AWWA JAW57954

Utility managers looking for strategies to assess pathogen removal by filtration with tools that are easier to use and more cost-effective than monitoring Cryptosporidium parvum directly will find this article of interest. The article discusses how oocyst-sized microspheres are easier, safer, and less expensive to work with than Cryptosporidium parvum and are also a reliable tool for assessing C. parvum removal by filtration. It also shows that the ability of filters to remove C. parvum is not the same during all phases of the filter cycle. Even when a filter is in compliance with drinking water regulations, its C. parvum removal capacity can be substantially worse near the end of a filter cycle compared with the earlier portions of the cycle. This work also emphasizes that process evaluations must consider all operating periods, not just optimized operation. Further, it suggests that there can be a real difference in water quality even when differences in turbidity are very small. Includes 16 references, table, figures.