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Empirical Models and Vulnerability Mapping
Published in Robert C. Knox, David A. Sabatini, Larry W. Canter, Subsurface Transport and Fate Processes, 1993
Robert C. Knox, David A. Sabatini, Larry W. Canter
Delineation Criteria — Delineation criteria include distance, drawdown, travel time, flow system boundaries, and the capacity of the aquifer to assimilate contaminants (assimilative capacity). These criteria are described below.The distance criterion defines the WHPA by a radius measured around a pumping well.The drawdown criterion defines the WHPA as the area around the pumping well in which the water table in unconfined aquifers or the potentiometric surface in confined aquifers is lowered by pumping.The time of travel criterion bases the WHPA boundary on the time required for contaminants to travel through the subsurface to the water supply.The flow boundaries criterion incorporates the known locations of ground water divides and other physical or hydrologic features that control ground water movement.The assimilative capacity criterion is based on the subsurface formation capacity to dilute, retard, mineralize, or otherwise attenuate contaminant concentrations to acceptable levels before they reach drinking water wells.
Environmental governance
Published in Neeru Bansal, R. Parthasarathy, Are SDGs a myth?, 2020
Neeru Bansal, R. Parthasarathy
Although such an initiative was started to regulate air pollution, it is required in the case of water pollution too. There is a need to keep a check on the total pollution load which can be added to the receiving water bodies. With an ever-increasing number of water polluting units, the amount of pollution being added by merely following the concentration-based standards fails to keep a check on the total pollution load being added to the receiving water body. This leads to going beyond the assimilative capacity and is one of the reasons for the poor quality, and rising number, of polluted water bodies. However, any market-based instrument will require a robust data base. This is currently not in place, as will be discussed in the upcoming chapters.
Natural Purification
Published in Subhash Verma, Varinder S. Kanwar, Siby John, Environmental Engineering, 2022
Subhash Verma, Varinder S. Kanwar, Siby John
Wastewater needs to be treated when the pollutant loading exceeds the assimilative capacity of the receiving water bodies. In the past, in the majority of cases, wastewater was directly discharged into receiving water bodies. It was assumed that the wastewater was diluted by a factor of hundreds so that the natural purification was good enough to maintain the quality of water in the receiving water body. The report of the Royal Commission on Sewage Disposal lays down certain standards, as indicated in Table 20.1.
A new enzymatic method assessing the impact of wastewater treatment plant effluents on the assimilative capacity of small rivers
Published in Journal of Environmental Science and Health, Part A, 2019
Dennis Langner, Bianca M. König, Denise J. Brettschneider, Andrea Misovic, Ulrike Schulte-Oehlmann, Jörg Oehlmann, Matthias Oetken
The objective of the present study was to establish a new method for the evaluation of treated wastewater and for assessing its impact on the assimilative capacity in the receiving waters. We focused on small WWTPs which often are less effective in the elimination of micropollutants and other contaminants compared to larger plants.[34] A further rationale for the focus on small WWTPs was that they are often located in the upper reaches of rivers or on smaller tributaries with low water flow. Consequently, their discharges can result in high proportions of treated wastewater and thus high exposure levels to wastewater-borne chemicals in the receiving waters. Therefore, we expected inhibitory effects of the WWTP effluents on microorganisms and on the activity of exoenzymes produced by these microorganisms, including BGL as a proxy for the assimilative capacity of surface waters. To test this hypothesis, we examined the effects of the discharges of two small WWTPs at two small rivers on the BGL activity in enriched extracts with C. uda. Because one of the two WWTPs was decommissioned during our investigation, we also had the chance to assess its impact on the assimilative capacity in the receiving river by a comparison of samples taken before and after the decommissioning. Here, we expected a rapid recovery of the previously inhibited BGL activity after the shutdown of the WWTP.