389Regulations 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 2001. 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.