Yang D, Zhang C, Ge S, Xie Y, Yuan L. Performance of single PN/A reactor under wide fluctuation of nitrogen load.
ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2024;
31:58083-58092. [PMID:
39306821 DOI:
10.1007/s11356-024-34898-z]
[Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/10/2023] [Accepted: 08/29/2024] [Indexed: 10/11/2024]
Abstract
Partial nitritation-anammox (PN/A) is a cost-effective technology in high ammonia-nitrogen wastewater treatment. However, PN/A is prone to instability as the ammonia-nitrogen sharply fluctuates. In this study, a packed bed reactor is employed to construct a single-stage PN/A system to investigate the operational characteristics and explore the denitrification mechanism. The effluent NH4+-N concentration, ammonia nitrogen removal rate (ARE), and total nitrogen removal rate (TNR) could be sustained at about 60 mg/L, 80%, and over 70%, respectively, when the influent nitrogen load rate (NLR) is changed from 0.733 to 0.879 kg-N/m3/day. Both ARE and TNR are decreased when NLR continues increasing to 1.026 kg-N/m3/day. The influent NLR decreases from 0.879 to 0.147 kg-N/m3/day, and ARE and TNR reached 98% and 85.4%, respectively. Therefore, the denitrification effect of the reactor could be recovered, and the excellent nitrogen removal capacity could be obtained within a wide range of influent NLR. Moreover, the high-throughput sequencing and metagenomic testing indicate that the Proteobacteria and Planctomycetes that the PN/A functional strains (i.e., ammonia-oxidizing bacteria (AOB) and anammox bacteria (AnAOB)) account for 38.8% in the sludge. The relative abundance of Nitrospira containing the nitrite-oxidizing bacteria (NOB) has dropped to 0.01%, and the functional gene nxr of the nitrite oxidation process is also inhibited. The relative expression of the functional gene is dominated by the short-range nitritation and anammox oxidation, which demonstrates that the nitrogen removal is mainly dominated by nitritation-anammox.
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