AWWA JAW64355

Monitoring removal of naturally occurring aerobic spores can serve as a surrogate for Cryptosporidium removal in drinking water treatment. However, because Cryptosporidium oocysts are removed more efficiently than spores during treatment involving clarification and filtration, spore removal monitoring provides a conservative estimate of the potential for Cryptosporidium removal in full-scale treatment processes. For example, facilities demonstrating spore removals of 4 logs or greater likely are achieving much greater Cryptosporidium removals. The authors argue that such facilities should be given a 1.5 credit above the 3 credits allowed by the Long Term 2 Enhanced Surface Water Treatment Rule, for a total of 4.5 credits. This would allow water providers to use the demonstration of performance credit rather than relying solely on the more expensive, technology-intensive alternatives in the Microbial Toolbox. Furthermore, spore monitoring offers utilities a supplemental tool for evaluating and optimizing their operations, the entire treatment process (raw through filtration) as well as individual unit processes. Includes 24 references, tables, figures.