High nitrogen removal performance of anaerobically treated fish processing wastewater by one-stage partial nitritation and anammox process with hydroxyapatite (HAP)-based syntrophic granules and granule structure

The one-stage partial nitritation and anammox process with the hydroxyapatite (HAP)-based syntrophic granules was studied for ammonium nitrogen removal from effluents of a self-agitated anaerobic baffled reactor treating fish processing wastewater. When in influent 1140 mg N·L-1, high rate efficiency 1.51 ± 0.10 kg N·m−3·d-1 88.2% were obtained, respectively. Anammox bacteria Candidatus Kuenenia stuttgartiensis oxidizing Nitrosomonas two most predominant bacteria, while nitrite activity low could be neglected during treatment. inorganic element properties sludge analyzed by several methods to confirm existence HAP granules. Optical microscopic observation scanning electron microscopy analysis revealed structure granular sludge. This study supports feasibility potential this high-efficiency