Greenhouse Gas Emission From Municipal Solid Waste Management In Changsha And The Mitigation Strategy

The quantity of municipal solid waste generation is quite impressing due to therapid developing economics, population explosion and the urbanization process.Greenhouse gas（GHG）generated in the waste treatment section. IntergovernmentalPanel on Climate Change（IPCC）reported that the GHG emission from municipalsolid waste contributes5%of the total emission and the IPCC regard the wastedisposal section as isolate section in the GHG emission calculation. Thus it’ sreasonable to take the waste management system as an important section in the GHGmitigation strategy.A lot of effort had been done in optimizing the waste management strategy. Thiscity built a waste transfer station. Besides the function of transfer, the station alsocarried out a source separation and recycle role in the management. Most of therecyclables can be recollected in this station. Changsha also carried out a food wasteplant beside the waste transfer station. The food waste generated in cafeteria andrestaurant would be separately collected, the food waste collected after being thethree-phase separation, which separated the oil part, the solid part and the leachatepart. The oil part is used as the feedstock of biodiesel making. An power plant whichgenerate electricity from biogas utilization was built in the landfill site. Energy savedthrough the biogas utilization strategy.Scenarios were set up based on the waste management practice in Changsha andGHG emission was calculated. Unitization of each section of waste managementstrategy can make the calculation easier. The method of LCA and FOD (First OrderDecay) was adopted in this study. The FOD can calculate the biogas emission fromlandfill and the LCA can assess other management strategies.The result indicates that the biogas emission contributes the most of the GHGemission from MSW management and the collection of biogas save the most GHGemission in each Scenario. The two means of waste pretreatment, waste sourceseparation and the isolate collect of food waste, also participate in the GHGmitigation. The mitigation is not just for the quantity reduction, but also for theavoided emission from the substitution of fuels and materials. The food waste recycled raw oil and the raw oil is the new feed stock of biodiesel.Two more management strategy was recommended in this research, Changshacity hasn’t carried out the strategy yet, but the GHG mitigation potential is amazing.One is the incineration for the final disposal, the other one is the CHP (combined heatand power) utilization in the landfill gas utilization. The GHG emitted fromincineration is fossil CO2, which has the smaller global warming potential than biogasemitted from landfill site. The CHP utilization has a higher recover rate than thesimple electricity generation.