Experimental Study of Aniline Wastewater Biodegradation:Mechanism and Microbial Characteristics

XU Mulin; MENG Hailing; LIU Zailiang; HUANG Ding; CAO Zupeng

doi:10.19672/j.cnki.1003-6504.0619.23.338

Abstract：A bench-scale sequencing batch reactor(SBR)was used to treat aniline wastewater,focusing on the simultaneous degradation of aniline and NH4+-N;meanwhile the mechanism and kinetics of bio-degradation,the characteristics of microor-ganisms in the biological treatment process of aniline wastewater were investigated,and the rule of pollutants degradation,activated sludge growth and microbial community evolution were analyzed during the experimental process.Consequently,it was found that when the aniline concentration was 250 mg/L,the removal rate of aniline and COD were respectively above 99.92％and 90.78％,alongside with a good nitrification feature(NH4+-N removal efficiency of ca 90.81％).However,when an-iline concentration was raised to more than 300 mg/L,the removal rate of aniline and COD decreased with notably inhibited nitrification within 12 hours.As to the bio-degrading kinetics,both microbial growth and substrate degradation conformed to the Haldane model,and the degradation of aniline by activated sludge was prior to the nitrification of NH4+-N.The analysis on community structure revealed that the activated sludge that had been acclimated significantly changed,i.e.,the dominant genus were mainly unclassified_Sphingobacteriales and unclassified_Planctomycetaceae,which had the ability to degrade aromatic hydrocarbons and remove nitrogen,respectively.Furthermore,the metabolic functions of key genes were compara-tively analyzed,the results speculated that activated sludge degraded aniline and then produced catechol and NH4+-N,and further catechol was degraded through ortho and meta metabolism,while NH4+-N was mainly transformed through nitrifica-tion,denitrification,synthetic glutamate assimilation and other multiple pathways.