Ground-Water Treatments Gain Ground

Ground water is the main source of the nation’s public water supplies and is also used extensively for agricultural and industrial purposes. Yet our reserves are constantly threatened by contamination. Approximately 75 percent of the 1,287 sites listed on the National Priority List contain contaminated ground water, according to the Environmental Agency. A few treatment techniques have proven especially effective in both results and costs. Air stripping is one of the most effective technologies for the removal of volatile organic chemicals (VOCs) from ground water. The process involves the pumping of contaminated ground water to the top of a stripping tower and through packing material. The packing material forces the VOC molecules to transfer from water to the air. Air sparging with soil vapor extraction involves injecting air into the contaminated aquifer, which forces contaminants into the ground water and soil where they are captured by the soil vapor extraction system. Carbon adsorption passes ground water through a series of carbon bed reactors while surfacial attraction removes contaminants from the influent. Biological treatment use microorganisms to transform contaminants into less toxic or nontoxic products. These cleanup technologies go a long way toward restoring this important water resource.