Electrodialysis reversal (EDR) and ion exchange as polishing treatment for perchlorate treatment

Abstract

Due to the development of a new analytical method that lowered the perchlorate detection limit to 4 μg/L, perchlorate has been detected in many drinking water sources. Perchlorate contamination is now recognized as a widespread concern affecting many water utilities. Furthermore, perchlorate is a very stable substance in aquatic systems and is therefore difficult to remove with conventional treatment processes. Magna Water Company in Utah, USA, provides chlorinated groundwater as potable water to the northwest section of Salt Lake County. The groundwater of one of their wells is contaminated with low levels of perchlorate and concentrations are expected to rise due to plume migration. High hardness, alkalinity, and TDS characterize this groundwater. An electrodialysis reversal (EDR) pilot unit was installed at an uncontaminated well. Various perchlorate levels were spiked into the feed water to test the full range of possible perchlorate concentrations. This paper provides EDR performance and cost data for perchlorate treatment. Based on perchlorate removal, the production cost varies between $1.10 and $1.50 per 1000 gal ($0.30 and $0.40/m 3). The presented data allow comparison with other treatment processes.