Potential mechanisms for bioregeneration of perchlorate-containing ion-exchange resin.
Ion-exchange (IX) is the most feasible technology for perchlorate removal from drinking water. Reuse of resins present challenges, however. Selective resins are non-regenerable, and are incinerated after one time use, while non-selective resins, when regenerable, produce a waste stream that contains high concentration of perchlorate that must be disposed of. A process to bioregenerate spent resin containing perchlorate with perchlorate-reducing bacteria (PRB) has been recently developed. In this research, potential mechanisms for bioregeneration of resin-attached perchlorate (RAP) were investigated. Batch bioregeneration experiments were performed using gel-type and macroporous-type resins. Various initial chloride concentrations and various resin bead sizes were used. The results of the bioregeneration experiments suggested that chloride, i.e. the product of perchlorate biodegradation, is more likely the desorbing agent of RAP; and increasing the concentration of chloride enhances the bioregeneration process. Both film and pore diffusion were found to be relevant with respect to the rate of perchlorate mass-transfer to the bulk liquid. Bioregeneration was found to be more effective for macroporous than for gel-type resins, especially in the case of macroporous resins with relatively small bead size in the presence of higher chloride concentration.
Civil Engineering Department, California State Polytechnic University Pomona, CA, USA. Electronic address: sharbat@cpp.edu.
Mohamadali
M
Sharbatmaleki
Department of Civil and Environmental Engineering, University of Nevada, Las Vegas, NV, USA.
Richard F
RF
Unz
Department of Civil and Environmental Engineering, University of Nevada, Las Vegas, NV, USA.
Jacimaria R
JR
Batista
D001419:Bacteria / Q000378:metabolism*; D060766:Drinking Water / Q000032:analysis; D007475:Ion Exchange Resins / Q000378:metabolism*; D007700:Kinetics; D010084:Oxidation-Reduction; D010472:Perchlorates / Q000378:metabolism*; D059027:Recycling; D014874:Water Pollutants, Chemical / Q000378:metabolism*; D018508:Water Purification / Q000379:methods*
D060766:Drinking Water; D007475:Ion Exchange Resins; D010472:Perchlorates; D014874:Water Pollutants, Chemical; C494474:perchlorate
Bioregeneration; Ion-exchange; Mass-transfer; Perchlorate