Setback distances between small biological wastewater treatment systems and drinking water wells against virus contamination in alluvial aquifers

• DOI: 10.1016/j.scitotenv.2016.08.075
• Publication Date: 2016-08-27T04:19:50Z
• Authors: A.P. Blaschke; J. Derx; M. Zessner; R. Kirnbauer; G. Kavka; H. Strelec; A.H. Farnleitner; L. Pang
• Keywords: Effluent land disposal; Setback distances; Environmental Engineering; Vadose zone; Water Wells; Enteric viruses; Wastewater; 01 natural sciences; Water Purification; 12. Responsible consumption; Water Quality; 11. Sustainability; Environmental Chemistry; Waste Management and Disposal; Groundwater; 0105 earth and related environmental sciences; 2. Zero hunger; Conservation of Water Resources; Drinking Water; Water Pollution; Models, Theoretical; Pollution; 6. Clean water; 3. Good health; Water quality; Water Microbiology; Small biological wastewater treatment systems; Monte Carlo Method

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 disposal fields and supply wells. In this study, calculated for alluvial sand gravel aquifers different vadose zone aquifer thicknesses horizontal gradients. This study applies to individual households settlements (1-20 persons) decentralized locations without access receiving surface waters but with the legal obligation treatment. The calculations based on Monte Carlo simulations using an analytical model that couples vertical unsaturated saturated flow transport. Hydraulic conductivities retention curves were selected reported distribution functions depending type subsurface media. enteric concentration effluent discharge was ranges faeces, infectivity, suspension factor, reduction mechanical-biological meet risk target <10-4infections/person/year, 12 log10 required, linear dose-response relationship total amount viruses, at very low exposure concentrations. results suggest vary widely ranging 39 144m aquifers, 66-289m 1-2.5km coarse aquifers. It also varies same thickness zones gradient. For vulnerable fast-flow like gravels, too large achieve practically. Therefore, category aquifer, high level recommended before discharged ground surface.