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GROUND WATER TREATMENT PROCESSES FOR ARSENIC REMOVAL
Citation:
Sorg*, T J. GROUND WATER TREATMENT PROCESSES FOR ARSENIC REMOVAL. Presented at WQTC, Salt Lake City, UT, 11/5-8/2000.
Description:
In 1975 EPA established a maximum contaminant level (MCL) for arsenic at 0.05 mg/L. In 1996, Congress amended the SDWA and these amendments required that EPA develop an arsenic research strategy and publish a proposal to revise the arsenic MCL by January 2000. The Agency proposed to reduce the arsenic MCL goal to be set at zero, and the proposed enforceable standard, or MCL to be 0.005 mg/L. Using data from 25 State databases, EPA estimated at 12.1% (5302) of the ground water Community Water Supplies (CWS) have average arsenic concentrations above 5 ug/L. The majority of these systems are very small systems serving populations of between 25 and 3,300. When EPA finalizes the arsenic MCL, many CWSs will be required to provide arsenic removal technology to meet it. Because arsenic is more frequently found in ground water than in surface water, ground water technologies will be of major interest. The current list of BATs (best available technologies) for arsenic removal is limited to six technologies, of which only two, ion exchange and activated alumina, will be of major consideration for the small CWSs treating ground water. Several other technologies, such as the iron removal processes, coagulation assisted filtration, and the iron based media products will be given serious consideration for certain situations. With time, the technologies may receive BAT status. The selection of the appropriate technology is dependent on many factors including removal capability, ease of operation, cost, waste generation and disposal. If some type of treatment system is in place, system modification will be the first consideration. If system modification will not achieve the necessary arsenic removal, add on or replacement technology may be required. Site specific conditions will likely determine the ultimate technology selected.