Full Description

An ion-exchange resin regeneration process has been developed that directlyregenerates ion exchange (IX) resins contaminated with perchlorate and nitrate. The processconsists of directly contacting perchlorate/nitrate-contaminated ion exchange resin with aperchlorate/nitrate-reducing microbial enrichment culture under anoxic/anaerobic conditionsleading to conversion of the perchlorate and nitrate loads on the resin to innocuous chloride andnitrogen gas, respectively. Bioregeneration tests were performed using spent resins loaded inthe laboratory with known amounts of perchlorate and nitrate. At prescribed intervals, samples ofthe resin were taken and eluted for perchlorate and nitrate analysis. The results show that bothnitrate and perchlorate were removed from the resin. After two days of operation, about 50% ofthe perchlorate and 80% nitrate were removed. After six days of operation more than 80% ofnitrate and 90% of the perchlorate were removed from the resin. Biofouling removal and of thebioregenerated resin was accomplished using various foulant agents and disinfectants. Theresults of the research confirm the feasibility of biological regeneration of ion-exchange resinscontaminated with perchlorate and nitrate. The process developed has several advantages.The first is conversion of the contaminant perchlorate and nitrate to innocuous chloride andnitrogen gas, respectively. This is in contrast to simply transferring the contaminants to thebrines. The second advantage is that biotreated resins can be reused several times, minimizing the cost to water utilities. Lastly, the process is environmentally sustainable because it eliminates the one-way use of resins,thereby minimizing the use of raw materials and energy needed to manufacture new resins. Includes 23 references, figures.

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Edition: Vol. - No. Published: 11/01/2007 Number of Pages: 10File Size: 1 file , 320 KB