Decanter Cake Research Articles

RSM-based co-gasification of palm oil decanter cake and sugarcane bagasse: Syngas production and biochar characteristics

The production of syngas (CO + H2) and biochar from biomass waste co-gasification promotes sustainable energy while addressing environmental remediation challenges. This study investigates the co-gasification of palm oil decanter cake (PODC) and sugarcane bagasse (SB) to optimize syngas production and obtain biochar in a fixed bed horizontal tube furnace reactor. Operating variables, including temperature (700–900 °C), biomass ratio (30–70 wt%), and particle size (0.25–2 mm), were optimized using Response Surface Methodology with the Box-Behnken design. Characterization analyses including Brunauer-Emmett-Teller (BET), Fourier Transformed Infrared (FTIR), and Field Emission Scanning Electron Microscopic (FESEM) analyses were conducted on the biochar. The optimal conditions yielded a syngas volume of 41.5 vol% and a biochar of 0.3 wt%, achieved at 900 °C temperature, 42 wt% PODC biomass ratio, and 2 mm particle size. BET analysis revealed a mesoporous structure biochar with surface area of 398.55 m2/g, pore volume of 0.13 cm3/g, and pore diameter of 6.49 nm. FTIR analysis indicated the presence of hydroxyl groups, carbonyl groups, aromatic compounds, and hydrocarbon structures. FESEM analysis showed well-defined pore structures on the biochar surface, with EDX analysis confirming a dominant carbon content of 83.32 wt%. These findings substantially enhance sustainable approaches in energy production, agriculture, and wastewater treatment, while effectively tackling environmental issues associated with biomass waste.

Upcycling lignocellulosic palm biomass via Black Soldier Fly Larvae (BSFL) composting incorporated with Ex-situ fermentation by Bacillus Subtilis

The growing demand of palm oil has caused expanding deforestation- one of the root causes for global warming. Drawn from the recent Conferences of the Parties (COP) 28, 39 % reduction in global carbon emission would need to be met by 2030 and this requires cooperation from all nations. Hence, the palm oil-producing nations could play their parts by upcycling palm waste biomass to promote sustainable palm oil production. Oil palm frond (OPF), a highly abundant biomass resulted from fruit pruning remains underutilized – mainly due to the undesirable biomass moisture level and low conversion technology readiness in the region. Composting OPF via Black Soldier Fly Larvae (BSFL) was proposed to overcome the technological barrier. However, OPF was not palatable for BSFL mainly being nutritionally deficient and highly lignocellulosic. Hence, ex-situ fermentation via Bacillus subtilis followed by blending with decanter cake (DC), nitrogenous palm waste was studied prior to BSFL composting. Results showed that treatment E (OPF:DC 3:7 wt) led to the highest BSFL weight gain (49 %) and biomass degradation (58 %) after 20 rearing days. The reared larvae consisted of 30 % and 22 % crude protein and lipid, respectively – making them an ideal insect meal. Overall, this research aims to give a preliminary overview of employing BSFL in composting highly recalcitrant palm waste biomass.

Response surface methodology and artificial neural network modelling of palm oil decanter cake and alum sludge co-gasification for syngas (CO+H2) production

Syngas (CO + H2) production through biomass gasification offers a promising and sustainable alternative to conventional fuels. This study investigates the co-gasification of palm oil decanter cake (PODC) and Alum Sludge (AS), utilizing response surface methodology (RSM) and artificial neural network (ANN) techniques to optimize and predict syngas production. Conducted in a fixed bed horizontal reactor, the experiment investigates temperature, airflow rate, and particle size as input parameters. Results revealed that optimal condition of 900 °C temperature, 10 mL/min airflow rate, and 2 mm particle size yielded the highest syngas production at 39.48 vol%. The RSM showed an R2 value of 0.9896, whereas ANN network revealed an overall R2 value of 0.971. Both models demonstrated strong alignment with experimental data and the modelled equation. This research demonstrates the effective use of statistical modelling to enhance the efficiency and effectiveness of syngas production, thereby fostering advancements in sustainable energy production.

Synergistic integration of hydrothermal pretreatment and co-digestion for enhanced biogas production from empty fruit bunches in high solids anaerobic digestion

This study investigates the co-digestion of hydrothermally pretreated empty fruit bunches (EFB) at 190 °C for 5 min (HTP190-EFB) with decanter cake (DC) to improve biogas production in high solid anaerobic digestion (HSAD). The HTP190-EFB exhibited a 67.98 % reduction in total solids, along with the production of 0.89 g/L of sugar, 2.39 g/L of VFA, and 0.56 g/L of furfural in the liquid fraction. Co-digestion of HTP190-EFB with DC at mixing ratios of 5, 10, and 15 %w/v demonstrated improved methane yields and process stability compared to mono-digestion of HTP190-EFB. The highest methane yield of 372.69 mL CH4/g-VS was achieved in the co-digestion with 5 %w/v DC, representing a 15 % increase compared to digestion of HTP190-EFB (324.30 mL CH4/g-VS) alone. Synergistic effects were quantified, with the highest synergistic methane yield of 77.65 mL CH4/g-VS observed in the co-digestion with 5 %w/v DC. Microbial community analysis revealed that co-digestion of hydrothermally pretreated EFB with decanter cake promoted the growth of Clostridium sp., Lactobacillus sp., Fibrobacter sp., Methanoculleus sp., and Methanosarcina sp., contributing to enhanced biogas production compared to mono-digestion of pretreated EFB. Energy balance analysis revealed that co-digestion of HTP190-EFB with DC resulted in a total net energy of 599.95 kW, 52 % higher than mono-digestion of HTP190-EFB (394.62 kW). Economic analysis showed a shorter return on investment for the co-digestion system (0.86 years) compared to the mono-digestion of HTP190-EFB (1.02 years) and raw EFB (2.69 years). The co-digestion of HTP190-EFB with 5 %w/v DC offers a promising approach to optimize methane yield, process stability, and economic feasibility, supporting the palm oil industry for producing renewable energy and sustainable waste management.

Potential of organic wastes typical of the Brazilian Amazon for fertilizer use in agriculture

Characterization of different organic wastes is essential to reveal alternative nutrient sources useful for agriculture. The objective of this work was to characterize a variety of organic wastes generated in the Brazilian Amazon in order to identify nutrient sources for potential use as organic fertilizers. Samples of nine different organic wastes from agricultural, livestock and forestry activities were collected in the state of Pará, Amazon region, Brazil. These samples were characterized using reference methods for analyses of organic fertilizers. Palm oil mill boiler ash was highly concentrated in P, K, Ca, and Mg and also highly alkaline, being considered a promising material for use as fertilizer and lime in acid soils. Palm oil mill decanter cake was the best N source; it also contained relevant amounts of K, S, and Zn. Cattle manure was more concentrated in N and oil palm empty fruit bunch in K. Residual eucalyptus charcoal was high in Ca but also in Na and Al. Oil palm fruit fiber, oil palm fruit shell, wood sawdust of the pile top, and wood sawdust of the pile slope were consistently poor in nutrients. All wastes presented low concentrations of As, Ba, Cd, Cr, Hg, Pb, and Se. This study identified organic wastes differing in prevalent nutrients for potential use as organic fertilizers. Such a difference could be explored in further studies by combining two or more wastes with complementary prevalent nutrients in order to better meet the nutritional requirements of different crops in the Brazilian Amazon.

Optimisation and economic analysis of industrial-scale anaerobic co-digestion (ACoD) of palm oil mill effluent (POME) and decanter cake (DC) using machine learning models: A comparative study of Gradient Boosting Machines (GBM), K-nearest neighbours (KNN), and random forest (RF)

The anaerobic co-digestion (ACoD) of palm oil mill effluent (POME) with decanter cake (DC), has been proposed as a solution to enhance biogas production in industrial-scale anaerobic covered lagoon systems. Despite the potential of ACoD, there is a limited exploration of machine learning techniques, such as Gradient Boosting Machines (GBM), K-nearest neighbours (KNN), and Random Forest (RF), specifically in the context of industrial-scale facilities and anaerobic co-digestion. In this study, these machine learning techniques were employed to develop prediction models for biogas production and BOD removal using three months of operational data from a local biogas plant, with GBM yielding the highest prediction accuracy (R2 = 0.9940, MAE = 0.0101, RMSE = 0.1438). Subsequently, GBM was used in the optimisation process to determine the optimal conditions for temperature, pH, and dilution ratio of DC in the anaerobic digester. The optimal conditions were found to be 40 °C, 7.1, and 0.11, respectively, representing a 21.58 % and 26.03 % increase in biogas production and BOD removal. This integrated approach provides a sustainable solution for maintaining year-round biogas production even when the supply of POME is limited, thereby contributing to renewable energy generation and waste management in the palm oil industry.

Examining the synergistic effects through machine learning prediction and optimisation in the anaerobic Co-digestion (ACoD) of palm oil mill effluent (POME) and decanter cake (DC) with economic analysis

The anaerobic co-digestion (ACoD) of palm oil mill effluent (POME) and decanter cake (DC) is gaining considerable attention as it helps to overcome insufficient feedstock issues in anaerobic digesters during low crop seasons. However, the ACoD process involves complex non-linear relationships between input parameters and process outcomes, posing challenges in accurately evaluating the synergistic effects and optimising biogas production on an industrial scale using traditional modelling approaches. In this study, three supervised machine learning algorithms, i.e., Random Forest (RF), Artificial Neural Network (ANN) and Elastic Net (EN) are applied to model the biogas production and COD removal from a biogas plant. These algorithms are used to learn and uncover the intricate interdependencies between input variables (e.g., temperature, organic loading rate, dilution ratio) and resulting synergistic effects on output variables (biogas production and COD removal) through their non-linear modelling capabilities. Results demonstrate that the Random Forest (RF) model provides the most accurate predictions for biogas production and COD removal, with a high coefficient of determination (R2) of 0.9961 and the lowest root mean square error (RMSE) of 0.110. Optimal conditions for the anaerobic digester, including a temperature of 41.4 °C, an organic loading rate (OLR) of 0.87 kg COD/m3day, and a dilution ratio of 1:10, led to a 14.9% improvement in biogas production (corresponding methane yield of 0.3 Nm3 CH4/kgCODremoved) and a 17.5% increment in COD removal efficiency (88.2%). Feature importance analysis revealed that the dilution ratio significantly influenced biogas production, while OLR played a dominant role in COD removal. Future research efforts will focus on implementing pre-treatment methods for DC in the ACoD system to further enhance biogas production.

Optimization of syngas production from co-gasification of palm oil decanter cake and alum sludge: An RSM approach with char characterization

The study explores co-gasification of palm oil decanter cake and alum sludge, investigating the correlation between input variables and syngas production. Operating variables, including temperature (700–900 °C), air flow rate (10–30 mL/min), and particle size (0.25–2 mm), were optimized to maximize syngas production using air as the gasification agent in a fixed bed horizontal tube furnace reactor. Response Surface Methodology with the Box-Behnken design was used employed for optimization. Fourier Transformed Infra-Red (FTIR) and Field Emission Scanning Electron Microscopic (FESEM) analyses were used to analyze the char residue. The results showed that temperature and particle size have positive effects, while air flow rate has a negative effect on the syngas yield. The optimal CO + H2 composition of 39.48 vol% was achieved at 900 °C, 10 mL/min air flow rate, and 2 mm particle size. FTIR analysis confirmed the absence of C─Cl bonds and the emergence of Si─O bonds in the optimized char residue, distinguishing it from the raw sample. FESEM analysis revealed a rich porous structure in the optimized char residue, with the presence of calcium carbonate (CaCO3) and aluminosilicates. These findings provide valuable insights for sustainable energy production from biomass wastes.

Industrial-scale anaerobic Co-digestion (ACoD) of palm oil mill effluent (POME) and decanter cake (DC) for maximizing methane yield: An integrated machine learning and simulation-based economic analysis approach

This study employs machine learning (ML) algorithms, including multiple linear regression (MLR), decision tree (DT) and support vector regression (SVR) to predict the methane yield from the anaerobic co-digestion (ACoD) of palm oil mill effluent (POME) and decanter cake (DC) in an industry-scale anaerobic covered lagoon. Results showed that the DT model outperformed the other models with a high R2 value of 0.9763 and the lowest MAE, MSE, and RMSE values. It exhibited over 95 % similarity to the actual results, validating its effectiveness in capturing real-world scenarios. Optimisation was conducted using response surface methodology (RSM) to achieve maximum biogas production (14,245 m3/day) and methane yield (0.285 Nm3 CH4/kg CODremoved), where the optimal range of pH, organic loading rate (OLR) and dilution ratio of DC were found to be 6.83–6.94, 0.82–0.83 kg COD/m3. day and 0.09–0.11 respectively. The ACoD process was simulated, and an economic analysis was performed using SuperPro Designer v10.6. ACoD of POME and DC was more economically viable than mono-digestion of POME, with a 43.16 % improvement in return on investment (ROI), considering the trade-off between the additional cost of pre-treating DC and the additional revenue from improved biogas production using ACoD.

Promoting industrial symbiosis and circularisation by optimising waste-based briquette shelf life

The fusion of the circular economy and industrial symbiosis has several advantages from an economic and developmental standpoint. Cooking energy security issues in Africa can partly be solved by the utilization of waste resources in energy technology decisions such as briquette. However, one of the limitations associated with waste-based briquettes has been identified as a reduction in efficiency when stored for a long period of time under varied storage conditions. The aim of this study was to ascertain the effects of storage time and exposure on the calorific value and mechanical characteristics of a waste-based composite briquette made from oil palm shell and decanter cake after 180 days of storage. The calorific value decreased by 12.99% and 31.40%, respectively, for sealed packaged storage and open-air storage. On the 180th day of the experiment, the packaged storage and the open-air storage registered 1000.48 kg/m3 and 870 kg/m3, 72.34% and 100%, 712% and 895%, and 118% and 143% for relaxed densities, shatter indices, resistance to impact, and hygroscopic properties respectively. Manufacturers within West Africa can adopt the findings in this study as a guide for their processes.

Evaluation of the potential use of thermotolerant lignocellulolytic Streptomyces thermocarboxydus ME742 and the mutant MEEMS15-16 as inoculum for effective composting of wastes from palm oil mill

Composting is a potential option for managing the large amount of waste from a palm oil mill, including empty fruit bunches (EFB) and decanter cake (DC). In this study, Streptomyces thermocarboxydus ME742 (WTME742) and its mutant MEEMS15-16 were used as lignocellulotytic inoculum to compost mixed EFB and DC (1:1) in a vertical cylindrical tank with moisture content maintained in the range of 50–70% for 40 days. Their effects were compared to microbial activators (LDD.1). In composting system, MEEMS15-16 showed rapid production for high cellulase (3.86 U/g) on day 3 with ability to sustain high lignin peroxidase over mesophilic stage, while WTME742 produced highest xylanase (11.07 U/g) and manganese peroxidase (100 U/g). After day 40, nutrient contents in all the composts met quality standard requirements of compost, except for the un-inoculated control. WTME742 provided a high nitrogen content (N:P:K was 1.72:1.21:2.35) with a considerably low C/N ratio (12.19) whereas MEEMS15-16 gave higher potassium content (N:P:K was 1.46:1.10:2.52) with a lower C/N ratio (11.09). Co-inoculum with LDD.1 also showed the promising results. Regarding spectral analyses (FTIR and XRD), MEEMS15-16 showed the greater ability for lignocellulosic matter transformation and composting using co-inoculum of MEEMS15-16 or WTME742 with LDD.1 provided high humification degree. The findings demonstrated the potential for use of WTME742 and MEEMS15-16 as inoculant in either single culture or the co-culture with LDD.1. These microbial inoculants would serve as the driving forces in facilitating degradation of palm oil mill wastes, and consequently enhancing the feasibility of compost production at industrial scale.

Kinetics and thermodynamic analysis of palm oil decanter cake and alum sludge combustion for bioenergy production

The main purpose of this research is to explore the thermo-kinetics of the combustion process involving palm oil decanter cake (PODC) and alum sludge (AS) for bioenergy production. Thermogravimetric analysis (TGA) was utilized for the investigation and analyzing of the combustion characteristics. Coats-Redfern methods was applied to estimate the activation energy (Ea) and pre-exponential factor (lnA) using twelve reaction mechanisms. TGA curve revealed that unlike PODC, AS and blends exhibit two degradation ranges. The mass loss of PODC/AS co-combustion reduced with AS addition. Kinetic study revealed that for range I, 50PODC+50AS has the best reaction rate with models P3 and P4. Ea and lnA for P3 and P4 model are (13.52 kJ/mol and 7.19 min−1) and (11.13 kJ/mol and 6.57 min−1) respectively. ΔH, ΔG, ΔS for P3 and P4 models are (8.4 kJ/mol, 131.15 kJ/mol, −0.2 kJ/mol.K) and (6.02 kJ/mol, 131.96 kJ/mol, −0.21 kJ/mol.K) respectively. For range II, 50PODC+50AS has the best reaction rate with model A3. The Ea and lnA for A3 model are 41.40 kJ/mol and 12.36 min−1 respectively. ΔH, ΔG, and ΔS for A3 model are 35.16 kJ/mol, 153.84 kJ/mol, and 0.16 kJ/mol.K respectively. Overall, 50PODC+50AS demonstrated the highest reaction rate, suggesting its superior suitability for bioenergy production.

Optimization for biohydrogen purification process by chemical absorption techniques

Palm oil decanter cake and crude glycerol, which are characterized by their highly biodegradable organic content and nutrient-rich composition, are attractive ingredients for biohydrogen production. In this experiment, we investigated (1) how to produce hydrogen more effectively by co-fermenting palm oil decanter cake and crude glycerol and (2) how to improve the quality of the hydrogen gas produced via chemical absorption technology. This study was divided into two parts. In the first part, the co-fermentation was conducted with a fixed decanter cake concentration of 1% total solids (TS) w/v and variable crude glycerol concentrations (0.25–2.0% w/v). The results showed that maximum biohydrogen production was achieved with 2.0% w/v crude glycerol, which had a hydrogen yield of 131 L kg−1 TSadded and a hydrogen productivity of 1310 mL L−1 d−1. In the second part of the experiment, biohydrogen purification was conducted using the chemical absorption technique by varying four different alkaline solutions: mono ethanolamine (MEA), ammonia (NH3), sodium hydroxide (NaOH), and potassium hydroxide (KOH). The highest hydrogen purity of 98.9% v/v was reached with the MEA solution at a 5 M concentration and a 280 mL min−1 feed mixed gas flow rate for an absorption time of 5 min. However, to achieve sustainable waste management in palm oil mill plants, the feasibility of integrating the biohydrogen production process with palm oil mill effluent from the biogas plants and applying a hydrogen gas quality improvement system need to be investigated further.

Growth response of oil palm seedling from decanter cake application as fertiliser substitute in nursery

Sustainable waste management is essential to safeguard the environment and corporate interests. Stringent regulations on quality of palm oil mill effluent (POME) discharge led to the introduction of more decanter machines, which increased output of dried POME solid namely oil palm decanter cake (OPDC). Therefore, a field experiment was planned to investigate how OPDC can be directly used as fertiliser for oil palm (OP) seedling to meet the needs of the plants. In polythene bags as planting media, topsoil was combined with OPDC at ratios of 10%, 20%, 30%, and 50%. This was followed by a reduction in inorganic fertiliser at levels of 25%, 50%, a predetermined nutrient deficiency input, and up to 100% for planting medium at a ratio of 50% OPDC to topsoil. Null hypothesis was tested by comparing vegetative development i.e., seedling’s girth, height, rachis length, frond production, petiole size and true leaf area at 3rd, 6th, and 9th month after planting (MAP). OP seedlings able to tolerate OPDC application up to 50% mixture ratio with topsoil from transplanting up to twelve months old of biological age. Growth response in treatments up to 50% and nil fertiliser input showed comparable results (P>0.005) against control in all parameters evaluated across three, six and nine months of growing period. Despite of full manuring input, OPDC application on OP seedlings has neither caused leaf phytotoxicity nor deficiency. In conclusion, OPDC can be applied directly to OP seedling as a fertiliser alternative with equal growth performance to standard method.

UNLOCKING THE POTENTIAL OF AGRICULTURE WASTE AS A SOIL AMENDMENT ON GROWTH PERFORMANCE OF SWEET CORN (Zea Mays.)

The decline in soil fertility of agricultural land and the abundance of agricultural wastes is a major problem in the environment. To overcome these problems, agricultural wastes have the potential to serve as a beneficial product that provides sustainable agriculture. The use of agricultural wastes as soil amendments is a sustainable practice in improving soil quality and plant productivity. Therefore, this study was carried out to evaluate the potential of agricultural wastes and agriculture wastes-derived biochars as soil amendments toward sweet corn (Zea Mays.) growth performance. The study was conducted in the greenhouse for 75 days. A randomized complete block design with four treatments (oil palm empty fruit bunch (EFB), EFB biochar, decanter cake, corn cob and corn cob biochar) in combination with mineral soil and four replication was used during the study. Plant height, stem diameter, and number of leaves were assessed for each treatment. Results indicate that corn cob biochar significantly increased the sweet corn height and plant diameter by respectively 11.0% and 25.0% as compared to the control. An increase in the stem diameter by 10.0% due to the application of EFB was observed at 45 days compared to the other treatments. In conclusion, the agricultural waste which is corn cob biochar were observed to have the potential in enhancing the sweet corn (Zea Mays.) growth.

Multivariate decisions: Modelling waste-based charcoal briquette formulation process

The current study sets out to optimize resource utilization by coupling data envelopment analysis (DEA) with the analytical hierarchy process (AHP) methodology to model sustainable binder choice without experimenting available binders. The results of the AHP showed that the cardboard pulp binder was the preferred material to use. Cardboard pulp binder, palm kernel decanter cake, and charred palm kernel shells in a ratio of 10: 20:70 was the used to manufacture composite briquettes. The values obtained for calorific value, specific fuel consumption, and average burning rate were 22.72 MJ/kg, 2.21 kg/L, and 4.87 g/min respectively for the optimal choice. The briquettes produced in this study promotes circular economy and provides a novel framework to address cooking energy poverty issues through the manufacturing of waste-based biofuels. To the best of our knowledge, this is the first study in sub-Saharan Africa to use these waste resources to create composite briquettes.

Regulation of ash slagging behavior of palm oil decanter cake by alum sludge addition

Combustion of palm oil decanter cake (PODC) is a propitious alternative waste to energy means. However, the mono-combustion of PODC prompt severe ash slagging behavior which give rise to reduction in heat transfer and also shorten the lifespan of combustion reactors. In this study, alum sludge (AS) was introduced at different proportion of 30%, 50% and 70% to revamp the slagging characteristics of PODC during combustion. The addition of AS improved ash fusion temperature of PODC during co-combustion as ash fusion temperature increased significantly under high AS dosage. Slagging and fouling indices showed that at 50% AS addition, slagging tendency of the co-combustion ashes can be ignored. The predictive model for PODC-AS combustion showed good correlation coefficient with 0.89. Overall, co-combustion of PODC and AS is an ideal ash related problem-solving route. The proposed PODC slagging preventive method by AS was based on: (1) limited amount of aluminum content in PODC-AS system resulted in development of refractory ash (2) reduction in proportion of basic oxide which act as ash bonding glue played important role in the regulation of slagging (3) reduction of cohesive bond by formation of spongy and porous structure which prevented ash slagging.

The Effectiveness of Rice Husk Ash as Additive in Palm Oil-Based Compost in Enhancing the Nitrogen Uptake by Brassica oleracea var. alboglabra L. (Chinese Kale) Plant

Rice husk ash (RHA), palm oil mill effluent (POME) sludge, and decanter cake can be utilized as compost to reduce environmental pollution. This research attempted to investigate the effect of RHA addition to palm oil-based compost in boosting the nitrogen (N) uptake and the growth of Brassica oleracea var. <i>alboglabra</i> L. (Chinese kale plant). Two categories of compost treatment were prepared in this study: Treatment 1 (control) and Treatment 2 [consisting of 10% (wt/wt) of RHA]. Both treatments were composted for 60 days until it was matured. The temperature and pH of the composts were recorded daily throughout the study. The treatments were analyzed for moisture, water-holding capacity, and nutrient content. The Chinese kale plant was grown in growing media and applied with Treatment 1 and Treatment 2 composts. The progress of plant growth was tracked every week. Based on the analysis, Treatment 2 exhibited a higher temperature and pH profile than Treatment 1. Meanwhile, the contents of N, P, and K were higher in Treatment 1 compost. However, Treatment 2 compost had higher silicon (Si) content, moisture content, and water-holding capacity. Based on the field test study carried out on the Chinese kale plant, the N uptake, and the growth of the plant, were found to be significantly higher when applied with Treatment 2 compost compared to Treatment 1 by 19% to 31% and 13% to 53%, respectively. It was proven that the addition of 10% RHA managed to provide an adequate amount of Si, moisture content, and water-holding capacity in Treatment 2 compost that can enhance the N uptake and improve the growth of the Chinese kale plant in this study.

Green Route Synthesis of Amorphous Silica from Oil Palm Decanter Cake: From Literature Review to Experiments

Numerous agricultural wastes are well-defined as low-cost sources and rich in silica content. The residue of oil palm wastes combustion seems a promising silica source and can be recovered through a straightforward method. In this study, the combustion followed by an alkaline extraction method was employed to extract high purity of silica. The oven-dried oil palm decanter cake (DOPDC) was heated at combustion temperatures of 600, 700, 800, and 900°C to produce OPDC ashes (OPDCA), followed by an alkaline extraction using 5M of NaOH solution. Thermogravimetric analysis (TGA) was used to observe the thermal behavior of DOPDC where the suitable combustion temperatures to produce silica ranged between 600 and 1000 ℃. X-Ray Fluorescence (XRF) analysis showed that silica contents were 31-36% after combustion, increasing to 76.95% after the chemical treatment. Moreover, the spherical shape of the silica was observed through electron microscope analysis. It was represented by the aggregation of silica after going through chemical treatment. The X-Ray Diffraction analysis also proved that the amorphous silica was produced, characterized by the hump-shaped spectrum. The infrared analysis confirmed that the silica had been successfully extracted from OPDCA by the presence of silica functional groups shown in the spectrum.

The Utilization of Palm Oil Mill Effluent Decanter Cake as an Organic Fertilizer on Edamame Type Soybean (Glycine max)

Decanter cake is a solid waste from a palm oil mill with quite a lot of availability and has not been utilized optimally. This research aimed to utilize decanter cake (DC) palm oil mill solid waste as solid Fertilizer and liquid Fertilizer to increase the growth and yield of Edamame. The research design used was a Randomized Block Design (RBD) with a treatment of solid DC with liquid DC, namely solid DC 0 tons ha-1, 10 tons ha-1, and 15 tons ha-1, with liquid DC concentrations of 0 % and 100 %. The variables observed were the number of leaves, number of pods, weight of pods, and yield of Edamame per hectare. The results showed that the highest number of leaves was achieved at 15 tons ha-1 solid DC dose with 100 percent liquid DC concentration. Likewise, the highest number of pods and weight of pods was at a quantity of 15 tons ha-1 and had the same effect as a dose of 20 tons ha-1 with a 100 percent liquid DC concentration. The best edamame yields per hectare were achieved in 15-ton ha-1 solid DC and 100 percent liquid DC concentrations.