bluuebunny/crossref_metadata_2025 huggingface dataset:
Increasing grid flexibility through ancillary services – Virtual Inertia and Fast Frequency Response implementation and testing in a PSPP with double-fed induction machines
Authors: Merbeth (né Sarodnik) R , Schönborn B , Bruns M , Jung A R
Published: December 2024

This paper describes the implementation and testing of Virtual Inertia (VI) and Fast Frequency Response (FFR) at the Frades 2 pumped storage power plant (PSPP) in Portugal to verify preceding numerical investigations and to demonstrate the potential of these ancillary services. This work was part of the activities of the EU-funded H2020 project XFLEX HYDRO. Frades 2 is equipped with two reversible Francis-type pump turbines, each coupled to a 420 MVA double-fed induction machine. The test results are compared to numerical simulations for various grid frequency scenarios in generating and pumping mode. It is shown that a single unit in VI mode can inject or extract a peak load of ±110 MW within less than 500 ms in to support the grid in the case of a sudden frequency change. In FFR mode the units can provide control energy of 40 MW in less than 2000 ms. The impact of these modes on wear and tear of the asset is analysed by means of strain gauge and shaft torque data collected during the site test campaign.
CFD Simulation of the turbine start-up of a pump-turbine with investigation of the usage of a porous domain for modelling very small guide vane angles
Authors: Zorn M , Riedelbauch S
Published: December 2024

With increasing number of transient operations, such as start and stop procedures in pump-turbines, CFD simulations of these sequences have become more important to understand the occurring flow phenomena and evaluate their impact on the pump-turbines lifetime. In the present work, the numerical setup for transient CFD simulations is discussed and a CFD simulation of a turbine start-up using a 29 million node mesh and the SBES turbulence model is carried out. The results demonstrate reasonable accuracy when comparing the overall trends with the available measurement data. However, significant underestimation of torque fluctuations as well as draft tube pressure fluctuations during the initial phase of the start-up is observed. In a subsequent study, the modelling of very small guide vane angles by a porous domain is investigated. An analytical function for the loss coefficient of the porous domain is applied up to different threshold values of the guide vane angle. A guide vane angle of 1° is identified as the best option regarding accuracy and computational effort.
Optimization of a diffuser augmented kinetic turbine with the island model
Authors: Tismer A , Riedelbauch S
Published: December 2024

An augmented kinetic turbine with a sectioned diffuser parameterized with thirty degrees of freedom is optimized using computational flow field simulations combined with the island model for parallelizing the optimization. The geometry and mesh generation is performed with an in-house design framework. The parallel optimization and the necessary database for migration are implemented in Python. For all runs an evolutionary optimization algorithm is used. Three different groups of runs with different initializations and migration strategies are investigated. The study shows good speedup values for a diverse initialization in combination with the database migration. Moreover, for several runs, a superior speedup value is observed. Additionally, the database migration handles homogeneous initializations better than commonly used strategies.
Computational fluid dynamics based transient investigation of the penstock in a hydropower plant
Authors: Khan F , Kumar A , Abbas A , Gupta D P , Binjolkar P
Published: December 2024

Water hammer is a hydraulic transient phenomenon that occurs at hydropower plants (HPP) when the discharge is rapidly decreased or closed, which can damage the HPP components, mainly penstock. Sudden Pressure rise and collapse of water columns or cavity forms due to the low pressure may cause severe damage. Understanding transient flow behavior is necessary to prevent harmful pressure fluctuations and ensure power plant safety. The present 3D computational fluid dynamics (CFD) study is carried out to predict pressure fluctuations, the occurrence of any cavitation, and water column separation at critical locations in the water conductor system from the surge tank to the turbine inlet due to low pressure caused by the closing of the hydraulic turbine guide vane valve at downstream of the penstock. The hydraulic domain of the penstock, connecting the head race tunnel to the turbine inlet, is created as per the HPP UHL-III actual water conductor system elevations, bent bifurcations, and geometric sizes. Transient CFD simulations for different load rejection conditions were performed in the Ansys CFX by modifying the Unsteady Reynolds Average Navier’s Stoke equation (URANS), incorporating the elastic effect of penstock material, and considering the variable density of the water, taking the compressibility. Transient pressure in the penstock was recorded at various locations. Further, minimum pressure inside the flow domain that falls in the no-column separation zone was also obtained.
Numerical Study of Sediment Erosion of a Francis Turbine with change in guide vane design
Authors: Kumar Sahu Rohit , Kumar Gandhi Bhupendra
Published: December 2024

The guide vane is a primary component influencing the sediment erosion of the turbines. For the current work, Francis turbine installed in the Bhilangana-III hydroelectric plant is numerically modelled to investigate the effect of guide vane design on turbine erosion. The existing guide vane profile has been modified to adopt an unsymmetrical hydrofoil shape. Two numerical models of the scaled turbine are developed using the commercial code ANSYS CFX. The first model is prepared with the existing guide vane, whereas the second model incorporates the modified guide vane. The erosion rate density is determined using a modified Grant and Tabakoff erosion model for different operating conditions and a sediment concentration range of 500 – 2500 PPM. The turbine with modified guide vanes showed a reduction in wear of guide vanes and runner by 12-23 % in comparison to that of the existing guide vanes. Further, the erosion is higher for both the part and high load conditions as compared to the best efficiency point operation.
Streamline rotodynamic pump model for two-phase flow simulation
Authors: Martel Simon , Matteo Laura , Mauger Gédéon , Bouvard Timo , Fortes-Patella Regiane
Published: December 2024

This study is concerned with the simulation of water-vapor two-phase flows in pressurized water reactors (PWR) primary pumps. The correct modeling of such flows is essential to predict the consequences of a Loss Of Coolant Accident (LOCA), an accident scenario involving a rupture in the reactor primary circuit. During such accidents, pressure loss leads to important coolant vaporization in the circuits, pumps and other system components.

A review of turbomachinery streamline models, used to represent pumps in system codes, is presented. Particular attention is paid to the model used in the CATHARE-3 system code, as its development is the motivation for the present work.

Numerical simulations were then performed using CATHARE-3 streamline pump model, currently validated for single-phase liquid flows. These simulations included test cases for pure liquid and vapor conditions, as well as one two-phase flow case, with inlet void fraction of approximately 10 %.

For pure liquid water, the agreement is good for discharge between 75% and 150% of nominal discharge. Results are satisfying up to 300% of nominal discharge for the single-phase vapor case. The two-phase results are close to experimental values around 75 and 130 % of nominal discharge.

Further work is required in order to consolidate the physical analysis and to improve and validate CATHARE-3 streamline pump model for two-phase flow conditions.
Simulation and validation of a Francis turbine load rejection procedure using OpenFOAM CFD code
Authors: Masoodi F , Goyal R
Published: December 2024

The effect of off-design operation on the health of hydraulic turbines is known to be adverse, with substantial compromise in efficiency, due to evolvement of flow instability in the draft tube and consequent pressure fluctuation. The worst-case scenario may entail resonance between developed pressure fluctuation and system natural frequencies and therefore lead to power swings, possible mechanical vibrations and machine wear and tear. Present global energy ambition, however, necessitates frequent off-design operation and as such development of accurate numerical methods to determine the anomalous flow field in the turbomachine is mandated. To this end, a load rejecting transient operation of a model high head Francis turbine from design operating point to part load condition is simulated using a hybrid turbulence modelling approach. A detailed analysis of the draft tube velocity field is carried out after validation of the test case with experimental investigations that have discerned similar results. Spatio-temporal features, such as central flow stagnation, flow separation, central flow recirculation and development of a precessing vortex core, which are embodiments of the vortex breakdown phenomenon are thoroughly analysed and discussed. Finally, the draft tube flow is visualized using streamlines on the meridional plane and tracked as the turbine transitions from design to part load operating conditions.
The influence of the free runners on the decelerated swirling flow from the draft tube cone of hydraulic turbines.
Authors: Bosioc A I , Szakal R , Tanasa C , Gherghe G , Susan-Resiga R.F.
Published: December 2024

Nowadays the renewable energy plays an key role in the development of safe and clean energy. Worldwide and especially in Europe the development of renewable energy is focused on development of new wind and solar power plants. Accordingly, these energy technologies introduce high power fluctuations in the electrical system, which are necessary to compensate by other energy sources. To compensate these power fluctuations, the electrical systems use new technologies as high-capacity electric batteries or classical technologies as hydropower. The new technologies as the batteries are used rarely, while the hydropower remain the only technology to response quickly at the electrical systems requirements. The hydropower with the hydraulic turbines has the capability to adapt faster at the electrical system requirements, but for hydraulic turbines this requirement comes with hydrodynamic consequences. Accordingly, at the outlet of the hydraulic turbines (in the conical diffuser), the hydraulic instabilities are developed (vortex rope occurs) accompanied by high pressure fluctuations. The present paper proposes adding free runner at the inlet of the conical diffuser, which rotates on an axle, with null momentum. For this purpose, have been designed and manufactured a series of four free (additional) runners (with different numbers of blades) to assess the performances of this method. Experimental investigations of unsteady pressure and velocity profiles using LDV system were performed downstream of the free runner. The velocity measurements have been performed on three survey axes, by measuring the meridian and circumferential velocity profiles. The unsteady pressure measurements were achieved at the conical diffuser wall on two levels. To better analyse the relevance of the free runners, the Fourier transform is applied on pressure signals. The results will clarify the functionality and limitations of this method for swirling flow control.
Assessment of the distributor layout influence on the vortical flow within the hydraulic turbine
Authors: Štefan David , Klement Jan , Urban Ondřej , Rudolf Pavel
Published: December 2024

The study presents analysis of conditions for the onset of vortices in the simplified geometry of the turbine domain. The simplified geometry, used for this analysis, is based on the physical model of the bladeless swirl generator developed by the research group from Brno University of Technology. This swirl generator was previously used for several studies of the spiral vortex structures generated in the diffuser part. In original geometry there are no guide vanes or other driving geometry features, thus the mixing mechanism is realized randomly, is strongly time-dependent and its behavior is linked to the swirl ratio between the axial and tangential inflows. From previous studies, the appearance of vortical structures with columnar-like shape was identified. Thus, the main aim for the current study is to assess the influence of distributor blade cascade on the onset and behavior of such vortical structures which resembles the ones observed in hydraulic turbines at low load conditions. For selected swirl ratio the distributor blades are designed specifically to influence flow with minimal effect. The distributor layouts with different number of blades are tested. The dynamics of vortices, their spatial shape and extend are examined through several post-processing tools. The results are mainly based on the CFD simulation employing a hybrid RANS+LES turbulence model.
Impact of Aerofoil Shapes on the Performance of Darrieus Vertical Axis Turbines: A Computational Study for Offshore Wind and Hydro Applications
Authors: Sharma Shubham , Singh Tomar Shivam , Dewan Anupam
Published: December 2024

An increasing energy demand, coupled with the depletion of fossil fuels and rising pollution levels, necessitates a shift towards renewable energy sources. Wind and hydro energy are a prominent renewable energy source, constituting more than 20% of the global electricity production. The objective of this study is to investigate the influence of different aerofoil shapes on the performance of Darrieus vertical axis turbine for the optimum tip speed ratio of 3.0 using Computational Fluid Dynamics (CFD) simulations. The focus is on six aerofoil profiles, namely, NACA 0012, NACA 0021, NACA 0030, S-1046, NACA 4421 and NACA 2412. Open-source CFD software OpenFOAM 9.0 is employed to perform two-dimensional unsteady Reynolds-Averaged Navier-Stokes (U-RANS) simulations using the SST k-ω turbulence model. This approach allows for the analysis of fluid characteristics around the turbine blades and an assessment of the aerodynamic performance of Darrieus turbine. The observed results provide an insight into the performance of various aerofoil profiles and help understand their strengths and shortcomings. By comparing the results, the aerofoil shape that yields the highest performance under the given conditions is identified. Additionally, the study investigates the effect of using asymmetric aerofoils on Darrieus turbine performance. This study is relevant to the optimization of the aerofoil shapes which can further enhance the efficiency and effectiveness of Darrieus turbines.
Assessment of synergistic cavitation and silt erosion performance of hydraulic turbine steel
Authors: Pechetti Durga , Chatterjee Dhiman , Kamaraj M
Published: December 2024

Hydraulic turbines endure degradation from cavitation erosion, silt erosion, corrosion, and fatigue, with combined silt and cavitation erosion exacerbating machinery deterioration, increasing repair costs, and reducing lifespan. While standardised tests for silt and cavitation erosion exist, they do not fully assess material suitability for such conditions. This study presents an accelerated testing methodology for 13Cr-4Ni Martensitic Stainless Steel, commonly used in hydraulic turbines, by comparing the effects of cavitation erosion, silt erosion, and combined cavitation and silt erosion. Experimental conditions include a submerged cavitating jet and two symmetrically placed submerged silt jets at a 30° impingement angle. Mass loss measurements are recorded to quantify performance under cavitation erosion, silt erosion, and combined cavitation and silt erosion. SEM imaging reveals distinct failure modes induced by these erosive modes. Results indicate that combined cavitation and silt erosion accelerate material degradation significantly, causing approximately 37 times more mass loss than the sum of their individual effects.
Retrofit and assessment strategies on heritage buildings: a case study of bank archive building in semarang old town area
Authors: Hermawan F , Raharjo P , Suwignyo R H D , Indarto H , Pamungkas G
Published: December 2024

Retrofitting in cultural heritage buildings to be revitalised has quite complex challenges, in addition to problems Efforts to maintain the performance of technical strength and repair limits on building elements are not flexible such as new buildings. This research aims to evaluate the method of implementing the revitalization of cultural heritage buildings through structural assessment. The case study method used on the Bank Archives Building object elaborated analysis to determine the safest Retrofit strategy. The analytical method used in this study is quantitative method using primary data obtained from direct observation and secondary data obtained from previous research case studies. The results showed that in planning a retrofit at the Bank Archives Building there were several technical and non-technical obstacles. Thus, the assessment method chosen includes several methods, including visual detail inspection, four non-destructive tests, one destructive test, and one soil test. These data are used to perform structural and geotechnical analysis. The results of structural analysis show that the quality of concrete in the structure of the Bank Archive Building does not meet the technical requirements of the building while the results of geotechnical analysis show that the decline in the structure of the Bank Archive Building has relatively little potential. The retrofit strategy that can be applied is a bending moment frame from a steel profile. This aims to increase the load capacity evenly distributed on the structure of the Bank Archives Building.
Diatoms as a bio-indicator for the coastal environment changes in Pasarbanggi mangrove conservation area, Rembang, Central Java
Authors: Kurniasih A , Soeprobowati T R , Dianti  , Putri E H , Jayanti A G R , Wanadri S B , Sujarwo P A
Published: December 2024

The coastal area of Pasarbanggi, Rembang has experienced significant coastline changes in the last 30 years. Changes in the stability of coastal ecosystems can be tracked by using bio-indicators whose traces are recorded in sediment. This research was conducted to determine changes in the ecosystem in the Pasarbanggi coastal area and its relationship to mangrove development using diatoms as the bio-indicator. Diatoms data is calculated to determine the abundance and diversity of its individuals. Based on the diatoms analysis, it is known that in the interval 26–50 cm, the abundance of diatoms is dominated by freshwater species, including Cyclotella meneghiniana and Cyclotella ocellata. From the satellite image, in 2002, the mangrove area has not developed yet and the sedimentation process is dominant. In the layer above it, at intervals of 1-25 cm, the sediment deposited in marsh environment. The diatoms diversity increased with the emergence of brackish and marine diatoms such as Tribionella granulata and Amphora coffeaeformis. In satellite imagery from 2018 to 2022, it appears that the development of mangrove area is significant. This shows that along with the mangrove development, there is an increase in ecosystem stability characterized by an increase in the diversity of diatoms species.
Recovery of solid waste as refuse derived fuel (RDF) to develop urban waste management through community empowerment
Authors: Zaman B , Sumiyati S , Wati H R , Aisy A R
Published: December 2024

Refuse Derived Fuel (RDF) is a solid waste processing technology that converts waste into fuel using its calorific value. Solid waste can be processed into RDF as briquettes in a smaller-scale society. Kalisalak Village, located in Batang District, Batang Regency, has the potential to utilize dry leaf waste into bio briquettes as a substitute for LPG gas for cooking. More than 80% of the Batang Regency area is agricultural land, so there is a lot of organic solid waste, especially dry leaves. This study aims to develop the potential of RDF as an alternative waste processing method to produce high-value products through community empowerment. The activity stages consist of field surveys, product prototype making, outreach and training for the community, and monitoring. The RDF process adopts a thermal method in processing waste due to its efficiency in recovering waste into renewable energy in a relatively short time. Dried leaf waste will go through a bio-drying process to reduce the water content by increasing its calorific value, thus producing waste with a lower water content. The bio-drying process is carried out using simple tools easily obtained by the local community. The resulting RDF bio briquette product can be sold and used as charcoal fuel.
Deployment of a Modern Sustainable Agricultural System Based on Drip Irrigation and Organic Liquid Fertilization in Patemon Village
Authors: Samadikun B P , Syafrudin  , Sumiyati S , Octaviani Y N , Andarista A F
Published: December 2024

In this era, technological advancements in agriculture are burgeoning rapidly. Despite widespread adoption, traditional practices persist in many regions, as exemplified by Patemon Village, where farmers rely on manual irrigation and fertilization. Additionally, synthetic pesticides continue to be widely used due to their perceived speed and efficacy in addressing pest issues. However, synthetic pesticides have drawbacks such as pest resistance, the killing of natural predators, environmental pollution issues, and are extremely hazardous to human health. This research aims to develop a systematic irrigation and fertilization system that assists farmers in optimizing their time and energy while minimizing wastewater usage and promoting the adoption of liquid organic fertilizers that support higher-quality and environmentally friendly agriculture. The design of the automated irrigation and fertilization system utilizes a drip irrigation system. The liquid organic fertilizer produced utilizes natural resources from plants and animal waste. The outcome of this program is the implementation of modern farming practices with automated irrigation and fertilization, as well as the use of environmentally friendly liquid organic fertilizers.
Impact of a municipal solid waste processing facility on microplastic pollution in Indonesia’s waterways
Authors: Andarani P , Rahma H H , Ningrum A W P , Istirokhatun T
Published: December 2024

Major cities are particularly affected by the escalating issue of municipal solid waste (MSW) pollution. Among the various forms of waste, plastic is especially concerning due to its persistence and tendency to fragment into microplastics. This study focuses on the Jangli River located in Semarang City, Indonesia, to quantify and characterize riverine microplastic pollution and assess the impact of the nearby a MSW Temporary Processing Site (TPS). Through water sampling, field observations, and laboratory analysis, we identified and classified microplastics by color and type, determining their abundance across different river points. Our findings reveal a correlation between the proximity to the processing site and increased microplastic levels. Specific hotspots along Jangli River were identified after the location of TPS, highlighting areas with the highest microplastic contamination. This research underscores the urgent need for targeted interventions to manage and mitigate secondary microplastic pollution, specifically solid waste, in Indonesia’s waterways, advocating for effective environmental control measures to protect aquatic ecosystems.
Assessing the transition from environmental education to education for sustainable development: a global perspective in higher education
Authors: Farliana N , Hardianto H
Published: December 2024

Education for sustainable development (ESD) is an official commitment driven by the United Nations (UN). In contrast, environmental education (EE) emphasizes environmental protection more. This analysis aims to assess the effectiveness and acceptance of the transition from EE to ESD, particularly among researchers in higher education institutions. This way, A global overview can be provided, highlighting the regions that adopt each educational model. The methods used include a systematic review for literature selection and meta-analysis parameters for data analysis. From the 7.439 papers analyzed, ESD’s progress and EE’s state by geographical area can be identified. Research findings show that certain regions adopt one of the two schools. It should be noted that ESD has become increasingly accepted globally since the decade promoted by UNESCO. Nonetheless, EE has played a more significant role in shaping the history of environmental education in certain regions. Additionally, more literature is needed to discuss the design and revision of economics curricula in the context of ESD. The originality of this paper lies in separating regions that adopt EE from those that adopt ESD, as well as explaining exceptional cases in the context of economic education involving ESD.
Accumulation of Copper (Cu) and Cadmium (Cd) Ions in Settling Basins to Assess the Effectiveness of the IPLT TPA Putri Cempo, Surakarta
Authors: Sunarhadi Amin , Kusumaningrum Lia , Nirwasita Hartono Daiva Ardhania , Naafi Diesta Atha’ul , Sutrisno Muhammad Tri , Mahmudah Umi , Alzahabi Muhammad Adib
Published: December 2024

Decreased water quality is caused by various human activities. One of the most dangerous types of water pollution is heavy metal pollution. Exposure to heavy metals can endanger human health even at low concentrations. One source of heavy metal pollution comes from domestic waste pollution from domestic activities, fecal waste. Fecal sludge contains solids dissolved in water, in the form of a mixture of organic materials and heavy metals, making it hazardous if not treated first before disposal. In this research, the author used water samples from the IPLT TPA Putri Cempo to determine the levels of Copper (Cu) and Cadmium (Cd) and the hazards posed by heavy metals, in order to assess the effectiveness of the Putri Cempo TPA IPLT system. The method used was wastewater sampling from the Putri Cempo landfill final sedimentation tank, sample preparation and analysis with atomic absorption spectrophotometer (AAS). The results of the investigation show that the final pool water at Putri Cempo landfill contains 0.0155 mg/L of copper and -0.0076 mg/L of cadmium, where these results are still below the threshold set by wastewater quality standards in Indonesia.
Ecotoxicity assessment of amoxicillin degradation product in aqueous media after photochemical process
Authors: Pratiwi W Z , Hadiyanto  , Widayat  , Baihaqi R A
Published: December 2024

Amoxicillin can have adverse effects on non-target bacteria in aquatic environments, causing disruption to the balance of aquatic ecosystems and promoting the emergence of antibiotic resistance. The Advanced Oxidation Process, namely UV/H2O2, is a promising method for the degradation of antibiotics such as amoxicillin due to its effectiveness. However, the degradation products might have ecotoxic potential and have not been studied; therefore, this study aims to evaluate the ecotoxicity of amoxicillin degradation using UV/H2O2. The in silico study was conducted using ECOSAR to theoretically assess the ecotoxicity of the ensuing transformation products on aquatic organisms. The ECOSAR calculations offer an early assessment of the possible hazard of amoxicillin degradation products in the aquatic environment. The research result shows that overall degradation products from the UV/H2O2 approach are not harmful in ecotoxicity, although some by-products still possess ecotoxic potential. Moreover, the findings of this study suggest that the mineralization level of amoxicillin degradation by-products is relatively low due to the production of hazardous compounds resistant to hydroxyl radical attack. This study highlights the necessity for a more comprehensive understanding of the by-products produced by the degradation process of amoxicillin using UV/H2O2 and their influence on aquatic ecosystems.
The Influence of Polypropylene Non-woven Plastic Waste on Alfisol Soil Quality
Authors: Khoironi A. , Najiyah A. N. , Baihaqi R. A. , Nurjannah  , Lukitasari M. , Kusmiyati
Published: December 2024

Non-woven polypropylene plastic is commonly used for manufacturing disposable masks, spun bond bags, and other waterproof equipment. The water-resistant properties of non-woven polypropylene provide an issue in the environment when it is disposed of in the soil system. This study aimed to assess the impact of non-woven polypropylene waste on soil quality and the quality of water that infiltrates the soil. This study used a prototype reactor filled with alfisol soil and non-woven polypropylene obtained from disposable masks and spund bond bags. The soil treatment was conducted over 60 days, with analyses performed on the soil and the infiltration water. The research findings revealed substantial disparities in the decreased alfisol soil bulk density, particularly in the soil with spun bond treatment. The degradation of non-woven polypropylene plastic in alfisol soil is confirmed by the intriguing findings of increased COD and TDS concentrations in the infiltration water. These concentrations indicate that the soil treated with foto-oxidized polypropylene non-woven material experienced an increase in both COD and TDS levels. Moreover, this scenario affects the soil’s ability to retain water due to the alteration in soil porosity.
The presence of microplastics in Surabaya coastal area and its correlation with conventional water quality parameters
Authors: Junior T , Nisaa A F , Karnaningroem N , Mardyanto M A
Published: December 2024

Microplastic’s existence has gained much attention due to its toxicity and harmful effects on marine life. One of the microplastic behaviours in the environment is to absorb hydrophobic pollutants. This behaviour might increase the toxicity of microplastics, affect the concentration of contaminants, and harm the environment. Kenjeran coastal area is a hotspot for human activities in Surabaya City, such as tourist, military training, and fishing activities. Therefore, the Kenjeran coastal area has a high potential to be polluted by plastics and microplastics. This study aimed to identify the abundance and polymer types of microplastics, as well as their correlations with chemical oxygen demand (COD) and total suspended solids (TSS) concentrations in the seawater of the Kenjeran coastal area. Sampling was conducted at three different points in March and April 2024. The average abundance of microplastics obtained was 63-102 particles/L. Meanwhile, the polymer types obtained were polyethylene, polystyrene, ethylene vinyl acetate, and polycarbonate. The correlation test results show that microplastic abundances do not have a significant correlation with COD and TSS concentration in seawater. This study can be used for further research in emerging pollutants and decision-making processes regarding plastic management from the source to the sea.
Recovery of Valuable Metals from Wastewater using Electrochemical
Authors: Oktiawan Wiharyanto , Sarminingsih Anik , Purwono Purwono , Afriana Dinda , Asdy Eva Rizqi
Published: December 2024

Today, wastewater is already considered a secondary resource due to its abundant nutrients, chemical energy content and other valuable constituents. However, recovery of valuable resources such as valuable metals from wastewater interesting to investigate. This study aims to recover valuable metalfrom wastewater using electrocoagulation (EC). This study used a cylindrically-shaped EC reactor with a total volume of 1500 mL. EC reactors are equipped with cathodes and anodes, which are spiral and cylindrical respectively. The result shows that the initial pH is low at 0.39, then decreases to 0.16 within 1 minute. After that, the pH gradually increases until it reaches its peak at 3.48 after 60 minutes. After 45 minutes, the pH increased significantly, suggesting that the electrocoagulation process could lead to an increase in pH in the wastewater. After 15 minutes, the temperature began to rise gradually, reaching 39.3°C after 60 minutes. This increase in temperature may be due to the ongoing electrocoagulation reaction and the heating effect of electrical voltage. Cr, a valuable metal, has a concentration of 2.09 mg/L, which dramatically decreases to 1.12 mg/L after 1 minute. Cr concentrations continued to decrease until they reached a low of 0.13 mg/L after 30 minutes. This indicates a significant recovery of Cr from wastewater.
Water efficiency analysis and optimization of chemical usage on productivity of demineralizer plant PT. Pupuk Iskandar Muda
Authors: Shara S , Hijrin M , Mastura R , Ramadhan S , Ikhsanuddin  , Wahyu S , Aulia Z , Syarwadi  , Duana C M
Published: December 2024

A demineralization process is carried out in industrial water treatment, and this process requires large amounts of chemicals that can increase the pollutant load of wastewater and harm ecosystems, biodiversity, and climate. Therefore, this study aims to analyze water efficiency and chemicals used in the water treatment process at the Demineralizer Plant. The analysis was carried out through a fishbone diagram and Nominal Group Technique (NGT) method to identify the problem so that the corrective solution is obtained, namely by backwashing the cation and anion resins periodically at 100,000 m3, maintaining the flow service setting for the demineralized plant at 90 - 100 m3/hour, and adjusting the specific gravity at the time of regeneration of Cation in the first Chemical. The results showed that PT made improvements. Pupuk Iskandar Muda has succeeded in carrying out a water efficiency of 484.87 m3. That impacts production costs, which decrease along with reduced chemical use. The company saved IDR 4.251.782 in 2021 after the repairs were carried out. Water efficiency and optimization of chemical use can save the cost of purchasing chemicals, minimize environmental impacts, and provide the best and most practical solutions at PT. Pupuk Iskandar Muda.
Determination of pollution load and river water quality status using the pollution index method (case study: Way Sekampung Watershed, Lampung Province, Indonesia)
Authors: Awfa D , Habibie M M , Imami A D , Azizah R N , Prayogo W
Published: December 2024

Way Sekampung watershed is a significant watershed from the Seputih Sekampung River in Lampung Province. Along the Way Sekampung watershed, there are several WTP intakes. However, the watershed is surrounded by rice field irrigation flows, domestic waste disposal, and tributary estuaries that can potentially reduce water quality values. This study aimed to identify water quality and calculate the water pollution load and the value of water quality status in the Way Sekampung watershed. The parameters tested include temperature, pH, TSS, BOD, DO, ammonia, and total coliform. In this study, the method used to identify water quality is the Pollution Index (IP) method, and for pollution loads, the APL and MPL methods are used. The research area is divided into four segments consisting of 4 water quality sampling points and 1 point source pollution load point. The results obtained parameters that do not meet the quality standards at all points are BOD, COD, and Total Coliform parameters. In calculating pollution load, three parameters are excessive: the Total Coliform parameter 36,295,776 kg/day, COD 738,555.84 kg/day, and BOD 216,691.2 kg/day. The water quality status of the Way Sekampung watershed, with an average total index value of 5.069, is categorized as moderately polluted.
Flood Hazard Zonation Using Geographic Information System: A Case Study Of Way Garuntang River Basin, Bandar Lampung
Authors: Sahid S , Yanto N P , Aziz F , Mardika M G I , Asferizal F , Zain S A , Ulhaq W D , Yunida D , Azizah R N , Imami A D , Awfa D
Published: December 2024

Flooding is a hydro-meteorological disaster that can have an impact not only on economic losses but also threatens human life. Flooding is the event of overflowing water in potential areas due to exceeding river’s capacity, which can be predicted by using flood inundation modeling. Flood modeling could be the first step to reduce the impact of losses caused by flood disasters. Rainfall data from 5 rain gauge stations over 15 years provides spatial and temporal distribution of data that can be used as inputs in flood modeling. This study aims to investigate the performance of flood inundation modeling using rain gauge data and to derive flood hazard zonation by combining flood depth and flood velocity through hydraulic modeling and GIS. The results show that the accuracy of the depth flood inundation model based on RMSE and MAE calculation is 2.56 m and 2.19 m. in addittion the flood distribution validation results show 46.60%. Although the accuracy results for flooding show differences that can be considered, this analysis is essential for understanding and planning spatial and water management in the study area, particularly in flood risk mitigation and hydrological infrastructure planning.
Assessment of groundwater vulnerability towards contamination using SI (Susceptibility Index) in Demak Regency, Indonesia
Authors: Santi Narulita , Putranto Thomas T , Zahra Firza Syarifa , Putri Maya A S
Published: December 2024

Water is one of the sources of life for humans. In Indonesia, many people utilize groundwater as a water source. Groundwater management must be done properly so that its utilization is sustainable. The potential for groundwater pollution is getting bigger with land change. One form of mitigation of groundwater pollution is to assess the vulnerability of groundwater pollution to pollution. The research location is in Demak Regency, which is one of the regencies directly adjacent to the capital city of Central Java Province. This will have a direct impact on the development of the city. The most visible thing is the increasing population which will have an impact on groundwater utilization in Demak Regency. This research uses the Susceptibility Index (SI) method. The results of the analysis show that the research location is divided into 2 classifications, namely high vulnerability and moderate vulnerability. High susceptibility has an SI index value between 72-88 and moderate susceptibility has an SI index value between 55 - 71. The factors that have the most influence on the difference in groundwater susceptibility classification to pollution in the research location are the depth of the water table, slope and land use.
Paving made from LDPE plastic waste, agricultural mulch waste and hot sand, case study of potato farming in the Dieng plateau
Authors: Faqih N. , Suripin  , Wulandari D. A. , Hermanto H. , Sunaryo  , Qomaruddin M.
Published: December 2024

LDPE plastic waste, prevalent in single-use products, poses significant environmental challenges. Repurposing this waste into paving materials provides an eco-friendly solution. The LDPE waste was cleaned, shredded, and mixed with hot sand in ratios of 60%-40%, 65%-35%, and 70%-30%. The mixtures were sintered at 120°C for 15 minutes and tested according to ISTM C140/C140M standards. The results demonstrate that increasing LDPE content enhances compressive strength. The 70%-30% mix exhibited the highest compressive strength at 36 MPa, whereas the 60%-40% mix showed the lowest at 30 MPa. Regression analysis revealed a strong positive correlation between LDPE content and compressive strength (R2 = 0.79), corroborated by T-tests and ANOVA. The Pearson correlation coefficient (r = 0.89) further indicated a robust relationship. These findings support the utilization of LDPE as a sustainable and effective material for paving applications.
The potential of retrofitting green roof to increase flood resilience in Jakarta
Authors: Widiachristy L , Orsi F
Published: December 2024

With climate change and urbanization intensifies, major cities are increasingly vulnerable to flooding. Green roofs have the potential to be a valuable tool for adapting to floods, but this benefit is not yet widely acknowledged. Although interest in applying nature-based solutions is rising, research has primarily concentrated on green roofs’ effectiveness on individual rooftops. This study analyses green roofs impact on flood susceptibility at the district level and examines how technical and social factors influence green roof suitability in Jakarta. Using exploratory design and mixed methods approach, this study performs suitability analysis and flood risk assessment through GIS-MCDA and AHP. The findings highlight that green roofs are most effective when implemented strategically, considering location and users. Although a single green roof might not have a major effect on flood risk, a network of them covering a large area could be very beneficial. This suggests that widespread green roof adoption could be critical for city in diversifying flood adaptation strategies to be more flood resilient in the future.
Green Building Assessment: A Case Study of Integrated Laboratory Building Diponegoro University Based on the Regulation of the Minister of Public Works and Public Housing No. 21 of 2021
Authors: Hatmoko J U D , Sari L I
Published: December 2024

Green building is an environmentally friendly building concept that has become increasingly important in addressing issues related to climate change, carbon emissions, and the greenhouse effect. This concept emphasizes reducing energy consumption and improving indoor environmental quality. This study aims to conduct a green assessment of a multi-storey building based on the Regulation of the Minister of Public Works and Public Housing No. 21 of 2021, using an Integrated Laboratory Building of the Engineering Faculty of Diponegoro University as the case study. The research method involves observation, measurement, and analysis based on green building criteria adopted from Ministerial Circular No. 1 of 2022, which provides technical guidelines for assessing the performance of green buildings. The aspects of the assessment in the planning stage of the building include site management, energy efficiency, water efficiency, indoor air quality, environmentally friendly materials, waste management, and wastewater management, with a total of 7 indicators. The results indicate that the building still needs to meet the green building criteria, with a total score of 30 out of 165 points or 18.2%. Recommendations from this study include the need for greater funding allocation for green building initiatives and the integration of green building principles from the early planning stages to ensure compliance with established standards and to maximize environmental and health benefits.
Revisiting Indonesian corporate carbon disclosure: does greenwashing obstruct true carbon reduction?
Authors: Wahyuningrum I F S , Mukhibad Hasan , Setyadharma Andryan , Oktavilia Shanty , Sriningsih  , Anwar Syaiful
Published: December 2024

With corporate disclosure of carbon information becoming steadily more important, there is a growing discussion regarding the assumption of a greenwashing issue within corporate carbon disclosure practices that raises the long-standing question of the sincerity of corporate concern. Prior studies of non-financial disclosure have predominantly focused on drivers of carbon disclosure without curiosity to ensure that carbon disclosure may be a substitute for poor carbon performance. This study investigates whether a company’s voluntary carbon disclosure accurately represents its carbon performance. The carbon disclosure score was measured based on content analysis of sustainability reports, and the carbon intensity of emissions was employed to calculate corporate carbon performance. Based on a sample of 38 Indonesian public companies in 2020-2022, the study finds carbon disclosure and carbon performance have a significant positive relationship, showing that carbon disclosure score reflects actual corporate carbon performance. This study finds, based on statistical graphs and hypothesis testing results, greenwashing undetected in the Indonesian context. Even so, this study offers practical suggestions for the government by providing standard guidelines for carbon emissions disclosure to facilitate diverse companies’ characteristics and companies should be confident of their performance to collect stakeholder attention.
Efficiency of Coal Mining Direction Based on Sedimentary Facies at PT Jambi Prima Coal, Sarolangun Regency, Jambi Province, Indonesia
Authors: Pangestu A R , Adni A , Fahrudin  , Qadaryati N
Published: December 2024

Indonesia requires a large amount of conventional energy for its current development and economic growth (e.g., coal). The coal distribution in the Sumatra Island (e.g., Muara Enim Formation) has been influenced by the sedimentary facies, resulting in the spatial geometry of the coal seams (i.e., direction and thickness). Furthermore, my study focused to analyse the sedimentary facies and the geometry of the coal seams. Based on the measured stratigraphic and borehole data, the research resulted in 4 types of sedimentary facies and coal seam geometry. The existing facies were distributary channel, crevasse splay, interdistributary bay, and swamps, which were part of the transitional lower delta plain. In the swamp facies, there are two coal seams (i.e., magma and dipa seam). The thickness of the magma seam increased towards the southeast, while towards the southwest happened to rise the dipa seam thickness. However, the dipa seam was affected by a channel facies phenomenon, causing to split into the dipa upper and dipa lower. Therefore, for determining the mining efficiency based on the sedimentary facies, the southern part of the magma and the dipa seam can be considered as the mining area, with the mining direction from the southeast towards the northwest.
A function of PVA/SiO2/CMC composite gel polymer electrolyte (GPE) for electrochemical performance of secondary zinc-air batteries (ZABs) respectively
Authors: Ulsak Mohammad Ghimnastiar , Devianto Hary , Widiatmoko Pramujo , Prakoso Tirto
Published: December 2024

ZABs are a desirable clean electrical energy storage technology to be developed. ZABs generates electricity through the zinc oxidation process at anode and oxygen reduction reaction at cathode. CV characterization to analyzing oxidation and reduction processes in ZAB-1P1S4C is attributed to the occurrence of oxidation (discharge) on the zinc surface with OH
− becoming a tetrahydroxyl dianion or

Z
n

(
O
H
)

4

2
−

and

Z
n

(
O
H
)

3
−

. An approach used for evaluating ZABs are called GCD characterization. There was a sharp drop in discharge curves of ZAB-1P and ZAB-3P. The sharp decrease in the ZAB-0A (1P) and ZAB-0B (3P) discharge curves occurs because the concentration of OH
− in the GPE decreases rapidly due to the evaporation of water so that OH
− which is intended for tetrahydroxyl dianions such as

Z
n

(
O
H
)

4

2
−

and zincate ion such as

Z
n

(
O
H
)

3
−

is very little formed. Another characterization is CCD characterisation to investigate influence of depth of the discharge curve and the rise in charge curve on CCD-1P4S4C. OCV is used to evaluate the difference in electric potential between a ZAB’s positive and negative terminals when no current is applied. Addition of SiO2 and CMC has effect of increasing the energy density and power density of ZAB-1P4S4C by 1.059 × 10−7 Wh/kg and 1.52 × 10−4 W/kg.