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PARTICLE ASSOCIATION EFFECTS ON MICROBIAL INDICATOR CONCENTRATIONS FOR CSO DISINFECTION
Citation:
Perdek*, J M. AND M Borst*. PARTICLE ASSOCIATION EFFECTS ON MICROBIAL INDICATOR CONCENTRATIONS FOR CSO DISINFECTION. In Proceedings, 2000 Joint Conference on Water Resources Engineering and Water Resources Planning and Management, Minneapolis, MN, July 30 - August 02, 2000. Environmental & Water Resources Institute (EWRI) of ASCE, Reston, VA, Sect 11, Chap 3, (2000).
Impact/Purpose:
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Description:
The effect of blending on indicator microorganism concentrations in combined sewer overflow (CSO) was investigated due to concerns that standard techniques fail to measure particle-associated organisms found in sewage. It was shown that blending CSO samples diluted in a mixture of chemicals (resulting in concentrations of 10-6 M. Zwittergent 3-12, 10-3 M EGTA, 0.01 Tris buffer, 0.01% peptone by weight, buffered to a pH of about 7) increases fecal coliform and Enterococcus concentrations measured by membrane filtration under certain conditions. Samples were blended at speeds from 17,000 to 22,000 rpm and at times from 0.5 to 10 min. Both blending speed and time affected measured indicator concentrations, with increased concentrations observed in samples blended at 22,000 rpm for 0.5, 1, 2, and 3 min. Blending decreased mean particle size, although no correlations between increased indicator microorganism concentration and decreased particle size were observed. Temperature increases that occurred with increased blending time may have resulted in temperature-induced decay.
