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5 <br /> 3 <br /> I <br /> Y n <br /> . 14 November 1995 ' <br /> AGE-NC Project No 95-0121 3 <br />' Page 16 of 20 , <br /> h A'third, but less common method of above-ground treatment of water is bioremediation For this 2 <br />' method, contactunated ground water is"treated" by adding hydrocarbon-degrading microbes or by <br /> i augmenting natural hydrocarbon degradation activities by the introduction of nutrients_ <br /> I ' <br /> 7 2 3 FEASIBELITY TESTING <br /> No aquifer testing has been performed at the site 'However, well EW-1 was completed for use as <br /> i <br /> a ground water extraction well as well as an SVE well If necessary, a pump test can be performed <br />' = using EW-1 to determine aquifer and pumping characteristics at the site ` <br /> There are several disadvantages tb "pump and treat methods" The most pronounced disadvantages a <br />' include 1) extended cleanup periods, resulting in elevated total costs although the maintenance of ' + <br /> this method is relatively cost-effective and 2) regulatory cleanup goals are rarely attainable, mostly <br />' due to recurring hydrocarbons in subsequent sampling events Ground water extraction is generally <br /> not a desirable method for remediation <br /> , ' <br /> 7 2 4 DURATION <br /> I Experience has shown that all systems involving ground water extraction require much more time <br /> than would be anticipated from aquifer tests and calculations of ground water discharge rates, and <br /> seldom achieve regulatory goals for ground water clean-up Systems typically operate for several <br /> years During this tune, pumps and other equipment may need replacement several times The primary <br /> utility of pump-and-treat systems is in preventing migration of contaminated ground water <br /> , I <br /> 7 2 5 COST <br /> Ground water extraction'is usually a very costly method of ground water treatment Costs for <br /> installation of a"pump and treat' system is typically$20,000 to $30,000, including installation of one <br /> large-dhameter extraction well However, once extracted, the contanvnated water has to be treated <br /> or disposed Treatment is lughly dependant upon the concentrations of dissolved hydrocarbons in <br /> the ground water For the Nomellun site, the cost per gallon could be as great as $2 00, based upon <br /> I the extraction/treatment of approximately 200,000 to 300;000 gallons of contaminated (ground water <br /> Costs for the entire treatment project would likely be between $200,000 and $650,000 <br /> i <br /> I , <br /> I <br /> t 'I <br />