Demonstration of a Low-Cost, Regenerable, Ion Exchange Process to Remove Perchlorate from Drinking Water

Problem Statement and Objectives

On January 26, 2006, the U.S. EPA adopted a reference dose (RfD) for perchlorate of 0.0007 mg/kg-day. This RfD equates to a Drinking Water Equivalent Level (DWEL) of 24.5 micrograms per liter (or 24.5 ppb). Most states that regulate perchlorate in drinking water require reduction to below 1 to 18 ppb. Current single-use and brine regenerable ion exchange processes for drinking water are expensive ($200 to >$500 per acre-foot). A perchlorate-selective, regenerable ion exchange process that minimizes or eliminates spent regenerating solutions would significantly reduce treatment cost.

Objectives:

Demonstrate performance of the weak base anion (WBA) resin technology for drinking water treatment in the State of California
Coordinate the demonstration with the California Department of Health Services (DHS)
Acquire data necessary to apply for a Domestic Water Supply Permit (DWSP)
Demonstrate zero-discharge, scavenger resin approach for treatment of spent regenerating solutions

Results and Benefits

A successful demonstration was conducted at Fontana, California, well site F-17. The perchlorate concentration in the treated water was reduced to below the method report limit (<0.19 ppb) using IC/MS/MS. Several resin regenerations were accomplished. The spent regenerating solution produced was less than 0.03% of the treated water. The spent regenerating solution was successfully treated using the zero-discharge scavenger resin approach to remove perchlorate to below method reports limits. The scavenger approach cost less than $5 per acre-foot to implement based on conditions at the Fontana demonstration site. Total treatment cost is projected to be less than $100 per acre-foot. The WBA resin process can be used to simultaneously remove both perchlorate and nitrate anions.

waste

• Pollution prevention and remediation