Seasonal effects on pilot-scale high-concentration activated sludge systems in cold regions. (April 2023)

• Record Type: Journal Article
• Authors: Shi, Xueying; Liu, Wenai; Nie, Zebing; Li, Qingzhe; Liang, Xin; Zhao, Wanli; Qu, Hong; Bian, Dejun
• Is Part Of: Journal of water process engineering. Volume 52(2023)
• Publication Date: 2023-04
• Subjects: Low-temperature sewage -- Activated sludge method -- Nitrogen and phosphorus removal -- Microbial community structure -- Functional gene; Water-supply engineering -- Periodicals; Saline water conversion -- Periodicals; Seawater -- Distillation -- Periodicals; Sanitary engineering -- Periodicals; Sewage -- Purification -- Periodicals; 627
• DOI: 10.1016/j.jwpe.2023.103575
• Languages: English
• ISSNs: 2214-7144

Abstract

Abstract: A one-year-long study was conducted in the cold northern Chinese region to investigate the seasonal temperature variation on the pollutant removal performance and the changes in microbial communities and functional gene abundance of a pilot-scale plug-flow high-concentration activated sludge system. The results showed that the system had a stable nitrogen and phosphorus removal capacity in cold regions with an annual average influent temperature of 11 °C. The COD and TP removal capacity of the system was basically stable throughout the year, with an annual average removal rate of 93.49 % and 95 % respectively. The NH4 + -N and TN removal capacity varied with seasons, and the average effluent water concentrations of NH4 + -N and TN in summer (0.44 and 7.13 mg/L) were significantly lower than those in winter (2.87 and 12.42 mg/L). The high-throughput sequencing results indicated that winter could cause a simultaneous decrease in microbial abundance and diversity. Specifically, a decrease in the abundance of such nitrifying bacteria as Ferribacterium probably led to some fluctuations in nitrification performance during winter, which started to somewhat improve in spring. The nitrogen removing microorganisms in the system were distributed in a diversified way. The simultaneous nitrogen and phosphorus removal was reinforced in winter due to DPAOs such as Thermomonas . The results of the functional gene prediction showed that winter could cause a decrease in the relative abundance of the nitrification process amoB, amoC, and hao genes and denitrification process nirK gene, while it less affected the remaining functional genes related to nitrogen and phosphorus removal. Highlights: The high concentration activated sludge system affected by seasonal changes could have stable pollutant removal effects. DPAOs played a major role at 8-14°C. The relative abundance of amoB, amoC and nirK genes decreased in winter. The relative abundance of phosphorus removal-related genes was less affected by seasonal changes.