ARCHIVED REPORTS XR0008636 - Laserfiche WebLink

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stripping, cascading, or waterfall aeration, diffuser striping, and surface aeration To remove compounds that are volatile at higher than ambient groundwater temperature, the air stripping system can be designed to preheat the water or is used in conjunction with a secondary treatment or polisher system, such as activated carbon Prior to choosing this method of treatment, flow rates, contaminant types and concentrations, groundwater chemistry, permitting requirements, and space and power requirements must be considered The air containing organic compounds is typically discharged from the system The ' air discharge should be modeled and permuted where required. Similarly, treatment of the air used to strip compounds from the water may be required by the permitting agencies. 2 2.2 Bioremediation Extracted groundwater may also be treated by use of an aboveground bioreactor Bioreactors utilize natural or specialized bacteria to remove organic contaminants through aerobic and anaerobic consumption and digestion processes Digested organic compounds are converted to biomass and harmless by-products such as methane, carbon dioxide, and inorganic salts The bioreactor design depends on contaminant concentration and type, flow rates, and groundwater chemistry Groundwater is pumped from the subsurface and enters a container that contains a sludge or film with a high microbe population that is exposed to the liquid The reactor capacity is large enough to allow both sufficient surface area for the introduction of the microbes into the groundwater and a sufficient residence time for the microbes to metabolize the organic compounds. The water may be pre-treated to ' adjust the pH and temperature, and to remove inorganic materials that may clog the reactor system or harm the microbes ' 2 2 3 Ultraviolet Degradation Ultraviolet (UV) degradation involves pumping extracted water through a UV light ' source Two methods of destruction of organic compounds utilizing UV light have been developed The first method utilizes either a natural or introduced hydroxyl radical source and a UV energy source to destroy organic compounds The UV light source frees hydroxyl radicals, usually from hydrogen peroxide or ozone, which then react with the organic compound to form carbon dioxide and a secondary by-product The second method of UV light destruction involves utilizing a plasma type UV light ' source with a focused wavelength This focused energy is absorbed by the organic compound, breaking the molecular bonds This reaction also produces carbon dioxide and a secondary by-product Depending on the type of organic compound being ' destroyed, the secondary by-product can potentially be hazardous and may need to be disposed of or treated ' Before utilizing this treatment alternative, groundwater chemistry, contaminant type and concentration, and flow rates must be evaluated r i