[Aerobic Degradation and Microbial Community Succession of Coking Wastewater with Municipal Sludge]

Abstract

Coking wastewater is a typical industrial wastewater with high toxicity. Its treatment with biological processes is often challenging because it contains constituents inhibiting microbial activity. To study the inhibitory effect and possible acclimation of microbes in coking wastewater treatment, municipal sludge was inoculated into coking wastewater. Time-dependent concentrations of COD, phenol, ammonia nitrogen, and thiocyanide in coking wastewater were analyzed. The microbial community structure was investigated by the Illumina high-throughput sequencing technology during inoculation. The results showed that COD began to decrease after 16 h and 97.1% of phenol disappeared after 40 h. Thiocyanide began to degrade at 72 h and was undetectable after 96 h. Accordingly, the concentration of ammonia increased as the thiocyanide concentrations decreased. High-throughput pyrosequencing analysis showed that the microbial community structure and species richness varied at different culture stages. In the stage of phenol degradation, the abundance of Acinetobacter and Pseudomonas increased rapidly; the species richness was 13.04% of the community at 48 h. In the stage of thiocyanate degradation, Sphingobacterium,Brevundimonas,Lysobacter, and Chryseobacterium were the dominant bacteria and were 16.13% of the community at 96 h. At 144 h, Fluviicola,Stenotrophomonas, and Thiobacillus became the dominant species and were 22.45% of the community abundance. The results showed that municipal sludge can rapidly overcome the toxicity of coking wastewater because the pollutants are degraded rapidly. The microbial community structure changed as wastewater components were degraded. Environmental factors and the competition among bacteria played a key role in microbial community succession.

Keywords: aerobic degradation; coking wastewater; microbial community succession; municipal sludge.