|Technology Selection and System Design, U.S. EPA Arsenic Removal Technology Demonstration Program, Round 1 (49 pp, 1.87 MB) (EPA/600/R-05/001) November 2004
In January 2001, EPA finalized the maximum contaminant level (MCL) for arsenic at 0.01 milligrams per liter (mg/L). EPA subsequently revised the rule to express the MCL as 0.010 mg/L (10 micrograms per liter). The final rule requires all community and nontransient, noncommunity water systems to comply with the new standard by February 2006.
In October 2001, EPA announced an initiative for additional research and development of cost-effective technologies to help small community water systems (those with fewer than 10,000 customers) meet the new arsenic standard and to provide technical assistance to operators of small systems in order to reduce compliance costs.
As part of this Arsenic Rule Implementation Research Program, EPA proposed a project to conduct a series of full-scale, long-term, on-site demonstrations of arsenic removal technologies, process modifications, and engineering approaches applicable to small systems in order to evaluate the efficiency and effectiveness of arsenic removal systems at meeting the new arsenic MCL.
For the Round 1 demonstration study, the selected arsenic treatment technologies included nine adsorptive media systems, one ion exchange system, one coagulation/filtration system, and one process modification. The adsorptive media systems used four different adsorptive media, including three iron-based media (ADI's G2, Severn Trent and AdEdge's E33, and USFilter's GFH) and one iron-modified activated alumina media (Kinetico's AAFS50, a product of Alcan). Since the inception of the project, 10 of 12 systems have been installed, with flow rates at all systems ranging from 37 to 640 gallons per minute.
This report provides the source water quality characteristics at each of the 12 demonstration sites and the rationale used to select the technologies for demonstration at each site. Information on the design and operation of each treatment system also is presented.
The selection of the technologies for demonstration at each location was a cooperative decision made by the water system, the state, and EPA. Many factors were considered in the selection process, including water quality, residual production and disposal, complexity of system operation, and costs. The selection of the adsorptive media and pretreatment methods depended on a number of factors that affect system performance:
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