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.CA...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 m^(3)/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/m^(3),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/mJ.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.展开更多
目前广泛分布在环境中的药物及个人护理品(pharm aceuticals and personal care products,PPCPs)在环境中的迁移、转化和处理已成为环境科学与工程研究的一个新的领域。污水处理厂排水是PPCPs进入环境中的主要途径。介绍了污水处理过程...目前广泛分布在环境中的药物及个人护理品(pharm aceuticals and personal care products,PPCPs)在环境中的迁移、转化和处理已成为环境科学与工程研究的一个新的领域。污水处理厂排水是PPCPs进入环境中的主要途径。介绍了污水处理过程中传统活性污泥法、膜处理技术以及氧化处理等主要工艺对PPCPs的去除机理,并对去除效果进行了比较。以传统活性污泥法及在其改进后的膜处理技术为基础的大部分现有污水处理厂只能够去除一部分PPCPs,并且主要通过吸附(如对于吐纳麝香、佳乐麝香、萨利麝香等脂溶性较高的有机物)和生物降解作用(如对于布洛芬,17β-雌二醇,雌酮等易反应的有机物)。然而,吸附了PPCPs的污泥通过土壤施肥又将PPCPs带入土壤中,进而会渗滤到地下水,或随径流水进入地表水中。因此,PPCPs并没有从根本上得以去除。相比之下氧化处理工艺(如氯化、臭氧氧化、紫外辐射)或这些工艺的组合能够将大部分的PPCPs进行氧化,去除效果明显优于以上2种技术。然而,氧化后产物的种类和毒理性需要更深入的研究。展开更多
基金This study was sponsored by the Beijing Natural Science Foundation(No.L182044)Youth Innovation Promotion Association CAS(No.2019172).
文摘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 m^(3)/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/m^(3),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/mJ.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.
文摘目前广泛分布在环境中的药物及个人护理品(pharm aceuticals and personal care products,PPCPs)在环境中的迁移、转化和处理已成为环境科学与工程研究的一个新的领域。污水处理厂排水是PPCPs进入环境中的主要途径。介绍了污水处理过程中传统活性污泥法、膜处理技术以及氧化处理等主要工艺对PPCPs的去除机理,并对去除效果进行了比较。以传统活性污泥法及在其改进后的膜处理技术为基础的大部分现有污水处理厂只能够去除一部分PPCPs,并且主要通过吸附(如对于吐纳麝香、佳乐麝香、萨利麝香等脂溶性较高的有机物)和生物降解作用(如对于布洛芬,17β-雌二醇,雌酮等易反应的有机物)。然而,吸附了PPCPs的污泥通过土壤施肥又将PPCPs带入土壤中,进而会渗滤到地下水,或随径流水进入地表水中。因此,PPCPs并没有从根本上得以去除。相比之下氧化处理工艺(如氯化、臭氧氧化、紫外辐射)或这些工艺的组合能够将大部分的PPCPs进行氧化,去除效果明显优于以上2种技术。然而,氧化后产物的种类和毒理性需要更深入的研究。
