Control and/or treatment of stormwater discharges and combined sewage overflows from urban areas are problems of increasing importance in the field of water quality management. Presented in this text are selected results of a comprehensive investigation and assessment of promising, completed and ongoing projects, representative of the state-of-the-art in abatement theory and technology; a look at recent legislation; and the identification of program needs and emphasis. Combined sewer overflows are major sources of water pollution problems, but even discharges of stormwater alone can seriously affect water quality. Current approaches involve control of overflows, treatment and combinations of the two. Control may involve maximizing treatment with existing facilities, control of infiltration and extraneous inflows, surface sanitation and management, as well as flow regulation and storage. A number of treatment methods have been evaluated including high rate screening and microstraining, ultra high rate filtration, dissolved air flotation, physical/chemical treatment, and modified biological processes.

"Program element no. 1BB034." "December 1974." Report prepared by Storm and Combined Sewer Section (Edison, N.J.), Advanced Waste Treatment Research Laboratory, National Environmental Research Center, Cincinnati, Ohio, and Metcalf & Eddy, Inc., Palo Alto , California, Conclusions: All facts point to a real requirement for treating and controlling stormwater runoff and combined sewer overflows. The multi-billion dollar treatment plant upgrading and expansion program now going on throughout the country will do much to alleviate pollution of our waters. However, means of mitigating the effects of urban runoff must also be found if we hope to abate the pollution in an optimal manner. Wet-weather standards are already being instituted by EPA and some states and localities. Recognizing this, EPA's Storm and Combined Sewer Technology Program will strive to be a prime support for this real-world application. Figures: Representative strengths of wastewaters -- Storage - treatment example -- Overview of storm water management model structure -- Isometric view of swirl regulator/concentrator. Tables: Summary of storage costs for various cities -- Comparison of treatment alternatives. Includes bibliographical references (pages 28-30).

Control and/or treatment of stormwater discharges and combined sewage overflows from urban areas are problems of increaseing importance in the field of water quality management. Over the past decade much research effort has been expended and a large amount of data has been generated, primarily through the actions and support of the U.S. Environmental Protection Agency's (EPA) Storm and Combined Sewer Research and Development Program. Presented in this text are selected results of a comprehensive investigation and assessment of promising, completed and ongoing projects, representative of the state-of-the-art in abatement theory and technology; a look at recent legislation; and the identification of program needs and emphasis. Combined sewer overflows are major sources of water pollution problems, but even discharges of stormwater alone can seriously affect water quality. Current approaches involve control of overflows, treatment and combinations of the two. Control may involve maximizing treatment with existing facilities, control of infiltration and extraneous inflows, surface sanitation and management, as well as flow regulation and storage. A number of treatment methods have been evaluated including high rate screening and microstraining, ultra high rate filtration, dissolved air flotation, physical/chemical treatment, and modified biological processes. A swirl flow regulator/solids separator of anular shape construction with no moving parts has been developed. High rate disinfection methods including new disinfectants have been applied. Promising approaches involve integrated use of controls and treatment. The most disappointing have generally lacked flexibility in their operation and design. Mathematical models have been developed and successfully applied at multiple levels of sophistication and complexity. Review notice -- Foreword -- Abstract -- List of figures -- List of tables -- Conclusions -- Recommendations -- Introduction -- problem definition -- Design constraints -- Management alternatives -- Results and costs -- Impact of legislation -- R & D needs and EPA program emphasis -- References.