There are approximately 10,000 combined sewer overflow (CSO) locations in the United States. During peak storm events they can release about 1.2 trillion gallons of waste and up to 95% of a municipality's raw sewage into surface waters. Although many cities have initiated programs, the CSO problem remains largely unsolved and continues to be a majo

Control and Treatment of Combined Sewer Overflows Second Edition Edited by Peter E. Moffa In cities where storm and sanitary sewers are operated as one system, storm runoff overflows remain the most common potential source of untreated human waste in the water supply—and the single biggest obstacle to achieving the swimmability goals of the 1972 Clean Water Act Amendments. Communities upgrading old systems in order to provide safe, EPA-compliant water to their growing populations face both logistical and financial challenges. Yet, in the last decade significant advances in combined sewage overflow (CSO) abatement have been realized. The National CSO Control Strategy was published in 1989, with the final CSO policy approved in 1994. The EPA has intensified research and development; receiving-water impacts have been quantified; more cost-effective plans, prototypes, and facilities have been tested and implemented; and the water supplies in over a dozen U.S. cities are showing dramatically diminished CSO pollution levels. This revised edition of Control and Treatment of Combined Sewer Overflows takes into account recent advances in research, planning, and practice to be the single most authoritative and up-to-date resource on CSO abatement. Written by expert CSO consultant Peter Moffa and a contributing team of top engineers, the book provides both the mathematical and analytical tools necessary for modeling current sewer systems and developing workable CSO abatement strategies. Control and Treatment of Combined Sewer Overflows, Second Edition Features: A condensed overview of federal CSO policy (watershed) Guidelines for minimum control, long-term control planning, screening and ranking, project funding, CSO monitoring and modeling, and performance measurement Fully updated discussions of mathematical models for combined sewer systems A wide range of practical control and treatment technology systems—many developed since 1989, and Recent Case Studies—a complete section on cost-effect analysis showing how a number of U.S. cities enact effective storage, abatement, and disinfection plans. This edition features new case studies on Rouge River, Charlotte, NC, and Decatur, IL, plus updated reports from Onondaga County, NY, and Washington, DC. Control and Treatment of Combined Sewer Overflows, Second Edition is an essential reference for wastewater and sanitary engineers, as well as city planners and administrators responsible for wastewater treatment. It is also the ideal textbook for advanced undergraduate and graduate students in wastewater and environmental engineering.

An advanced electrolytic generator has been developed for on-site production of sodium hypochlorite for disinfection of overflows from combined sewer systems. In this system an electrochemical cell electrolyzes sodium chloride brine to chlorine gas and sodium hydroxide solution, which are reacted immediately outside the cell to produce a 5 to 10% sodium hypochlorite solution. Significant advances in safety and economy have been realized by use of a hydraulically impermeable cation exchange membrane. The most critical components have operated for over 3000 hours with no deterioration of performance. The generator requires 1.6 KWH of electricity and 2.1 pounds of salt per pound of sodium hypochlorite. The operating cost for systems larger than 500 pounds of hypochlorite per day is projected to be 3 to 4 cents per pound of hypochlorite.