Full-scale study of pollutants removal in printing and dyeing wastewater based on anaerobic baffled reactor-A/O coupling process and microbial community analysis

Improved anaerobic baffled reactor-anoxic/oxic (ABR-A/O) coupling process was used for printing and dyeing wastewater treatment in our full-scale study, which was able to reach the effluent standard stably, especial for the characteristic pollutants and aromatics removal. According to our results of microbial community analysis by polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE), the divisions of ABR enabled the functional microorganisms to distribute in different compartments and contributed to each compartment of performing its own functions with more efficiency. The first, second, and third compartments are major in macromolecular organics hydrolysis and sulfate reduction, while the main responsibilities of the fourth, fifth, and sixth compartments are aromatic compounds degradation and denitrification. Many kinds of aromatic anaerobic degradation microorganisms were found in our ABR, such as Pseudomonas stutzeri, Dechloromonas aromatic, Pseudomonas putida, and Aromatoleum aromaticum. Initially, abundances of bcrA genes climbed up and then dropped along with the sequential six compartments of ABR and it indicated that the highest aromatics degradation efficiency were obtained at the fifth compartment, rather than other compartments, which was probably caused by its moderate substrate concentration and biodegradability.