Presenter: Miss. Weili Ye, Chinese Academy for Environmental Planning（CAEP）
Co-author(s): Mr. Shuojia Peng, Chinese Academy for Environmental Planning（CAEP）
Sub-theme
4. Supporting Aquatic Ecosystem Health and Functions
Topic
4-8. Water quality improvement
Body
In China, some rivers have a serious shortage of natural runoff, which may lead to the sewage discharged from Wastewater Treatment Plant (WWTP) sometimes becoming the main "ecological water replenishment" to the river channel. Under this condition, different measures were used to improved water quality without evaluation of cost and effect. In this study, we interviewed Sewage experts and government officials, made literature comparison with different kinds of effluent standards and limitations to collect data and information. Research shows that there are three treatment methods to improve the water quality nowadays: continuous tightening of discharge standards, ecological restoration through wetlands construction, or recycling the wastewater of WWTP. But we don’t know which kind of strategy would be better. Thus, we carried out scenario assumptions and designed indicators to evaluate the effect of water pollution control. Analysis shows that there is an upper limit for strict discharge standards, the construction of constructed wetlands is subject to objective factors such as climate and land acquisition, and the social acceptance of sewage recycling is not high. The advantages and disadvantages of a single strategy are very obvious, and the implementation of strategy combination is relatively economic and reasonable. A statistical analysis of sewage treatment in Beijing, Tianjin and other provinces shows that stricter standards generally improved water quality. However, the marginal benefits of continuous tightening of standards are diminishing. In the next step, more combined measures should be taken to reduce pollution in sewage treatment, rather than just tightening standards. We developed a set of evaluation methods based on Data envelopment analysis (DEA) model, which can be used to evaluate the implementation efficiency of strategies, and recommend the most appropriate water pollution treatment strategies to cities. This strategy would be able to guide those cities to develop water pollution control strategies more ecological, energy-saving and efficient.