Metabolic insights into the interaction between nitrogen removal and 4–chlorophenol reduction of anammox consortia

Abstract

The response characteristic and performance stabilization of anammox process under the stress of the potential organic pollutants support the application of ammonia–nitrogen wastewater treatment. In the present study, nitrogen removal performance was significantly suppressed with the addition of 4–chlorophenol. The activity of anammox process was inhibited by 14.23% (0.1 mg/L), 20.54% (1 mg/L) and 78.15% (10 mg/L), respectively. Metagenomic analysis revealed a significant decrease in the abundance of KEGG pathways associated with carbohydrate and amino acid metabolism with increasing 4–chlorophenol concentration. Metabolic pathway profiles suggest that putrescine is down–regulated at high 4–chlorophenol stress due to inhibition of nitrogen metabolism processes, while it is up–regulated to reduce oxidative damage. In addition, the presence of 4–chlorophenol induced an enhancement of EPS and bacterial debris decomposition, and a partial conversion of 4–chlorophenol to p–nitrophenol. This study unravels the mechanism of effect on anammox consortia in response to 4–CP, which could provide supplementary to facilitate its full-scale application.