Anaerobic Palm Oil Mill Effluent Research Articles

Effect of Initial Carbon to Nitrogen Ratio on the Degradation of Oil Palm Empty Fruit Bunch with Periodic Addition of Anaerobic Palm Oil Mill Effluent Sludge

The objective of this study was to evaluate the effect of different initial carbon to nitrogen (C/N) ratios on the organic matter degradation during active co-composting of oil palm empty fruit bunch (OPEFB) and palm oil mill effluent (POME) anaerobic sludge. The initial C/N ratio was varied from 25:1, 35:1 and 45:1. Co-composting was conducted by periodic addition of sludge to maintain the moisture content and enrich the compost product. The organic matter (OM), carbon to nitrogen profile and compost maturity index were analysed. The results showed that the initial C/N ratio of 35:1 was the best initial C/N ratio. In addition, the C/N ratio of 35:1 gave the best OM degradation. The appropriate amount of initial C/N ratio coupled with the correct composting process parameters such as daily mixing, suitable pH and moisture content improved the organic matter degradation. It reduced the composting time from 40-60 days to 30 days.

Evaluating Fertilizer-Drawn Forward Osmosis Performance in Treating Anaerobic Palm Oil Mill Effluent.

Fertilizer-drawn forward osmosis (FDFO) is a potential alternative to recover and reuse water and nutrients from agricultural wastewater, such as palm oil mill effluent that consists of 95% water and is rich in nutrients. This study investigated the potential of commercial fertilizers as draw solution (DS) in FDFO to treat anaerobic palm oil mill effluent (An-POME). The process parameters affecting FO were studied and optimized, which were then applied to fertilizer selection based on FO performance and fouling propensity. Six commonly used fertilizers were screened and assessed in terms of pure water flux (Jw) and reverse salt flux (JS). Ammonium sulfate ((NH4)2SO4), mono-ammonium phosphate (MAP), and potassium chloride (KCl) were further evaluated with An-POME. MAP showed the best performance against An-POME, with a high average water flux, low flux decline, the highest performance ratio (PR), and highest water recovery of 5.9% for a 4-h operation. In a 24-h fouling run, the average flux decline and water recovered were 84% and 15%, respectively. Both hydraulic flushing and osmotic backwashing cleaning were able to effectively restore the water flux. The results demonstrated that FDFO using commercial fertilizers has the potential for the treatment of An-POME for water recovery. Nevertheless, further investigation is needed to address challenges such as JS and the dilution factor of DS for direct use of fertigation.

Integration of copperas and calcium hydroxide as a chemical coagulant and coagulant aid for efficient treatment of palm oil mill effluent

Palm oil mill effluent (POME) is highly polluted wastewater that is to the environment if discharged directly to water source without proper treatment. Thus, a highly efficient treatment with reasonable cost is needed. This study reports the coagulation treatment of POME using integrated copperas and calcium hydroxide. The properties of copperas were determined using scanning electron microscopy (SEM), Fourier transform infrared (FTIR), X-ray diffraction (XRD), and X-ray fluorescence (XRF). Coagulation was conducted using jar test experiments for various coagulant formulations and dosages (1000–5000 mg/L), initial pH (4–10), stirring speed (100–300 rpm), and sedimentation time (30–180 min). The characterisation results show that copperas has a compact gel network structure with strong O–H stretching and monoclinic crystal structure. The effectiveness of integrated copperas and calcium hydroxide (Ca(OH)2) with the formulation of 80:20 removed 77.6%, 73.4%, and 57.0% of turbidity, colour, and chemical oxygen demand (COD), respectively. Furthermore, the integration of copperas and Ca(OH)2 produced heavier flocs (ferric hydroxide), which improved gravity settling. The coagulation equilibrium analysis shows that the Langmuir model best described the anaerobic POME sample as the process exhibited monolayer adsorption. The results of this study show that copperas with the aid of Ca(OH)2 demonstrated high potential in the removal of those parameters from POME with acceptable final pH for discharge. The utilisation of this by-product as a coagulant in effluent treatment can unlock the potential of copperas for wider applications, improve its marketability, and reduce gypsum waste generation from the TiO2 industry.

Cultivation and application of Scenedesmus sp. strain UKM9 in palm oil mill effluent treatment for enhanced nutrient removal

Palm oil mill effluent (POME) contains nutrients such as carbon, nitrogen and phosphorus, and poses a threat to the environment especially if released untreated into water bodies. The phylum Chlorophyta contains microalgae from the genus Scenedesmus which are utilised as bioremediation agents. This study was conducted to evaluate the performance of Scenedesmus sp. UKM9 to remove chemical oxygen demand (COD) and nutrients (NH4+ and PO43−) from anaerobic POME by considering photoperiods and pollutant loading rates as environmental parameters. The results showed that the removal of COD (57% removal) and NH4+ (100% removal) was the highest in a 12h:12h (light:dark) photoperiod and a pollutant loading rate of 61.67 mg L−1 day−1 COD. Removal of PO43− (91% removal) was highest in a 16h:8h (light:dark) photoperiod and a pollutant loading rate of 11.67 mg L−1 day−1 COD. The removal of COD, nitrogen and phosphate occurred via the actions of microalgae through assimilation, bacteria through oxidation and precipitation through the formation of calcium phosphate complexes. These findings suggest that Scenedesmus sp. strain UKM9 is a potential bioremediation agent for treating POME.

Comparative Assessment for Mechanical Vapour Recompression and Multi-effect Evaporation Technology in Palm Oil Mill Effluent Elimination

Due to the alarming methane emission from anaerobic palm oil mill effluent (POME) treatment practices in palm oil mills, POME elimination strategy is considered as an alternative zero waste solution towards methane mitigation apart from biogas recovery. By dewatering the effluent, POME evaporation technology provides opportunities in water recycling, oil recovery, effluent elimination and process integration with downstream refinery. One of the challenges for implementing POME evaporation is the extensive thermal energy use, which threatens energy efficiency and carbon footprint of palm oil mill. Advanced technologies such as multi-effect evaporation (MEE) and mechanical vapour recompression (MVR) can be considered to reduce steam demand for POME evaporation. Recently, electrical-driven MVR evaporator emerges as a popular solution for solution concentration and food powder production. In MVR systems, evaporated vapour is recompressed by power-consuming mechanical energy to enable steam reuse and reduction in fresh steam demand. In this paper, MEE and MVR evaporation systems are considered for POME dewatering in the integrated palm-oil based complex (POBC) optimisation. A fuzzy multi-objective optimisation model was developed to evaluate the trade-offs of economic benefits, energy consumption and environmental impacts between thermal and electrical driven evaporation techniques for sustainable POBC design. MEE was selected in the fuzzy optimal POBC with aggregate satisfaction of four objectives and improved the EP and GHG reduction of baseline study by 12 % and 61 %. Single-effect MVR POME evaporator contributed to 64 % thermal cost savings with overall 1.5 % reduction in POBC profitability. The optimal results and electricity-to-steam (ETS) price analysis have provided critical insights into the feasibility of MEE and MVR evaporation in POMs. Reducing electricity tariff to achieve ETS ratio below 1.27 could increase the economic favourability of MVR-implemented POBC.

Microalgae-bacteria interaction in palm oil mill effluent treatment

Palm oil mill effluent (POME) contains a substantial amount of nutrients and a significant amount of indigenous microorganisms that consume the nutrients for their growth. In this study, we demonstrated that cultivation of microalgae in POME was able to reduce its carbon and nutrient contents. Three native microalgae isolates, namely, Coelastrella sp. UKM4, Chlamydomonas sp. UKM6 and Scenedesmus sp. UKM9, were cultured in sterilized and unsterilized anaerobic POME to evaluate the microalgae-bacteria interactions for phycoremediation of POME. The results showed higher COD removal in unsterilized POME than in sterilized POME due to microalgae-bacteria consortia interaction. Of the three microalgae isolates, the interaction of Scenedesmus sp. UKM9 with bacteria showed the highest COD and PO43− removal percentages. For NH4+ removal, all three isolates showed removal of more than 80 % in both sterilized and unsterilized POME. Quantitative real-time polymerase chain reaction analysis showed that the quantities of bacteria were constant after the treatment, while the quantities of microalgae changed. Metagenomics analysis showed that the community of bacteria shifted after microalgae cultivation in POME, with Actinobacteria, Bacteroidetes, Planctomycetes and Proteobacteria being the major phyla.

Resolving stability issue of thermophilic high-rate anaerobic palm oil mill effluent treatment via adaptive neuro-fuzzy inference system predictive model

Abstract Palm oil mill effluent is a highly polluting and corrosive liquid waste generated from crude palm oil processing. Its varying characteristics depending on the crop season and loading rate of the milling process complicate the handling of anaerobic digestion of palm oil mill effluent. To ease monitoring and aid decision making to handle operation anomalies, this study adopts Adaptive Neuro-Fuzzy Inference System with hybrid learning algorithm and subtractive clustering to predict the output from a thermophilic high-rate anaerobic digester treating palm oil mill effluent. Influent pH, chemical oxygen demand, organic loading rate and historical data of effluent pH, chemical oxygen demand and total suspended solids were utilized to build the model for output prediction of treated effluent (pH, chemical oxygen demand and total suspended solids). Trained models were validated with experimental data. The models were able to predict the effluent pH, chemical oxygen demand and total suspended solids satisfactorily with average error of less than 8.32% and standard deviation of less than 7.65% with closely followed pattern between the actual values and simulated results. The viability of adaptive neuro-fuzzy inference system in modelling palm oil mill effluent using thermophilic high-rate anaerobic digester is further demonstrated by coefficient of determination, R2 of 0.82, Root Mean Square Error of 0.0377, Index of Agreement of 0.95 and d-factor of 0.0496.

Preservation of mesophilic mixed culture for anaerobic palm oil mill effluent treatment by convective drying methods

ABSTRACTWhile anaerobic digestion is a reliable method that treats the waste and produces renewable biomethane fuel, the necessary sludge in liquid form is difficult to handle due to the constant biogas generation. Therefore, this study investigates the possibility of convective air drying, namely heat pump and hot air circulation oven as preservation methods for anaerobic microbial sludge. Drying was conducted at various temperatures, ranging from 22 to 70°C. The study found that heat pump drying at 22°C resulted in highest chemical oxygen demand removal of 55.3% as well as the least log reduction in methanogens and anaerobes at 1.4 and 2.4, respectively.

Kinetics of Anaerobic Digestion of Palm Oil Mill Effluent (POME) in Double-Stage Batch Bioreactor with Recirculation and Fluidization of Microbial Immobilization Media

Palm Oil Mill Effluent (POME) becomes big problem for palm oil industries, especially for Crude Palm Oil (CPO) industry since it produces 3 tons of POME for every ton of CPO production.The high amount of organic loading in POME makes it potential as a substrate in anaerobic digestion to generate biogas as renewable energy source. The most common but conventional method by using open lagoon is still preferred for most CPO industry in Indonesia to treat POME because of its simplicity and easiness. However, this method creates new major problem for the water bodies since it has no significant chemical oxygen demand (COD) removal and needs wide area. Besides, greenhouse gas (CH4) is also released during the process. An innovation was made in this study by designing vertical column process equipment to run an anaerobic digestion of POME. The vertical column was functioned as anaerobic fluidized bed reactor (AFBR). To enhance the digestion rate in AFBR, natural zeolite was used as the immobilization media and the inoculum was taken from digested biodiesel waste. This research aimed to determine the kinetic constants of double-stage anaerobic POME digestion for COD removal and biogas production. To get close to the real condition, the POME used in this experiment had 8,000 mg/L of sCOD (the real sCOD was ±16,000 mg/L). The experiment was conducted under room temperature with up-flow velocity between 1.75 and 2.3 cm/s for optimum fluidization of immobilization media.

Nutrients assessment of anaerobic palm oil mill effeluent (AnPOME) as an alternative media for microalgae culture

The main aim of the present study is to investigate the availability of macronutrient andmicronutrient in AnPOME. All collected samples were analyzed using HACH method. Theresults reveal that the C/N and N/P ratio of the AnPOME is six times more than the theoreticalvalue. Concentration of micronutrients also shown higher concentration range compared tothat of the Bold Basal Medium (BBM). However, the concentration of phosphorus inAnPOME six times lower than nitrogen indicates that phosphorus limitation in AnPOME.Hence, this finding suggested the best microalgae to be grown in AnPOME is mixotrophic orheterotrophic mode. Overall, reuse of AnPOME replacing synthetic growth is highlyrecommended considering that enough composition of macronutrient and micronutrient inAnPOME and inexpensive alternative to synthetic media.Keywords: microalgae; Anaerobic Palm Oil Mill Effluent (AnPOME); BBM; macronutrient;micronutrient.

Preservation of thermophilic mixed culture for anaerobic palm oil mill effluent treatment by convective drying methods

The generation of huge amount of liquid waste known as palm oil mill effluent is a major problem in oil palm industry. Meanwhile, anaerobic biodegradation of such organic effluent at thermophilic condition is a promising treatment technology due to its high efficiency. However, storage and transportation of thermophilic mixed culture sludge are challenging due to constant biogas generation and heating requirement. Hence, drying of thermophilic sludge was conducted to obtain dormant thermophiles and thus enables easier handling. In this study, thermophilic sludge was dried using heat pump at 22 and 32 °C as well as hot air oven at 40, 50, 60, and 70 °C. Subsequently, quality of dried sludge was examined based on most probable number enumeration, chemical oxygen demand, and methane yield. Average drying rate was found to increase from 3.21 to 17.84 g H2O/m2 min as drying temperatures increases while average moisture diffusivity values ranges from 5.07 × 10−9 to 4.34 × 10−8 m2/s. Oven drying of thermophilic mixed culture resulted in highest chemical oxygen demand removal and lowest log reduction of anaerobes at 53.41% and 2.16, respectively, while heat pump drying resulted in the highest methane yield and lowest log reduction of methanogens at 53.4 ml CH4/g COD and 2.09, respectively. To conclude, heat pump at 22 °C was most suitable drying technique for thermophilic mixed culture as the original methane-producing capability was largely retained after drying, at a slightly lower yet still comparable chemical oxygen demand removal when palm oil mill effluent was treated with the rehydrated culture.

MICROBIAL COMMUNITY ANALYSIS IN ANAEROBIC PALM OIL MILL EFFLUENT (POME) WASTEWATER BY DENATURING GRADIENT GEL ELECTROPHORESIS (DGGE)

Microorganisms play a key role in wastewater bio-treatment processes and understanding the microbial community structure is of great importance to improve treatment performance. Denaturing gradient gel electrophoresis (DGGE) was used to monitor succession of the microbial community and thus predominant bands were sequenced to reveal the microbial community composition inside palm oil mill effluent (POME) wastewater.DNA bands from DGGE gels were excised with a sterile blade and placed in 1.5 ml eppendorf tube containing 50 μl deionized water (ddH2O). Tubes were incubated overnight at 4C to elute the DNA. Eluted DNA was purified using QIAquick gel extraction kits (QIAGEN, Inc., Valencia, CA) and was frozen and thawed three times.Microbial DNA successfully excised and purified from DGGE was amplified using polymerase chain reaction (PCR).Five micro liters of the supernatant were used as a template to re-amplify the DNA using 16s rDNA primers,341f (with no GC-clamp) (5'- cct-acg-gga-ggc-agc-ag-3') and reverse(r) primers 907r (5'-ccc-cgt-caa-ttc-att-tga-gtt-t-3'). Amplification was repeated referring to the steps in ‘PCR amplification of 16s rDNA’. PCR products from agarose gels were cut and purified using QIAquick Gel Extraction Kit (QIAGEN, Inc., Valencia, CA), which were similar to the purification steps after recovery of DNA from DGGE, and sequenced in both directions with the same primers (with no GC-clamp) as used in PCR. Moreover, start-up is an important step in establishing proper community structure in all kinds of biological treatment processes. In anaerobic POME wastewater, 6 sequences of Firmicutes, 5 sequence of Proteobacterium and 2 sequences of Bacteroidetes were found through denaturing gradient gel electrophoresis (DGGE) results. Sequence closely related to Rummeliibacillus suwonensis strain G20 was detected grows at band BE10, BE11, BE12, BE15, BE16, BE17 and BE18. Meanwhile BE25 and BE26 were found at ban d after treatment process done.Rummeliibacillus suwonensis is an aerobic, Gram-positive, rod shaped, round-spore-forming bacteria which were isolated from aerobic condition.

Utilization of Agro-Industrial Residues from Palm Oil Industry for Production of Lignocellulolytic Enzymes by Curvularia clavata

Production of crude palm oil generates a huge amount of palm oil mill effluent (POME) and oil palm empty fruit bunch (OPEFB), leading to adverse environmental impacts. This study seeks to explore the ability of Curvularia clavata in the utilization of such waste to produce lignocellulolytic enzymes such as carboxymethyl cellulase, xylanase, manganese peroxidase, laccase and lignin peroxidase. Raw POME generated from the milling process is discharged to the raw pond, followed by generation of anaerobic POME that is an intermediate step in treatment process. Utilization of raw POME produces higher enzyme activities compared to anaerobic POME. This simultaneously resulted in detoxification and significant removal of COD (67 %), BOD3 (45 %), total polyphenolic (50 %) and ammoniacal nitrogen (61 %) of POME. Under submerged fermentation of OPEFB, C. clavata produces 3569 U/mL of xylanase, which has a potential application in the production of xylanase.

Bioelectricity generation in microbial fuel cell using natural microflora and isolated pure culture bacteria from anaerobic palm oil mill effluent sludge

A double-chambered membrane microbial fuel cell (MFC) was constructed to investigate the potential use of natural microflora anaerobic palm oil mill effluent (POME) sludge and pure culture bacteria isolated from anaerobic POME sludge as inoculum for electricity generation. Sterilized final discharge POME was used as the substrate with no addition of nutrients. MFC operation using natural microflora anaerobic POME sludge showed a maximum power density and current density of 85.11mW/m2 and 91.12mA/m2 respectively. Bacterial identification using 16S rRNA analysis of the pure culture isolated from the biofilm on the anode MFC was identified as Pseudomonas aeruginosa strain ZH1. The electricity generated in MFC using P. aeruginosa strain ZH1 showed maximum power density and current density of 451.26mW/m2 and 654.90mA/m2 respectively which were five times higher in power density and seven times higher in current density compared to that of MFC using anaerobic POME sludge.

Improved biogas production from palm oil mill effluent by a scaled-down anaerobic treatment process

This is a scale-down study of a 500-m3 methane recovery test plant for anaerobic treatment of palm oil mill effluent (POME) where biomass washout has become one of the problems because of the continuous mixing of effluent during anaerobic treatment of POME. Therefore, in this study, anaerobic POME treatment using a scaled down 50-l bioreactor which mimicked the 500-m3 bioreactor was carried out to improve biogas production with and without biomass sedimentation. Three sets of experiments were conducted under different conditions in terms of biomass sedimentation applied to the system. The first experiment was operated under semi-continuous mode whereas the second and third experiments were operated based on mix and settle mode. As expected, biomass retention improved the anaerobic process as the POME treatment incorporated with mix and settle system were able to operate at an organic loading rate (OLR) of 3.5 and 6.0 kg COD/m3/day respectively, while the semi-continuous operated anaerobic treatment only achieved OLR of 3.0 kg COD/m3/day. The highest biogas and methane production rates achieved were 2.42 m3/m3 of reactor/day and 0.992 m3/m3 of reactor/day, respectively at OLR 6.0 kg COD/m3/day. The biomass or solids retention in the reactors was represented by the total solids measured in this study.