377Summaries of EPA Arsenic Publications - Arsenic
Regulations on the Disposal of Arsenic Residuals from Drinking
Water Treatment Plants EPA 600-R-00-025
As with other production processes, water treatment systems produce a product and a
residual of that product. With the passage of the various federal statues, restrictions have
been placed on the discharge of residuals to water bodies and onto land. This report
summarizes federal regulations and selected state regulations that govern the
management of residuals produced by small drinking water treatment systems removing
arsenic from drinking water. Arsenic is a naturally occurring contaminant in ground water
and many small water treatment facilities use ground water as their primary source of
water. Under the Safe Drinking Water Act (SDWA), a maximum contaminant level (MCL)
of 0.05 mg/L has been established for arsenic in drinking water. Under the 1996 SDWA
Amendments, the EPA is required to develop a revised arsenic regulation by January
- Concerns have been raised as to the technical feasibility and regulatory implication
of a more stringent arsenic MCL on the disposal of the residuals from arsenic removal
processes. This document reports on five water treatment processes known to be effective
for arsenic removal from small ground water systems. The five processes are anion
exchange, activated alumina adsorption, iron/manganese removal, media adsorption, and
membrane processes. For each technology, a brief description is provided of the treatment
process along with a discussion of the residual production characteristics.
An overview is provided of the federal regulations that apply to the management of
residuals, with a focus on arsenic removal residuals. The purpose of this overview is to
provide guidance to water suppliers on the federal regulatory requirements of residuals
management to better evaluate compliance of existing practices and to plan for needed
changes in treatment plant operations.
Specific disposal methods are summarized by the form of the residuals including liquid
residuals (direct discharges, indirect discharges, underground injection, and land
disposal) and solid/sludge residuals (solid waste landfill, hazardous water landfill, lagoons,
reuse of hazardous waste, reuse of solid waste, and off-site disposal) and the method in
which the residuals are managed. Federal regulations summarized include the Clean
Water Act (NPDES, Pretreatment), SDWA (Underground Injection Control and lagoons),
and Resource Conservation and Recovery Act (Subtitles C/D). In addition to the federal
regulations that impact the management of arsenic drinking water treatment residuals,
regulations imposed by seven states were also reviewed.
The seven states (Arizona, California, Maine, Nebraska, New Mexico, Nevada, and
Pennsylvania) were chosen based on arsenic occurrence and regional representation.
The review of the state regulations also focused on characterizing the requirements that
apply to different management options available for liquid and solid residuals generated
by treatment systems that remove arsenic from drinking water. It was found that many
components of the state regulatory programs were generally consistent with the federal
minimum requirements.