AWWA WQTC60563

This paper describes an innovative portable continuous flow centrifuge (PCFC) that was developed and tested at Tufts University sponsored by a grant from the US Environmental Protection Agency (USEPA)(STAR). The PCFC dimensions are 18 inches x 14 inches x 20 inches and weighs 30 lbs. It holds a disposable 250 mL bowl which produces a concentrate that is compatible with existing USEPA-approved methods for IMS-based purification and subsequent confirmation under epifluorescence microscopy. When tested at Mohawk Valley Water Authority (MVWA), PCFC recoveries for source water were 66.8% for Giardia and 60.1% for Cryptosporidium (n=5), a considerable improvement compared to filtration. The PCFC was validated under Method 1623 Tier 1 validation. Recoveries of Cryptosporidium and Giardia from 15-liter volumes of seeded reagent water were 36% and 37%, respectively. Recoveries for 15-liter of seeded source water samples were 69% and 82%, respectively. At the completion of the optimization of the method under laboratory conditions, the PCFC was tested through Tier 2 validation Alternative Test Procedure (ATP). This too was funded by the EPA STAR program. These studies were performed by 4 independent EPA approved laboratories, using 50-L source water samples. Tier 2 mean recovery results for Cryptosporidium (42.5% for spiked distilled water, 37.4% for spiked source) demonstrate that the PCFC meets and exceeds the acceptance criteria for method 1623. The PCFC ATP is at the final phases of approval by USEPA. We believe the PCFC is a user-friendly, cost-effective, and much simplified alternative method of concentration of protozoa from large volumes of source water samples under LT2 monitoring. Includes 6 references, tables, figures.