Effects of Temperature on Aerobic Treatment of Anaerobically Digested Palm Oil Mill Effluent (POME)

Photocatalytic Technology for Palm Oil Mill Effluent (POME) Wastewater Treatment: Current Progress and Future Perspective

The palm oil industry produces liquid waste called POME (palm oil mill effluent). POME is stated as one of the wastes that are difficult to handle because of its large production and ineffective treatment. It will disturb the ecosystem with a high organic matter content if the waste is disposed directly into the environment. The authorities have established policies and regulations in the POME waste quality standard before being discharged into the environment. However, at this time, there are still many factories in Indonesia that have not been able to meet the standard of POME waste disposal with the existing treatment technology. Currently, the POME treatment system is still using a conventional system known as an open pond system. Although this process can reduce pollutants’ concentration, it will produce much sludge, requiring a large pond area and a long processing time. To overcome the inability of the conventional system to process POME is believed to be a challenge. Extensive effort is being invested in developing alternative technologies for the POME waste treatment to reduce POME waste safely. Several technologies have been studied, such as anaerobic processes, membrane technology, advanced oxidation processes (AOPs), membrane technology, adsorption, steam reforming, and coagulation. Among other things, an AOP, namely photocatalytic technology, has the potential to treat POME waste. This paper provides information on the feasibility of photocatalytic technology for treating POME waste. Although there are some challenges in this technology’s large-scale application, this paper proposes several strategies and directions to overcome these challenges.

Performance comparison between mesophilic and thermophilic anaerobic reactors for treatment of palm oil mill effluent

The anaerobic digestion of palm oil mill effluent (POME) was carried out under mesophilic (37°C) and thermophilic (55°C) conditions without long-time POME storage in order to compare the performance of each condition in the field of Sumatra Island, Indonesia. The anaerobic treatment system was composed of anaerobic hybrid reactor and anaerobic baffled filter. Raw POME was pretreated by screw decanter to reduce suspended solids and residual oil. The total COD removal rate of 90-95% was achieved in both conditions at the OLR of 15kg[COD]/m(3)/d. The COD removal in thermophilic conditions was slightly better, however the biogas production was much higher than that in the mesophilic one at high OLR. The organic contents in pretreated POME were highly biodegradable in mesophilic under the lower OLRs. The biogas production was 13.5-20.0l/d at the 15kg[COD]/m(3)/d OLR, and the average content of carbon dioxide was 5-35% in both conditions.

Start-up, steady state performance and kinetic evaluation of a thermophilic integrated anaerobic-aerobic bioreactor (IAAB)

Thermophilic treatment of palm oil mill effluent (POME) was studied in a novel integrated anaerobic-aerobic bioreactor (IAAB). The IAAB was subjected to a program of steady-state operation over a range of organic loading rate (OLR)s, up to 30 g COD/L day in order to evaluate its treatment capacity. The thermophilic IAAB achieved high chemical oxygen demand (COD), biochemical oxygen demand (BOD) and total suspended solids (TSS) removal efficiencies of more than 99% for OLR up to 18.5 g COD/L day. High methane yield of 0.32 LCH(4) (STP)/g COD(removed) with compliance of the final treated effluent to the discharge limit were achieved. This is higher than that of the mesophilic system due to the higher maximum specific growth rate (μ(max)) of the thermophilic microorganisms. Besides, coupling the model of Grau second order model (anaerobic system) with the model of Monod (aerobic system) will completely define the IAAB system.

Performance comparison of mesophilic and thermophilic aerobic sidestream membrane bioreactors treating high strength wastewater

This study compares membrane fouling and removal efficiencies of organic and nitrogen in thermophilic (47 and 60°C) and mesophilic (30°C) aerobic sidestream airlift membrane bioreactors (SA-MBRs). These reactors were fed with high strength molasses-based synthetic wastewater at an organic loading rate (OLR) of 24.75 kg COD/m(3)d. Removal efficiencies of COD, NH(4)(+) and TKN were compared. The sidestream filtration was conducted with microfilter and ultrafilter. SA-MBRs with microfilter were operated in continuous and intermittent operation modes, while with the ultrafilter only continuous operation mode was employed. The excessive membrane fouling observed in thermophilic SA-MBRs with microfilter under continuous filtration mode, could be significantly reduced by the application of cake layer pre-coating or replacing microfilter with ultrafilter. This membrane fouling under the thermophilic condition could be linked to higher protein generation within the reactors. Soluble COD removal efficiencies were higher in thermophilic conditions while the sludge yields were significantly low in thermophilic SA-MBRs.

Mesophilic and thermophilic aerobic batch biodegradation, utilization of carbon and nitrogen sources in high-strength wastewater

This study compares organic and nitrogen removals of thermophilic and mesophilic aerobic processes. The experiments were performed in three 7.2L sequential batch reactors (SBRs) operated at 30, 47 and 60°C. Molasses based synthetic wastewater consisting chemical oxygen demand (COD): 11,200 mg/L, total kheljal nitrogen (TKN): 770 mg/L, ammonical nitrogen (NH(4)): 560 mg/L was the feed medium. Biokinetic parameters, COD, NH(4)(+) and TKN removal efficiencies were compared under six different operating conditions. Five times lower sludge production and similar COD removal were observed in thermophilic SBRs compared to mesophilic SBR under 8.25 kg COD/m(3)d loading rate. However at 24.75 kg COD/m(3)d there were no differences in terms of sludge production while COD removals were varied as 59%, 80% and 82% at 30, 47 and 60°C respectively. A mechanism was developed to understand the varying behaviors of thermophilic aerobic process. Stripping is the major mechanism for nitrogen removal in thermophilic SBRs.