Next Generation of High-Capacity Perchlorate-Selective Resins for Drinking Groundwater Treatment

Identification and Significance of the Opportunity. Perchlorate is a water-soluble anion that has emerged as a major contaminant of drinking groundwater sources in the United States. Various states have set public health goals for acceptable perchlorate levels in drinking water. For example, the State of California established a maximum concentration limit (MCL) of 6 ppb (mg/L) in October 2007 and proposed in January 2011 to reduce the MCL for ClO4• in drinking water from 6 ppb to 1 ppb. Single-pass ion exchange (IX) with selective and disposable resins is currently the best available technology for treating drinking groundwater sources with ClO4• concentration less than 100 ppb. However, commercial perchlorate-selective resins (PSRs) have a relatively low exchange/operational capacity with a strong-base capacity (SBC) ranging from 0.65 eq/L to 0.85 eq/L. As result, the overall cost becomes prohibitive when treating drinking groundwater sources with higher perchlorate concentrations (e.g., 100 ppb to 1000 ppb) or containing large concentrations of competing anions, such as nitrate. Next Generation of High-Capacity PSRs. AquaNano has developed a new PSR with high exchange capacity—an SBC of 1.50 eq/L—that meets the specifications for commercial PSRs in crush strength, particle-size distribution and bead integrity. Preliminary experiments show that the column operational capacity of AquaNano’s PSR is 1.70 times higher than that of a commercial PSR with a reported SBC of 0.85 eq/L for perchlorate extraction from a makeup groundwater containing an effluent ClO4• concentration of 10 mg/L. Project Objectives and Research Plan. In Phase I of this EPA SBIR proposal, we will explore the commercialization of this new PSR as disposable media for single-pass IX systems. This Phase I SBIR EPA proposal has three specific objectives: Scale up and optimize our resin-preparation procedures to consistently produce 5- to 10-Kg batches of a commercial-grade PSR with high SBC (~1.50 eq/L). Verify and validate the performance of these new high-capacity PSRs through column field tests at two groundwater sites in California. Collect the data required to develop a roadmap for a Phase II SBIR proposal to accelerate the commercialization of this new PSR. Expected Results and Commercial Potential. We expect the successful completion of the Phase I project to provide the data needed to develop a Phase II SBIR proposal to validate AquaNano’s PSR as high-capacity media for perchlorate removal from drinking groundwater using single-pass IX treatment processes.