COMBINED SEWER OVERFLOW CONTROL USING STORAGE IN SEAWATER

This paper describes the flow balance method facility (FBM) used to co ntrol a combined sewer overflow (CSO) and a statistically based effici ency evaluation for the system. The FBM uses containment within a rece iving water body (in this case seawater) to store CSO followed by pump back to the wastewater treatment plant for treatment. The efficiency e valuation uses a mass balance incorporating measured specific conducti vity and how volumes with their probability distributions in a Monte C arlo model to calculate probable volumes of seawater in the pumpback a nd hence efficiency of the system. The methods described in the paper refer to phase 1 and form the basis for monitoring phase 2 of the proj ect. Important aspects of this analysis for phase 2 of the FBM demonst ration included: confirmation of the reliability of specific conductiv ity to determine the volume of seawater in the pumpback; an indication of the sensitivity of the predicted efficiency to variation in the pa rameters used; and therefore, identification of the relative importanc e of the different data distributions to allow more effective data col lection in phase 2.