Zhang Tian-Yuan, Tan Qian, Wang Shu-Ping
College of Water Resources and Civil Engineering, China Agricultural University, Beijing 100083, China.
Huan Jing Ke Xue. 2019 Jul 8;40(7):3223-3232. doi: 10.13227/j.hjkx.201810217.
Coordinated utilization of clear and reclaimed water in urban water supply systems has attracted wide attention from both academic and industrial communities. Although the potential and impacts of water reuse have been explored in previous studies, there is still a lack of model-based research that can optimize the utilization of clear and reclaimed water among multiple sectors and at multiple locations and the associated operations of multiple water treatment plants. In this study, an optimization model was developed for supporting the coordinated supply of clear and reclaimed water in urban water supply systems. This model was formulated based on the conversion relationships among clear water, wastewaters, and reclaimed water resources as well as a number of constraints such as the water reclamation capacities of existing wastewater treatment plants. The developed model provides optimal plans for allocating clear and reclaimed water and for operating wastewater treatment plants in a complex water supply system. The optimization model was applied to a case study in the central districts of Beijing, China. Optimal results were generated under both business-as-usual (BAU) and alternative scenarios in which the utilization scale of reclaimed water was capped and not capped, respectively, according to the existing city plans. Under the BAU scenario, reclaimed water accounted for 32% of the total water used, and contributed 60%, 30%, and 42% of agricultural, industrial, and environmental water consumption, respectively. The supply-demand contradiction of reclaimed water was apparent in Haidian and Shijingshan districts. Compared to the BAU scenario, the alternative scenario achieved 0.621 billion yuan more in economic gain, consumed 36.59% more reclaimed water, and reduced clear water use by 14.02%. The alternative scenario also improved the use of the capacities of existing facilities and promoted water reuse. Moreover, the operation plans of wastewater treatment plants for increasing the utilization amount of reclaimed water was provided. The developed model could be widely applied to other water-scare cities with water reclamation potential without loss of generality.
城市供水系统中清水与再生水的协同利用已引起学术界和工业界的广泛关注。尽管以往研究已探讨了中水回用的潜力和影响，但仍缺乏基于模型的研究，无法在多个部门和多个地点优化清水与再生水的利用以及多个污水处理厂的相关运营。本研究开发了一个优化模型，以支持城市供水系统中清水与再生水的协同供应。该模型基于清水、废水和再生水资源之间的转换关系以及一些约束条件（如现有污水处理厂的中水回用能力）构建。所开发的模型为复杂供水系统中清水和再生水的分配以及污水处理厂的运营提供了优化方案。该优化模型应用于中国北京市中心区的案例研究。根据现有城市规划，分别在常规情景（BAU）和替代情景下生成了最优结果，替代情景中再生水利用规模分别设置了上限和无上限。在常规情景下，再生水占总用水量的32%，分别占农业、工业和环境用水量的60%、30%和42%。海淀区和石景山区再生水的供需矛盾明显。与常规情景相比，替代情景实现了多6.21亿元的经济收益，再生水消费量增加了36.59%，清水使用量减少了14.02%。替代情景还提高了现有设施的利用效率，促进了中水回用。此外，还提供了污水处理厂增加再生水利用量的运营计划。所开发的模型可广泛应用于其他具有中水回用潜力的缺水城市，且不失一般性。
