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Currently, there is research being conducted to find more ideal and practical indicators of Cryptosporidium removal by the treatment process. This new research has suggested that Clostridium perfringens, Aerobic Spore Forming Bacteria (ASF), and coliphages are good indicators of treatment efficiency for removal or inactivation of Cryptosporidium, and may even be correlated to particle count removal. Given these claims, the Philadelphia Water Department decided to investigate the applicability of such surrogates to monitor treatment process performance. Monthly plant intake and effluent monitoring for three water treatment plants was conducted from August 1997 to August 1998, to screen for ASF, Bacillus ssp., and Clostridium perfringens as indicators of treatment process performance. It was observed that C. perfringens did not occur consistently or at high enough densities to measure log removals by the treatment process. ASF was always detected in raw water and over 80% of the time in finished water samples, and was reduced, on average, by 3 logs during treatment. Treatment plant and filter profiling studies showed a correlation between ASF spore density and particle counts in the sedimentation and clarification processes. However, after clarification the correlation between ASF spores and particle counts was not evident. In fact, ASF spores were removed less by the filtration process than particles, which was unexpected. Includes 9 references, tables, figures.

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Edition: Vol. - No. Published: 08/29/1999File Size: 1 file , 160 KB