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Nitrogen removal via nitritation pathway for low-strength ammonium wastewater by adsorption, biological desorption and denitrification

Chen, Zhenguo, Wang, Xiaojun, Chen, Xiaozhen, Chen, Jing, Feng, Xinghui, Peng, Xingxing
Bioresource technology 2018 v.267 pp. 541-549
adsorption, aeration, ammonia, ammonium, bacteria, biofilm, cost effectiveness, denitrification, denitrifying microorganisms, desorption, high-throughput nucleotide sequencing, microbial communities, nitrification, nitrites, nitrogen, wastewater, wastewater treatment, zeolites
Stable nitritation for low-strength ammonium wastewater was the key obstacle for cost-effective and low-carbon biological nitrogen removal. A zeolite biological fixed bed (ZBFB) and an anoxic sequencing batch reactor (ASBR) were successfully applied for achieving nitritation-denitrification of low-strength ammonium wastewater by adsorption, biological desorption and denitrification. Based on free ammonia inhibition on biofilm, stable nitrite accumulation could be realized with suitable operational time and aeration in biological desorption. During cycle operation, adsorption effluent NH4+-N kept at 3.0–4.0 mg/L, biological desorption effluent NO2−-N maintained at 226.8–243.2 mg/L with average nitrite accumulation ratio of 97.18%, and nitrite removal rate was about 0.628–0.672 kg NO2−-N·m−3·day−1, revealing obvious feasibility of ZBFB and ASBR for low-strength ammonium wastewater treatment. High-throughput sequencing analysis results further presented significant microbial community variations happened after cycle operation, with ammonia oxidizing bacteria enrichment and nitrite oxidizing bacteria inhibition in ZBFB and dominance of denitrifiers in ASBR.