Performance and Stability of Pre-commercialized Integrated Anaerobic–Aerobic Bioreactor (IAAB) for the Treatment of Palm Oil Mill Effluent (POME)

Abstract

AbstractThis chapter aims to evaluate the performance of a pre-commercialized Integrated Anaerobic–Aerobic Bioreactor (IAAB) (3000 m3) under variable organic loadings and environmental conditions with respect to effluent quality and methane yield. During the steady state operation of IAAB, the system achieved 99% of removal efficiency for Chemical Oxygen Demand (COD), and Biochemical Oxygen Demand (BOD) and methane yield up to 0.26 L CH4/g COD at organic loading rate (OLR) of 2.0–20.0 g COD/L day. Achievement of BOD <100 mg/L throughout 200 operational days with 45% of compliance was reported. The system could significantly reduce 70% of footprint and 78% of hydraulic retention times compared with current conventional treatment systems (e.g., cover lagoon, anaerobic bioreactor, etc.). During the operation, there are number of issues such as scum formation and foaming in the system. By manipulating the sludge recirculation rate within the range of 70–140 m3/h, the scum and foaming issues are resolved in anaerobic compartment. Meanwhile, the foaming issues in aerobic compartment were successfully resolved by dosing the advanced biological formulation produced by Novozymes, namely Bioremove 5100 and Bioremove 3200 at optimum ratio of 50:50. Further work on optimization for the recirculation flow rate in the anaerobic compartment with consideration of fluid dynamics and microbiology is required to achieve 100% compliance of BOD <100 mg/L.KeywordsPalm oil mill effluent (POME)AnaerobicAerobicIntegrated anaerobic–aerobic bioreactor (IAAB)BiogasMethane yield