This study evaluates turbidity removal performance and daily Polyaluminum Chloride (PAC) use at SPAM Katulampa, Bogor, based on routine operational data under fluctuating raw water turbidity. Daily operational data from 10 February to 10 March 2026 were analysed, including raw water turbidity, treated water turbidity, PAC consumption, and flow rate. Descriptive statistics, time-series plots, turbidity removal calculation, and exploratory scatter plots with linear trendlines were used to assess treatment stability and the relationship between PAC use and turbidity. Raw water turbidity varied widely from 12.00 to 262.97 NTU, while treated water turbidity remained low at 0.52–0.91 NTU, below the 3 NTU national turbidity limit. Turbidity removal ranged from 94.9% to 99.8%, indicating stable performance of the treatment process. Daily PAC use ranged from 324.75 to 519.60 kg/day. However, the linear relationships between raw water turbidity and PAC use (R² = 0.0148), and between PAC use and treated water turbidity (R² = 0.0021), were very weak. The results indicate that low treated-water turbidity was maintained despite high raw-water variability, but this stability cannot be attributed solely to PAC use. It is more appropriately understood as the combined performance of coagulation, flocculation, sedimentation, filtration, and routine operational control. Higher-resolution operational data are needed to evaluate real-time PAC dose response and process optimization.
This study aims to validate the performance of a liquid-liquid (biodiesel-water) separation system using an Oil Palm Empty Fruit Bunch (OPEFB)-based coalescer filter through a computational simulation approach. The separation design evaluation was conducted using SuperPro Designer v10 software in batch operation mode. The modelling covered the entire stages, starting from the transesterification reactor, water washing, to the final separation in the coalescer filter unit (P-5). The equipment’s performance was evaluated based on the mass fraction profile of the final product compared to the waste stream content. The simulation model projected that the OPEFB coalescer filter is capable of operating optimally as a heavy and light phase separator. The product stream composition was dominated by Fatty Acid Methyl Ester (FAME) at 100%, while water, methanol, glycerol, and residual catalyst were comprehensively isolated into the heavy phase (waste) stream. The design of the OPEFB coalescer filter has proven to be theoretically highly feasible in separating post-washing biodiesel-water emulsions, allowing it to proceed to the physical fabrication and empirical testing stages.
Pencemaran air sungai akibat tingginya beban limbah organik menjadi permasalahan lingkungan yang serius, ditandai oleh tingginya nilai COD. Penelitian ini bertujuan menganalisis potensi eco-enzyme dari limbah kulit buah dalam menurunkan nilai COD pada air sungai tercemar secara batch. Eco-enzyme dibuat dari kulit pisang, jeruk, semangka, pepaya, dan nanas dengan rasio 3:1:10 (bahan organik:molases:air) melalui fermentasi tiga bulan. Pengujian dilakukan terhadap air sungai artifisial dengan variasi konsentrasi 5%, 10%, dan 15% selama 12 hari. Parameter yang diukur meliputi pH, suhu, DO, dan COD. Hasil menunjukkan eco-enzyme memiliki bioaktivitas protease, amilase, dan lipase. Penurunan nilai COD intensif pada hari ke-1 hingga ke-5 dan mencapai steady state pada hari ke-9 hingga ke-12. Konsentrasi 5% memberikan nilai COD akhir terendah (22-30 ppm) dengan kulit pisang dan nanas sebagai bahan baku terbaik.
Seaweed (Sargassum sp.) in Gunungkidul has potential as a third-generation bioethanol feedstock, but its development remains constrained by low conversion efficiency and reliance on laboratory-scale equipment. This study examines bioethanol production using an appropriate technology approach with equipment available in domestic market and evaluates the effect of HCl (1-5%) and silicone antibfoam addition (0.07-0.14% w/v) on the stability of the hydrolysis process. The experimental results showed that hydrolysis without antifoam produced uncontrollable foam with material loss up to 16%. Antifoam addition successfully controlled the foam, reduced loss to 5%, and increased Brix to 6-8%. Field measurements with a refractometer showed ethanol content of 22% (v/v), but laboratory verification using gas chromatography (GC) revealed ethanol content of 0.09% and total sugar in dried seaweed of 0.04%, far below literature values. This discrepancy proves that the refractometer overestimation is due to dissolved solids interference. Additionally, during the hydrolysis process, corrosion on SS304 and Cl2 gas were identified, requiring pH neutralization mitigation and scrubber system. Solid waste from fermentation has potential as an organic fertilizer mixture with water content of 91.35%, C-Organic of 0.975%, Total N of 0.07%, K₂O of 0.565%, and P₂O₅ of 0.070%. Integration with downstream industries such as the alginate industry (HCl 3% scenario) save consumption NaOH by 35,63% and HCl by 14,36%. This study concludes that appropriate technology framework is feasible for replication at the community scale, however, pretreatment optimization on raw material and standardized testing validation needs to be established and controlled.
Rubber seeds (Hevea brasiliensis) from Aceh plantations, Indonesia, offer a promising non-edible feedstock for biodiesel synthesis via transesterification due to their high oil content addressing fossil fuel depletion and environmental challenges. This study examines the effect of transesterification time on biodiesel yield and quality using a novel CaO-ZnO/γ-Al₂O₃ heterogeneous catalyst. Rubber seed oil was extracted via Soxhlet method with n-hexane, degummed with phosphoric acid, and transesterified with methanol (1:15 molar ratio, 3 wt% catalyst) at 70°C for 60, 70, and 80 minutes. Oil characterization revealed low moisture (0.012%) and free fatty acids (7.96%). Maximum yield reached 95% at 70 minutes, attributed to optimal triglyceride-methanol interactions before saturation. Density values (903.5-941.5 kg/m³) exceeded SNI 7182:2015 limits (≤860 kg/m³) due to incomplete glycerol separation, while kinematic viscosity met standards (2.67-2.88 mm²/s). GC-MS of the optimal sample identified key fatty acid methyl esters: octadeca-9,12-dienoic acid (33.13%), oleic acid (3.37%), linoleic acid (2.40%), and hexadecenoic acid (1.04%). These results confirm rubber seed biodiesel viability with process optimization needed for density compliance, promoting waste valorization in rubber-producing regions.
The urge to develop more sustainable foam for food packaging is increasing due to the high potential danger of the usage of Styrofoam as food packaging. This study aimed to determine the physical qualities of bio-foam, which was prepared using Pleurotus ostreatus F2 as the fungal microorganisms and the composite of coconut fiber and coffee pulp as substrates. This research was designed as Randomized Complex Block Design with two factors and four repetitions. The ANOVA results showed that both independent factors and their interactions have a very significant effect on the density, porosity, water absorption, and biodegradability of the resulting bio-foam. The higher percentage of Pleurotus ostreatus F2 added (60%) tended to produce bio-foam with lower density, porosity, and water absorption compared to the lower percentage (50%). However, prolonged fermentation up to 5 days tended to increase density, porosity and water absorption of bio-foam. Resulted biofoam has potential to be used as food packaging with further improvement to strengthen the matrix and enhance ethe water absorption quality.
Pulp and paper industry wastewater contains very potential pollutants, especially suspended solids, BOD, and COD which are stable colloids and difficult to separate. To reduce the COD content in paper industry wastewater, the addition of coagulant chemicals is needed. The coagulant used is 20% poly aluminum chloride (PAC) with a variation of 100-600 mg/L and polymer with a dose of 1-6 mg/L to reduce COD and color in wastewater treatment. The settling time used is 1-25 minutes. The effect of adding PAC coagulant is able to reduce COD and color of wastewater at the optimal point, but when the addition of PAC is excessive, the COD and color of the wastewater increase again. The results found that the optimum conditions occurred at a PAC dosage of 400 mg/L and a polymer dosage of 4 mg/L with a settling time of 20 minutes, resulting in a reduction of TSS, COD, and color to 12 mg/L, 102 mg/L, and 123 PtCo, respectively. The combination of coagulation-flocculation-sedimentation processes under these optimum conditions proved effective as a tertiary treatment to meet wastewater quality standards for the paper industry
Sugarcane extract (Saccharum officinarum Linn) is a natural beverage rich in sucrose, glucose, and fructose, making it sweet and refreshing. However, its high sugar content, combined with high water activity and the absence of natural preservatives, makes it highly perishable. These conditions create an ideal environment for microbial growth, leading to enzymatic browning, fermentation, and contamination by spoilage microorganisms, significantly reducing its shelf life. To extend its shelf life while maintaining quality, effective preservation methods are essential. This research evaluates High Pressure Processing (HPP) as a non-thermal preservation technique, comparing untreated sugarcane extract (T1) with HPP-treated extracts at 400 MPa for 10 minutes (THPPc) and at lower pressures (200 MPa and 300 MPa). Analyses included Total Plate Count (TPC), yeast and mold (Y&M) counts, total coliforms, Escherichia coli, and physicochemical properties such as viscosity, water activity, brix, moisture, and color. Results indicated that HPP significantly reduced TPC from 2.60 × 10⁴ CFU/mL in untreated extract to 1.39 × 10² CFU/mL in THPPc. The Y&M count in the HPP-treated extract was less than 1.0 CFU/mL, compared to 1.20 × 10⁴ CFU/mL in the untreated sample. HPP also maintained key physicochemical properties, reducing viscosity from 18.00 mPa.s in T1 to 12.50 mPa.s in THPPc, while preserving color stability and sweetness perception. This study shows that HPP is an effective preservation method for sugarcane extract, providing a viable alternative to thermal processing by minimizing quality degradation and ensuring microbial safety.
The rising demand for nickel in electric vehicle batteries drives the adoption of hydrometallurgical processing, notably Atmospheric Leaching (AL) and High-Pressure Acid Leaching (HPAL), primarily using acid solutions like sulfuric acid for Ni extraction. Although AL offers lower operating costs and simpler equipment, it is typically challenged by high levels of Fe impurities and elevated acid consumption compared to HPAL. To address these limitations, this research investigated optimizing AL by manipulating key process parameters: time and temperature. The study focused on lateritic nickel ore leaching using 0.8 M sulfuric acid, maintaining a solid-to-liquid (S/L) ratio of 20% and a stirring speed of 350 rpm. Experiments were conducted across temperatures of 75, 85, and 95oC and durations from 2 to 8 hours. The optimal result was achieved at 95oC for 8 hours, yielding the highest Ni extraction of 55.81% and the lowest total acid consumption of 1399.45 kg/ton of ore. This indicates that increased temperature and duration accelerate the Ni reaction rate with the sulfuric acid. The extraction of Fe rapid initially decreased significantly over time due to saturation, which directly contributed to the desirable reduction in overall acid consumption.
Plastic waste is a global environmental issue due to its non-biodegradable nature. One potential solution is the development of eco-friendly bioplastics derived from natural materials. This study aims to develop bioplastics based on sago starch with the addition of microfibrillated cellulose (MFC) from empty palm oil fruit bunches as a reinforcing filler to enhance mechanical properties. Additionally, plasticizers such as glycerol and sorbitol were added to improve the elasticity of the bioplastic. The plasticizer concentrations used were 1, 5, 10, 20, and 30% w/w. Characterization was conducted through mechanical property tests (tensile strength, elastic modulus, and elongation percentage), morphological analysis using SEM, and structural analysis with Fourier Transform Infrared Spectroscopy (FTIR spectroscopy). The results showed that the addition of 5% glycerol produced a tensile strength of 26.39 MPa with an elongation of 1.2%, while 20% sorbitol yielded a tensile strength of 25.35 MPa with an elongation of 6.2%. Based on the Indonesian National Standard (SNI) for plastics, the combination of sago starch and MFC with 20% sorbitol provided the best mechanical properties, with a tensile strength of 25.35 MPa and an elongation percentage of 5.6%. In conclusion, sago starch-based bioplastic with MFC from oil palm empty fruit bunches has the potential to serve as an environmentally friendly alternative to synthetic plastics
Plastic waste recycling has been extensively studied, particularly in applications such as paving blocks, asphalt mixtures, and composite boards. One critical parameter affecting the quality of these products is material hardness. This study examines the effect of CaCO₃ addition on the hardness of polymer composite materials. The preparation process involved collecting, washing, drying, sorting, and shredding plastic waste, followed by mixing High Density Polyethylene (HDPE) and Low-Density Polyethylene (LDPE) at a ratio of 1:5. Calcium carbonate (CaCO₃) was added at varying concentrations (0%; 0,5%;1,0%; 1,5%, and 2,0%), and the mixture was melted using an extruder and subsequently molded. The results indicate that the addition of 1,5% CaCO₃ yields the highest and most stable hardness value across three tests, achieving 4,77 HV with a standard deviation of 0,0577. Furthermore, microstructural analysis reveals that up to 1,5% CaCO₃ leads to the most uniform filler distribution, optimizing both hardness and material stability. This study reveals that increasing CaCO₃ concentration enhances composite material hardness when evenly distributed and homogeneous. However, excessive CaCO₃ concentration may result in agglomeration, negatively impacting composite properties.
Biscuits are a popular snack due to their practicality, affordability, and potential as a high-nutrition food. However, biscuit production in Indonesia still depends on imported wheat flour, which poses challenges, especially for people with gluten intolerance or wheat allergies. Therefore, the development of local flour alternatives is essential to support food diversification and reduce wheat dependence. Sorghum (Sorghum bicolor (L.) Moench) is a potential local cereal with high carbohydrates and gluten-free properties but contains tannins that can reduce nutritional quality. This study aimed to evaluate the effect of NaOH soaking on reducing tannin content in sorghum flour and its application in biscuit production with soybean flour fortification as a protein source. Sorghum was soaked in NaOH solution (0.1–0.3%) at 30–50°C. Biscuits were formulated with soybean flour substitution levels of 0–50%. The biscuits were analyzed for proximate composition, tannin content, and sensory properties. Data were analyzed using ANOVA test. Results showed that NaOH soaking reduced tannin content up to 72.455 ppm. Soybean flour substitution significantly affected protein, fat, and carbohydrate content (p < 0.05) but not crude fiber. The highest protein content (8.03%) was found in biscuits with 50% soybean flour, while the highest carbohydrate content (64.40%) was in biscuits without soybean flour. Sensory analysis showed no significant difference between biscuit variants (p > 0.05). This study demonstrates the potential of NaOH-modified sorghum flour combined with soybean flour fortification for producing high-nutrition biscuits and supporting local flour diversification in Indonesia.
In Indonesia, earthworms specifically Lumbricus rubellus are generally underutilized, often used only as fishing bait and not yet fully optimized for their potential as a protein source. This study aimed to optimize the extraction of protein from Lumbricus rubellus using variations in NaCl concentration and incubation time. The extraction process was conducted using the Response Surface Methodology (RSM) with a Central Composite Design (CCD), involving two independent variables: NaCl concentration (3%, 6%, and 9%) and incubation time (24, 48, and 72 hours). The measured responses were dissolved protein, total dissolved solids (TDS), and pH of the extract. The results showed that the optimal condition for protein extraction was at 3% NaCl concentration and 24 hours of incubation, yielding the highest level of dissolved protein. The highest TDS was recorded at 45.5 ppm under the condition of 9% NaCl and 24-hour incubation, while the lowest TDS was 34.3 ppm at 9% NaCl and 72 hours. The pH values ranged from 4.18 to 4.47, with the highest pH observed at 3% NaCl and 24 hours. These findings demonstrate that both NaCl concentration and incubation time significantly influence the efficiency of protein extraction from Lumbricus rubellus, with lower concentrations and shorter times generally producing better results.
Indonesia's pulp and paper production capacity was 5.5% of global production capacity in 2021. As an effort to support the development of the pulp and paper industry in Indonesia, pulp from empty oil palm fruit bunches (EFB) waste which are currently abundant is being tried to develope as raw material for brown paper. To simplify the process of developing pulp quality from EFB, the authors tried to design a rotary digester on a laboratory scale as a EFB digesting machine. The steps used in this research are assembling digester, making pulp, and finally analyzing the data. The digester machine was successfully designed to carry out the pulping process with operating conditions at a pressure of 7 bar, a temperature of 160°C, and a stirrer speed of 80 rpm with a maximum capacity of 1.3 L. The designed rotary digester is capable of producing pulp with an optimal yield level (43%) under reaction conditions, a temperature of 100°C and a NaOH concentration of 5%.
Mercury (Hg) is a highly toxic heavy metal with no biological benefits, posing significant environmental and health risks upon exposure. This study investigates the adsorption characteristics of chicken eggshell-derived adsorbents for the removal of Hg from aqueous solutions. The adsorbent preparation involved washing, drying, calcination, and KOH activation. Results indicated that the 170-mesh size adsorbent exhibited the highest adsorption efficiency, achieving a 99.70% removal rate of Hg. adsorption capacity tests revealed values ranging from 79,90 to 88,90 mg/g, conforming to the Indonesian National Standard (SNI) for activated carbon. Functional group analysis using Fourier-Transform Infrared Spectroscopy (FT-IR) identified a significant increase in aldehyde and ketone groups post-activation. The adsorption process reached equilibrium within 90 minutes, with optimal removal efficiency observed at an initial Hg concentration of 3,0 mg/L. These findings suggest that chicken eggshell-based adsorbents are a cost-effective and efficient solution for mitigating Hg contamination in wastewater, offering a sustainable alternative to conventional methods.
The textile industry is a major contributor to pollution, with 10-15% of dyes lost in wastewater during processing, including Methyl Violet. The degradation products of these dyes are often carcinogenic. Conventional biological treatment methods are ineffective due to the complex nature of synthetic dyes. A study aimed to develop a new photocatalytic activity using a UV A lamp and sonolysis using a sonicator. The study modified TiO2/Activated Carbon from Rice Husk as a catalyst to degrade Methyl Violet and textile industry effluent effectively, which was dual benefits as an adsorbent-photocatalyst. Results showed that the degradation by sonolysis and photolysis was 12.99% and 79.16%, respectively. The degradation by photolysis was 14.95% and 94.12%. The light and catalyst with the highest percentage of degradation were TiO2/activated carbon with UV A light of 94.12%. This study aims to develop effective treatment techniques for the textile industry's dyes.
The palm oil industry produces POME (Palm Oil Mill Effluent) liquid waste. POME is generally brownish, has an odor, and contains dissolved and suspended solids in the form of colloids and oil residue with a high Chemical Oxygen Demand (COD) content. Currently, the POME processing system still uses a conventional system known as the open pond system. This research aims to reduce the burden of organic materials related to removing COD levels, and color. It can solve the technical and operational obstacles of conventional processing systems. One of the extensive efforts to process POME is to develop Fenton-based photocatalytic technology, namely the Fenton-TiO2-UV method. Photocatalytic technology has several general processes involving semiconductor photocatalysts such as TiO2 and photon (UV) energy sources. In this study, the Fenton-TiO2-UV method was used with variations in the Fenton molar ratio of 1:100, 1:200, 1:300 (v/v), reaction times of 30, 60, and 90 minutes with TiO2 concentration 0.6% and uses 2 UV lamps (15 watts). This study achieved the maximum color degradation percentage at a Fenton molar ratio of 1:100 with a reaction time of 30 minutes, namely 95.28%. Meanwhile, the maximum COD degradation percentage was achieved at a Fenton molar ratio of 1:100 with a reaction time of 90 minutes, namely 98.88%.
Fermentation in coffee provides new modulation to the taste and sensory profile of coffee, thereby enhancing its flavor quality. Lactic Acid Bacteria (LAB) strains are used for fermentation in the wet process and have been proven to improve the overall flavor of the coffee. Therefore, in this study, coffee fermentation will be carried out using Lactococcus lactis subsp. to improve coffee flavor quality. The study begins with preparing the starter medium, starter culture, and fermentation. Subsequently, proximate analysis and a cupping test are conducted to assess the flavor profile of the coffee. The results of this study show that coffee fermentation can increase the number of LAB with longer fermentation times. Furthermore, proximate results indicate that fermented Robusta coffee contains 7.86% less fat compared to non-fermented Robusta coffee, which has 15.02% fat. The cupping test results for fermented Robusta coffee reveal a total score of 81, with the clean cup and uniformity aspects scoring 10. This total is higher than that of non-fermented Robusta coffee, thus proving that fermentation using Lactococcus lactis subsp. can improve coffee flavor quality.
Coal is still the world's main energy source, widely used in power generation, steel production materials, cement industry, alumina processing plant paper factories and other chemical industries. Burning coal with high sulfur content produces sulfur dioxide gas (SO2), which can directly or indirectly disrupt the environment and contribute to air pollution and the formation of acid rain. Therefore, desulfurization has become an interesting research topic to improve coal quality. In this research, coal desulfurization is carried out using aloe vera gel as a solvent. 300 ml of aloe vera gel was contacted with 50 grams of coal using a magnetic stirrer with varying stirring speeds of 500 and 750 rpm, for duration 2, 3, 5 and 7 hours. Then, separated, dried, and analyzed for sulfur content, ash content, and calorific value. The results showed that the sulfur content decreased by 19.11% to 24.61%, the ash content decreased by 8.51% to 12.56%, and the calorific value was obtained respectively 6439cal/g, 6381 cal/g, 6433 cal/g, and 6467 cal/g.
Indonesia is one of the leading Pulp and paper producers globally, with an estimated annual growth rate of 3.5%. However, domestic production has not yet fully met the domestic needs and export demand for paper. Currently, hydrogen peroxide (H2O2) and chlorine dioxide (ClO2) are the primary bleaching agents used in Pulp and paper production. This research aims to evaluate the effects of H2O2, ClO2, and temperature on product quality parameters, specifically the tensile and tear indices. The variations of ClO2 used are 2%, 0.4%, and 0.7%; H2O2 concentrations are 0.1%, 0.2%, and 0.4%; and the temperatures used are 75°C and 85°C. The study found that the addition of ClO2 at a concentration of 0.7% resulted in the highest tensile index of 76.9 N.m/g and a tear index of 3.5 m.N.m²/g. The addition of H2O2 at a concentration of 0.1% resulted in a tensile index of 83.9 N.m/g and a tear index of 9.4 m.N.m²/g. Temperature variations did not significantly affect the tensile and tear indices, with the tensile index reaching 9.35 m.N.m²/g. The addition of H2O2 is essential as it enhances the bleaching process and improves the mechanical properties of the Pulp, which is beneficial for optimizing bleaching conditions to enhance product quality, thus meeting both domestic needs and export demands.
