RENEWABILITY ASSESSMENT OF WATER RESOURCES BASED ON EMBODIED WATER ACCOUNTING OF WASTEWATER TREATMENT

摘要

Artificial wastewater treatment engineering plays an increasingly important role in removing pollutant and assuring human society of ready-for-reuse water resources. However, a wastewater treatment system needs a lot of socioeconomic products to sustain its operation and all these products have consumed water resources during their production. The lifecycle water consumption, i.e., embodied water of a wastewater treatment system may partially offset its benefits in renewing wastewater. The method of systems accounting as a combination of process analysis and ecological input-output analysis is proposed in this work to trace embodied water of a wastewater treatment system, based on which an indicator as the ratio of lifecycle water required to the water purified is devised to assess the renewability of water resources. Two case studies have been carried out for a constructed wetland ecological wastewater treatment system and a traditional activated sludge wastewater treatment system in Beijing. It is revealed that the traditional wastewater treatment technology is more efficient in renewing wastewater than the ecological one. The contributed method and indicator can not only used to compare the renewability of different wastewater treatment technologies, but also be transplanted to trace the lifecycle water use of other systems, especial water related system or energy related system to extend our knowledge on water-energy-nexus.