Control Strategy for Storm-Generated Sanitary-Sewer Overflows

Abstract

This paper presents a strategy for the abatement of pollution from storm-generated sanitary-sewer overflows (SSO). Because of the great lengths of sanitary sewer systems, it is often less expensive to use alternatives to sewerline rehabilitation for infiltration/inflow (I/I) and associated SSO control. Extensive sanitary sewer system rehabilitation can (1) be relatively costly; (2) take a long time to complete; and (3) be extremely disruptive to traffic, businesses, and property owners. I/I control studies have found that just correcting I/I in street sewers will not necessarily correct the problem because building connections contribute as much as 70–80% of the infiltration load. Building connection rehabilitation can be infeasible economically because of the shear number of connections or impractical because of the difficulty in dealing with property owners. Inflow elimination or reduction, cost-effective sewer rehabilitation, and collection system inspection with associated clean out and repair must be performed in all cases; and an integrated economic and feasibility analysis using a combination of maximizing flow to the wastewater treatment plant and maximizing treatment capacity must be considered for controlling the remaining SSO. SSO can be abated using combined sewer overflow (CSO) control methods. SSO and CSO are both mixtures of municipal sewage, storm water, and ground water.