • Includes a methane correction factor according to the type of site (waste management correction factor). Default values range from 0.4 for shallow unmanaged disposal sites (> 5m) to 0.8 for deep (<5m) unmanaged sites; and 1 for managed sites. Uncategorized sites given a correction factor of 0.6 • The former DOC dissimilated was reduced from 0.77 to 0.5 – 0.6, due to the presence of lignin. 41 Consultative Group of Experts (CGE) Training Materials for National Greenhouse Gas Inventories

  42. Default Method – Tier 1 • The fraction of methane in landfill gas was changed from 0.5 to a range between 0.4 and 0.6, to account for several factors, including waste composition. • Includes an oxidation factor. Default value of 0.1 is suitable for well managed landfills. • It is important to remember to subtract recovered methane before applying an oxidation factor. 42 Consultative Group of Experts (CGE) Training Materials for National Greenhouse Gas Inventories

  43. Default method – Tier 1 good practice example • Emissions of methane (Gg/yr) = [(MSWT*MSWF*L0) -R]*(1-OX) where MSWT= Total municipal solid waste MSWF= Fraction disposed at SWDS L0 = Methane generation potential R = Recovered methane (Gg/yr) OX = Oxidation factor (fraction) 43 Consultative Group of Experts (CGE) Training Materials for National Greenhouse Gas Inventories

  44. Methane Generation Potential L0 = (MCF*DOC*DOCF*F*16/12 (GgCH4/Gg waste)) where: MCF = Methane correction factor (fraction) DOC = Degradable organic carbon DOCF = Fraction of DOC dissimilated F = Fraction by volume of methane in landfilled gas 16/12 = Conversion from C to CH4 44 Consultative Group of Experts (CGE) Training Materials for National Greenhouse Gas Inventories

  45. Other Approaches • Include a fraction of dry refuse in the equation • Consider a waste generation rate (1 kg per capita per day for developed countries; half of that for developing countries) • Use gross domestic product (GDP) as an indicator of waste production rates. 45 Consultative Group of Experts (CGE) Training Materials for National Greenhouse Gas Inventories

  46. IPCC Good Practice Guidance Approach 46 Consultative Group of Experts (CGE)

  47. Theoretical First Order Kinetics Methodologies (Tier 2) • Tier 2 considers the long period of time involved in organic matter decomposition and methane generation. • Main factors: • Waste generation and composition • Environmental variables (moisture content, pH, temperature and available nutrients) • Age, type and time since closure of landfill. 47 Consultative Group of Experts (CGE) Training Materials for National Greenhouse Gas Inventories

  48. Base Equation • QCH4 = L0R(e-kc - e-kt) QCH4 = methane generation rate at year t (m3/yr) L0 = degradable organic carbon available for methane generation (m3/tonne of waste) R = quantity of waste landfilled (tonnes) k = methane generation rate constant (yr-1) c = time since landfill closure (yr) t = time since initial refuse placement (yr) 48 Consultative Group of Experts (CGE) Training Materials for National Greenhouse Gas Inventories

  49. Good Practice Equation • Time t is replaced by t-x, a normalization factor that corrects for the fact that the evaluation for a single year is a discrete time rather than a continuous time estimate • Methane generated in year t (Gg/yr) = Sx [(A*k*MSWT(x)*MSWF(x)*L0(x)) * e-k(t-x) ] for x = initial year to t • Sum the obtained results for all years (x). 49 Consultative Group of Experts (CGE) Training Materials for National Greenhouse Gas Inventories

  50. Good Practice Equation (cont.) • Where: t = year of inventory x = years for which input should be added A = (1-e-k)/k; normalisation factor which corrects the summation k = Methane generation rate constant MSWT (x)= Total municipal solid waste generated in year x (Proportional to total or urban population if no rural waste collection) L0(x) = Methane generation potential 50 Consultative Group of Experts (CGE) Training Materials for National Greenhouse Gas Inventories

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