January 2017
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31 Reads
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January 2017
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31 Reads
December 2016
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385 Reads
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31 Citations
The Science of The Total Environment
Contamination of groundwater by pathogenic viruses from small biological wastewater treatment system discharges in remote areas is a major concern. To protect drinking water wells against virus contamination, safe setback distances are required between wastewater disposal fields and water supply wells. In this study, setback distances are calculated for alluvial sand and gravel aquifers for different vadose zone and aquifer thicknesses and horizontal groundwater gradients. This study applies to individual households and small settlements (1–20 persons) in decentralized locations without access to receiving surface waters but with the legal obligation of biological wastewater treatment. The calculations are based on Monte Carlo simulations using an analytical model that couples vertical unsaturated and horizontal saturated flow with virus transport. Hydraulic conductivities and water retention curves were selected from reported distribution functions depending on the type of subsurface media. The enteric virus concentration in effluent discharge was calculated based on reported ranges of enteric virus concentration in faeces, virus infectivity, suspension factor, and virus reduction by mechanical-biological wastewater treatment. To meet the risk target of < 10 −4 infections/person/year, a 12 log 10 reduction was required, using a linear dose-response relationship for the total amount of enteric viruses, at very low exposure concentrations. The results of this study suggest that the horizontal setback distances vary widely ranging 39 to 144 m in sand aquifers, 66–289 m in gravel aquifers and 1–2.5 km in coarse gravel aqui-fers. It also varies for the same aquifers, depending on the thickness of the vadose zones and the groundwater gradient. For vulnerable fast-flow alluvial aquifers like coarse gravels, the calculated setback distances were too large to achieve practically. Therefore, for this category of aquifer, a high level of treatment is recommended before the effluent is discharged to the ground surface.
August 2016
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93 Reads
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27 Citations
The Science of The Total Environment
Contamination of groundwater by pathogenic viruses from small biological wastewater treatment system discharges in remote areas is a major concern. To protect drinking water wells against virus contamination, safe setback distances are required between wastewater disposal fields and water supply wells. In this study, setback distances are calculated for alluvial sand and gravel aquifers for different vadose zone and aquifer thicknesses and horizontal groundwater gradients. This study applies to individual households and small settlements (1–20 persons) in decentralized locations without access to receiving surface waters but with the legal obligation of biological wastewater treatment. The calculations are based on Monte Carlo simulations using an analytical model that couples vertical unsaturated and horizontal saturated flow with virus transport. Hydraulic conductivities and water retention curves were selected from reported distribution functions depending on the type of subsurface media. The enteric virus concentration in effluent discharge was calculated based on reported ranges of enteric virus concentration in faeces, virus infectivity, suspension factor, and virus reduction by mechanical-biological wastewater treatment. To meet the risk target of b10−4 infections/person/year, a 12 log10 reduction was required, using a linear dose-response relationship for the total amount of enteric viruses, at very low exposure concentrations. The results of this study suggest that the horizontal setback distances vary widely ranging 39 to 144 m in sand aquifers, 66–289 m in gravel aquifers and 1–2.5 km in coarse gravel aquifers. It also varies for the same aquifers, depending on the thickness of the vadose zones and the groundwater gradient. For vulnerable fast-flow alluvial aquifers like coarse gravels, the calculated setback distances were too large to achieve practically. Therefore, for this category of aquifer, a high level of treatment is recommended before the effluent is discharged to the ground surface.
January 2015
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30 Reads
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4 Citations
January 2006
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35 Reads
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9 Citations
March 2003
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14 Reads
This article summarises the main bases and results of a three-year research project carried out at three sewage treatment works situated in the "See-winkel" area on Lake Neusiedl, investigating what repercussions the percolation of treated waste water has on the quality of groundwater. Boron and other substances contained in the water proved particularly suited to identify affected groundwater areas. Apart from chemical parameters as e.g. residual DOC pollution, microbial pollution was recognised as being a particularly critical parameter. The principal result obtained from the project was the possibility of devising a procedure for the planning, authorisation, and supervision of sewage treatment plants using percolation, capable of being used as important know-how also by Austrian companies working abroad.
October 2001
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216 Reads
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75 Citations
Letters in Applied Microbiology
The relationship between the rate of beta-D-glucuronidase hydrolysis (GLUase-HR) and the E. coli concentration in rivers differing in the extent of faecal pollution was investigated. It was hypothesized that the rate of GLUase-HR is a better surrogate parameter for E. coli concentrations than estimated numbers of faecal coliforms (FC). The GLUase-HR of the water sample filter residues was determined as the rate of cleavage of 4-methylumbelliferyl-beta-D-glucuronide. FC and E. coli concentrations were enumerated using mFC and Chromocult Coliform agar, respectively. Regression analysis revealed that a 90% variation of the variable log GLUase-HR was directly related to the variable log E. coli concentrations. The observed relationship between the log of the FC count and the log of the GLUase activity could be explained by the hydrolysis activity of the E. coli population, as E. coli is a part of the FC group. The data suggest that the log of the GLUase-HR can be used as a surrogate parameter for the log of the E. coli concentrations. GLUase-HR determination may provide a rapid alternative technique to estimate E. coli concentrations in freshwaters.
... They are hence a significant source of contaminants, e.g., nutrient and pathogen leaks into aquifers. Viral concentrations of up to 10 9 viruses/L have been measured below conventional septic systems (Anderson and Weber, 2004;Blaschke et al., 2016). Under optimal operation conditions (i.e., correctly designed, installed, and maintained septic systems), viral removal in ISS is about 4 log (Lusk et al., 2017;Adegoke and Stenstrom, 2019;Eregno and Heistad, 2019;Blaschke et al., 2016). ...
December 2016
The Science of The Total Environment
... Recommendations for the siting of pit latrines differ across countries; they range from 15 to 75 m between the groundwater source and the sanitation unit. Ensuring an adequate distance between wastewater disposal facilities and drinking water wells is crucial to safeguard the water sources against microbial contamination [21]. To our knowledge, no research has been done to link on-site sanitation facilities to the faecal contamination of boreholes that are located on the same household premises at the specific sites investigated in the present study. ...
August 2016
The Science of The Total Environment
... However, the framework directive does not provide for the monitoring of microbiological indicators, only the Bathing Water Directive 2006/7/EU [10] includes the assessment of the microbial load of this type of waters by the content of fecal indicator bacteria. There are data from periodic studies on the ecological status of the largest European riverthe Danube River, in which the waters along the entire river course are analyzed not only for the regulated chemical, physicochemical and biological indicators, but also for the content of fecal indicator bacteria, as established an indirect indicator for the assessment of waterborne pathogens [17,19,20]. ...
January 2015
... Despite efforts to preserve its ecosystem, the Danube faces severe physical, chemical, and biological pollution, especially in its upper part, the Pokutsko-Bukovynian Carpathians (Pall et al., 2013;Kolarevich et al., 2011). Researchers have classified the microbiological quality of water in the Danube basin into different classes based on standard indicators of fecal and organic pollution (Eiler et al., 2022;Kavka et al., 2006;Winter et al., 2007;Kirschner et al., 2009;Kirschner et al., 2017). The Siret and Prut rivers, originating in the Ukrainian Carpathians, were categorized as critical and strongly fecal pollution classes, respectively. ...
Reference:
Sanitary Microbiological
January 2006
... Among the enzyme assay methods, the β-D-glucuronidase (GLUC) and β-D-galactosidase are enzymes used for the detection of E. coli and coliform bacteria, respectively. Scientific findings indicate high correlations between the GLUC activity and typical membrane filtration techniques in samples from freshwater, [12][13][14] creek water, 15 and wastewater. 13 Reported automated fluorometric prototypes include the TECTA™ B16 system 16 and the ColiSense device. ...
October 2001
Letters in Applied Microbiology