Jurnal Presipitasi: Media Komunikasi dan Pengembangan Teknik Lingkungan
Jurnal Presipitasi (P-ISSN: 1907-817X and E-ISSN: 2550-0023) is a peer-reviewed academic journal published by the Environmental Engineering Departement, Faculty of Engineering, Universitas Diponegoro, Indonesia, and has been in continuous publication since 2006. The journal serves as a scholarly platform for the dissemination of original research articles and state-of-the-art review papers in the fields of Environmental Science and Environmental Engineering. The journal is nationally accredited under the National Journal Accreditation system (ARJUNA), managed by the Ministry of Research and Technology/National Research and Innovation Agency (RISTEK–BRIN), and is currently ranked in the Second Grade (SINTA 2). The official short title of the journal is J. Presipitasi. Scholars and practitioners who are interested in contributing to the journal’s academic community as reviewers or editors are kindly invited to visit the following link for further information. Publications schedule: March, July, November | more info Language: English Article Processing Charges: please see the following link | more info Indexing: DOAJ, SINTA, Google Scholar, etc. | more info Ready to submit your manuscript? Please follow [Author Guidelines] Contact: presipitasi@live.undip.ac.id For Hardcopy Order: more info
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Microplastics Removal Strategies in Aquatic Environments
Microplastics (MPs) have been globally detected in aquatic environments. The abundance of MPs contributed to the negative effects on aquatic ecosystems. Thus, it’s critical to create effective solutions for removing MPs from water. In this review, we compared several methods, including physical, physicochemical, and biological approaches, towards membrane filtration. The physical filtration technology is the simplest way in comparison with other methods. However, the removal ability of physical filtration against smaller MPs than 20 𝜇m becomes a crucial concern. Then, the other option is an adsorption method. Although the adsorption option is an inexpensive method, the undesirable aspect during adsorbent usage may not be environmentally friendly in aquatic systems. The similar problem is also demonstrated by chemical approaches in terms of coagulation and electrocoagulation treatment. Consequently, the biological methods were found to be less toxic to the environment. Even though it provides safe conditions to the environment, the biological approach needs a long time to degrade MPs. To overcome their disadvantages, the membrane technology offers efficient removal of MPs and no addition of chemical usage. However, the main point to pay attention to is that each technology has benefits and drawbacks. Therefore, the application of multiple technologies for MPs removal is considered.
Copyright 2025 Jurnal Presipitasi : Media Komunikasi dan Pengembangan Teknik Lingkungan http://creativecommons.org/licenses/by-nc-sa/4.0
Key Factors in Improving the Sustainable Performance of Urban Drinking Water Services
Water is a basic element for human survival, yet although 71% of the Earth's surface consists of water, only 1% of it is accessible to humans. Climate change, urbanization, and environmental issues are challenges experienced by the efforts of drinking water services in urban areas. In addition to providing sufficient drinking water, drinking water services must also pay attention to energy use and carbon emissions. This study aims to determine the factors that impact the sustainable performance of drinking water services in urban areas. The research method was conducted using bibliometric analysis. The analysis was conducted on 50 reputable articles with a publication period of 2013-2023, with the keywords urban water and municipal water. According to previous research, the water supply system in urban areas can be divided into three sub-systems: raw water, water treatment, and distribution. If associated with sustainability, the factors can be divided into economic factors, such as affordability, continuity, and quantity. Environment: pollution and carbon emissions. Social: accessibility and customer behavior. Most previous studies have focused only on economic aspects, further studies are needed to integrate all these factors into a performance measurement system to help decision-makers align strategic targets into operation level activities.
Sustainable Valorization of Used Biochar for Hexavalent Chromium Removal from Wastewater and Soil Fertility Enhancement
Environmental pollution from wastewater and soil contamination remains a critical global concern, with current treatment methods often facing limitations in scalability, cost, or environmental safety. Biochar, a carbon-rich material derived from biomass pyrolysis, has emerged as a sustainable adsorbent for heavy metals and organic pollutants. While its use in environmental remediation is well-established, the fate and reuse of spent biochar have received limited attention. This comprehensive review explores the untapped potential of used biochar, particularly for the removal of hexavalent chromium (Cr(VI)) from wastewater and its role in enhancing soil fertility. We critically analyze current practices, mechanisms of Cr(VI) removal using spent biochar, regeneration techniques, and field applications, while highlighting circular economy frameworks that promote resource efficiency. The study integrates empirical evidence from recent case studies and offers policy recommendations to support large-scale implementation. This work is the first to provide an integrative review of the reuse of spent biochar with a dual focus on wastewater treatment and soil enhancement, underpinned by a circular economy perspective. It addresses critical research gaps by evaluating regeneration techniques, post-use functionality, and practical field applications, thereby positioning spent biochar as a viable, low-cost, and eco-friendly alternative in environmental management systems.
Flood Hazard Mapping via High-Resolution Imagery
Urban flooding in low-lying coastal zones like Way Lunik, Bandar Lampung, presents a growing challenge driven by rapid land use change, degraded infrastructure, and limited hydrological planning. This study combines high-resolution UAV-derived Digital Surface Models (DSM), national elevation data (DEMNAS), satellite imagery, and field-based drainage surveys to analyze flood risk in the Way Lunik watershed. Hydrological modeling shows that the watershed acts as a terminal catchment with low slopes and only two main discharge points, making it prone to runoff accumulation and tidal backflow. Significant mismatches between modeled and observed drainage patterns stem from blocked channels, informal settlements, and outdated infrastructure. Land cover analysis (2017–2023) reveals substantial growth in impervious surfaces, especially over former green or agricultural areas, increasing runoff and decreasing infiltration. Field surveys confirm drainage blind spots, unplanned flow paths, and encroached outlets in industrial and residential zones. The study also maps building types and clusters of flood-prone areas, often overlapping with marginalized neighborhoods and public facilities. By integrating elevation data, UAV imagery, and ground mapping, this research provides a spatially detailed assessment of urban flood hazards, emphasizing the importance of watershed-scale planning, infrastructure renewal, and the role of UAVs in adaptive flood risk management.
Analysis of Soil Fertility and Sustainability of Shallot Intensive Farming
Larangan District is one of the shallot-producing areas that the government prioritizes for agricultural intensification. The high intensity of agriculture in Larangan District causes soil fertility and sustainability disparities. This research evaluates soil fertility and the sustainability of shallot farming intensification activities in Larangan District, Brebes Regency. Soil fertility evaluation used two different approaches: Base Cation Saturation Ratio (BCSR), which referred to Koppitke & Menzies research in 2007 and assessment through a combination of soil chemical properties, as referred to Soil Research Center of Indonesia. Sustainability analysis was carried out using the Rapid Appraisal for Farming (RAP-Farm) approach with a multi-aspect sustainability analysis method, with a total of 6 aspects (ecological, economic, social, institutional, technological, and logistics, and infrastructure) with 36 factors. The results of the research show that Larangan District has a moderate soil fertility status, with a nutrient unbalance from cation ratio analysis. Sustainability status shows a less sustainable status with aspects that have values below the limit, namely ecology, economics, and technology.
The Spatial Distribution of Petroleum Hydrocarbon Contamination in Groundwater Around Fuel Storage Tank
Groundwater is vital for domestic, agricultural, and industrial use; however, previous studies have indicated that its quality often fails to meet drinking water standards. The sources of groundwater contaminants can be from domestic, industrial, saltwater intrusion, surface waste ponds, pipelines, mine pits, underground storage tanks, waste pits, etc. This research investigates the spatial distribution of Total Petroleum Hydrocarbons (TPH) contamination in groundwater surrounding fuel storage tanks, using the LeGrand method to assess groundwater vulnerability based on five physical environmental parameters. The study employs a quantitative approach, incorporating primary data from well measurements and secondary data from geological and land use maps. The results reveal that shallow groundwater levels significantly increase vulnerability to contamination, while the type of soil and aquifer permeability also play critical roles in contaminant transport dynamics. In the second research location, the analysis focuses on benzene contamination, with low concentrations below 0.02 ppb. Despite the low levels detected, the potential for contamination remains a concern due to the proximity of the gas station to residential areas. Statistical correlation analysis demonstrates a significant inverse relationship between TPH concentrations and vulnerability scores. The study underscores the importance of preventive measures to mitigate contamination risks, involving collaboration among stakeholders.
Sustainable Strategies to Reduce Water Pollution from Domestic Wastewater Discharge
Urban rivers are increasingly threatened by pollution from domestic and industrial waste, leading to water quality degradation. The Pampang River in Makassar, an essential water source for residential, agricultural, and industrial use, faces growing pressure from untreated wastewater discharge. This study evaluates the current water quality status of the Pampang River by analyzing BOD, COD, pH, and temperature, and projects future pollution trends using predictive modeling. Water samples were collected from six strategic locations along the river to represent various pollution sources. BOD and COD were analyzed according to SNI 6989.72:2009 and SNI 6989.02:2019, while pH and temperature were measured in situ. A time series regression model predicted pollution levels over the next five years. Results indicate BOD (4.426–6.439 mg/L) and COD (34.1594–43.4827 mg/L) remain within regulatory standards but show an upward trend, potentially exceeding acceptable limits in 3–4 years. pH (7.39–8.08) and temperature (31.9°C–34.4°C) reflect the impact of detergents and urban runoff, threatening biodiversity and oxygen levels. Without intervention, the river's pollution will escalate, posing ecological and health risks. Sustainable strategies, including better wastewater treatment, stricter industrial regulations, and community-based waste management, are essential for long-term water quality sustainability.
Environmental Sensitivity Analysis of Oil Spills: A Case Study in Coastal Areas
The coastal areas of Karawang Regency are at risk of being affected by oil spills originating from oil pipelines leaking. The purpose of this research is to develop an environmental sensitivity index based on the assessment standards of the National Oceanic and Atmospheric Administration, with research locations in the Karawang Coast. The results showed that the resources in the Karawang coastal area that sensitive to oil spills are shoreline type of mangrove with a total length of 34.76 km of shoreline; consist of dense mangrove forest with an area of 173.14 ha; capture fisheries with 6,832 fishermen with a production of 9,319.38 tons/year; and aquaculture involving 5,643 fishing households with a production of 43,389.45 tons/year. The environmental sensitivity index value was concluded as very sensitive for mangrove beaches, mangrove forests in all locations and aquaculture in the Tirtajaya & Batujaya areas, while the capture fisheries and the capture aquaculture were concluded as sensitive. The environmental sensitivity index maps of the three themes indicated that the socio-economic component is the most sensitive component compared to other components. Specifically, the socio-economic components that were the most sensitive to the impact of oil contamination were aquaculture and capture fisheries areas.
Land Use Change Impact on Erosion and Sedimentation in Kreo Sub-Watershed, Central Java
Ministry of Forestry has designated Kreo Sub-watershed, part of Garang Watershed, a critical area due to high erosion rates contributing to flooding in Semarang. Rapid land use changes accelerate environmental degradation, increasing erosion and sedimentation risks. This study measures erosion and sedimentation rates in Kreo Sub-watershed using SWAT (Soil and Water Assessment Tool), determines Erosion Hazard Index, and proposes erosion control solutions based on Land Rehabilitation and Soil Conservation Analysis (ARLKT) with vegetative conservation. ARLKT approach includes simulating new land use scenarios to assess their impact on erosion reduction. To ensure SWAT modelling accurately represents field conditions and not overestimate, allowing conservation recommendations based on ARLKT applied appropriately, a field-based sedimentation analysis also conducted. The study utilizes rainfall, soil type, slope, and land use data in 2019 and 2024 from satellite imagery and validated using a confusion matrix. Results indicate a shift in Erosion Hazard Index from predominantly ‘Moderate’ in 2019 to ‘High’ in 2024, underscoring urgent need for sustainable watershed management. By integrating remote sensing, field validation, and hydrological modeling, this study offers a precise, data-driven approach to erosion control. The findings serve critical reference for policymakers in developing effective conservation strategies to enhance watershed resilience.
Integrating Mining Management Strategy with Mining Area Sustainability Index
Mining in Central Bangka Regency has continued to grow since the era of regional autonomy, with the dominance of alluvial tin mining which has a major impact on the environment. The rise of unconventional mining has exacerbated land degradation, increased the area of critical environments, and reduced the quality of ecosystems. This study aims to assess the value of sustainability based on the Mining Area Sustainability Index as a basis for formulating development policies. The results show that mining activities cause a reduction in forest cover and an increase in the level of environmental criticality, especially due to unconventional mining which is difficult to control. The community has a positive perception of mining activities. The results showed a sustainability score in the less sustainable category (42.55), with the environmental aspect as the lowest aspect. To improve the sustainability score, a moderate policy scenario was chosen as the best strategy, focusing on managing environmental impacts, utilizing ex-mining land, and improving community health and safety. With the right policy approach and synergy between stakeholders, the sustainability of the mining sector in Central Bangka Regency can be achieved.
Comparing K-Means and K-Medoids for Industrial Air Pollution Analysis in Central Java
Air is a fundamental necessity for all living beings, especially humans. However, human activities whether intentional or unintentional can degrade air quality through pollution. This study compares the performance of the K-Means and K-Medoids clustering algorithms in analyzing the air pollution load from the industrial sector in Central Java in 2021. Using a quantitative approach and R Studio software, the analysis focuses on SO₂ and NO₂ pollution data obtained from the official Central Java BPS website. The results indicate that the K-Medoids algorithm with the silhouette method yields the most optimal clustering performance, with the lowest Davies-Bouldin Index (DBI) value of 0.6201437 and 10 distinct clusters. Notably, Cluster 1 comprises districts with the highest industrial air pollution burden such as Banjarnegara Regency, which recorded 14,472 industries and NO₂ and SO₂ concentrations of 20 μg/m³ and 6 μg/m³, respectively. These findings demonstrate that clustering algorithms not only help reveal spatial pollution patterns but also provide critical insights for prioritizing targeted mitigation efforts and informing environmental policy-making in industrially active regions.
Mapping the Potential of Organic Waste as a Bioconversion Substrate for Black Soldier Fly Larvae (BSFL) in Surabaya City and Sidoarjo Regency
Waste management remains a critical challenge in Indonesia, particularly in urban areas. Bioconversion using Black Soldier Fly Larvae (BSFL) presents a sustainable solution for transforming organic waste into high-value biomass rich in protein and fat. The objective of this study was to investigate the potential utilization of organic waste from markets, bakeries, and rejected products from the food and beverage (F&B) industry (specifically creamer and milk), as BSFL substrates, while mapping the existing bioconversion sites. Data was collected through interviews, observations, and field measurements. Primary data included location details, technical specifications, implementation constraints, and BSFL bioconversion sites. Waste composition was analyzed via Loud Count Analysis during a 4-day sampling period. This research was conducted in Surabaya City and its surroundings. The results indicate that market waste mostly consists of dark green vegetables (26.5%), other vegetables (64.1%), and year-round fruits (53.9%). Furthermore, the daily average rejected bread is 2.6-2.7 kg. Rejected foods and beverages include creamers, liquids, and sweetened condensed milk. The facility processes 16.16 tons/day of substrate potential, producing 44.61 tons fresh larvae and 53.85 tons frass, with profits of IDR 58.1-969.6 million. The findings demonstrate significant potential for utilizing local organic waste as BSFL substrates in the study area.
Analysis of Pore Water Pressure and Seepage During The Impounding Stage of Randugunting Dam
Piping induced by seepage poses a significant risk to the stability of Randugunting Dam, located in Blora Regency, Central Java. This study aims to assess the geological and engineering geological conditions of the study area and to analyze the behavior of pore water pressure and seepage during the impounding stage. The methodology includes geological and engineering geological mapping, as well as field monitoring using instruments such as vibrating wire piezometers, v-notch, and observation wells. These field results were then compared with Finite Element Method (FEM) analysis conducted in GeoStudio SEEP/W 2018. The pore water pressure values derived from FEM analysis were generally higher than the actual values recorded by the piezometers. Groundwater levels observed in the wells showed a strong correlation with rainfall intensity. The actual seepage discharge measured at the v-notch was 0.000118 m3/sec, whereas the FEM analysis yielded a significantly higher discharge of 0.01271 m3/sec. Despite this, the measured discharge remains within safe limits, being less than 0.016 m³/s (2% of inflow) and below 0.14 l/min/m. Nevertheless, the higher discharge indicated by FEM analysis suggests a potential risk of piping that warrants attention.
Quick Assessment of Landslide Potential Using Satellite Imagery in Bili-Bili Reservoir Catchment Area
Landslides are among the most unpredictable and destructive sediment-related disasters, especially in mountainous regions with complex terrain and limited field accessibility. In 2004, a catastrophic landslide from the Mount Bawakaraeng Caldera delivered more than 100 million cubic meters (MCM) of sediment into the Bili-Bili Reservoir, filling its dead storage and threatening its long-term functionality. his study uses Sentinel-1A satellite imagery and Differential Interferometric Synthetic Aperture Radar (DInSAR) to perform a rapid, spatially driven assessment of landslide hazards in the Bili-Bili Reservoir Catchment Area. The results reveal surface deformation of up to ±1.55 meters, concentrated in upstream zones. High-risk areas span 71.00 km², with an estimated mobilizable volume of 110.04 MCM and a potential sediment yield of 27.14 MCM per year, nearly equal to the reservoir’s dead storage. To mitigate this threat, the study proposes an integrated mitigation framework. Structural interventions include rehabilitating existing sediment control systems and constructing new sabo dams. Non-structural strategies such as slope revegetation and bioengineering are also recommended. This study demonstrates how remote sensing can identify subtle ground deformation and provides actionable insights for safeguarding critical water infrastructure in sediment-prone tropical watersheds.
Isotope Analysis of 18O and 2H: A Coastal Confined Aquifer Case Study
In 2023, groundwater quality in Semarang declined due to excessive extraction, leading to land subsidence and reduced groundwater availability. Prolonged dry seasons caused drought in ten villages across five sub-districts. This study aims to investigate geological conditions, groundwater flow patterns, and the spatial distribution of pH, TDS, hardness, electrical conductivity, and major ions (Na⁺, Ca²⁺, Cl⁻, and HCO₃⁻). Additionally, it seeks to interpret groundwater evolution through Gibbs diagram analysis and identify groundwater origins using stable isotopes (¹⁸O and ²H). The methodology involves stable isotope analysis to trace groundwater sources and evaluate d-excess values, which are linked to drought conditions and recharge mechanisms. Water chemistry analysis was performed to characterize ion concentrations, while the Gibbs diagram was used to identify the dominant geochemical processes influencing groundwater. The study area comprises claystone, marl, sandstone, volcanic breccia, and alluvium, with 60 sampling points spanning Upper and Lower Semarang. Water types identified include NaHCO₃, NaCl, CaHCO₃, MgHCO₃, and NaSO₄. NaHCO₃ was the most common, followed by NaCl and CaHCO₃. Isotope analysis revealed several points with d-excess <10 (e.g., SB-10L, SB-20L, SA-4, SA-8, SA-29), indicating groundwater recharge from modern rainfall, typically characterized by d-excess values >10.
Optimization of District Metered Areas for Reducing Non-Revenue Water
Non-revenue water (NRW) is a significant issue for water supply in Indonesia, with a national NRW rate of 33.7% in 2022 and even higher at PT Air Minum Giri Menang (PT AMGM) at 36.21%. Although District Metered Areas (DMA) were implemented in 2018, their effectiveness has been limited due to poor monitoring. This study evaluates the current DMA conditions by creating a water balance and using EPANET 2.2 software for analysis, along with formulating optimization strategies through technical, financial, and institutional assessments. The research identifies fifteen DMAs, with five being well-established. Two DMAs were chosen for optimization. Simulations showed that many pipes in these DMAs did not meet flow speed standards. Water pressure in DMA Graha Permata Kota was fully satisfied at 100%, while DMA Elit Kota Mataram achieved 84.5%. The study noted a significant NRW reduction by an average of 27.26% in the selected DMAs. The total repair cost was Rp 14,725,300, leading to additional annual revenue of Rp 128,747,424 and a positive feasibility analysis. Institutional performance was rated as "good," but an increase of 14 field staff for water loss control is needed.
Assessing Urban Carbon Sequestration Capacity under Land Use Changes
A significant amount of global greenhouse gas (GHG) emissions comes from Indonesia, largely driven by deforestation and land degradation. As a developing nation, it is also dealing with the growing pressures of urban expansion. This study assesses the distribution of carbon stock in Parepare City, South Sulawesi, Indonesia. Notably, Parepare City has not yet experienced extensive land-use transformations, retaining substantial carbon stock, which positions it as a proactive case study for preventing future carbon loss amidst ongoing urbanization. Using the InVEST Carbon Storage and Sequestration model with SPOT 7 satellite imagery (2016) and global carbon density data, the research quantifies carbon storage across various land use/land cover (LULC) types. Analysis reveals natural ecosystems, particularly mixed forests and fields, hold the highest carbon storage potential. The total estimated carbon stock in Parepare City is 1,456,909.41 Mg C. These findings emphasize the urgent need for climate-responsive land management, including forest conservation, and urban greening, to enhance local carbon sinks and support Indonesia's climate change mitigation goals. This assessment provides crucial insights for urban planners and policymakers to balance growth with ecosystem conservation for a susta00inable future.
Utilization of Tofu Wastewater as a Fish Supplement: Impact on Fish and Economic Analysis
Tofu liquid waste produced by the tofu industry in rural areas is often not reprocessed and has the potential to cause pollution if left untreated, so it is necessary to utilize tofu liquid waste which is the main idea in this research. The aim of this research is to analyze the potential for utilizing tofu liquid waste into fish supplements through the fermentation process with EM4 and Nitrobacter Plus and analyzing the economic and environmental benefits of utilizing tofu liquid waste into fish supplements. This research was conducted using an experimental method using a Completely Randomized Design (CRD) with 4 treatments and 3 replications. This research result showed that the provision of fish supplements from fermented tofu liquid waste has no significant effect on absolute weight growth, absolute length growth, specific growth rate, feed conversion ratio and survival rate. Based on the results of the economic analysis, the utilization of tofu liquid waste as a fish supplement was considered economically feasible with a Benefit Cost Ratio (BCR) of 1.285, Net Present Value (NPV) of Rp. 16,320,630,763 and Return on Investment (ROI) of 48.4%.
Utilization of Pyrolysed Tyres Scrap as Heavy Metal Adsorbent
Scrap tires continuously generated due to increasing motorized vehicle use. In Indonesia, tire waste generation reaches approximately 11 million tons annually. One processing method is pyrolysis, which converts tires into carbon, oil, and metals. However, the carbon, comprising 25–30% of tire conten, remains underutilized. This study aims to compare the performance of Tire-derived Activated Carbon (TAC) and Commercial Activated Carbon (CAC) in Pb(II) removal from wastewater. The carbon was activated using 98% H₂SO₄ (1:1 w/w) and heated in a fluidized bed reactor at 600, 650, and 700 °C for 1 hour. The optimal TAC was produced at 600 °C, with a specific surface area of 103.162 m²/g. FTIR analysis confirmed the presence of -OH, C=C, and C=O functional groups, and SEM revealed a porous structure. Adsorption tests at varying pH and initial Pb(II) concentrations showed optimum performance at pH 5 and 30 mg/L. The Langmuir model fitted the data well, indicating monolayer adsorption on a homogeneous surface. TAC achieved 96.32% removal efficiency in synthetis medium and a maximum adsorption capacity of 240.80 mg/g, significantly higher than CAC (62.68%, 151.366 mg/g). These results demonstrate the potential of TAC as an effective low-cost alternative adsorbent for heavy metal removal.
Effect of Floating Plants on Constructed Wetland Microbial Fuel Cell Treating Domestic Wastewater
Sustainable domestic wastewater treatment is urgently needed amid water scarcity and rising energy demands. The Constructed Wetland–Microbial Fuel Cell (CW-MFC) system integrates phytoremediation and bioelectricity production by electroactive microorganisms, yet previous studies rarely compared the synergistic effects of different plant species within this system, limiting its optimization. This study evaluated CW-MFC performance using three plant configurations (Pistia stratiotes, Eichhornia crassipes, and their combination) integrated with Lactobacillus plantarum at two concentrations (2×10⁸ CFU/mL and 5×10⁸ CFU/mL). The reactors were operated for 18 days under identical hydraulic conditions to assess BOD, COD, ammonia, and TSS removal efficiencies and power density generation. Results showed that Eichhornia crassipes achieved the highest pollutant removal efficiencies with COD reduction up to 82%, while the system with 2×10⁸ CFU/mL bacterial concentration produced the highest power density of approximately 1032 mW/m². Interestingly, lower bacterial concentrations yielded higher power outputs, possibly due to reduced microbial competition for electron transfer sites, enhancing electroactive bacteria performance. In conclusion, integrating Eichhornia crassipes with L. plantarum at 2×10⁸ CFU/mL optimizes both pollutant removal and bioelectricity production, confirming CW-MFC as an environmentally friendly technology with potential for sustainable wastewater treatment and renewable energy generation.
Cellulose Hydrolysis of Mask Waste Using Aspergillus niger and Eco-Friendly Microwave Pretreatment
The management of used medical mask waste has become a significant issue due to the increased volume of waste during and after the pandemic. Medical mask waste contains cellulose compounds that can be converted into derivatives such as glucose, which are then processed into bioethanol as an alternative energy source. This study aims to hydrolyse medical mask waste using cellulase enzymes from Aspergillus Niger to produce glucose. The cellulase enzyme composition was varied (5 ml, 15 ml, and 25 ml) to determine the optimal hydrolysis conditions. The glucose produced was measured using DNS reagent assay with spectrophotometry at a wavelength of 540 nm. The highest amount of glucose was obtained under optimal conditions with 25 ml of cellulase enzyme after 48 hours of hydrolysis, amounting to 88.16 ppm. Subsequently, the glucose from hydrolysis was fermented using Saccharomyces cerevisiae, and the fermentation product was analysed for ethanol concentration using GC-FID. The products of fermentation ware 0.017% ethanol concentration from mask waste fermentation. Hydrolysis is an environmentally friendly alternative solution for handling mask waste.
Sustainable Stabilization of Expansive Soil Using Rice Husk Ash, Sisal Fiber, and Lime
Expansive soils pose a major challenge to infrastructure stability due to their significant volumetric changes during wetting and drying cycles. Conventional stabilizers such as cement and lime are effective but carbon intensive. The use of agro-industrial residues combined with natural fibers presents a sustainable alternative, though it remains insufficiently investigated in tropical environments. This study examines the synergistic effects of rice husk ash (RHA), sisal fiber, and lime on the engineering behavior of expansive soil. Laboratory tests conducted in accordance with BS 1377 and ASTM standards included Atterberg limits, compaction, unconfined compressive strength (UCS), and California bearing ratio (CBR). XRF analysis confirmed the high silica content of RHA, indicating strong pozzolanic potential when blended with lime. The results showed that small percentages of RHA (12.5–17.5%) yielded the most significant improvements: plasticity index reduced from 32.6% to 12.7%, linear shrinkage decreased from 12.7% to 4.3%, the maximum UCS was 0.69 MPa, and soaked CBR increased to 48% compared with 3.8% in unstabilized soil. Beyond 17.5% RHA, strength and compaction performance declined due to excess fines and incomplete pozzolanic bonding. The findings from this study demonstrate that agro‑industrial residues and natural fibres can provide low‑carbon, locally sourced solutions for subgrade stabilization.
Performance Evaluation of Local Organism in Wastewater Treatment
Biofilters are a type of attached growth biological treatment that is considered effective among other biological treatments because of their more affordable energy operating costs, easy maintenance and operational requirements, and low environmental impact. However, there is still minimal research related to the use of local microorganisms for biological wastewater treatment. Therefore, this study aims to improve biological wastewater treatment in the cracker industry in Indramayu using local microorganisms equipped with a biofilter that utilizes natural andesite stone as a medium for microorganism growth. The best reduction in BOD anaerobically reached 79.45% and 58.91% aerobically, obtained at a flow rate of 11.11 ml/minute on the 53rd and 45th days. The increase in the BOD/COD effluent ratio from 0.22 to 0.47 during treatment indicated a decrease in biologically degradable compounds and an increase in the effectiveness of local microorganisms in reducing organic matter. Therefore, in this study, we successfully designed a biofiltration system derived from local microorganisms to effectively remove pollutants from wastewater, particularly in the cracker industry.
Optimizing Nutrient Removal in Agriculture Wastewater Using Electrocoagulation Technology
Water pollution exacerbates global water crises by reducing freshwater availability and quality. Agricultural wastewater, containing pesticides, herbicides, fertilizers, and organic matter, can contaminate water bodies if untreated. This study optimizes electrocoagulation (EC) parameters—voltage, time, and calcium concentration—to maximize nitrogen compound removal using response surface methodology (RSM). Results show a nitrate reduction of 88.37% (2.960 mg/L) at 45 V, 15 minutes, and 7 mg/L calcium, while ammonia was reduced by 99.37% (0.016 mg/L) at 30 V, 1.5 minutes, and 4.5 mg/L calcium. Calcium enhances coagulation by forming calcium hydroxide. The optimal conditions for nitrate and ammonia removal (3.709 mg/L and 1.338 mg/L) were 45 V, 15 minutes, and 5.09 mg/L calcium. EC also removed 96.73% of iron, with magnesium concentrations remaining very low (0.001 mg/L).
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Integrated Management of Scope 3 Emissions in the Steel Supply Chain
Scope 3 emissions constitute the largest and most difficult-to-manage component of the carbon footprint of the steel industry; however, they remain underexplored owing to fragmented data systems and the absence of holistic analytical approaches. This study presents an integrated, real-data-driven framework for quantifying and reducing Scope 3 emissions in a medium-scale steel supply chain in West Bengal, India. Primary operational data were collected from upstream suppliers, midstream manufacturing operations, and downstream distributors using transport logs, meter-based energy records, scrap inspection sheets, on-site walk-throughs, and structured stakeholder interviews. Environmental Value Stream Mapping (EVSM) coupled with life-cycle emission accounting was applied to six process stages (UP1, UP2, MS1, MS2, DS1, and DS2), revealing the Electric Arc Furnace (MS1) as the dominant hotspot, contributing more than 90% of the total Scope 3 emissions. Circularity metrics, namely the Scrap Quality Index (SQI) and Material Circularity Index (MCI), demonstrated that higher scrap quality and increased recycled content can significantly decrease upstream embodied emissions. A cooperative game-theoretic model quantified abatement opportunities for suppliers, the manufacturer, and distributors, showing that full coalition formation {U, M, D} generated the highest net payoff (₹1.89 million). Shapley value allocation confirmed the manufacturer as the major beneficiary (97.6%), with proportionate gains assigned to suppliers and distributors. The results highlight that collaborative governance, enhanced circularity, optimized logistics, and renewable energy integration, particularly solar-based electricity substitution, collectively offer a high-impact pathway for Scope 3 decarbonization. The proposed multi-method framework provides a transparent, equitable, and industry-ready decision support system for accelerating low-carbon transitions in the Indian steel sector.