Fate and Transport of Biological and Inorganic Contaminants from On-Site Disposal of Domestic Wastewater
- R.B. Reneau *,
- C. Hagedorn and
- M.J. Degen
An on-site wastewater disposal system (OSWDS) is the primary method for domestic waste disposal in sparsely populated areas and in numerous suburban counties. The most common OSWDS is a septic tank with a subsurface soil absorption system that relies on gravity to move wastewater from the residence to the soil with minimal pretreatment of waste before application to the soil. Much of the renovation occurs as the wastewater percolates through the soil prior to reaching ground or surface waters. In 1980, 20.9 million residences (24.1% of the total in the USA) applied approximately 14 × 109 L of domestic wastewater to U.S. soils each day. These numbers emphasize the need for assessing the effect of OSWDS on the quality of the environment. This review addresses the potential impact of selected biological and chemical contaminants present in domestic wastewater on environmental quality. Inefficient use of a soil's renovative capacity (primarily because of poor effluent distribution) can result in extensive travel distances for biological or chemical contaminants as well as hydraulic failure of the OSWDS. The need for further investigation of the potential for water contamination from nitrogenous components and possible mechanisms to reduce the degradation potential of N is addressed. Most studies assume that the dynamics of viral translocation through soil resemble those of fecal bacteria. This assumption may not be correct. Lastly, a critical examination of fate of N, viruses, and fecal bacteria introduced into soils via alternative OSWDS and modified conventional OSWDS should be a priority research initiative.
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