Development and Evaluation of Ultrafiltration Methods to Concentrate Pathogens from Reclaimed Water
Year Released: 2010
Funding Partners: Bureau of Reclamation, California State Water Resources Control Board
Total Investment: $231,507 (Cash: $175,000, In-Kind: $56,507)
Principal Investigators: Christine L. Moe, PhD, Emory University, and Vincent Hill, PhD, PE, Centers for Disease Control and Prevention
Drought and rapid development in metro Atlanta has led to water scarcity and greater indirect potable water reuse. Public concern about the quality of reclaimed water discharged into the lake prompted interest in developing more feasible methods to test reclaimed water for microbial pathogens and indicator organisms. Ultrafiltration (UF) offers an economical and rapid method to simultaneously concentrate a range of waterborne pathogens from reclaimed water and is a critical first step for water quality monitoring.
Goals and Objectives
The project developed a simple, effective UF procedure to detect multiple pathogens from reclaimed water.
When the experimental data indicated that calf serum blocking of ultrafilters did not result in substantially higher microbial recoveries from reclaimed water, the project focused on elution as the key technique for achieving high recoveries.
Findings and Conclusions
The results from 10-L and 100-L experiments with reclaimed water from two different facilities indicate that UF, followed by a simple elution technique using 0.01% Tween 80, can result in effective simultaneous recovery of diverse microbes, including vegetative bacteria, spore-forming bacteria, viruses, and parasites, from reclaimed water. The performance goal set for this project (at least 50% recovery for all study microbes at a 95% confidence limit) was largely met, with only a few exceptions.
In addition to demonstrating good microbial recovery and associated sensitive detection limits, the project also determined that none of the three ultrafilters studied provided significantly better performance. This useful finding suggests that the UF-elution method will work equally well with a variety of ultrafilters and that staff at water reclamation facilities can select the most appropriate ultrafilter based on cost or operational characteristics. A summary of ultrafilter specifications and operational characteristics for this study is provided in the report. As anticipated, the ultrafilter with the largest pore size and greatest surface area was associated with higher filtration rates and lower pressures to achieve these rates. However, these differences in operational conditions are minor because of the similar microbial recovery performances determined for each ultrafilter type.