Non-Public Wastewater Pump Stations—Do You Know Their Impact on Your System?

In recent years, collection system evaluation studies (CSESs) aimed at identifying the structural and mechanical deficiencies in sewage systems have advanced and become an integral part of cost effective rehabilitation plan development. Standards and publications developed by local, regional, and national agencies and organizations have made these CSESs more efficient and consistent in capturing existing sewer defects and also in gathering physical and hydraulic information needed for system analysis. In addition, development of hydraulic analysis programs has made building a computerized system model a rewarding investment to many municipalities. However, in communities where flat terrain creates a reliance on pumping and lifting of wastewater to the treatment plant, pumping facilities owned and operated by private entities may be overlooked.Private pump stations (commercial, industrial, institutional, etc.) are typically constructed as an immediate fix when no nearby wastewater facilities exist or to overcome sewer elevation differences. In many cases, insufficient documentation and coordination between the developer, engineer, permitting agency, and sewer system operator renders this component of the collection system seemingly non-existent after installation. To avoid unpleasant and sometimes costly consequences, privately owned pump stations must be identified, and evaluated based on their impacts to the collection system, as well as the system's impact on private facilities. Private pump stations should at least be understood in any system-wide capital improvement plan, especially multi-million dollar programs.In this paper, the authors will introduce this important, yet overlooked, component of the collection system, as well as its potential hydraulic and physical impact on the collection system. The paper will describe in detail the action plan for addressing private pump stations developed as part of a multi-year, 455 million Sewer System Evaluation and Rehabilitation Program (SSERP) for the Sewerage and Water Board (S&WB) of New Orleans including the identification process, data collection effort, and analysis of hydraulic impacts.