Microbial communities in anaerobic wastewater treatment systems of fermented rice noodle processing wastewater

The anaerobic hybrid reactor (AHR) has been used for treating fermented rice noodle processing wastewater, containing salt concentration of 16 g/L with COD ranges of 8,000-15,000 mg/L. The AHR system tolerated high salt concentration at an organic loading rate (OLR) of 3.0 g COD/L.d and hydraulic retention time (HRT) of 4 days. The different activity of microorganisms in the suspended zone and the attachment zones in the AHR was found. Therefore, this study aimed to assess the population dynamic of microorganisms in the AHR. Blvii28-wastewater-sludge was found as dominant salt-tolerant bacteria increased from the original salt-adapted microbial consortium with relative abundance of 28.0% and 8.39% at the suspended zone and attachment zones of AHR, respectively. Pseudarcobacter was found at 8.2% relative abundance at the suspended zone whereas Pseudomonas was found at 1.8% at the attachment zone as similar as the inoculum. Blvii28-wastewater-sludge was likely responsible for the hydrolysis and acidogenesis, while Pseudomonas and Pseudarcobacter might play a critical role in the removal of organic nitrogen in the wastewater. In addition, the dominant salt-tolerant methanogen genus Methanocorpusculum was observed at 3.52% at the attachment zone of AHR, but lower than 0.5% in the suspended zone of AHR. Thus, our study provides novel insights into the establishment of pilot-scale AHR for treating salinity wastewater by using salt-adapted microbial consortium.