Microbial community composition and function in a pilot-scale anaerobic-anoxic-aerobic combined process for the treatment of traditional Chinese medicine wastewater

- Desired effluent quality was achieved by an ANA-AN-AE combined process.
- Comprehensive microbial community was investigated by high-throughput sequencing.
- Bacteroidetes, Firmicutes and Proteobacteria were dominant phyla in the reactors.
- Bacteroidales, Geobacter, ZB2 were the core genera in the combined process.
- The relationship between microbial community and function of sludge was linked.

Biodegradation of traditional Chinese medicine (TCM) wastewater was investigated in a pilot-scale anaerobic-anoxic-aerobic combined process, which was composed of an expanded granular sludge blanket (EGSB) reactor, a hydrolysis acidification (HA) reactor and a biological contact oxidation (BCO) reactor. In stable stage, the average values of COD and color in the combined process effluent were 45.7 mg L−1 and 13 times, respectively. Excellent linear relations (R2 > 0.915) were achieved between color and UV254 at three color levels. Comprehensive community structures of the combined process were analysed by Illumina MiSeq Sequencing, which revealed that microbial community in the aerobic reactor had the greatest diversity and richness. Bacteroidetes, Firmicutes and Proteobacteria were dominant phyla in the three reactors, and Bacteroidales, Geobacter, ZB2 were the predominant functional microorganisms in the anaerobic, anoxic and aerobic reactors, respectively. Good removal efficiencies and presence of core microorganisms confirmed that the combined process was feasible for treating TCM wastewater.