Environment and Natural Resources Journal

Dynamic Integrated Model for Sustainable Solid Waste Management in Bengkulu City

Defi Ermayendri — 2025-08-18

Rapid urbanization and increased consumption patterns have intensified municipal solid waste (MSW) challenges in developing cities. This study applies a system dynamics model to project waste generation, management costs, and landfill requirements in Bengkulu City, Indonesia, over a 20-year period. Four scenarios were simulated: business-as-usual, minimum (25%), moderate (50%), and optimistic (65%) waste reduction. The model integrates critical parameters including population growth, waste generation rates, recycling capacity, and community participation. Results indicate that without intervention, cumulative waste volume will overwhelm landfill capacity and escalate operational costs. Conversely, implementing waste reduction strategies—such as strengthening source separation, expanding composting and waste banks, adopting advanced technologies, and enforcing supportive policies—substantially reduces landfill dependency and operational expenses. The optimistic scenario demonstrates the highest efficiency, reducing required landfill land by over 85% and significantly lowering management costs. This study highlights the importance of multi-stakeholder collaboration, digital monitoring integration, and circular economy principles in urban waste governance. The model offers a practical decision-support framework for policymakers aiming to develop resilient, inclusive, and sustainable waste management systems in similar urban contexts.

The Effect of Chemical Composition and Boiling Time in Kraft Method on Paper Making Based on Palm Oil Trunk (Elaeis guineensis Jacq.)

Muhammad Syukri — 2025-08-20

The rapid expansion of palm oil plantations in Indonesia generates significant waste, including an estimated 77.692 tons/ha of palm oil trunks. It is essential to recycling these trunks into valuable raw materials. Given their high cellulose content, palm oil trunks are promising for paper production. This study investigates the production of paper from palm oil trunks (Elaeis guineensis Jacq.) using the kraft process with variations in chemical composition and boiling time. Three chemical compositions are tested, involving sodium hydroxide (NaOH), sodium sulfate (Na₂SO₄), and sodium carbonate (Na₂CO₃), along with boiling times of 90, 120, and 150 min. Paper quality are analyzed through water absorption, tensile strength, grammage, and visual appearance. The optimal kraft method for water absorption and tensile strength involves a 120-minute boiling time and a chemical composition of 20% NaOH, 9% Na₂S, and 4% Na₂CO₃, resulting in a water absorption of 59.33 mm, tensile strength of 11.26 kN/m, and a grammage of 65 g/m². Additionally, the clean, hole-free surface of the best-performing paper further validates the method's effectiveness. This study demonstrates that high-quality paper can be produce from palm oil trunks using optimal kraft process parameters, supporting sustainable waste utilization.

Modelling Air Pollution in Thailand: Insights from Community Mobility Data

Padcharee Phasuk — 2025-08-29

This research investigates the relationship between community mobility and air pollution in Thailand, utilizing econometric and machine learning approaches to provide useful insights for policymakers to counter this issue. Data was sourced from the pollution database provided by the Ministry of Natural Resources and Environment and the community mobility database from a Google Trend search. The methodology of the research includes data extracting and pre-processing. The data analysis used an econometric model utilized Generalized Method of Moments, and a Machine Learning employed Support Vector Machines Results of the econometric analysis reveal that residential mobility, workplace mobility, and park mobility have a significant positive relationship with changes in air pollution. The support vector machine results show that community mobility explains 58.50% of air pollution variation and has a prediction accuracy of 94.47% on the training set. The results also suggest that pollution problems should be monitored closely when air pollution changes by 20%. These findings enhance the understanding of the complex factors influencing air pollution and offer valuable insights for developing effective mitigation strategies.

The Influence of Age and Management on Soil Physicochemical Properties and Heavy Metal Accumulation in Post-Tin Mining Lands on Bangka Island

Farhan Erdaswin — 2025-09-09

Bangka Island is one of the largest tin producers in Indonesia and the world, covering an area of 156,531.3 hectares. Tin mining activities have significantly degraded post-mining land, altering soil properties and increasing heavy metal retention. This study aimed to evaluate the impact of post-tin mining land age and management on soil physical and chemical properties and total heavy metal concentration. Soil samples were collected using a stratified sampling method from three representative sites with similar climatic conditions: newly mined land (0 years), reclaimed land (7 years), and minimally managed land (20 years). Physical parameters were measured directly in the field, except for bulk density, air-dried soil moisture, and texture fraction, which were analysed in the laboratory alongside chemical parameters. The findings indicate that as post-tin mining land ages, soil physical properties such as bulk density, soil hardness, air-dried soil moisture, and texture fractions change, while infiltration decreases, indicating compaction. Meanwhile, post-tin mining management in the form of reclamation significantly improves soil chemical quality, including pH, organic carbon, organic matter, and phosphorus availability. Heavy metal accumulation is more strongly influenced by land age than management practices; however, appropriate management can reduce heavy metal availability and enhance overall soil quality. Partial least squares structural equation modeling (PLS-SEM) analysis confirms that soil physicochemical properties mediate the relationship between land age, management, and heavy metal accumulation in post-tin mining sites.

Levels of Microplastics in Aquatic Ecosystem Components of the Kedung Ombo Reservoir, Central Java: Analysis of Water, Tilapia (Oreochromis mossambicus), Sediment, Macroalgae, and Gastropods

Noor Maulidah — 2025-09-08

The widespread use of plastics in daily activities poses a significant threat to aquatic environments and human health, primarily because plastics degrade into microplastics that easily accumulate in biota and may cause harm when ingested. The aim of this study was to identify the abundance and types of microplastics in water, gastropods, tilapia fish, macroalgae, and sediments. This study was conducted from September to December 2024 in the Kedung Ombo Reservoir. The abundance, shape, and size of microplastics were analyzed using an Olympus CX23 binocular microscope with a 4×/0.10 objective lens. Polymer type analysis of the microplastics was conducted using Fourier Transform Infrared (FTIR) spectroscopy. The abundance of microplastics found at each observation station, consisting of water, gastropods, tilapia fish, macroalgae, and sediment samples, was 122, 2,088, 2,700, 1,036, and 8,847 particles/kg, respectively. Microplastics were classified based on their size into small (<0.5 mm), medium (0.5-<1 mm), and large (1-5 mm), with percentages of 72%, 13%, and 15%, respectively. The shapes of the detected microplastics included fibers (39%), fragments (19%), films (17%), pellets (15%), and foams (11%). The microplastics detected were black (33%), red (15%), purple (6%), yellow (12%), blue (8%), green (6%), and clear (20%). The microplastics identified were polyethylene terephthalate (PET), polyethylene (PE), and polystyrene (PS). The abundance of microplastics has been detected in various compartments of the Kedung Ombo Reservoir. This needs to be monitored regularly, because microplastic accumulation on organisms can be harmful to health and the environment.

Soil Carbon Sequestration in Rice-Based Cropping Systems in Batac, Philippines

Arlene L. Gonzales — 2025-09-03

This study focused on the assessment of capacity of farm soils to sequester carbon under different rice-based cropping patterns. The results of this study may be valuable for the formulation of soil and crop management for climate change mitigation in the agriculture sector in Ilocos Norte, Philippines. This study was conducted in major cultivated areas in the City of Batac, characterized by intensified and diversified cropping patterns centered around rice cultivation. A quantitative research design was employed to determine the different cropping patterns and their influence on soil organic carbon (SOC). The dominant cropping patterns observed in Batac City was rice, followed by any of the following crops; corn, shallot, eggplant, rice, tomato, pepper, garlic and tobacco. These cropping patterns are assumed to have an influence in soil pH, organic matter (OM), % carbon, phosphorus (P), potassium (K), bulk density, soil texture, moisture content, and soil carbon stock (SOC). Results showed that soil organic matter content in various cropping patterns was proportional to the soil carbon stock in the soil. The analysis of variance between cropping patterns exhibited high variability in OM and SOC with an F-value >1. Rice-tobacco exhibited the highest carbon stock (1.80%), while rice-garlic (0.63%) and rice-corn (0.60%) had the lowest. Understanding the influence of crop biomass and management through this study can be beneficial in the design of informed decision-making strategies and advocacy on cropping pattern management, which can be disseminated to farmers to enhance the carbon sequestration potential of agricultural lands.

Assessing Aquatic Plant Diversity and Management Potential in Wetlands in Northwestern and Southwestern Bangladesh

Md. Foysul Hossain — 2025-09-17

Aquatic plants are essential organisms for assessing ecological health and for managing and conserving aquatic biodiversity. The present study investigated the diversity of aquatic flora, in addition to their applications and management, in northwestern (Gajner Beel) and southwestern (Padma Beel) Bangladesh. This research utilized a mixed-methods approach, incorporating observation of the study area for collecting samples, qualitative interviews, and quantitative surveys. A total of 38 aquatic plant species of 4 types belonging to 16 orders and 23 families were recorded from the two wetlands. Asterales was the predominant order in both wetlands, with Araceae and Asteraceae being the largest families. Almost half (44%) of the aquatic plants in both ecosystems bloomed during the rainy season. In Gajner Beel and Padma Beel, 41% and 48% of aquatic plants, respectively, rarely occurred, while 31% and 41% of aquatic weeds were frequent, respectively. Approximately a quarter of the plants have an unevaluated IUCN conservation status, with about 13% of plants in Gajner Beel and 15% in Padma Beel being exotic. Farmers only employ manual or mechanical techniques to control common aquatic weeds, without any preventive measures. About 74% of the aquatic plants in both regions are used for various purposes by local people, including traditional medicine, human food, animal feed, raw materials for handicrafts, and fertilizers. The study examined management approaches for the aquatic flora in both regions, emphasizing their potential utilization.

Selective Adsorption of Cationic Dyes by Hydrochar Derived from Spirogyra sp. Algae via Temperature-Varying Hydrothermal Carbonization

Muhammad Badaruddin — 2025-09-16

This study synthesized hydrochar adsorbents at varying temperatures 150°C (HC150) and 250°C (HC250), using the hydrothermal carbonization (HTC) method from Spirogyra sp. (SPG) and characterized them using XRD, FTIR, SEM, and BET analyze. XRD results confirmed a dominant CaCO₃ phase (JCPDS 01-086-2334) in all samples, with new peaks and shifts in HC150 and HC250 indicating structural changes from hydrochar formation. FTIR spectra revealed functional groups such as O-H, C=O, C-O, and C-N-S in SPG, with notable reductions in O-H and phenolic signals in HC150 and HC250, suggesting chemical transformations. SEM analysis revealed that SPG exhibits a smooth, sheet-like morphology, while HC150 formed uniform particles and HC250 developed a rough, porous surface, indicating increased carbonization, surface heterogeneity, and enhanced adsorption potential. BET analysis showed a marked increase in surface area and a transition from macroporous to mesoporous structures in HC150 and HC250, enhancing their adsorption capabilities. Adsorbents exhibited selective adsorption toward methylene blue (MB). Surface charge analysis revealed similar pHpzc values slightly below neutral, promoting favorable electrostatic interactions with cationic MB. Adsorption followed pseudo second order (PSO) kinetics compared to pseudo first order (PFO), indicating chemisorption, while isotherm modeling highlighted HC250 strong fit to the Freundlich model. Thermodynamic assessments confirmed HC250 superior performance, exhibiting more negative ∆G, lower ∆H, and higher ∆S values, signifying spontaneous, energy-efficient, and affinity-driven adsorption. Regeneration tests further underscored HC250 stability, with removal efficiency maintaining above 50% after four cycles (90.14% to 53.55%). In comparison, HC150 showed good reusability (80.56% to 51.88%), while SPG declined significantly (56.23% to 50.20%) after two cycles.