Development and Evaluation of Ultrafiltration Methods to Concentrate Pathogens from Reclaimed Water
Christine L. Moe, PhD, Emory University
Vincent Hill, PhD, PE, Centers for Disease Control and Prevention
After a review of literature on the ultrafiltration (UF) and our direct experience with UF procedures, this project was designed with the goal of developing 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.
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.
(2010, 32 pages, 04-013-1)
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