Comprehensive Assessment And Application Potential Estimation Of Municipal Solid Waste Co-processing In Cement Kiln

China is faced with an urgent challenge for municipal solid waste(MSW)management during its rapid urbanization.Some landfills have been operated over their capacities to meet the continuously increasing demand for MSW treatment.The construction of new treatment facilities is usually time-consuming,so the addition of new treatment capacity lags far behind the increasing production of MSW.Cement kilns co-processing of MSW,featuring the advantages of effective waste reduction,low capital costs,and no extra land area required,can provide important MSW treatment capacity as supplement to traditional treatment facilities.However,cement kilns co-processing of MSW is still relatively new technology in China.Quantitative assessments of the reliability,the environmental-energy-economic benefits,and the application potential of this technology are necessary to evaluate its applicability in China and to provide information for relevant decision-making.This study developed a technology efficiency evaluation model for cement kiln co-processing of MSW leveraging data envelopment analysis(DEA)technique.Empirical time-series operational data of a cement kiln was used to evaluate the treatment performance and stability of the technology,which,together with the results of life-cycle assessment(LCA)and net present value assessment,served to develop a comprehensive technology efficiency indicator system considering multiple aspects,including waste reduction,hazard elimination,resource recovery,and economic sustainability.The assessment results of cement kilns co-processing were compared with existing main-stream solid waste treatment technologies such as incineration and sanitary landfills.Further,this study evaluated the application potential of cement kilns co-processing based on China’s planning of MSW management facilities as well as the production capacity and spatial distribution of 1,066 cement enterprises nation-wide.Finally,this work proposed incentive policies to facilitate the application of this technology according to the result of project net present value assessment.Results of this work lead to the following conclusions:(1)The investigated cement kiln is close to its production frontier for MSW co-processing,with fairly mature technologies and stable operation of the facilily.The co-processing has no obvious influence on the production system.(2)Compared to traditional technologies such as incineration and landfills,cement kiln co-processing of MSW has better performance in terms of waste reduction and pollutant emission.The waste reduction rate of the cement kiln co-processing is 214%higher than that of landfills,and 20.6%-73.0%higher than incineration.The global warming potential,eutrophication potential,and photochemical ozone creation potential of cement kiln co-processing of MSW are lower than those of landfills by 99.7%,77.2%,and 90.0%,and incineration by 77.2%,82.4%,and 92.4%respectively.(3)The total theoretical treatment capacity of cement kiln co-processing nation-wide is 4,273.7-6,890.5 t/yr,equivalent to 58.4%-80.7%of the estimated capacity gap in 2020.(4)On average,subsidy of 108 RMB/t MSW is recommended for the economic sustainability of cement kiln co-processing.If the current tax policy regarding MSW treatment facilities also applies to cement kiln co-processing,97 RMB/t subsidy is recommended,which is comparable to the financial subsidy level for traditional MSW treatment technologies.