城市合流制管网分质截流模型的构建

Build-up of Quality-based Interception Model for an Urban Combined Sewer System

在合流制排水系统改造过程中,截流倍数的取值与水文、环境、经济等因素有关,截流倍数取值越小,其环境污染程度越严重,反之则环境污染程度越轻,但截流管的基建投资、污水厂改造运行管理费用、泵站扩建等投资越大。为兼顾环境与经济两因素,提出一种优化设计截流倍数的方法——分质截流模型,该方法可同时考虑经济费用和水环境污染两方面约束,尽量使经济投资和污染程度降到最低。应用分质截流模型优化设计截流倍数后,在污水厂处理能力允许范围内,把污染相对严重的污水更多地截流到污水厂,污染相对较轻的污水则排入受纳水体,减轻环境负担。

In the reconstruction of a combined sewer system, the value of interception ratio relates to hydrological, environmental, economic and other factors. A smaller interception ratio leds to more serious environmental pollution. A bigger interception ratio reduces environmental pollution but requires greater investments for intercepting sewer infrastructure, wastewater treatment plant reconstruction and pumping station expansion. To take into account both the environmental and economic factors, an opti- mized design method of interception ratio, namely quality-based interception model, was presented. The comprehensive method could minimize the pollution level as well as economic investment. After optimizing the interception ratio using quality-based interception model, designed within the permitted scope of sewage treatment plant capacity, sewage with relatively high pollution level was intercepted to the sewage treatment plant, sewage with relatively low pollution level was discharged to the receiving water body, thus reducing the environmental burden.