Process for the removal and destruction of perchlorate and nitrate from

Abstract

A process for concentrating and destroying the perchlorate and nitrate anions present in ground water and drinking water sources is disclosed. In the process, the perchlorate and nitrate anions present in feed water are concentrated into a much smaller effluent stream. A typical process configuration involves using a continuous contacter apparatus known as ISEP wherein the perchlorate present in feed water is adsorbed on to an ion-exchange resin resulting in a perchlorate-free treated water. The ISEP unit also incorporates a regeneration zone where the adsorbed perchlorate is effectively removed from the resin using relatively low volumes of concentrated brine solution as the regenerant. The waste from the ISEP unit is a concentrated brine solution containing perchlorate and other anions that may be present in the feed stream. This waste stream from the ISEP unit is treated by a combination of: i) bioreactor or a catalytic reactor that removes perchlorate and nitrate (if present) anions ii) sulfate removal (if needed) by nanofiltration or other established methods and iii) filters and a disinfectant system to render the brine stream re-usable. The resulting stream is recycled back into the process. The entire process results in a very small waste stream that needs disposal. The process can be applied to feed water streams containing either perchlorate alone or perchlorate and other anions such as nitrate, sulfate and bicarbonate.