Last data update: Jun 24, 2024. (Total: 47078 publications since 2009)
Records 1-2 (of 2 Records) |
Query Trace: Schneeberger CL [original query] |
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Removals of cryptosporidium parvum oocysts and cryptosporidium-sized polystyrene microspheres from swimming pool water by diatomaceous earth filtration and perlite-sand filtration
Lu P , Amburgey JE , Hill VR , Murphy JL , Schneeberger CL , Arrowood MJ , Yuan T . J Water Health 2017 15 (3) 374-384 Removal of Cryptosporidium-sized microspheres and Cryptosporidium parvum oocysts from swimming pools was investigated using diatomaceous earth (DE) precoat filtration and perlite-sand filtration. In pilot-scale experiments, microsphere removals of up to 2 log were obtained with 0.7 kg.DE/m2 at a filtration rate of 5 m/h. A slightly higher microsphere removal (2.3 log) was obtained for these DE-precoated filters when the filtration rate was 3.6 m/h. Additionally, pilot-scale perlite-sand filters achieved greater than 2 log removal when at least 0.37 kg/m2 of perlite was used compared to 0.1-0.4 log removal without perlite both at a surface loading rate of 37 m/h. Full-scale testing achieved 2.7 log of microspheres and oocysts removal when 0.7 kg.DE/m2 was used at 3.6 m/h. Removals were significantly decreased by a 15-minute interruption of the flow (without any mechanical agitation) to the DE filter in pilot-scale studies, which was not observed in full-scale filters. Microsphere removals were 2.7 log by perlite-sand filtration in a full-scale swimming pool filter operated at 34 m/h with 0.5 kg/m2 of perlite. The results demonstrate that either a DE precoat filter or a perlite-sand filter can improve the efficiency of removal of microspheres and oocysts from swimming pools over a standard sand filter under the conditions studied. |
Fate and transport of enteric microbes from septic systems in a coastal watershed
Schneeberger CL , O'Driscoll M , Humphrey C , Henry K , Deal N , Seiber K , Hill VR , Zarate-Bermudez M . J Environ Health 2015 77 (9) 22-30 Onsite wastewater treatment systems (OWTS) are commonly used in coastal areas to treat household wastewater. These systems represent potential sources of fecal pollution of groundwater and nearby surface water. OWTS are expected to reduce microbial concentrations in wastewater; however, system and environmental factors can affect treatment efficiency and impacts on ground and surface water. In the study of OWTS described in this article, the authors sampled septic tanks and groundwater at two households in coastal North Carolina between October 2009 and October 2011. Samples were tested for the fecal indicator microbes E. coli, enterococci, and Clostridium perfringens. Microbial source tracking was also performed in year two. Results showed that enteric microbe concentrations in groundwater significantly decreased with distance from the OWTS. Human markers of fecal contamination were also detected in the OWTS and downgradient groundwater, indicating that OWTS can impact the microbial quality of shallow groundwater. |
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