集中式污水处理系统的最佳规模研究

综合分析污水处理厂的吨水投资、管网投资和运行费用有助于弄清城镇污水末端处理的规模效应。研究表明,中、小规模污水处理厂的吨水投资、运行费用在不同处理工艺间均存在规模效应,且相关性显著;大型和特大型污水处理厂的吨水投资和运行费用均保持在较低的范围内,且随着处理规模的增加而逐步稳定;当污水管网的收集规模<6×104m3/d时,其吨水投资的规模效应突出;随着污水管网规模的增大,吨水管网投资趋于较低的水平。当污水处理厂仅作为排水系统的末端环节时,综合考虑污水处理厂和收集管网的单位投资及运行费用等因素,最佳的处理规模为10×104m3/d左右;当污水处理厂具有污染治理和污水再生回用的双重功能而成为水资源循环的中间环节时,适宜的污水处理规模受多种因素的影响,区域性的半集中式处理模式将成为一种可行的选择。

Study on Optimized Scale of Centralized Municipal Wastewater Treatment System

The relationship between the municipal wastewater treatment scale of the wastewater treatment plant(WWTP) and unit(per m~3/d),management and operation investment costs was analyzed.It is showed that for small and middle scaled WWTPs,the treatment scales are evidently effective.The investment costs per m~3 water and the operation costs of WWTP reduce gradually due to the increase of wastewater treatment capacities.However,for large and very large scaled WWTPs,the investment costs per m~3 and sewer systems and operational costs are in a comparatively lower limit.When the sewer system of WWTPs is under 60 000 m~3/d,the scale for unit investment costs becomes outstanding.As the number increases,unit price scale gradually drops.When WWTP is used only for the end-of-pipeline treatment system for pollution control without any wastewater reuse,the economical treatment size is about 100 000 m~3/d.This figure is with the consideration of the unit prices and the operation costs of WWTP,collection network and other influencing factors.When a WWTP has double functions of pollution control and wastewater reuse,and the source water comes from environmental friendly sources with other possible influences,a regional semi-central treatment mode will be a feasible choice.