Application of glucose for improving NH₄⁺-N removal in micro-polluted source water by immobilized heterotrophic...

Bio-enhanced activated carbon (BEAC) filters have shown potential in source water purification. The key drawback of this system is the difficulty of the set-up at low temperature. Here, glucose was applied to help immobilize more functional heterotrophic nitrifiers and further improve NH₄⁺-N removal by BEAC. Results showed that pre-loading glucose on granular activated carbon could achieve better immobilization efficiency with 5.12 × 10⁸ CFU/g-DW C biomass and 3.77 mg TF/L/g-DW C dehydrogenase activity after artificial immobilization, which were separately 12.5 and 4.2 times of the control. 95-d running data at different conditions showed the superiority of both immobilization and NH₄⁺-N removal could last and defend environment changes during relatively long period. Even at the end of operating, the abundance of targeting genus (Acinetobacter) still occupied 9.59% of microbial communities on BEAC, while this value was only 1.24% without pre-loading glucose. Biolog-ECO plate analysis found pre-loading glucose improved organic nitrogen metabolism effectively, along with carbohydrate, amino, alcohol, amine and carboxylic acid metabolism on BEAC.