INCREASING KNOWLEDGE OF CSO TECHNOLOGIES

摘要

In the UK, the current and future focus on capital investment in wastewater treatment is based around improving the quality of effluent discharging into our coastal and inland waterways. In particular funding is targeted towards sanitary parameters at smaller works and at combined sewer overflows (CSO's) as these are major infrastructure components that influence downstream river and coastal water quality. However one of the major problems associated with the design of such structures is the prediction of stormwater discharge quality, in terms of aesthetics (in the UK regarded as solids larger than 6 mm in 2 directions), BOD, TSS and NH4-N. Such performance has to be assessed for a range of operating conditions and variable influent flow and loads. Traditionally the solution for the retention of BOD and solutes has been to incorporate storage solutions, many of which are extremely costly. Screens are commonly used to retain the aesthetics in the system and there have been major research initiatives to assess the performance of screens [1]. Many of these devices are new and novel and currently there are a number of research programmes that examine the in-situ performance of screens and their requirement for maintenance. The performance of a screen is a function of many parameters but key variables include the design flow rate and the number and nature of the aesthetic particles introduced to the screen. This paper concentrates on two aspects of this research into aesthetics: Firstly, the prediction of the quantities of aesthetic pollutants and secondly the performance of static screens to retain these pollutants.