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SEWER AND TANK FLUSHING FOR CORROSION AND POLLUTION CONTROL
Citation:
Fan*, C Y., R Field*, W. C. Pisano, J. Barsanti, AND J. J. Joyce. SEWER AND TANK FLUSHING FOR CORROSION AND POLLUTION CONTROL. Preparing for the 21st Century; Proceedings of the 26th Annual Water Resources Planning and Management Conference; June 6-9, 1999, Tempe, Arizona. Wilson, E.M. (Ed.). reston, VA: American Society of Civil Engineers, 1999, 11 p, Tempe, AZ, 6/6-9/1999.
Description:
This paper presents an overview of the causes of sewer deterioration and control methods that can prevent or arrest this deterioration. articular, the paper addresses the use of inline- and combined sewer overflow (CSO) storage tank-flushing systems for removing sediments and minimizing hydrogen sulfide production and associated corrosion.
During low-flow dry-weather periods, toxic gases are generated from organic solids deposited in combined sewers by sanitary wastewater. These gases are reduced to hydrogen sulfide and then oxidized to sulfuric acid which can deteriorate pipe material. Furthermore, these sediments are discharged during storm events, causing degradation of receiving water quality. Thus, dry-weather sediments not only create hazardous conditions and sewer degradation, but also contribute significant pollutant loads to receiving waters during high flow, wet-weather periods.
The performance of two technologies, i.e., the tipping flusher and the flushing gate was evaluated at 18 facilities in Germany, Canada, and the United States. Results indicated that both technologies appear to be cost-effective for flushing solids and debris from CSO storage tanks. In addition, the flushing gate proved to be most efficient for flushing large diameter flat sewers. A cost-effectiveness analysis for an actual project will be presented comparing flushing gate technology with conventional large pipe cleaning operations using buckets.