Combined sewer overflows (CSO) are a historic and integral part of the wastewater infrastructure by protecting the downstream Wastewater Treatment Works (WwTW) from flooding by diverting the effluent into a nearby receiving body. In recent years, the perception of CSOs is synonymous with the detriment of the water quality of the receiving water body.

Current legislation is to minimise the frequency of the activation of the CSO as well as its spill volume . To satisfy these requirements, Water companies are proceeding with a strategy to reduce the spill frequency and duration of the CSOs in their networks, accomplished by passive means of using more storage tanks or by more active means of real time control of their network. This strategy is based on the hydraulic relationships of the waste water network; which are more understood than the water quality relationships in the receiving water body.

The aim of this project is to develop a real time control algorithm that attempts to mitigate the impact of CSO discharges on the water quality of the receiving water body rather than reducing the spill frequency or spill volume. The algorithm will be data driven due to the relative lack of understanding of the water quality relationships in comparison to the hydraulic properties of the receiving water body.