[Bioregeneration of Anion Exchange Resin Used in Nitrate Removal]

Anion exchange resin is a feasible adsorbent for nitrate removal because of its high efficiency and cost-effectiveness, but brine regeneration complicates subsequent wastewater procedures. Bioregeneration degrades the nitrate from the nitrate-laden resin, which can decrease brine solution usage and waste discharge. In this study, based on investigation of the effect of carbon source, for example, glucose, sodium acetate, sodium lactate, and methanol, on bioregeneration, nitrate-laden resin was employed to investigate the effects of inoculum amount and salt concentration on bioregeneration with sodium acetate as the carbon source. The results showed that the bioregeneration process comprised chemical desorption and biological denitrification and was limited by the biological process. With increasing inoculum amount, the bioregeneration time was remarkably reduced. Nitrate on the resin could be completely biodegraded within 10 h when the inoculum amount (measured as VSS) was higher than 0.6 g·L