International Journal of Eco-Innovation in Science and Engineering (IJEISE)

Sediment Characteristics and Impacts at Tugu Dam, Trenggalek, East Java

2025-08-19T08:40:45+00:00

Dam infrastructure plays a crucial role in the development and management of water resources. The Tugu Dam was constructed in 2014 and completed in 2021. High erosion rates in the Tugu Dam watershed area are a primary factor contributing to sedimentation within the reservoir. It is inevitable that river inflows carry sediment loads into the dam, which subsequently settle and cause reservoir siltation. This sedimentation-induced reduction in storage capacity can significantly impact the operational performance of the Tugu Dam. The objective of this final project is to determine the amount of sedimentation deposited, analyze the sedimentation patterns, and learn how to perform sediment modeling using the HEC-RAS application. This study employs HEC-RAS version 6.0, a software developed by the US Army Corps of Engineers, widely used for hydrologic analyses including river flow, flood modeling, dam breach simulations, and sediment transport analysis. The data utilized are secondary data obtained from the Brantas River Basin Organization (BBWS Brantas). Based on the calculations and analyses conducted in this study, sediment transport modeling requires three primary data inputs: geometric data, hydrologic data, and sediment data. The modeling results indicate a decrease in dead storage capacity from an initial 1,040,000 m³ to 832,516.85 m³ over a 33-year period, representing a reduction of 19.95%. Additionally, the effective storage capacity slightly decreased from 8,667,000 m³ to 8,666,000.01 m³, corresponding to a minimal reduction of approximately 0.0115%. The sediment deposition pattern identified in the Tugu Dam reservoir through HEC-RAS modeling is uniform, with a total sediment accumulation volume of 207,483.14 m³.

Extraction and Characterization of Crude Arabinoxylan from Breadfruit (Artocarpus altilis)

2025-09-22T08:58:48+00:00

Arabinoxylan is a dietary fiber belonging to the non-starch polysaccharide family and is known for its health-promoting properties, such as antioxidant and immunomodulatory effects. However, the extraction efficiency and structural integrity of arabinoxylan are strongly influenced by processing conditions, particularly temperature. Breadfruit (Artocarpus altilis) is a potential local source of arabinoxylan, containing up to 2.49% fiber, yet its extraction characteristics have not been widely investigated. Therefore, this study aimed to determine the effect of different extraction temperatures on the characteristics of crude arabinoxylan extracted from breadfruit using water as the solvent. A completely randomized design with one factor, extraction temperature (40°C, 45°C, and 50°C), was used with a 24-hour extraction period. The crude arabinoxylan obtained was characterized for yield, moisture content, ash content, starch content, and monosaccharide profile using HPLC. The results showed that extraction temperature significantly affected the physicochemical characteristics of crude arabinoxylan. The highest yield (4.1%) was obtained at 50°C, while the lowest starch and ash content occurred at 45°C. HPLC analysis revealed that arabinose was present in all treatments, whereas xylose was not detected; the highest arabinose concentration (1.04%) was found at 40°C. These findings indicate that lower extraction temperatures better preserve arabinose content, while higher temperatures enhance yield, suggesting that extraction temperature plays a crucial role in optimizing both purity and quantity of arabinoxylan from breadfruit.

Recovery of Manganese Dioxide (MnO₂) from Dry Cell Battery Waste via Microwave-Assisted Hydrometallurgy: A Mass Balance Study

2026-02-27T06:20:27+00:00

The increasing accumulation of dry cell battery waste necessitates efficient recovery methods for valuable materials like manganese dioxide (MnO₂). This study investigates the mass balance and recovery efficiency of MnO₂ from dry cell battery waste using a microwave-assisted hydrometallurgical process. The procedure consisted of three primary stages: material preparation, microwave-assisted acid leaching, and oxidative precipitation. Leaching was conducted using 100 mL of 1.2 M H₂SO₄ and 2% H₂O₂ at 80°C for 50 minutes, achieving an MnO₂ leaching recovery yield of 96.76% by converting manganese and zinc into soluble manganese sulpahte (MnSO₄) and zinc sulphate (ZnSO₄). Subsequent oxidative precipitation utilizing 0.25 M potassium permanganate (KMnO₄) successfully converted dissolved Mn²⁺ into solid MnO₂ with purity 96.57%, while zinc remained in the filtrate as soluble salts. The comprehensive mass balance analysis across all stages demonstrated minimal material loss, confirming the high efficiency and selectivity of the process toward manganese recovery. These findings indicate that integrating microwave-assisted hydrometallurgy with oxidative precipitation is an effective and sustainable approach for recovering high-purity MnO₂ from dry cell battery waste.

Potential Application of Microwave-assisted Methods for Metal Extraction from Fly Ash: Review

2026-02-06T02:34:52+00:00

Fly ash is a solid waste product resulting from the combustion of coal or biomass that contains various valuable metals such as Si, Al, Fe, Ca, and Mg. The utilization of fly ash as a source of secondary metals is considered important from both economic and environmental perspectives. Various extraction methods have been applied, including conventional acid leaching, biogenic leaching, alkali leaching, and hydrometallurgy; however, each has limitations regarding efficiency and environmental impact. This study examines the application of a microwave-assisted extraction method that utilizes rapid and uniform heating to enhance the metal dissolution process. Comparative results from various sources indicate that extraction via the microwave method yields higher metal recovery than other methods, such as conventional hydrometallurgical, biogenic, and pyrometallurgical approaches, particularly for aluminium compounds, with recoveries of around 95-96%. The advantages of this method are associated with lower solvent consumption, shorter processing times, higher energy efficiency, and greater environmental friendliness. Thus, the microwave-assisted method is the most effective and efficient technique for metal extraction from fly ash, regardless of the need for further research on industrial-scale applications.

Synthesis of Ca–Si–K–P Composite from Carbide Lime and Rice Husk using Precipitation Method

2026-04-07T01:53:59+00:00

The development of compositionally multinutrient composite offers a promising pathway to overcome the limitations of conventional fertilizer systems that predominantly focus on N–P–K. In this study, a Ca–Si–K–P composite was synthesized via a controlled precipitation route utilizing carbide lime waste and rice husk ash as sustainable precursors. The effects of precipitation pH (7–11) and calcination temperature (600–1000 °C) on oxide composition and yield were systematically investigated. The results demonstrate that increasing pH from 7 to 11 significantly enhances CaO content, reaching its optimum at pH 9–11, while SiO₂ content decreases by up to ~20–30% under highly alkaline conditions due to increased silicate solubility. The K₂O fraction remains relatively low (<10 wt%) across all conditions, primarily due to dissolution losses and thermal volatilization, whereas P₂O₅ exhibits minor variation (<5 wt%) within the studied pH range. Increasing calcination temperature from 600 to 1000 °C leads to a relative increase in SiO₂ content by approximately 10–15%, accompanied by a decrease in CaO fraction and partial loss of K₂O and P₂O₅ at temperatures ≥900 °C. The product yield exceeds 100% due to KOH addition during pH adjustment and shows a decreasing trend with temperature, dropping by approximately 10–20% from 600 to 1000 °C as a result of dehydration and decarbonation processes. Overall, alkaline precipitation conditions (pH 9–11) combined with moderate calcination temperatures (700–800 °C) provide the most favorable balance between compositional homogeneity and yield. These findings highlight the potential of waste-derived resources and precipitation engineering in producing composition controlled Ca–Si–K–P composites, offering significant prospects for application as advanced multinutrient fertilizer precursors.

Biohydrogen Production from Organic Waste by Fermentation : A Review

2026-04-08T05:40:45+00:00

Biohydrogen production from organic waste represents a promising renewable energy alternative that can contribute to reducing dependence on fossil fuels. Biohydrogen is an environmentally friendly energy carrier, as it produces no carbon emissions during utilization and possesses a high energy content. Fermentation-based processes have been extensively studied due to their ability to operate without light, under relatively mild temperature and pressure conditions, and to utilize a wide variety of organic wastes as substrates. The present review article deals with the production of biohydrogen from organic waste by different fermentation methods, emphasizing the characteristics of the feedstock and the effect of the operating parameters on the efficiency of the process. The literature review demonstrated that dark fermentation is a promising sustainable route for biohydrogen production. But the relatively low hydrogen yields and the need for strict operating conditions mean that further optimization is needed to apply this technology effectively on an industrial scale, particularly in terms of improving the yield efficiency and reducing operational expenses. This study seeks to identify and compare the operating conditions reported in the literature that correlate with higher biohydrogen yield.

Effect of Washed Process Fermentation on Specialty Coffee Flavor

2026-05-13T01:53:10+00:00

Specialty coffee represents a high-value agricultural commodity whose overall quality is profoundly influenced by post-harvest processing parameters, with fermentation constituting a critical determinant in the development of its distinctive sensory profile. Among various processing techniques, the washed process, characterized by controlled wet fermentation has been widely recognized for its capacity to generate unique and refined flavor attributes. The present study sought to investigate the influence of differential fermentation durations within the washed process framework on the sensory characteristics of Arabica specialty coffee. A sensory evaluation was conducted using the standardized cupping test in accordance with Specialty Coffee Association (SCA) protocols, employing trained panelists to assess multiple flavor dimensions. Analytical observations indicated discernible variations in sensory attributes as a function of fermentation duration, thereby reinforcing the necessity of stringent quality control measures with particular emphasis on fermentation management. These insights highlight the pivotal role of optimizing fermentation time in enhancing flavor complexity while mitigating the emergence of undesirable off-flavors. It is further recommended that subsequent research endeavors explore the targeted application of defined microbial starters in conjunction with the systematic optimization of fermentation parameters, in order to advance both the consistency and the sensory excellence of specialty coffee production.