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Effect of nitrobenzene on the performance and bacterial community in an expanded granular sludge bed reactor treating high-sulfate organic wastewater

Li, Jun, Li, Wentao, Luo, Gan, Li, Yan, Li, Aimin
Frontiers of environmental science & engineering 2019 v.13 no.1 pp. 6
Bacteroidetes, Desulfovibrio, Firmicutes, bacterial communities, bioreactors, community structure, high-throughput nucleotide sequencing, nitrobenzenes, sludge, sulfate-reducing bacteria, sulfates, wastewater
Nitrobenzene (NB) is frequently found in wastewaters containing sulfate and may affect biological sulfate reduction process, but information is limited on the responses of sulfate reduction efficiency and microbial community to the increased NB contents. In this study, a laboratory-scale expanded granular sludge bed reactor was operated continuously to treat high-sulfate organic wastewater with increased NB contents. Results successfully demonstrated that the presence of more than 50 mg/L NB depressed sulfate reduction and such inhibition was partly reversible. Bath experiments showed that the maximum specific desulfuration activity (SDA) decreased from 135.80 mg SO ₄²‒ /gVSS/d to 30.78 mg SO ₄²‒ /gVSS/d when the NB contents increased from none to 400 mg/L. High-throughput sequencing showed that NB also greatly affected bacterial community structure. Bacteroidetes dominated in the bioreactor. The abundance of Proteobacteria increased with NB addition while Firmicutes presented an opposite trend. Proteobacteria gradually replaced Firmicutes for the dominance in response to the increase of influent NB concentrations. The genus Desulfovibrio was the dominant sulfate-reducing bacteria (SRB) with absence or presence of NB, but was inhibited under high content of NB. The results provided better understanding for the biological sulfate reduction under NB stress.