Current ion exchange approaches for perchlorate remediation are expensive ($200 to >$500 per acre-foot). The primary reasons for the high cost are resin replacement, in the case of single-use systems, and salt consumption and brine disposal, in the case of brine regenerable systems. A perchlorate-selective, regenerable ion exchange process that minimizes or eliminates spent regeneration solution was needed to significantly reduce treatment cost.

Objectives:

• Develop and demonstrate a regenerable, perchlorate-selective ion exchange process capable of removing perchlorate to <4 ppb

• Demonstrate an efficient regeneration technique with the goal of limiting spent regenerating solution to < 0.05% of the treated groundwater volume

• Demonstrate effective destruction or removal of perchlorate in the spent regenerating solution to enable discharge or reuse

Results and Benefits

ARA and The Purolite Company developed a new, regenerable, weak base anion (WBA) resin ion exchange process for perchlorate (patent pending) and conducted a successful field demonstration at Redstone Arsenal, Alabama. The WBA resin process completely removed perchlorate from groundwater that had an initial concentration of 1500 to 2200 ppb. Multiple regenerations were conducted to demonstrate repeatable performance and minimization of spent regenerating solution to less than 0.05% of the treated water volume (a 20 to 50-fold improvement over state-of-the-art). Spent regenerating solution was successfully treated by biodegradation and by a “zero-discharge” scavenging approach. The ion exchange technology developed using WBA resin will reduce treatment cost to less than $100 per acre-foot. This project was sponsored by the Environmental Security Technology Certification Program (ESTCP).