Insights into nitrogen removal from leather wastewater by anaerobic ammonium oxidation process: Performance and microbial structure

This study aimed to assess the suitability of anaerobic ammonium oxidation (anammox) process for leather wastewater treatment using two up-flow anaerobic sludge blanket bioreactors by pumping synthetic and real wastewater (named SR and RR), respectively. Both reactors were operated steadily with an average nitrogen removal efficiency of 94-96 % at chemical oxygen demand (COD) level of 100-200 mg center dot L 1, which were rapidly deteriorated as the COD level increased to 300 mg center dot L 1 even if at the same COD to total nitrogen (TN) (COD/TN) ratio. The reactor performances could restore after pumping with synthetic wastewater, and then continued to effectively treat leather wastewater. Furthermore, the relative abundance of Candidatus Kuenenia in reactor RR was increased by 34.8 % compared with the reactor SR on day 120. The results revealed that the anammox process can be used for the leather wastewater treatment, thus broadening the engineering application of anammox-based process in industrial wastewater.