While a growing number of wastewater treatment plants(WWTPs)are being retrofitted from the conventional activated sludge(CAS)process to the membrane bioreactor(MBR)process,the debate on the techno-economy of MBR vs.CAS has continued and calls for a thorough assessment based on techno-economic valuation.In this study,we analyzed the operating data of 20 large-scale WWTPs(capacity≥10000 m3/d)and compared their techno-economy before and after the retrofitting from CAS to MBR.Through cost-benefit analysis,we evaluated the net profit by subtracting the operating cost from the environmental benefit(estimated by the shadow price of pollutant removal and water reclamation).After the retrofitting,the removal rate of pollutants increased(e.g.,from 89.0％to 93.3％on average for NH3-N),the average energy consumption increased from 0.40 to 0.57 kWh/m3,but the operating cost did not increase significantly.The average marginal environmental benefit increased remarkably(from 0.47 to 0.66 CNY/g for NH3-N removal),leading to an increase in the average net profit from 19.4 to 24.4 CNY/m3.We further scored the technical efficiencies via data envelopment analysis based on non-radial directional distance functions.After the retrofitting,the relative cost efficiency increased from 0.70 to 0.73(the theoretical maximum is 1),while the relative energy efficiency did not change significantly.The techno-economy is closely related to the effluent standard adopted,particularly when truncating the extra benefit of pollutant removal beyond the standard in economic modeling.The modeling results suggested that MBR is more profitable than CAS given stricter effluent standards.

Tingwei Gao;Kang Xiao;Jiao Zhang;Wenchao Xue;Chunhai Wei;Xiaoping Zhang;Shuai Liang;Xiaomao Wang;Xia Huang

College of Resources and Environment,University of Chinese Academy of Sciences,Beijing 101408,China;Yanshan Earth Critical Zone and Surface Fluxes Research Station,University of Chinese Academy of Sciences,Beijing 101408,China;State Key Joint Laboratory of Environment Simulation and Pollution Control,School of Environment,Tsinghua University,Beijing 100084,China;Department of Energy,Environment and Climate Change,School of Environment,Resources and Development,Asian Institute of Technology,Klong Luang,Pathumthani 12120,Thailand;School of Civil Engineering,Guangzhou University,Guangzhou 510006,China;College of Environmental Science and Engineering,Beijing Forestry University,Beijing 100083,China;Research and Application Center for Membrane Technology,School of Environment,Tsinghua University,Beijing 100084,China

环境科学与工程前沿

[1]Tingwei Gao;Kang Xiao;Jiao Zhang;Wenchao Xue;Chunhai Wei;Xiaoping Zhang;Shuai Liang;Xiaomao Wang;Xia Huang-.Techno-economic characteristics of wastewater treatment plants retrofitted from the conventional activated sludge process to the membrane bioreactor process)[J].环境科学与工程前沿,2022(04):111-123

Techno

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