| Transport and fate of Cryptosporidium parvum oocysts in intermittent sand filters. | |
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MedLine Citation:
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PMID: 11763038 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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The transport potential of Cryptosporidiim parvum (C. parvum) through intermittent. unsaturated, sand filters used for water and wastewater treatment was investigated using a duplicated. 2(3) factorial design experiment performed in bench-scale, sand columns. Sixteen columns (dia = 15 cm, L = 61 cm) were dosed eight times daily for up to 61 days with 65,000 C. parvum oocysts per liter at 15 degrees C. The effects of water quality, media grain size, and hydraulic loading rates were examined. Effluent samples were tested for pH, turbidity, and oocyst content. C. parvum effluent concentrations were determined by staining oocysts on polycarbonate filters and enumerating using epifluorescent microscopy. At completion, the columns were dismantled and sand samples were taken at discrete depths within the columns. These samples were washed in a surfactant solution and the oocysts were enumerated using immunomagnetic separation techniques. The fine-grained sand columns (d50 = 0.31 mm) effectively removed oocysts under the variety of conditions examined with low concentrations of oocysts infrequently detected in the effluent. Coarse-grained media columns (d = 1.40 mm) yielded larger numbers of oocysts which were commonly observed in the effluent regardless of operating conditions. Factorial design analysis indicated that grain size was the variable which most affected the oocyst effluent concentrations in these intermittent filters. Loading rate had a significant effect when coarse-grained media was used and lesser effect with fine-grained media while the effect of feed composition was inconclusive. No correlations between turbidity, pH, and effluent oocyst concentrations were found. Pore-sizc calculations indicated that adequate space for oocyst transport existed in the filters. It was therefore concluded that processes other than physical straining mechanisms are mainly responsible for the removal of C. pavum oocysts from aqueous fluids in intermittent sand filters used under the conditions Studied in this research. |
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Authors:
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A J Logan; T K Stevik; R L Siegrist; R M Rønn |
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Publication Detail:
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Type: Evaluation Studies; Journal Article; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, Non-P.H.S. |
Journal Detail:
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Title: Water research Volume: 35 ISSN: 0043-1354 ISO Abbreviation: Water Res. Publication Date: 2001 Dec |
Date Detail:
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Created Date: 2001-12-12 Completed Date: 2002-04-09 Revised Date: 2006-11-15 |
Medline Journal Info:
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Nlm Unique ID: 0105072 Medline TA: Water Res Country: England |
Other Details:
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Languages: eng Pagination: 4359-69 Citation Subset: IM |
Affiliation:
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Department of Environmental Science and Engineering, Colorado School of Mines, Golden 80401, USA. alogan@mines.edu |
Export Citation:
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APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
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Animals Cryptosporidium parvum* Eggs Filtration Flocculation Hydrogen-Ion Concentration Membranes, Artificial Particle Size Porosity Silicon Dioxide Water Movements Water Purification / methods* |
| Chemical | |
Reg. No./Substance:
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0/Membranes, Artificial; 7631-86-9/Silicon Dioxide |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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