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Pilot-Scale Testing Of Diatomaceous Earth Filtration For Removal Of Cryptosporidium Oocysts, Jerry E. Ongerth, Primrose E. Hutton
Pilot-Scale Testing Of Diatomaceous Earth Filtration For Removal Of Cryptosporidium Oocysts, Jerry E. Ongerth, Primrose E. Hutton
Faculty of Engineering and Information Sciences - Papers: Part A
No abstract provided.
De Filtration To Remove Cryptosporidium, Jerry E. Ongerth, Primrose E. Hutton
De Filtration To Remove Cryptosporidium, Jerry E. Ongerth, Primrose E. Hutton
Faculty of Engineering and Information Sciences - Papers: Part A
Laboratory-scale testing investigated the degree of Cryptosporidium oocyst reduction provided by diatomaceous earth (DE) filtration. Three grades of DE from two manufacturers were used in the tests. Reduction was measured using seeded river water applied to Walton test filters. Tests were run for filtration rates of 1 and 2 gpm/sq ft (2.4 and 4.9 m/h). Each run was replicated three times, and quality control was rigorous. Approximately 6 logs of reduction in the concentration of Cryptosporidium oocysts can be expected under routine operating conditions using DE grades having permeability of <1.2 Darcy. Log reductions varied predictably according to the permeability of the DE grade and the filtration rate; they were significantly higher at the higher filtration rate. Agreement was excellent between runs, enabling researchers to distinguish with consistent statistical significance the differences in performance.
Comparison Of Two Methods For Detection Of Cryptosporidium & Giardia In Water, Eva C. Nieminski, Frank W. Schaefer Iii, Jerry E. Ongerth
Comparison Of Two Methods For Detection Of Cryptosporidium & Giardia In Water, Eva C. Nieminski, Frank W. Schaefer Iii, Jerry E. Ongerth
Faculty of Engineering and Information Sciences - Papers: Part A
The steps of two immunofluorescent-antibody-based detection methods were evaluated for their efficiencies in detecting Giardia cysts and Cryptosporidium oocysts. The two methods evaluated were the American Society for Testing and Materials proposed test method for Giardia cysts and Cryptosporidium oocysts in low-turbidity water and a procedure employing sampling by membrane filtration, Percoll-Percoll step gradient, and immunofluorescent staining. The membrane filter sampling method was characterized by higher recovery rates in all three types of waters tested: raw surface water, partially treated water from a flocculation basin, and filtered water. Cyst and oocyst recovery efficiencies decreased with increasing water turbidity regardless of …
Identification Of Cryptosporidium Oocysts In River Water, Jerry Ongerth, Henry Stibbs
Identification Of Cryptosporidium Oocysts In River Water, Jerry Ongerth, Henry Stibbs
Faculty of Engineering and Information Sciences - Papers: Part A
Water samples were collected from four rivers in Washington State and two rivers in California and examined for the presence of Cryptosporidium oocysts. Oocyst-sized particles were concentrated from 20-liter samples of water by membrane filtration, centrifugation, and differential sedimentation. The particle concentrate was then deposited on a 25-mm-diameter membrane filter for oocyst identification by indirect immunofluorescence assay. The identification procedure had a limit of detection of about five oocysts per liter. Cryptosporidium oocysts were found in each of 11 river water samples examined. Concentrations ranged from 2 to 112 oocysts per liter. The finding of Cryptosporidium oocysts in all samples …
Immunofluorescence Detection Of Cryptosporidium Oocysts In Fecal Smears, Henry H. Stibbs, Jerry E. Ongerth
Immunofluorescence Detection Of Cryptosporidium Oocysts In Fecal Smears, Henry H. Stibbs, Jerry E. Ongerth
Faculty of Engineering and Information Sciences - Papers: Part A
An indirect fluorescent antibody (IFA) procedure was developed for the detection of Cryptosporidium sp. oocysts in human, nonhuman primate, and bovine fecal smears. The procedure, which takes about 90 min to perform, involves the use of a rabbit antiserum against Cryptosporidium oocysts isolated from dairy cattle. Cross-specificity testing of the IFA method revealed no reactivity with yeasts, various amoebae, Giardia lamblia, Chilomastix sp., or Blastocystis sp. and only very weak cross-reactivity with coccidian oocysts of other genera. IFA detection of oocysts in human and nonhuman primate fecal smears was far more sensitive than was dimethyl sulfoxide-carbolfuchsin staining. Moreover, IFA detection …