Cometabolic degradation of low-strength coking wastewater and the bacterial community revealed by high-throughput sequencing

• Cometabolic substrate effectively improved the low-strength CWW treatment.
• The bacterial diversity of glucose-added group was higher than glucose-free group.
• Operating conditions drastically changed bacterial community.
• Thauera, which can degrade aromatic compounds, enriched in cometabolic system.

Cometabolism technology was employed to degrade low-strength coking wastewater (CWW) in Sequencing Batch Reactor (SBR). The bacterial community compositions were monitored by high-throughput sequencing. Cometabolic substrate effectively improved the chemical oxygen demand (COD) removal efficiency in glucose-added system (A1) compared to glucose-free system (A0). Meanwhile, A1 exhibited larger biomass, better settlement performance, and higher dehydrogenase activity (DHA). More importantly, high-throughput sequencing revealed that dominant populations in A1 were quite different with A0. Thauera (9.27%), Thermogutta (7.58%), and Defluviimonas (4.6%) began to enrich in A1 after cometabolic substrate supplement. Especially, Thauera, as the most dominant populations in Al, could degrade a wide spectrum of aromatic compounds, which may contribute to the better system performance. This work would provide a novel option to treat low-strength CWW, discern the relationship between bacterial community and CWW quality, and further explore the cometabolic degradation through bacterial community structures.

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