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Titel |
Domestic wells have high probability of pumping septic tank leachate |
VerfasserIn |
J. E. Bremer, T. Harter |
Medientyp |
Artikel
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Sprache |
Englisch
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ISSN |
1027-5606
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Digitales Dokument |
URL |
Erschienen |
In: Hydrology and Earth System Sciences ; 16, no. 8 ; Nr. 16, no. 8 (2012-08-03), S.2453-2467 |
Datensatznummer |
250013405
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Publikation (Nr.) |
copernicus.org/hess-16-2453-2012.pdf |
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Zusammenfassung |
Onsite wastewater treatment systems are common in rural and semi-rural areas
around the world; in the US, about 25–30% of households are served by a
septic (onsite) wastewater treatment system, and many property owners also
operate their own domestic well nearby. Site-specific conditions and local
groundwater flow are often ignored when installing septic systems and wells.
In areas with small lots (thus high spatial septic system densities), shallow
domestic wells are prone to contamination by septic system leachate. Mass
balance approaches have been used to determine a maximum septic system
density that would prevent contamination of groundwater resources. In this
study, a source area model based on detailed groundwater flow and transport
modeling is applied for a stochastic analysis of domestic well contamination
by septic leachate. Specifically, we determine the probability that a source
area overlaps with a septic system drainfield as a function of aquifer
properties, septic system density and drainfield size. We show that high
spatial septic system density poses a high probability of pumping septic
system leachate. The hydraulic conductivity of the aquifer has a strong
influence on the intersection probability. We find that mass balance
calculations applied on a regional scale underestimate the contamination risk
of individual drinking water wells by septic systems. This is particularly
relevant for contaminants released at high concentrations, for substances
that experience limited attenuation, and those that are harmful even at low
concentrations (e.g., pathogens). |
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