Mathematical Modeling of Existing Two Stage Anaerobic Digestion Process for Palm Oil Mill Wastewater

Abstract

This work is an attempt to describe the dynamics of a two-stage industrial biogas plant using palm oil mill effluent (POME) and the mixture of POME with effluent from rubber factory (LTE), both at steady state and transient peroid before system failure accurred. One incident occurred in POME treatment plant when LFE bypassed its digesters and mixed together with palm-oil-mill wastewater due to no space in the existing latex wastewater ponds under water flooding during heavy raining period. The model was developed based on simplified ADM1 incorporating the effects of ALK/VFA and pH on the microbial growth. The model prediction for such scenario was in agreement with the actual data from the incident which occurred during November 2014. The Steady state simulation estimated that Ss reduced from 74,917 to 2856 mg/l at HRT 15 d which agreed well with the actual data. Dynamic simulation after adding LTE predicted that the Ss reduced to 20,300 at HRT 10.71 d which was the correct trend albeit rather imprecise. That was considered satisfactory for future operational purpose. This discrepancy was due to the difficulty in estimating many process parameters. In general the model demonstrates the usefulness of the ADM1 in describing behavior of an anaerobic wastewater treatment system from palm oil mill industry and can be used for the purpose of future design and operating of the existing plants.

Biochemical Methane Potential of Palm Oil Mill Effluent (POME) Co-Digested with Rubber Latex Effluent (LTE): Effect of POME/LTE Ratio and Temperature

“…It was found that the plant failed within 75 days of operation. It was observed that after 60 days of co-digestion, the pH dropped sharply, and the plant started to fail irreversibly [19]. Thus, it is anticipated that the optimum/synergistic POME: LTE ratio (> 0.5) found in this work may not be applied directly to the continuous system with prolonged operation.…”

“…It was found that the plant failed within 75 days of operation. The failure dynamics of the incident was not clear, but it was observed that after 60 days of co-digestion, the pH dropped sharply, and the plant started to fail irreversibly [19].…”

Co-digestion of palm oil mill effluent with chicken manure and crude glycerol: biochemical methane potential by monod kinetics

“…Biogas plants from POME are relatively stable, easy to start-up and control, thus providing an excellent co-digestion platform. Different kinds of animal dung [ 22 ], rubber-latex effluent, aerobic and anaerobic sludges were used to co-digest with POME to improve C/N balance and provide richer trace elements [ 23 ].…”

“…POME's anaerobic digestion modeling is currently somewhat limited, but research in this field is expanding rapidly in recent years [ 23 , 24 , 25 , 26 ]. Ramadhani et al.…”

“…Using Monod kinetics with sulfate inhibition, Yingthavorn et al. [ 23 ] developed a model to describe the instability of co-digestion of POME and rubber factory effluent on an industrial scale. After calibration with data from a commercial operation, the model could reasonably explain the system's failure of the system, but the prediction was rough and required further refinement.…”