Sequencing Batch Reactor and Bacterial Community in Aerobic Granular Sludge for Wastewater Treatment of Noodle-Manufacturing Sector

The sequencing batch reactor (SBR) has been increasingly applied in the control of high organic wastewater. In this study, SBR with aerobic granular sludge was used for wastewater treatment in a noodle-manufacturing village in Vietnam. The results showed that after two months of operation, the chemical oxygen demand, total nitrogen and total phosphorous removal efficiency of aerobic granular SBR reached 92%, 83% and 75%, respectively. Bacterial diversity and bacterial community in wastewater treatment were examined using Illumina Miseq sequencing to amplify the V3-V4 regions of the 16S rRNA gene. A high diversity of bacteria was observed in the activated sludge, with more than 400 bacterial genera and 700 species. The predominant genus was Lactococcus (21.35%) mainly containing Lactococcus chungangensis species. Predicted functional analysis showed a high representation of genes involved in membrane transport (12.217%), amino acid metabolism (10.067%), and carbohydrate metabolism (9.597%). Genes responsible for starch and sucrose metabolism accounted for 0.57% of the total reads and the composition of starch hydrolytic enzymes including alpha-amylase, starch phosphorylase, glucoamylase, pullulanase, alpha-galactosidase, beta-galactosidase, alpha-glucosidase, beta-glucosidase, and 1,4-alpha-glucan branching enzyme. The presence of these enzymes in the SBR system may improve the removal of starch pollutants in wastewater.