An Integrated Pilot-Scale Upflow Anaerobic Sludge Blanket (UASB) and Aerotank System for the Treatment of Rice Paper Production Wastewater: A Case Study from Phu Hoa Dong, Ho Chi Minh City, Vietnam

The present study investigated the feasibility of using an integrated pilot-scale UASB and aerotank system for treating high-strength wastewater generated from a household rice paper manufacturing unit. The MLSS in the aerotank increased from 1.62 ± 0.06 to 3.23 ± 0.05 g/L over a 7-day period. 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. Further, over a 20-week 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. 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. DNA sequence analysis indicated that the anaerobic sludge was predominantly populated by the Bacillus sp. The findings demonstrated that the integrated pilot-scale UASB and aerotank system exhibited high removals of TSS, COD, and BOD₅ during the treatment of a high organic load-containing rice paper production effluent. The generation of biogas and the methane content of the biogas were also determined in the present study. The integrated pilot-scale UASB and aerotank system established in this study is affordable, has a small footprint, relatively simple installation and operational procedures, and it is suitable for treating wastewater from an individual small-scale rice paper production facility.