| In recent years,the problems in water resources shortage and water quality pollution are increasing severe,which are greatly damage the health of water body and the security of water provision.Wastewater treatment plants(WWTPs)are able to purifying water quality,reducing the damage on natural water environment caused by directly emissions of wastewater.As an ecosystem with unique environmental characteristics,wetlands not only have the ability to store tremendous water resources,but also play critical role in multiple aspects.At present,numerous studies have been carried out on the WWTPs life cycle assessment(LCA)and wetland ecosystem valuation.However,the research objects and assessment results were differ greatly,failure to formation unified and reliable conclusions,which thus were lack of universality for practical case studies and unable to provide effective data reference and decision support.Firstly,this paper performed Meta-analysis to existing WWTPs LCA research findings,aiming to determine the overall energy consumption and environmental impact intensities of wastewater treatment industry.Meanwhile,the performance of WWTPs in their lifecycle in terms of various influence factors including studied region,treatment process,treatment capacity and discharge standard were analyzed by Meta-analysis.The results of Meta-analysis are able to offer decision-making support for upgrading of WWTPs,promoting the wastewater treatment industry developed toward to "low carbon,energy conservation and reclamation".Secondly,this paper conducted Meta-analysis on the study of wetland ecosystem services valuation in China region,obtaining the synthesis values of wetland ecosystem in a large-scale.On this basis,the disparities of wetland values under different influence factors comprising wetland type,wetland area,geographical location and time scale were quantitatively identified.Results can provide more all-round and systematic data support for the ecological restoration and scientific management of wetlands,as well as to help decision makers better understand the comprehensive value among resource,ecology,economy and environment of wetlands.The Meta-analysis results indicate that,the totality energy consumption and environmental impact intensities of WWTPs in their lifecycle cannot to be ignored,especially the energy use and global warming potential(GWP)to be reached 0.36kWh/m3 and 0.48kg CO2-eq/m3,respectively.Compared to other regions,the WWTPs located in China regions performed poorly in evaluation indicators such as energy use,GWP,acidification potential(AP)and eutrophication potential(EP).A/A/O process is usually accompanied by the highest energy use and environmental impact among three treatment processes.The medium-large wastewater treatment capacities(5-20m3/d)are performed most balanced in terms of energy consumption and environmental emissions.Compared to discharge standard of Grade I-A,the Grade I-B has lower intensity on energy use,GWP and AP,yet adverse eutrophication would be induced.The total value of wetland ecosystem is reached 17.85×104 RMB/(hm2·a).The rank of magnitude of total value per ha in terms of different wetland types was river wetland,constructed wetland,marsh wetland,lake wetland,and offshore and coastal wetland.Along with the increase of wetland area,the total value per ha of wetland ecosystem was accordingly decreased.The wetland located in central part of China has the highest unit value,followed by wetland located in east,west and north parts.Furthermore,with the passage of years,the unit value of wetland ecosystem exhibited an obviously upward trend. |
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