Pilot-Scale Investigation of the Integrated Anaerobic–Aerobic Bioreactor (IAAB) Treating Palm Oil Mill Effluent (POME): Startup and Performance Evaluation

Electrochemical oxidation of palm oil mill effluent using platinum as anode: Optimization using response surface methodology

This work investigates the electrochemical oxidation of palm oil mill effluent (POME) treatment using platinum (Pt) as anode and graphite as a cathode. The response surface methodology was used to investigate the relationships between different factors conditions (voltage, electrolysis time and chemical support) and responses of the treatment (chemical oxygen demand reduction, colour removal, and total oil removal). A quadratic mathematical model was chosen for all responses using Box-Behnken Design (BBD) with R² 0.9853 for COD reduction, R² 0.9478 for colour removal and R² 0.9185 for total oil removal. According to Derringer's function desirability, under the optimum condition (Voltage 15, electrolysis time 2 h, and 19.95 mg/L NaCl) of POME treatment, 84% of COD reduction, 98% of colour removal and 99% total oil of removal could be achieved. These results indicate that platinum as an anode material is effective for the electrochemical oxidation treatment of POME.

Simulation and Optimisation of Integrated Anaerobic-Aerobic Bioreactor (IAAB) for the Treatment of Palm Oil Mill Effluent

This study highlights an innovative piece of hybrid technology, whereby the combination of anaerobic and aerobic processes into a single reactor, namely, the integrated anaerobic–aerobic bioreactor (IAAB) can surpass the limits of conventional methods treating palm oil mill effluent (POME). Optimisation of IAAB using SuperPro Designer V9 simulator for maximum biogas yield while addressing its economic and environmental trade-offs was conducted for the first time. Parameters such as hydraulic retention time (HRT) and organic loading rate (OLR) were optimised in the anaerobic compartment from 10 days and 6.2 g COD/L day to 9 days and 6.9 g COD/L day, respectively. Furthermore, sludge recycle ratio was optimised from 20% to 50% in the aerobic compartment. The optimisation was successful where the biogas yield increased from 0.24 to 0.29 L CH4/g CODremoved with excellent Chemical Oxygen Demand (COD), and Biological Oxygen Demand (BOD) removal efficiencies up to 99% with 5.8% lower net expenditure. This simulation results were comparable against the pre-commercialized IAAB with 11.4% increase in methane yield after optimisation. Economic analysis had proven the optimised process to be feasible, resulting in return on investment (ROI), payback time, and internal rate of return (IRR) of 24.5%, 4.1 years, and 17.9%, respectively.