Treating Tapioca Starch Industrial Wastewater Using Two-Phase Multi-Staged Up-Flow Anaerobic Sludge Blanket (MS-UASB)

A laboratory-scale, two-phase multi-staged up-flow anaerobic sludge blanket (MS-UASB) treatment system was monitored over time in order to evaluate its treatment efficiency and performance when treating non-diluted industrial tapioca starch wastewater under ambient temperature in Thailand. The system consisted of an acidification (AC) reactor and MS-UASB reactor and was operated for 280 days. The two-phase MS-UASB achieved a maximum organic loading rate (OLR) of 8 kg-COD/m3/day for the overall system and reached 80.5% of chemical oxygen demand (COD) removal efficiency. Based on the inlet wastewater of each reactor, the AC reactor removed 61.85% of suspended solids and achieved acidification of the wastewater to produce volatile fatty acids at over 50%. Meanwhile, the MS-UASB reactor achieved 74.5% COD removal efficiency. Further analysis found that the increase in soluble extracellular polymeric substances per bound extracellular polymeric substances (S-EPS/B-EPS) was related to the floating sludge phenomenon, which occurred under excess OLR condition.