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Biological treatment of high strength ammonia wastewater containing 2,4-dichlorophenol in a membrane bioreactor: System performance and microbial community

Li, Mingrun, Han, Fei, Meng, Zijun, Yang, Qingwei, Xu, Weiying, Wei, Dong, Du, Bin, Wei, Qin
Bioresource technology reports 2019 v.7 pp. 100233
2,4-dichlorophenol, Firmicutes, Nitrospirae, Proteobacteria, ammonia, ammonium nitrogen, biological treatment, fouling, membrane bioreactors, microbial communities, nitrifying bacteria, oxygen, polysaccharides, toxicity, tryptophan, wastewater
Two membrane bioreactors (toxic MBR and blank MBR) were established and compared to treat high ammonia wastewater in the presence and absence of 2,4-dichlorophenol (2,4-DCP). After 130 days operation, both MBRs expressed NH4+-N removal efficiency (>95%) and 2,4-DCP removal efficiency was (96.47 ± 1.54) %. Specific oxygen uptake rate (SOUR) data showed that nitrifying bacteria receive more severe inhibition than heterotrophic bacteria. Trans-membrane pressure (TMP) data indicated that the presence of 2,4-DCP caused more serious membrane fouling. The protein/polysaccharide ratio increased to 1.1 and 6.3 in the loosely bound EPS (LB-EPS) and tightly bound EPS (TB-EPS) after 2,4-DCP addition. Excitation-emission matrix (EEM) showed that TB-EPS were mainly composed of aromatic and tryptophan PN-like substances, and LB-EPS of humic acid-like and fulvic acid-like substances. The microbial community analysis showed that the abundance of Proteobacteria, Firmicutes, and Nitrospirae under 2,4-DCP stress increased from 22.56%, 27.10%, and 1.27% to 38.89%, 28.25% and 3.59%, respectively.