Superfund Research Program
New Oxidative Technology Shows Promise For Treating Organic Chemical Contaminants in Water
Environmental scientists estimate that chemical contaminants from ground spills, buried wastes, and other sources have migrated into the groundwater on over 80 percent of the country's Superfund sites. Once chemicals reach an aquifer, groundwater can carry the contaminants far from their original source into private and municipal water supplies, as well as to wetlands, streams and lakes. Environmental scientists and engineers have been challenged to clean up polluted aquifers in order to protect human populations and aquatic ecosystems from the harmful effects of chemical exposures.
While clean up of polluted groundwater is necessary to protect drinking water supplies and ecological health, it has been a costly and complicated endeavor. On many hazardous waste sites the contaminated water is pumped to the surface and treated. Some of the water treatment methods are slow and produce by-products that must be disposed of as hazardous waste. Advanced treatment technologies are greatly needed to reduce the costs and accelerate the process of cleaning up this important natural resource.
In an effort to expedite the clean up of organic chemical contaminants in groundwater and other types of water, scientists at the Environmental Research Center at SUNY-Oswego (a part of the SUNY-Albany Superfund Basic Research Program) have developed an advanced oxidative technology, known as Electrochemical Peroxidation, that effectively breaks down polychlorinated biphenyls (PCBs), volatile organic compounds, as well as other types of toxic organic compounds that are commonly found on hazardous waste sites.
Electrochemical Peroxidation involves the use of electricity, steel electrodes and hydrogen peroxide to break down organic compounds to carbon dioxide, water, and small amounts of chlorides if any of the contaminants are chlorinated. The treatment process works by introducing an electric current into the contaminated liquid or slurry. Additions of hydrogen peroxide into the electrolyzed liquid produce free radicals that attack and break down available organic matter. This electrochemical treatment process is highly effective and very efficient: bench scale experiments with the technology indicate the oxidative process is capable of rapidly destroying a broad range of organic contaminants at concentrations of several ten ppm (parts per million) with reaction times of under one minute.
Based on success at the laboratory scale, researchers in the Environmental Research Center have designed and constructed an on-site, continuous flow Electrochemical Peroxidation reactor that is highly portable and capable of treating up to 15-20 liters of contaminated liquids per minute. Over the past two years, the portable reactor has been used to degrade PCBs in extracted groundwater, as well as surface water, at the Oswego Castings Superfund site in New York. The reactor was also used to break down benzene, toluene, ethylbenzene, and xylenes in groundwater contaminated by gasoline at the Onondaga Nation located near Syracuse, New York.
Because the laboratory and bench scale applications were so promising, a pilot scale demonstration is currently being considered by the Air Force Center for Environmental Excellence for use at a U.S. Air Force Base. The demonstration is planned for late summer/fall of 1998 to treat up to 100 gallons of contaminated water per minute. An in situ application is also under consideration for use at the Onondaga Nation gasoline spill site where Electrochemical Peroxidation is being considered for the degradation of organic compounds, including MTBE (a gasoline additive), in drinking water supplies.
In addition to its excellent performance, this innovative technology is cost effective. Preliminary cost estimates to degrade chlorinated and non-chlorinated contaminants are less than $1.00/1000 gallons of water, which is highly competitive in comparison to existing technologies. Because Electrochemical Peroxidation works rapidly, has harmless end-products, and can treat a broad range of organic chemicals inexpensively, this method shows significant promise as a cost competitive technology for the remediation of organic chemical contaminants in surface and groundwater.
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