Electrochemical Treatment and Recycling of Spent Perchlorate-Contaminated Ion-Exchange Regeneration Brine

Eltron Research & Development, Inc. (Eltron) proposes to develop an ion-selective, polymer membrane electrode capable of detecting perchlorate in water at low parts per billion (ppb) concentrations. With the discovery of perchlorate contamination in an increasing number of drinking water sources and an increase in regulation of perchlorate in drinking water, some wells are shut down because no cost-effective treatment strategy exists. Decreasing the costs associated with disposing of spent, contaminated resin or regeneration brine will lower the cost of ion-exchange strategies for the treatment of perchlorate. Brine disposal is estimated to be 5 percent of the total cost of ion-exchange treatment, and resin disposal is estimated to be 1 percent. In addition, the system will remove the waste stream associated with disposal of the perchlorate-contaminated resin and brine by recycling spent regeneration brine. Additional cost savings will be realized by eliminating the purchase of salt to replace disposed brine. The system will employ a large surface area cathode to overcome previously reported shortcomings of electrolytic systems for perchlorate treatment. In Phase I, the cathode will be developed and tested in one of Eltron’s proven electrolytic cell designs. Testing will be followed by a feasibility study to compare the cost of installation and operation of a pilot-scale system of appropriate size for small drinking water production units to bioreactors, granular activated carbon systems, and other ion-exchange treatment strategies. In Phase I, destruction of perchlorate in the system will be demonstrated. Performance and interference testing of the single cell will provide performance data and operation parameters for testing of a pilot-scale unit in Phase II. Eltron has a long history of developing electrolytic water treatment systems and has a pilot-scale H2O2 generation system currently under evaluation by a possible partner. Eltron also has developed a background patent position in electrolytic water treatment systems. The team assembled by Eltron for this project has experience in electrochemistry and, specifically, in electrolytic water treatment systems. The existing technology and experience will help to speed development of the proposed technology to a marketable system.