市政污泥处理处置工艺碳排放核算及碳减排路径OA

[Objective]Currently,four mainstream municipal sludge treatment and disposal process routes have been formed in China,namely,deep dewatering-landfill,aerobic fermentation-land use,anaerobic digestion-land use,and drying incineration-construction materials utilization.Each process has its own advantages,disadvantages and applicable conditions.However,the carbon emission level of each process is not clear,which makes it difficult to implement carbon emission as a measurement index for process comparison.[Methods]According to the guidelines of Intergovernmental Panel on Climate Change,the carbon emission amounts of the whole sludge treatment and disposal processes,from sludge transportation out of the wastewater treatment plant to final disposal,are comprehensively calculated by the emission factor method after determining the accounting boundary.It includes the carbon emission caused by the release of methane(CH4)and dinitrogen monoxide(N2O)during the treatment and disposal processes,the carbon emission caused by electricity consumption,drug consumption,energy consumption,transportation,etc.,and the carbon emission reduction caused by resource and energy substitution.Moreover,based on the calculation results,the carbon emission reduction path of sludge treatment and disposal is discussed.[Results]The carbon emission intensities of sludge deep dewatering-landfill,aerobic fermentation-land use,anaerobic digestion-land use,and drying incineration-construction materials utilization are 1 465.75,933.46,880.35,752.33 kg CO2/(t DS),respectively.[Conclusion]It is found that under the same accounting boundary,drying incineration-construction materials utilization is the sludge treatment and disposal process with the least carbon emission by comparison,which can be given priority in the process selection of new projects.In addition,when the applicable condition or disposal route of sludge is restricted and a certain process must be adopted,carbon emission can also be reduced through measures such as sludge reduction at the source,key technical parameters optimization,resources and energy recovering.