Petrochemical wastewater often contains high concentrations of phenol and sulfate that must be properly treated to meet discharge standards. This study acclimated anaerobic-activated sludge to treat saline phenolic wastewater with sulfate reduction and clarified the diversity and degradation mechanism of the microbial community. The active sludge in an upflow anaerobic sludge blanket (UASB) reactor could remove 90 % of phenol and maintain the effluent concentration of SO4 2− below 400 mg/L. Cloning and sequencing showed that Clostridium spp. and Desulfotomaculum spp. were major phenol-degrading bacteria. Phenol was probably degraded through the carboxylation pathway and sulfate reduction catalyzed by adenosine-5′-phosphosulfate (APS) reductase and dissimilatory sulfite reductase (DSR). A real-time polymerase chain reaction (RT-PCR) showed that as phenol concentration increased, the quantities of 16S rRNA gene, dsrB, and mcrA in the sludge all decreased. The relative abundance of dsrB dropped to 12.46 %, while that of mcrA increased to 56.18 %. The change in the electron flow ratio suggested that the chemical oxygen demand (COD) was removed mainly by sulfate-reducing bacteria under a phenol concentration of 420 mg/L, whereas it was removed mainly by methanogens above 630 mg/L.
Bibliographical noteFunding Information:
Supported jointly by the National Natural Science Foundation of China (51378208, 41273109), Specialized Research Fund for the Doctoral Program of Higher Education (20110074130002), Program for New Century Excellent Talents in University (NCET-13-0797), Innovation Program of Shanghai Municipal Education Commission (14ZZ059), and Fundamental Research Funds for the Central Universities (222201313008). We would like to thank the anonymous referees for their helpful comments regarding this paper.
© 2015, Springer-Verlag Berlin Heidelberg.
- Anaerobic treatment
- Bacterial community
- Degradation mechanism
- High sulfate concentration
- Phenolic wastewater
- Real-time PCR