400Technology Selection and System Design, USEPA Arsenic
Demonstration Program Round 1
EPA 600-R-05-001
On January 18, 2001, the U.S. Environmental Protection Agency (EPA) finalized the
maximum contaminant level (MCL) for arsenic at 0.01 mg/L. EPA subsequently revised
the rule text to express the MCL as 0.010 mg/L (10 μg/L). The final rule requires all
community and non-transient, non-community 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 (<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’s Office of Research
and Development (ORD) 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 include nine
adsorptive media systems, one ion exchange system, one coagulation /filtration system,
and one process modification.
The adsorptive media systems use four different adsorptive media, including three iron-
based media (i.e., ADI’s G2, Severn Trent and AdEdge’s E33, and USFilter’s GFH), and
one iron-modified activated alumina media (i.e., Kinetico’s AAFS50, a product of Alcan).
The flowrate of these systems ranges from 37 to 640 gallons per minute (gpm).
This report provides the source water quality characteristics at each of the 12
demonstration sites and the general 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, 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 the system performance, including arsenic concentration and
speciation, pH, and the presence of competing anions, as well as media-specific
characteristics such as costs, media life, and empty-bed contact time (EBCT)
requirements.