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The Problems and Experience in the implementation of the methane emission inventory from Municipal Waste Sector. Gao Qingxian Center for Climate Impact Research, SEPA of China Chinese Research Academy of Environmental Science (CRAES).
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The Problems and Experience in the implementation of the methane emission inventory from Municipal Waste Sector Gao Qingxian Center for Climate Impact Research, SEPA of China Chinese Research Academy of Environmental Science (CRAES)
The default method will give a reasonable annual estimate of actual emissions if the amount and composition of deposited waste have been constant or slowly varying over a period of several decades. If the amount or composition of waste disposed of at SWDS is changing more rapidly over time, however, the IPCC default method will not provide an accurate trend. For example, if there is a reduction in the amount of carbon deposited at SWDS, the default method will underestimate emissions and overestimate reductions. IPCC Good Practice Guidance
Methane Emissions (Gg/yr) MSWT= Total production of MSW(Gg/yr) MSWF = The Ratio of treatment of MSW(%) MCF = The methane correction factor DOC = The Degradable Organic Carbon DOCF = The ratio of DOC in MSW F = the ratio of methane in landfill gases(default value =0.5) R = reused amount of methane (Gg/yr) OX = oxidation factor(default value = 0)
The Problems encountered • Population Statistics Data • Data of MSW Generation Rates • The Disposed Rate of MSW to SWDSs • The aAnalysis Composition of MSW • The Degradable Organic Carbon (DOC) Content of Waste • Categories of Waste Disposal Sites • Other Default Values Recommended by IPCC
Underestimated Overestimated Total production of MSW(Gg/yr) Chinese Municipal Construction Statistics Year Books MSWT For developing countries and countries with economies in transition, the population data may be the total urban population only, because the rural population is assumed to dispose of waste in such a way that CH4 emissions are extremely low. (revised 1996 IPCC Guidelines) Waste Generation (kg/capita/day) PT: Total population PC: Population in the City PR: Population in rural area PE: Exotic population in the City The survey shows that there are about 70 million people from rural areas who worked in urban areas in recent 10 years
Carrying Amount MSWT Revised 1996 IPCC Guidelines: Total MSW can be calculated from Population (thousand persons) x Annual MSW generation rate (Gg/thousand persons/yr). Weigh( metage) Visual Based on the real situation, the carrying amount should be modified, after vast investigation on the carrying amount and disposal percentage, the experts group of China concluded that the carrying amount of municipal waste should be multiply a coefficient 0.76. Considering the real situation of municipal waste collection, there are only 75% municipal waste are carried and treated into disposal sites. But In China, we have The Municipal Construction Statistics Yearbook, in which have carrying amount and disposal percentage of municipal waste.
Categories of Waste Disposal Sites: Geographical status of China • Northeast • Northwest • North of China • East of China • South of China • Southwest • Middle of China The Carrying Amount of Waste in 7 Regions of 1994
In different region, according the scope of the city, we classified the cities of China into 5 types: Super City〔 > 2 Million 〕, there 14 super cities in China and we survey 10 cities of them and got the real data of them; Large City〔 1~2 Million 〕, there 23 lager cities in China and we survey 15 cities of them and go to site investigation for 6 larger cities; Big City〔 0.5~1 Million 〕, there 47 big cities in China and we survey 21 cities of them and go to site investigation for 6 big cities; Medium City〔 0.2~0.5 Million 〕, there 159 big cities in China and we survey 39 cities of them and go to site investigation for 11 big cities; Small City〔 <0.2Million 〕, there 425 small cities in China and we survey 52 cities of them and go to site investigation for 2 big cities; Fro Region, To get investigation information of waste and its treatment from 47 cities in East region of China, 42 cities in North of China, 48 cities in West and Middle region of China; To carry out site survey in 15 cities in east region, 10 cities in north region and 10 cities in west and middle region.
The Statistic Chart of Municipal Waste during 1979~2000 of China
The Degradable Organic Carbon (DOC) Content of Waste: In revised 1996 IPCC Guidelines for National Greenhouse Gas Inventory: In our calculation, Per Cent DOC (by Weight)=0.26(A)+0.28(B)+0.30(C)+0.07(D) Where: A Paper ; B Wood and straw; C Textiles; D Food waste。 Per Cent DOC (by Weight) = 0.4A+0.17B+0.15C+0.30D
Analysis Composition of MSW in China: ① Organic waste increase rapidly(~50%); ② Inorganic Waste decrease (~23.34%); ③ Recycle waste increase (~26.6%); ④ Combustible waste increase.
the weighted average of carbon content of various components of waste stream Fresh waste
Northeast of China To determine DOC from the composition of waste listed below: Kitchen Waste Papers Rubbers and Plastic Textile Woods and Straw Others Notes: the dust include sweeping dust, dust, it account for almost 50% of total other waste composition. The Composition of Waste in China: Kitchen Waste Papers Rubbers and Plastic textile woods and straw metal Glass Brick and Stone Others (1)Synthesis Areas of Resident, Serving and Manufactory; (2)New Developing Districts; (3)Old Residential Districts; (4)Synthesis Supermarket with foods stuffs; (5)Modern Supermarket with daily article for use; (6)a landfill with 1000 tone of daily input; Middle of China
The measure principle 2K2Cr2O7+3C+8H2SO4=2K2SO4+2 Cr2(SO4)3+3CO2+8H2O K2Cr2O7+6FeSO4+7H2SO4= K2SO4+ Cr2(SO4)3+ 3Fe2(SO4)3+7H2O Where: V0is the consumption of FeSO4 standard volume in reference (ml); V: is the consumption of FeSO4 standard volume in samples (ml); M: Standard liquor concentration of FeSO4 (molL-1) 0.003:1/4 the milli-moore mass of Carbon atom(g); W: The weight of dry sample materials(g); 1.1 is the correction coefficient
Sample analysis result For fresh waste only IPCC
Sample analysis result • Because there are more containing amount of moisture in kitchen waste in China, the DOC value of kitchen waste(10.2%) in China is lower than IPCC default value(15%). • Due to the wood and straw waste in China mostly is dry, and there are not too much fresh woods and straw waste in China, so the DOC value of wood and straw (35.5%)in China is higher than IPCC default value(30%).
IPCC Recommended Method about Calculating the Methane Correction Factor (MFC) The methane correction factor (MFC) accounts for the fact that unmanaged SWDS produce less methane from a given amount of waste than managed SWDS, as a larger fraction of waste decomposes aerobically in the top layers of the SWDS. The calculation of MFC is listed below:
GHGs Inventory Calculating Database Software