Waste water contamination sites

Environmental releases of hazardous waste from contaminated sites can result in transport through several media. The most common pathways include (i) transport through the subsurface to groundwater and (ii) atmospheric transport after release into the air. Other less common pathways after release include surface waters, and plant and animal uptake. 

Groundwater is vulnerable to pollution by chemicals carried by rainwater, leaching from waste sites or from waste water carrying industrial or agricultural effluent. Treatment of drinking water may remove some, but not all, of these contaminants. Some polycarbonate or metal water pipes that are lined with epoxy resin lacquers may release bisphenol A. 

Subsurface drains are essentially permeable barriers designed to intercept the groundwater flow. The water must be collected at a low point and pumped or drained by gravity to the treatment system (Figure 8). Subsurface drains can also be used to isolate a waste disposal area by intercepting the flow of uncontaminated groundwater before it enters into a contaminated site. 

For most smaller operators, the waste water discharge from pretreatment equipment, blowdown receivers, and FSHR equipment typically discharges into a city sewer. Most larger factories, process plants, and power stations, on the other hand, incorporate some form of waste water treatment facility to balance the pH level, remove oils and pre-cipitable solids, or otherwise reduce the contamination load before the discharge of water from the site. 

Initial field investigations of old, heterogeneous disposal sites where waste types are insufficiently documented, thus deferring expensive priority pollutant analysis until the fact and location of ground water contamination is established ... 

Alternative 2 leaves all of the contaminated waste at the site and relies solely upon a cap and institutional controls to prevent exposure. Although the alternative water supply lowers the risk of ingesting contaminated groundwater from existing wells, the institutional controls would not be effective for more than 5 to 10 years in preventing the installation of new wells and the injection of contaminated groundwater. 

Table 1 indicates primary pollutant sources and waste modes, and Table 2 indicates the primary and secondary sources and associated pollutants. The primary sources of soil contamination include land disposal of solid waste sludge and waste-water industrial activities and leakages and spills, primarily of petroleum products. The solid waste disposal sites include dumps, landfills, sanitary landfills, and secured landfills. 

Other than aerial application over swamps for mosquito abatement, disulfoton is not known to be used over water. Potential sources of release into surface water include discharge of waste water from disulfoton manufacturing, formulation, and packaging facilities (HSDB 1994). Leaching and runoff from treated fields, pesticide disposal pits, or hazardous waste sites may contaminate both groundwater and surface water with disulfoton. Entry into water can also occur from accidental spills. Small amounts of volatilized disulfoton may be removed from the atmosphere as a result of wet deposition and may enter surface water (Racke 1992). 

Occupational exposure to higher than background levels of chloroform can be expected to occur in some occupations although few quantitative exposure data were located. Populations with the highest potential exposures appear to be workers employed in or persons living near industries and facilities that manufacture or use chloroform operators and individuals who live near municipal and industrial waste water treatment plants and incinerators, and paper and pulp plants and persons who derive their drinking water from groundwater sources contaminated with leachate from hazardous waste sites. 

Isophorone is released to the air mainly in urban centers, as a result of evaporation of solvents containing this chemical. Isophorone can enter surface waters from industrial effluent discharges or from runoff from soils at hazardous waste or other contaminated sites. Isophorone disappears... 

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