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.