International Journal of Hydrological and Environmental for Sustainability
International Journal of Hydrological and Environmental for Sustainability (IJHES) [e-ISSN: 2828-5050 & p-ISSN:2828-6405] is an internationally recognised peer-reviewed journal for the dissemination of innovations and solutions focused on enhancing water and Environment management best practice. The journal aims to publish high-quality, peer-reviewed research that advances scientific knowledge on hydrological systems, environmental processes, and sustainability-oriented solutions. The journal provides an interdisciplinary platform for studies integrating hydrology, environmental engineering, environmental chemistry, and Earth sciences to support sustainable management of water resources, environmental protection, and subsurface system understanding. The journal emphasizes process-based, analytical, experimental, and geoscientific approaches that contribute to sustainable development, pollution mitigation, groundwater and geothermal system evaluation, and environmentally relevant geophysical investigations. Since 2022, IJHES issues 3 times a year (February, June, and October). Please click here for more scope and focus journal information. To Register an account as Author please contact ijhes.editor.foundae@gmail.com
Assessment of Energy Efficiency and Conservation at the UNTAG Surabaya Rectorate Building Using EDGE and GREENSHIP
The building subsector is the largest contributor to greenhouse gas emissions in Indonesia’s energy sector, with approximately 90% of its emissions stemming from electricity consumption. The implementation of green building concepts is one of the efforts to improve energy efficiency and reduce these emissions. This study aims to evaluate the energy efficiency and conservation (EEC) score in the GREENSHIP rating system and compare it with energy savings estimates using the excellence in design for greater efficiencies (EDGE) Building App at the Rectorate Building of the University of 17 August 1945 in Surabaya. The study employed a quantitative descriptive method based on electricity consumption data and observations of electricity usage for the GREENSHIP evaluation, as well as calculations of the Window-to-Wall Ratio (WWR) and building characteristics for energy performance simulations using the EDGE Building App. The results show that the GREENSHIP EEC score reached only 7 out of a total of 36 points, while the EDGE simulation indicated a potential energy savings of 26.37%. These results indicate that EDGE focuses on the percentage of energy savings compared to a baseline building, whereas GREENSHIP evaluates the implementation of energy management, efficiency, and conservation strategies more comprehensively. Therefore, a high level of energy savings does not necessarily result in a high GREENSHIP score without the comprehensive application of energy efficiency criteria.
Copyright (c) 2026 Kresna Gemilang, Endah Safitri, Sholihin As'ad https://creativecommons.org/licenses/by-nc-sa/4.0
Evaluation of Lake Sentani Water Quality Using Pollution Index, STORET, CCME-WQI, BC-WQI, and NSF-WQI Methods
Lake Sentani is the largest lake in Papua and serves as an important source of raw water, fisheries, and livelihoods for communities in Jayapura. Increasing anthropogenic pressures from settlements, agriculture, aquaculture, and tourism have raised concerns regarding the deterioration of its water quality. This study compared the water quality status of Lake Sentani using five assessment methods: Pollution Index (IP), STORET, CCME-WQI, BC-WQI, and NSF-WQI. Water samples were collected from five stations representing littoral, limnetic, and human-activity-influenced zones. The analyzed parameters included physical (temperature, TDS, TSS, turbidity, and Secchi depth), chemical (pH, dissolved oxygen, BOD₅, COD, nitrate, phosphate, ammonia, and sulfate), and biological (total coliform) indicators. The results indicated IP values ranging from 3.95 to 6.43 (lightly to moderately polluted), STORET scores from –20 to –44 (moderately to heavily polluted), CCME-WQI values from 47.3 to 71.2 (marginal to fair), BC-WQI values from 44.7 to 68.5, and NSF-WQI values from 46.1 to 70.3. Station S3 (Sentani Town) consistently exhibited the poorest water quality, whereas Station S4 (Ayapo) showed the best condition. Elevated BOD₅, phosphate, ammonia, and total coliform were identified as the principal parameters contributing to water quality degradation. The five assessment methods produced generally similar spatial patterns across the sampling stations, with Pearson correlation coefficients ranging from 0.89 to 0.97, although these correlations should be interpreted cautiously given the limited number of monitoring stations. Among the evaluated approaches, CCME-WQI provided a balanced assessment by integrating the scope, frequency, and magnitude of water quality exceedances, making it a suitable framework for routine monitoring of tropical lake ecosystems under the conditions examined in this study.
Copyright (c) 2026 Bambang Suhartawan, Daawia Daawia https://creativecommons.org/licenses/by-nc-sa/4.0
Sustainable Waste Management through Material Flow Analysis and Waste Diversion Rate: A Case Study of Sekolah Alam Bogor, Indonesia
Sekolah Alam Bogor (Bogor Nature School) provides a relevant case for examining school-based circular waste management in Indonesia. Although the school applies reduce, reuse, and recycle (3R) principles, their implementation remains suboptimal due to the absence of systematic flow mapping and quantitative evaluation. This study aims to quantify waste generation and composition, map material flows, and evaluate the Waste Diversion Rate (WDR) of the school’s circular waste management system. A mixed-method case study was applied, combining field observation, in-depth interviews, and direct weighing of waste over 14 effective school days across five source units: Pre-School, Elementary School, School Kitchen, Middle School, and School of Makers, The results show an average waste generation of 165.15 kg/day, dominated by organic waste (71.23%), with inorganic waste accounting for 28.77%. Salam Permaculture composts organic waste, recyclables are channeled to Bank Sampah Salam Aid, and residues are incinerated. The system achieved an internal Waste Diversion Rate (WDR) of 76% (77.79% when community-contributed recyclables from the Dropzone program are included), indicating substantial waste diversion. However, approximately 24% of the waste (39.70 kg/day) remains as residue treated through incineration, whose emissions and ash quality were not assessed and require further evaluation. These findings indicate that systematic flow mapping and data-driven evaluation are essential for strengthening source-based waste management in educational institutions.
Copyright (c) 2026 Nur Fitri Hasanah, Mimin Aminah, Eko Ruddy Cahyadi https://creativecommons.org/licenses/by-nc-sa/4.0
Geological Risk Assessment, Environmental Management Practices, and Sustainable Mining Operations: Evidence from a Survey-Based SEM-PLS
The mining industry faces significant challenges in maintaining sustainable operations due to geological uncertainty, environmental degradation, and increasing demands for effective environmental management. Geological hazards such as slope instability, landslide potential, groundwater inflow, mine drainage problems, erosion, and waste rock instability may directly affect environmental quality and operational sustainability. This study examines the relationships among Geological Risk Assessment (GRA), Environmental Management Practices (EMP), and Sustainable Mining Operations (SMO) using survey responses from 150 mining professionals in Indonesia, covering coal, nickel, copper, and gold mines. A cross-sectional survey design and Structural Equation Modeling–Partial Least Squares (SEM-PLS) were applied to assess the associations among GRA, EMP, and SMO and to evaluate the mediating role of EMP. The results indicate that GRA is positively associated with EMP (β = 0.718) and SMO (β = 0.402), while EMP positively affects SMO (β = 0.424). EMP also partially mediates the relationship between GRA and SMO, with an indirect effect of β = 0.305. These findings suggest that geological risk assessment contributes to sustainable mining by strengthening environmental management practices, particularly in relation to mine water management, erosion control, land reclamation, waste management, and environmental impact monitoring. The study provides a conceptual SEM-PLS model linking geological risk, environmental management, and sustainable mining performance, offering practical insights for improving environmentally responsible mining operations in Indonesia.
Copyright (c) 2026 Obed Patiung, Restyana Aulya, Zahwa Paewa https://creativecommons.org/licenses/by-nc-sa/4.0
Flood Inundation Mapping in Medan Maimun, Medan City Using HEC-RAS 2D and the Nakayasu Synthetic Unit Hydrograph
Flood inundation mapping is a critical tool for urban flood risk assessment in tropical cities. This study investigates flood inundation extent in Medan Maimun Sub-district, Medan City, one of the most flood-prone areas in North Sumatra, Indonesia, where flood depths of approximately 3 meters were reported in February 2022 and December 2023. The study aims to: (1) determine design rainfall through frequency analysis and calculate design flood discharge for return periods of 2, 5, 10, 25, 50, and 100 years using the Nakayasu Synthetic Unit Hydrograph (SUH Nakayasu) method; (2) simulate flood routing using two-dimensional hydraulic modeling; and (3) map the resulting flood inundation extent for each return period. Rainfall frequency analysis used annual maximum rainfall data from two stations for the period 2014–2023, with the Log Pearson III method selected based on Chi-Square goodness-of-fit testing. Design flood discharges ranged from 383.403 m³/s at the 2-year return period to 555.149 m³/s at the 100-year return period. Flood routing and inundation mapping were performed using HEC-RAS version 5.0.7 integrated with RAS Mapper. Total inundation area increased from 110.982 ha at the 2-year return period to 126.581 ha at the 100-year return period, covering approximately 41.6% of the sub-district area at the 100-year return period. The model was not formally calibrated or validated against observed flood data; results should be interpreted as indicative of relative flood risk patterns rather than precise predictions. The flood inundation maps produced provide a useful scientific basis for flood mitigation planning in Medan city, Indonesia.
Copyright (c) 2026 Sarra Rahmadani, Dewi Fitria Marlisa, Rumilla Harahap, Siti Zulfa Yuzni, Nanda Savira Ersa, Cut Meuthia Rani, Al Fatahillah, Muh. Ilham Anggamulia, Yusuf Aulia Lubis, Anni Zahara Putri, Wisnu Prayogo https://creativecommons.org/licenses/by-nc-sa/4.0
Reusable and Reconfigurable Material Concepts for Post-Disaster Temporary Modular Shelters: A Systematic Review From An Environmental Sustainability Perspective
Post-disaster temporary shelters in Indonesia often generate significant construction waste because of their single-use nature. This study aims to map reusable and reconfigurable concepts as the foundation of Temporary Modular Shelter (TMS) material design and to analyse their contributions to environmental sustainability. A Systematic Literature Review (SLR) following the PRISMA 2020 protocol was conducted on peer-reviewed articles and indexed proceedings published between 2015 and 2025, retrieved from Scopus, ScienceDirect, and Google Scholar. Of 412 records initially identified, 87 peer-reviewed studies met the inclusion criteria. Thematic analysis was performed using NVivo 12 with a hybrid deductive–inductive coding approach. The findings show that reusable–reconfigurable principles are operationalised through modular systems and reversible dry connections that allow shelter components to be potentially reused or adapted for permanent housing construction. Five main material components were identified: frames, wall panels, roofs, flexible elements, and flooring/base modules. The approach is reported in the reviewed literature to support construction waste reduction, circular economy practices, lower embodied carbon, and improved resource efficiency, although the magnitude of these benefits varies with material type, transport distance, and the number of reuse cycles. This study contributes an integrative sustainability-based framework linking reusable–reconfigurable principles with post-disaster TMS material systems. Remaining challenges include module standardisation, local human resource capacity, comprehensive Life Cycle Cost analysis, and socio-economic integration. The framework provides a reference for policymakers, researchers, and practitioners developing adaptive and sustainable temporary housing in disaster-prone regions.
Copyright (c) 2026 Sely Novita Sari, Sarwidi, Fitri Nugraheni, Albani Musyafa https://creativecommons.org/licenses/by-nc-sa/4.0
Oil Palm Empty Fruit Bunch-Derived Cellulose Acetate-Zeolite Mixed Matrix Membrane Adsorbers (MMMAs) for Ammonia Removal in Palm Oil Mill Effluent Wastewater Treatment
This study developed cellulose acetate-zeolite mixed matrix membrane adsorbers (CA-zeolite MMMAs) using cellulose acetate synthesized from OPEFB as the polymer matrix and natural mordenite zeolite as the adsorptive inorganic filler. The membranes were fabricated to enhance ammonia-nitrogen removal from synthetic ammonia solution and palm oil mill effluent (POME). Zeolite incorporation improved several membrane properties, including pure water flux, swelling degree, and porosity, compared with pristine cellulose acetate membranes. However, tensile strength and elongation decreased after zeolite addition, indicating a trade-off between adsorption-related properties and mechanical flexibility. The optimum adsorption performance was achieved using the CA-zeolite MMMA with 30% zeolite loading and a contact time of 70 min, producing an ammonia adsorption capacity of 1.051 mg/g under the selected operating conditions. Adsorption kinetic analysis showed that the pseudo-second-order model provided a better fit than the pseudo-first-order model, with an R² value of 0.9104. The adsorption equilibrium was better represented by the Langmuir isotherm model, with an R² value of 0.9247. The optimized membrane also showed regeneration potential, with first-cycle regeneration efficiencies of 83.37% using NaCl and 73.52% using HCl. When applied to actual POME, the membrane reduced ammonia concentration from 173.93 mg/L to 50.161 mg/L in batch adsorption and 52.136 mg/L in filtration, corresponding to removal efficiencies of 71.16% and 70.02%, respectively. Although the treated effluent remained above the regulatory discharge limit of 20 mg/L, the results demonstrate that OPEFB-derived CA-zeolite MMMAs have potential as pretreatment or polishing materials for ammonia-nitrogen removal from POME.
Copyright (c) 2026 Saiful, Cut Riski, Julinawati Julinawati, Mutia Farida, Mohd Rashidi Abdull Manap https://creativecommons.org/licenses/by-nc-sa/4.0
Removal of COD, BOD, and Detergent from Laundry Wastewater Using Coconut-Shell Activated Carbon in Batch and Continuous Fixed-Bed Adsorption
Laundry wastewater contains high organic matter and detergent residues that may degrade the receiving water quality if discharged without treatment. This study investigated the performance of coconut-shell activated carbon for reducing chemical oxygen demand (COD), biochemical oxygen demand (BOD), and detergent concentration in laundry wastewater, using batch and continuous fixed-bed adsorption systems. Four activation treatments were evaluated at the batch stage: no activation, NaOH 0.2 N, HCl 0.1 N, and sequential NaOH 0.2 N–HCl 0.1 N. The best activator was then applied in a continuous upflow column with adsorbent thicknesses of 15, 20, and 25 cm. HCl 0.1 N produced the highest batch removal efficiencies, reaching 73.30% for COD, 71.53% for BOD, and 75.73% for detergent. Adsorption equilibrium for all parameters was better described by the Freundlich model than by the Langmuir model, indicating adsorption on a heterogeneous carbon surface. In the continuous system, the 25 cm bed showed the highest concentration-based removal, reaching 97.12% for COD, 97.03% for BOD, and 99.66% for detergent, and provided the longest breakthrough delay. However, the 20 cm bed yielded the highest average pollutant-load reduction, indicating a more balanced operational performance. Hydraulic conductivity decreased from 0.000058 to 0.000036 m/s during operation, suggesting progressive pore blockage and adsorbent saturation. These results demonstrate that coconut-shell activated carbon has good potential as a simple and practical adsorbent for decentralized laundry wastewater treatment.
Copyright (c) 2026 Alexander Tunggul Sutan Haji, Mujaroh Khotimah, Putri Setiani, Amelia Gultom, Ichi Fiaqi Hamada, Abentin Estim, Wisnu Prayogo https://creativecommons.org/licenses/by-nc-sa/4.0
Sustainable Water Infrastructure Assessment of Raw Water Availability and Demand in a Nickel Mining-Impacted Watershed: A Case Study of the Pali River, East Halmahera, Indonesia
Rapid regional development, population growth, and land-use conversion associated with nickel mining have intensified pressure on raw water resources in many tropical watersheds. In mining-affected regions, the sustainability of water infrastructure depends not only on projected demand but also on the long-term reliability of raw water availability under low-flow conditions. This study assesses raw water availability, future clean water demand, and watershed protection requirements for the Pali River, the main gravity-fed raw water source for Maba City, East Halmahera, Indonesia. A quantitative hydrological approach was applied by integrating population projection, water demand estimation, watershed delineation, rainfall–runoff analysis using the F.J. Mock water balance model, and mining-induced catchment reduction scenarios. Water demand was projected to 2045, while dependable discharge was evaluated using Q90 low-flow reliability. The results show that the projected average clean water demand for Maba City reaches 36.19 L/s in 2045. Under the baseline non-mining condition, the Pali River watershed has an effective catchment area of 1.75 km² and a Q90 dependable discharge of 17.19 L/s. This value is already insufficient to meet the projected average demand under critical dry-season conditions. Mining-related catchment contraction further reduces the effective watershed area to 0.733 km² under Scenario 1 and 0.2973 km² under Scenario 2, decreasing dependable discharge to 7.20 L/s and 2.92 L/s, respectively. These findings indicate that the Pali River alone cannot provide a reliable long-term raw water supply for Maba City. Protection of the entire contributing watershed, development of alternative raw water sources, additional storage infrastructure, and continuous water quality monitoring are therefore essential to support sustainable water infrastructure planning in this nickel mining-impacted watershed.
Copyright (c) 2026 Hanie Teki Tjendani, Muliastuti, Sajiyo, Bambang Trigunarsyah, Buntara Sthenly Gan https://creativecommons.org/licenses/by-nc-sa/4.0
Mechanical Performance and Sustainability Potential of Concrete Incorporating Waste Polytetrafluoroethylene Fibers
This study investigates the feasibility of utilizing waste polytetrafluoroethylene (PTFE) fibers as a recycled additive in concrete to support plastic waste valorization and sustainable construction material development. Waste PTFE fibers obtained from industrial seal production were mechanically processed into irregular fiber-like particles with sizes of approximately 4–6 mm and incorporated into concrete mixtures at 0.2%, 0.4%, 0.6%, and 0.8% by weight of concrete. The effects of PTFE fiber addition on workability, splitting tensile strength, and flexural strength were evaluated using cylindrical and beam specimens tested according to SNI and ASTM standards. The results show that increasing PTFE fiber content reduced concrete workability, as indicated by a decrease in slump from 125 mm for the control mixture to 75 mm for the mixture containing 0.8% PTFE fibers. The incorporation of untreated PTFE fibers also decreased mechanical strength. Compared with the control concrete, splitting tensile strength decreased by 6.924%–18.474%, while flexural strength decreased by 15.409%–32.060%. This reduction is attributed to the smooth, hydrophobic, chemically inert, and low-friction surface characteristics of PTFE, which weaken adhesion between the fibers and the cementitious matrix and reduce load-transfer efficiency. Although untreated waste PTFE fibers did not improve the tensile-related mechanical performance of concrete, their use may contribute to plastic waste utilization in construction materials. Further surface treatment, fiber modification, and mix design optimization are required before waste PTFE fibers can be effectively applied as reinforcing materials in sustainable concrete.
Copyright (c) 2026 Lilis Zulaicha, Oggi Heicqal Ardian, Anggi Hermawan https://creativecommons.org/licenses/by-nc-sa/4.0
Evaluation of Microbiological Indicator Contamination (Escherichia coli) and Heavy Metal Levels in Edible Fish from Situ Bambon, Ciracas: A Health Risk Assessment
Situ Bambon in Ciracas, East Jakarta, is utilized by the local community for daily activities ranging from recreation, angling, to net fishing. The community frequently utilizes the areas around the inlet, midstream, and outlet to catch fish. This study aims to evaluate the content of the microbiological indicator E. coli and heavy metal levels in edible fish from Situ Bambon Ciracas to obtain a comprehensive Health Risk Assessment. The results showed that the microbiological contamination levels through the Escherichia coli indicator in edible fish ranged from <1.8 to 13.9 MPN/g, indicating that fish samples in the inlet 1 and outlet 2 areas failed to meet food safety standards (< 3 APM/g). The worst concentrations of Cadmium (Cd) and Lead (Pb) in edible fish from Situ Bambon were found in the inlet 2 area, with a Cd value of 0.83 mg/kg and a Pb value of 0.80 mg/kg. The obtained Cd and Pb contamination levels exceeded the Maximum Contaminant Limits (MCL) established by PerBPOM Number 9 of 2022, where Cd was approximately 8.3 times higher, while Pb exceeded the limit by about 2.7 times. The Health Risk Assessment (HRA) indicated that the Hazard Index (HI) value of 1.489 exceeded the allowable tolerance threshold of 1.0. Risk contribution analysis showed that Cd accounted for 51.0% of the total HI risk, while Hg contributed 35.0%. Furthermore, the carcinogenic risk (cancer) was evaluated through the Total Risk (TR) for Cadmium (Cd) because it possesses the highest Slope Factor (SF) of 0.38 (mg/kg-day)⁻¹, calculated based on the Lifetime Average Daily Dose (LADD) and SF, yielding a result of 3.37 x 10⁻⁷. This value remains below the internationally acceptable carcinogenic risk threshold of TR < 10⁻⁶. The environment-fish-human exposure cycle in Situ Bambon has reached a hazardous threshold and demands top-priority intervention to protect public health.
Copyright (c) 2026 Haerul Anwar, Nadirahillah, Faisal M Jasin, Bayu Achil Sadjab, Cornelia Victoria Anghel, Amir Machmud https://creativecommons.org/licenses/by-nc-sa/4.0
Hydrological Effects on Rock Mass Quality and Rippability of Heterogeneous Karstic Limestone
The proposed study area is located approximately 1.9 km southwest of the main cement plant in Tuban, Indonesia. This research aims to evaluate the rippability characteristics of the limestone formation underlying the planned development site. The assessment is based on data obtained from a geotechnical borehole investigation (CR-1), integrated with previous subsurface exploration results. The site is designated for shallow foundation systems designed to withstand bearing pressures ranging from 300 to 800 kPa. Subsurface conditions are characterized by karstic limestone with complex hydrogeological features. The limestone exhibits high sensitivity to water infiltration, dissolution processes, and mechanical property degradation under saturated conditions. Significant spatial variability in rock mass quality and strength is observed over relatively short vertical and horizontal distances. The uppermost layer comprises residual lateritic (red) soil derived from in-situ weathering of the underlying limestone. The presence of limestone gravels and boulders within the residual soil indicates a transitional interface between the overburden and the more competent limestone strata. The limestone formation consists of heterogeneous materials, including highly porous honeycomb-textured rock and relatively intact, sound limestone, distributed irregularly across the site. This heterogeneity results in considerable variability in mechanical strength and excavation response. The findings provide essential insights into the rippability behavior of the limestone and its implications for foundation design and construction planning in karst environments.
Copyright (c) 2026 Foundae (Foundation of Advanced Education) https://creativecommons.org/licenses/by-sa/4.0/
Lithological Controls on Acid Mine Drainage Formation: An Integrated Rock Characterization of AMD Sources in the Sungai Seluang Area, East Kalimantan, Indonesia
Acid Mine Drainage (AMD) represents a critical environmental challenge in coal-mining regions, particularly due to its long-term impacts on surface water quality and surrounding ecosystems. This study investigates the lithological controls on AMD formation in the Sungai Seluang area, East Kalimantan, Indonesia, through an integrated rock characterization approach. The novelty of this research lies in linking detailed lithological attributes and pyrite micro-morphology with AMD generation potential and its implications for riverine water systems. Macroscopic lithological observations were combined with standardized pH testing (SNI 6989.11:2019) and Scanning Electron Microscopy (SEM) to evaluate the acid-generation characteristics of representative rock units. The results indicate that 92% of the analyzed samples are classified as Potentially Acid Forming (PAF), while only 8% are Non-Acid Forming (NAF). The study area is lithologically dominated by claystone (42%), sandstone (31%), and shale (27%), all of which commonly exhibit intense oxidative staining, pervasive fracturing, and weathering features that significantly enhance sulfide exposure to oxygen and water. SEM analyses reveal the presence of both euhedral and framboidal pyrite, with framboidal pyrite identified as particularly reactive and influential in accelerating acid production. Measured pH values are predominantly acidic (<6), indicating a high AMD potential that poses a serious threat to the Sungai Seluang system through acidification and metal mobilization. These findings demonstrate that lithology and micro-scale mineralogical characteristics play a decisive role in controlling AMD formation and its environmental consequences. The integrated approach adopted in this study provides a robust framework for early AMD source identification and supports the development of more effective geochemical management strategies aimed at protecting water quality and minimizing long-term environmental degradation in coal-mining areas.
B-Li-Cl Trend Line Can Distinguish The Dominance of Hydrothermal Water and Surface Water: A Case Study of Geothermal in Tengchong, Southwestern China
The Boron-Lithium-Chlorine (B-Li-Cl) trend line serves as a valuable geochemical tool for distinguishing the dominance of hydrothermal water and surface water in geothermal environments. In this study, we applied the B-Li-Cl trend line to analyze the geochemical characteristics of water samples from the Tengchong geothermal area in Southwestern China. Our results reveal distinct patterns that differentiate hydrothermal water from surface water, offering insights into the geochemical processes and interactions occurring in this region. The lower Cl/Li and Cl/B ratio values of meteoric water with a Cl concentration of <10 (mg/L) indicate that mixing occurs not only when migrating upwards, but also inwards. The absence of a trend formed at a Cl concentration of <10 (mg/L) proves that the Cl concentration can be diluted by mixing with meteoric water. Meanwhile, the concentrations of Li > 100 (µg/L) and B > 1 (mg/L) form a downward trend from magmatic water, while the concentration of B < 1 (mg/L) has a downward trend from meteoric water. Both interpretations confirm that the behaviour of Lithium and Boron towards temperature changes has the same tendency, which can illustrate the origin of hydrothermal water formation.
Copyright (c) 2025 Foundae (Foundation of Advanced Education) https://creativecommons.org/licenses/by-sa/4.0/
Production and Characterization of Bioethanol from Tobacco Stalks via Acid Hydrolysis and Fermentation
The increasing demand for energy and the environmental impacts of fossil fuel consumption have encouraged the development of renewable and sustainable energy sources. Bioethanol derived from lignocellulosic biomass represents a promising alternative fuel due to its renewability and reduced competition with food resources. This study investigates the potential of tobacco stalks, an underutilized agricultural residue, as a feedstock for bioethanol production through acid hydrolysis and fermentation processes. Dried tobacco stalks were hydrolyzed using 1 M sulfuric acid at 110 °C for 3 h to produce fermentable sugars, followed by batch fermentation using Saccharomyces cerevisiae with variations in yeast concentration and fermentation time. The fermentation products were purified by simple distillation and characterized using refractometry, density measurement, GC–MS, and bomb calorimetry. The hydrolysis process yielded a sugar concentration of 7.6%. Refractometric analysis indicated ethanol concentrations in the range of 64–68% (v/v), while density measurements suggested lower effective ethanol purity due to residual water and non-ethanol components. GC–MS analysis confirmed ethanol as the dominant compound, with relative contents ranging from approximately 52% to 73%, accompanied by acetic acid and minor volatile by-products. The calorific value of the produced bioethanol ranged from 4,825 to 4,983 kcal/kg and increased with fermentation time. The results demonstrate that tobacco stalks have considerable potential as a lignocellulosic feedstock for bioethanol production, although further process optimization is required to enhance ethanol purity and overall conversion efficiency.
Environmental Sustainable Utilization of Agricultural Waste–Based Sterilization for White Oyster Mushroom Cultivation: An FTIR Study of Optical Vibrational Properties
This study investigates the environmentally sustainable use of agricultural waste–based sterilization in white oyster mushroom (Pleurotus ostreatus) cultivation and its influence on mycelial optical vibrational properties. A small-scale industrial rice husk furnace was employed as an eco-friendly and low-cost sterilization system, providing an alternative to conventional fossil fuel–based energy sources. Potato Dextrose Agar (PDA) was used as the growth medium, while different sterilization levels were applied to obtain uncontaminated media and high-quality mycelial growth. Three sterilization levels were systematically analyzed using Fourier Transform Infrared (FTIR) spectroscopy to evaluate optical behavior at various cultivation stages. The optical properties of the mycelium were assessed through Longitudinal Optical (LO) and Transverse Optical (TO) vibrational modes derived from FTIR spectra. The results indicate that increasing the sterilization level leads to a consistent shift of both LO and TO modes toward higher wavenumbers, reflecting changes in molecular bonding and structural characteristics of the mycelium. Furthermore, longer boiling durations at 102 °C using the rice husk furnace resulted in higher transmittance values, attributed to the partial evaporation or reduction of certain organic compounds within the mycelium. Comparative analysis among cultivation stages shows that the planting spawn (F2) exhibits lower transmittance than the spreading spawn (F1), while the pure culture (F0) demonstrates the highest transmittance. These differences are closely related to variations in mycelial density, with F2 having the greatest mass per unit volume. Overall, the findings confirm that agricultural waste–based sterilization supports environmentally sustainable mushroom cultivation while significantly affecting the optical and structural properties of mycelium.
Building Trust for Sustainable Land Rehabilitation: Community Involvement and Management Post-Mining
Post-mining land use sustainability is critical for mitigating environmental degradation and ensuring long-term community benefits. This study identifies gaps in participation and highlights innovative strategies for addressing trust deficits in land management. Through advanced statistical methods such as Structural Equation Modeling (SEM), the research pinpoints the pivotal role of transparency and trust-building in driving community engagement. Additionally, the study explores the implications of global best practices in land rehabilitation and how these can be adapted to local contexts like Pongkor, Bogor Regency. By integrating insights from international case studies, this analysis underscores the need for tailored community outreach programs that align with cultural and socioeconomic dynamics. The findings contribute to broader discussions on sustainable practices and provide actionable recommendations for policymakers to enhance the effectiveness of post-mining rehabilitation efforts.
Fabrication and Characterization of Environmentally Friendly Bioplastic Film Based on Chitosan from Cassava Peel Starch
Bioplastics are renewable materials capable of natural degradation and can be synthesized using bio-organic compounds such as cellulose, chitosan, carboxymethyl cellulose (CMC), and glycerol. Cassava peels, an agricultural byproduct, are a rich source of starch and cellulose, making them a promising raw material for bioplastic production. This study aims to fabricate and characterize chitosan-based bioplastic films using cassava peel starch, with a focus on optimizing their mechanical and biodegradation properties. Bioplastic films were prepared by combining cassava peel starch, chitosan, CMC, and glycerol, with chitosan concentrations varied at 45% and 75%. The films were evaluated for surface morphology using Scanning Electron Microscopy (SEM), tensile strength, elongation at break, water absorption capacity, and biodegradability. SEM analysis revealed that chitosan concentration significantly influenced the film morphology, which in turn affected mechanical and swelling properties. The highest tensile strength (0.07 MPa) and elongation (22.5%) were observed in films with 75% chitosan. Water absorption peaked at 93.32% for the same formulation. Biodegradability tests showed complete degradation (100%) within 12 days for films with 45% chitosan. These findings demonstrate that cassava peel starch combined with chitosan can produce biodegradable films with tunable properties, offering a sustainable alternative for packaging and other applications.
Analysis of Subsurface Faults Using 3D Gravity Method Based On Satellite Image Data: Insights into Indo-Australian and Eurasian Plate Subduction in the Formation of An Accretionary Prism
This geophysical study employs the gravity method to analyze subsurface fault structures in the Simeulue Island region. The area lies within an active tectonic zone where the Indo-Australian Plate subducts beneath the Eurasian Plate, making it a critical site for understanding subduction dynamics and accretionary prism formation. Secondary gravity and topographic data were acquired from TOPEX satellite imagery. The primary objective is to identify gravity anomalies and delineate subsurface geological features such as faults, folds, and fractures based on variations in the Earth's gravitational field caused by density contrasts between rock units. The gravity method is particularly effective due to its sensitivity to such density differences. Qualitative interpretation was conducted using Surfer 16, while quantitative modeling utilized Oasis Montaj. Results reveal high Bouguer anomaly values in the southwest, corresponding to the plate convergence zone, and low anomaly values extending from the southeast to northwest, associated with the accretionary prism. The 2D model illustrates the subduction of oceanic crust with a density of 3.43 g/cm³ beneath continental crust with a density of 2.67 g/cm³. The 3D model further reveals that subduction becomes evident at a depth of approximately 16.11 km, with the crustal thickness in the accretionary prism zone reaching around 19.92 km. The 3D approach provides a more comprehensive spatial visualization of the subduction geometry and density distribution, offering insights that surpass conventional 2D analysis. These findings contribute to a deeper understanding of regional geodynamics and may serve as a reference for seismotectonic studies and disaster mitigation efforts in the surrounding area.
Integrated Flood Risk and Embankment Stability Modeling in the Comoro River, Timor-Leste using HEC-RAS and GIS
Dili, the capital city of Timor-Leste, is increasingly vulnerable to flooding due to its geomorphological characteristics and rapid urban expansion. The Comoro River, the largest of several rivers traversing the city, has experienced multiple significant flood events in recent years most notably in March 2020, April 2021, and February 2022 resulting in severe damage to infrastructure and disruption to local communities. Urban development has led to watershed degradation, sediment accumulation, reduced channel capacity, and embankment overtopping, exacerbating flood risks in densely populated areas. This study aims to assess flood risk and evaluate embankment resilience using an integrated modeling approach. Design flood discharge was estimated using the Log Pearson Type III distribution and the Nakayasu synthetic unit hydrograph, with validation through Chi-Square and Kolmogorov-Smirnov goodness-of-fit tests. Hydraulic simulations were conducted using HEC-RAS 6.1.0 programme, while flood inundation mapping was performed with ArcGIS 10.3 to identify critical flood-prone zones and guide mitigation strategies. Results indicate a peak discharge of 192.141 m³/s for a 25-year return period flood. Mitigation measures proposed include embankment construction and river normalization at vulnerable cross-sections. HEC-RAS simulations demonstrate that these interventions significantly reduce flood inundation. The embankment slope stability factor was calculated at 7.55, indicating a high level of structural safety. The estimated cost for implementing these flood control measures is USD 571,366.87. This study provides a replicable framework for flood hazard modeling and infrastructure planning in urban river systems, contributing to climate-resilient development and evidence-based decision-making in Southeast Asian contexts.
Copyright (c) 2025 Kris Minaryo, Hanie Teki Tjendani, Esti Wulandari, Rahmad Junaidi, Andiyan Andiyan, Shreeniwas Omanwar https://creativecommons.org/licenses/by-sa/4.0/
Hydrological Assessment and Irrigation Water Optimization Based on Cropping Patterns in the Way Bungur Irrigation Area, Indonesia
Efficient water management is essential for sustaining agricultural productivity, particularly in regions supported by technical irrigation systems such as the Way Bungur Irrigation Area in Pringsewu Regency, Indonesia. Although water availability in this region is generally adequate, its utilization remains inefficient due to cropping schedules that are not aligned with seasonal hydrological conditions, especially during the dry season. This study evaluates irrigation water requirements based on crop types and the official Cropping Pattern Plan (SK RTT), and compares them with water availability estimated using the F.J. Mock hydrological model. Input data include rainfall records, climatological parameters, river discharge, and field measurements. Crop water requirements were calculated using the FAO Penman–Monteith method, while water availability was assessed through dependable flow analysis. Results indicate that water availability in the Way Bungur watershed generally exceeds irrigation demand across three cropping seasons. However, temporal mismatches between planting schedules and water surplus or deficit periods lead to suboptimal water use. These findings highlight the importance of integrating annual water balance analysis into cropping pattern planning to enhance allocation efficiency, reduce risk, and promote sustainable agricultural development.
Water management in a circular economy and resilience context
Assessing Anthropogenic Pressure through Biomonitoring: Aquatic Biota as Indicators of Water Quality in an Urban Lake
Urban areas in Jakarta face significant pressure on clean water resources due to increasing population and anthropogenic activities. This research aims to conduct biomonitoring of the Situ Bambon Ciracas lake ecosystem, East Jakarta, by analyzing water quality and the community structure of macrozoobenthos, phytoplankton, and zooplankton as bioindicators. A descriptive quantitative method was used, involving measurements of water physical-chemical parameters (TDS, TSS, pH, BOD, COD, Total-P) and identification of aquatic biota. The results indicate that the water quality of Situ Bambon Ciracas lake is lightly to moderately polluted, dominated by organic compounds. BOD (5−34.67 mg/L) and COD (17.05−193.56 mg/L) values consistently exceeded the Class 3 water quality standards, and TDS showed an increasing trend. The biota community structure reflects these conditions: macrozoobenthos showed moderate diversity (H′=1.2, E=0.6). Phytoplankton (H′=3.12−3.2, E=0.74−0.76) and zooplankton (H′=2.11−2.16, E=0.76−1.95) showed high diversity and evenness, but were dominated by bioindicator species tolerant to organic pollution (e.g., Oscillatoria sp., Nitzschia sp., Colpoda sp., Closterium sp.). The positive correlation between the abundance of these bioindicator species and high BOD and COD confirms organic waste as the main driver of ecological change. In conclusion, the Situ Bambon Ciracas lake ecosystem is under significant anthropogenic pressure. The dominance of pollution-tolerant species, despite existing diversity, highlights the urgency of comprehensive management and restoration efforts to maintain the sustainability of this urban lake.
Water Balance Analysis for Irrigation Sustainability in the Way Kelutum Irrigation Area
The sustainability of irrigated agriculture in regions with pronounced seasonal rainfall variability depends on maintaining a balance between water availability and crop water demand. This study evaluates the irrigation water balance in the Way Kelutum Irrigation Area, Pringsewu Regency, Lampung, Indonesia, through a semi-monthly analysis integrating crop water requirements and dependable river discharge. Crop water demand was estimated using the Penman–Monteith method, while dependable discharge at an 80% reliability level was calculated using the F.J. Mock model based on rainfall, climatological data, and watershed characteristics. The results indicate that effective rainfall contributes substantially to meeting crop water requirements during the early rainy season, whereas irrigation supply becomes the primary source of water during the dry season. The dependable discharge of the Way Kelutum River varies between 0.10 and 1.40 m³/s throughout the year. Semi monthly water balance analysis shows that available water resources are sufficient to support two rice-growing seasons over an irrigated area of 42.04 ha, while water deficits occur for secondary crops during the peak dry period. By emphasising intra-seasonal water balance dynamics rather than annual-scale averages, this study provides practical insights for determining operational cropping patterns in small-to-medium irrigation schemes, particularly under conditions of limited dry-season water availability.
Copyright (c) 2026 International Journal of Hydrological and Environmental for Sustainability https://creativecommons.org/licenses/by-sa/4.0/
Geochemical and Mineralogical Insights into Hydrothermal Alteration in the Beruang Kanan Non-Vulcanic Area, Central Kalimantan, Indonesia
Previous studies have revealed significant hydrothermal alterations within the Beruang Kanan Non-Volcanic Area, Central Kalimantan, Indonesia, resulting in extensive ore mineralizations. This study aims to examine the effects of hydrothermal processes on rock alteration, delineate alteration zones, and establish their relationship to metal mineralization. The research area, situated in the Tumbang Miri district of Gunung Mas regency, forms part of the Corrugated Hills Geomorphological Unit and is traversed by the Schwaner Mountains, with elevations ranging from approximately 50 to 400 meters. Stratigraphic analysis identifies three primary rock units, ordered from oldest to youngest: the Tuffaceous Sandstone Unit, the Dacitic Tuff Unit, and the Andesite Unit. Hydrothermal alterations have resulted in three distinct alteration zones sericitic, argillic, and propylitic characterized by secondary mineral assemblages. This study provides a comprehensive framework for understanding the geological and mineralization dynamics of non-volcanic hydrothermal systems in Central Kalimantan, Indonesia
Thermal Comfort and Airflow in Air-Conditioned Systems: Insights from Computational Fluid Dynamic Simulations
Air conditioning (AC) systems are vital for ensuring thermal comfort in enclosed spaces, particularly in tropical regions like Indonesia, where high temperatures and humidity can challenge human productivity and well-being. This study investigates airflow distribution patterns in air-conditioned rooms using computational fluid dynamics (CFD) simulations, specifically employing the SST k-ω turbulence model. Simulations were conducted in a 3.5 × 3.55 × 3 m closed room with varied inlet temperatures (289.15–297.15 K) and airflow velocities (2–4 m/s). Results indicate that for every 2 K increase in inlet temperature, the average room temperature rises by approximately 1.37 K. Additionally, a 0.5 m/s increment in airflow velocity leads to an average temperature increase of 0.16 K. The airflow was observed to form a dominant jet stream from the AC inlet, flowing diagonally toward the lower part of the room, creating a low-altitude recirculation zone. This phenomenon influences thermal mixing and occupant comfort significantly. Validation of the CFD model revealed its robustness, with an average temperature deviation of 328.15 K and an Nash-Sutcliffe Efficiency (NSE) score of 0.858. Furthermore, the study suggests optimizing AC placement and operation parameters to enhance energy efficiency while maintaining comfort. These findings provide actionable insights into airflow behavior in tropical environments, promoting better design practices for cooling systems, which are crucial for sustainable development and improved living conditions in tropical climates.
Airflow Air Temperature Air Velocity Computational Fluid Dynamic (CFD)
Sustainable Bioethanol Production from Carica (Carica pubescens) Peel Waste: Optimization of Acid Hydrolysis and Fermentation Time
The global energy crisis and continued reliance on fossil fuels have intensified the search for sustainable alternative energy sources, particularly biomass-derived biofuels. One promising yet underutilized resource is the peel waste of Carica pubescens, a papaya variety indigenous to the Dieng Plateau. This study investigates the potential of Carica peel waste as a bioethanol feedstock through sulfuric acid (H₂SO₄) hydrolysis and fermentation using Saccharomyces cerevisiae. To optimize sugar yield, the concentration of H₂SO₄ was varied between 0.1 M and 0.8 M, while fermentation durations were set at 96, 120, 144, and 168 hours. Results indicated that hydrolysis with 0.8 M H₂SO₄ produced the highest sugar concentration (6.8%). The most effective fermentation period was 120 hours, yielding 64% bioethanol with a density of 0.8679 g/mL, a calorific value of 4,831 kcal/kg, a flame height of 14.6 cm, and a combustion temperature of 438°C. These findings demonstrate the viability of Carica peel waste as a valuable raw material for bioethanol production. Its high efficiency and favorable fuel properties highlight its potential for integration into local renewable energy initiatives, contributing to sustainable energy development. Further studies on large-scale implementation and process optimization are recommended to maximize its industrial application.
High-Resolution Resistivity Analysis of Andesite Rock Distribution in Kulon Progo’s Mineral-Rich Terrain
This study employs integrated geophysical methods to analyze the spatial distribution and subsurface geometry of andesitic rock formations in the Mujil Hill area, Kulon Progo, Yogyakarta. Electrical resistivity imaging (ERI), using a dipole-dipole configuration, was conducted to identify high-resistivity zones (>1000 Ωm), which are interpreted as fresh andesitic intrusions. These zones are consistently found at an average depth of 10 meters, embedded within moderately resistive volcanic breccia. Near-surface layers with low resistivity values (<100 Ωm) are associated with weathered volcanic deposits or unconsolidated soil. To enhance subsurface structural interpretation, resistivity data were complemented with gravity modeling, providing a more comprehensive geological assessment. The results confirm the lateral continuity and shallow emplacement of andesite bodies, highlighting their potential as a local source of construction material. This integrated geophysical approach supports sustainable mineral resource development and aligns with the objectives of the regional economic empowerment program, contributing to the responsible utilization of local geological resources.
Characterization of Thermal Waters Origin from the Back Arc Lampung Province, Indonesia: An Evaluation of Stable Isotopes, Major Elements, and Li/Cl Ratios
This study reports chemical and isotope data from thermal water samples collected in the Natar area (back-arc Lampung province), Indonesia. Based on the geologic map, Lampung-Panjang Fault is the source of this thermal water appearance with Quaternary volcanic and metamorphic rock in the basement. It is located close to the Quaternary extinct volcano (Mount Betung) around 20 km to the southwest. Therefore, this study aims to provide information on geochemical characteristics and the origin of thermal waters in Natar's non-volcanic area. Variables such as stable isotopes, major, and Li/Cl ratios were analyzed. Furthermore, the thermal waters collected from a well in a different location have a moderate temperature ranging from 47°C to 54°C with 6.23 pH. Lithium and Chloride concentrations as well as Isotope δ18O and δD ranges from 0.02 mg/L to 0.04 mg/L, 5.19 mg/L to 46.12 mg/L, -5.26 ‰ to -2.65 ‰, and -5.26 ‰ to -2.65 ‰, respectively. The stable isotope showed that the thermal water samples have a shift value of Ã³18O similar to hydrothermal water. The result also has a positive correlation with the distribution of the Li/Cl ratio plotted close to the magmatic water. Consequently, the Natar hot springs may have formed due to the magmatic process of Mount Betung Quaternary with a lower temperature than an active volcano.
Copyright (c) 2023 Foundae (Foundation of Advanced Education) https://creativecommons.org/licenses/by-sa/4.0/
Analysis of Reservoir Temperature Estimation using Major Elements in Sulili Geothermal Field, South Sulawesi, Indonesia: Implications for Geothermal Energy Forecasts
Geothermal is a natural resource energy in the form of hot water or steam that forms in reservoirs within the earth through the heating of subsurface water by hot igneous rocks. Based on field surveys, the Sulili area shows characteristics of geothermal energy in the form of hot springs. The research aims to use the Na-K geothermometer to find out the temperature of the geothermal reservoir below the ground and the Na-K-Mg geothermometer to look into the type of fluid that is in the geothermal reservoir. The research employs the geochemical analysis method in conjunction with the Na-K geothermometer method. Reservoir subsurface temperature is estimated at EPU station 1 at 326.504°C, EPU station 2 at 473.369°C, and station EPU 3 at 456.508°C. According to the results, the hot springs at the three sites are chlorides with temperatures below ground that are part of the high-temperature geothermal system and are >225°C. The hot spring is in the immature water group. Based on the calculation, the Sulili Geothermal Field with an average reservoir temperature of 418°C is approximately 68.33 MWh. This is a simplified calculation, and actual energy output can vary based on several factors, including the specific characteristics of the geothermal reservoir and the efficiency of the power plant.
A Comparative Study of Coal Quality: Insights from Actual and Proximate Analysis Models
Coal quality plays a pivotal role in determining its efficiency and environmental impact when used as a fuel source. This study aims to conduct a comprehensive comparison of coal quality by employing two analytical approaches: Actual Analysis and Proximate Analysis. Actual Analysis evaluates the fundamental characteristics of coal, including carbon content, hydrogen, sulfur, and trace elements. In contrast, Proximate Analysis focuses on determining moisture content (TM), ash (ASH), total sulphur (TS), and calorific velocity (CV). By integrating the insights gained from both models. The difference in coal quality is caused by the following factors, coal cleaning, coal getting, drainage making, and human error. Difference between actual coal quality parameters and model coal quality in January – March 2024; moisture content (TM) (0.2 - 1.59 % ar), ash (ASH) (0.76-5.01 % adb), total sulphur (TS) (0.1-0.6 % adb), calorific velocity (CV) ar (4-145 kcal/kg). In contrast, Proximate Analysis focuses on determining moisture content, volatile matter, ash, and fixed carbon. By integrating the insights gained from both models, this paper elucidates the strengths and limitations of each method, highlighting their relevance in industrial applications and environmental considerations. The findings provide a nuanced understanding of coal quality, paving the way for more informed decisions in its utilization and management. This study emphasizes the importance of selecting the appropriate analytical method to achieve optimal performance and sustainability in coal utilization.