An integrated pilot scale UASB and aerotank system for the treatment of rice paper production wastewater: A case study from Phu Hoa Dong, Ho Chi Minh City, Vietnam

Abstract

The objective of this study was to investigate the feasibility of using an integrated pilot-scale UASB (up flow anaerobic sludge blanket) and aerotank system for treating high organic load wastewater generated during household rice paper manufacturing. There was no significant change in the mixed liquor suspended solids (MLSS) content in the UASB over a 30-day period. However, the MLSS in the aerotank increased from 1.62 ± 0.06 to 3.23 ± 0.05 g/L over a 7-day period. The DNA sequence analysis indicated that the anaerobic sludge was predominantly populated by the Bacillus sp. The UASB achieved a removal efficiency of 69.2–82.2% for total suspended solids (TSS), 66.5–82.9% for chemical oxygen demand (COD), and 81.2–92.8% for biochemical oxygen demand (BOD5) while treating the rice paper production effluent over a 30-day period. The UASB achieved removal efficiencies of 80.6–90.3% for TSS, 82.2–83.3% for COD, and 85.6–86.4% for BOD5 over a 20-week period. The aerotank achieved a removal efficiency of 89.0-94.1% for TSS, 94.5–95.5% for COD, 96.8–98.1% for BOD5, 91.8–95.4% for total nitrogen (TN), and 89.2–94.6% for total phosphorous (TP) during a period of 7 days. The findings demonstrated that the integrated pilot-scale UASB and aerotank system exhibited high removals of TSS, COD, and BOD5 for the treatment of high organic load containing rice paper production effluent.