Environmental impact assessment of sewage sludge incineration treatments

Life cycle inventories of sewage sludge during traditional landfill handling and three incineration treatment processes(drying-incineration treatment,co-combustion with coal and co-incineration with municipal solid waste for electricity generation)were collected and analyzed by means of LCA(life cycle analysis)to determine the energy consumption and environmental effects.Landfill handling has the lowest energy consumption(2.24 kg standard coal)and total environment impact loading(46.55×10-3,PET)for 1.0 t wet sludge.Drying-incineration treatment requires the largest energy consumption,about 111.12 kg standard coal.Due to the recovery of the internal chemical energy of sewage sludge,the consumption of fossil fuel is decreased by co-incineration with municipal solid waste or with coal.The environmental emissions during these two co-incineration processes are mainly acids and nutrients,which play a significant role in the local regional impact.Therefore,flue gas purification during the sludge incineration process still needs to be emphasized,so as to further decrease the acid gas and dioxin emissions.