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Enhancement of the adaptability of anammox granules to zinc shock by appropriate organic carbon treatment

Ni, Lingfeng, Wang, Yayi, Lin, Ximao, Yan, Yuan, Zhang, Yao, Wang, Weigang
Bioresource technology 2018 v.268 pp. 496-504
anaerobic ammonium oxidation, bacteria, chemical oxygen demand, granules, heavy metals, organic carbon, sodium acetate, wastewater, zinc
Heavy metals, which are commonly present in high ammonia-containing wastewater, can cause inhibitory effects to anammox reaction. This study proposes a novel approach to enhance the adaptability of anammox granules to heavy metal [Zn(II)] shock by organic carbon (sodium acetate, NaAc) treatment, paying special attention to optimization of the treatment dosage and duration. For granules treated with 200 mg chemical oxygen demand (COD)/L NaAc for 2 d, the activity recovery (six cycles) efficiency after Zn(II) (40 mg/L) shock reached 127.4%. The extracellular polymeric substance (EPS) production increased by 168% and heterotrophic bacteria mildly proliferated (increased by 14%) in such granules compared with the control. The dramatic recovery capacity was likely due to the entrapment and barrier function of EPS and the outer-layer proliferated heterotrophic bacteria. This finding offers a useful process to enable maximum adaptability of anammox granules from heavy metals shocks, allowing anammox technology to be more widely applied.