Indonesian Journal of Environmental Management and Sustainability

Microalgae-Based Wastewater Treatment as Green Solution for Sustainable Degradation and Its Challenges: A Review

Eva Musifa — 2025-12-10

Releasing polluted water directly into the environment causes serious problems because it contains harmful substances that can damage aquatic life and human health. To reduce these risks, it is important to treat and clean wastewater effectively. Microalgae have shown promise as a natural and sustainable way to treat wastewater. The microalgae help to remove pollutants and can also recover useful resources and energy from the water. The study used a systematic review methodology to identify and evaluate the role of microalgae wastewater treatment. The method was used since it provides a structures and transparent framework for selection, assessment and synthesize of evidence from relevant literature. This review highlights the benefits of using microalgae for wastewater treatment, as well as the challenges involved. Ongoing research focuses on improving these methods, including combining microalgae with bacteria to make the process more efficient and scalable. Despite some difficulties like contamination risks and regulatory issues, future advances especially in genetic engineering and hybrid systems are expected to improve microalgae-based wastewater treatment and make it a key tool for protecting the environment, while multidisciplinary collaboration combining molecular biology research, environmental engineering, public policy, and utilization of this technology at the industrial and societal levels that should be under consideration.

Mapping World Trends in the Peatland Restoration Literature: An Overview of Bibliometric Analysis

Irfandi Pratama — 2025-12-10

Anthropogenic activities have degraded peatlands in various regions worldwide. To protect and restore peatlands and their ecosystems, sustainable peatland restoration efforts have been undertaken. These efforts have attracted the attention of researchers to assess the success rate, benefits, and protection of restored ecosystems. This study highlights trends, issues, and recent developments through a bibliometric analysis of articles on peatland restoration from an environmental security perspective, published in the Scopus database. The researcher identified 94 journal articles published between 1994 and 2022 and analyzed them using VOSviewer and NVivo 12 Plus software. The results show that research on peatland restoration is playing an important role from an environmental security perspective with increasing recent progress, and has high relevance for rewetting, revegetation, and cost benefits. In contrast, the main issues in peatland restoration are water, ecosystem, and carbon. Experts measure restoration progress through water levels and related issues. Then the peatland ecosystem absorbs about 30% of the world’s carbon and vice versa; when degraded, they release carbon. Recommendations for future research focus on harmonizing peatland restoration efforts with an environmental security perspective and educating local communities about the benefits that can increase the success of restoration and preservation of peatland ecosystems, as well as efforts to increase protection through advocacy for these marginal ecosystems.

Optimization of Acetone Concentration and Reflux Ratio for Enhanced Oil Extraction from Spent Bleaching Earth: A Response Surface Methodology Approach

Clarissa Putri Monica — 2025-12-10

Spent bleaching earth with an oil content exceeding 3% is classified as hazardous and toxic waste, requiring appropriate processing prior to environmental disposal. Extraction is one effective method for processing spent bleaching earth. This study focuses on the optimization of oil extraction from spent bleaching earth using acetone as a solvent, specifically analyzing the effects of solvent concentration and reflux ratio on oil recovery efficiency and evaluating the quality of recovered bleaching earth for potential reuse in vegetable oil refining processes. The extraction method employed was soxhlet extraction using acetone as the solvent. Five different acetone concentrations (50%, 60%, 70%, 80%, and 90%) were tested in combination with five reflux ratios (2, 3, 4, 5, and 6), creating a total of 25 experimental conditions. Response surface methodology (RSM) was utilized to optimize these parameters and identify the ideal conditions for maximum oil recovery. The experimental design and statistical analysis were conducted using Design Expert 13.0.5.0 software. The quality of recovered bleaching earth was assessed against Indonesian National Standards (SNI) for potential reuse applications. The optimization results indicated optimal conditions of 69.15% acetone concentration and a reflux ratio of 4, yielding a maximum oil recovery rate of 17.52%. Analysis of the recovered bleaching earth showed that while it met most SNI standards for bleaching earth quality parameters, the pH remained acidic (below neutral), indicating that alkaline pretreatment would be necessary before the material could be effectively reused in vegetable oil bleaching processes. The study demonstrates that acetone-based soxhlet extraction can effectively recover oil from spent bleaching earth while producing a secondary product suitable for reuse after appropriate pH adjustment.

Biogas Production Using Continuous Stirred Tank Reactor (CSTR) from Palm Oil Mill Effluent (POME) Utilizing Mesophilic Bacteria

Suratni Afrianti — 2025-12-10

Energy is essential for human life, yet dependence on fossil fuels and other non-renewable resources contributes to global energy crises and environmental degradation. Biogas is an environmentally friendly alternative that has the potential to partially replace fossil fuels. Palm Oil Mill Effluent (POME), which contains high concentrations of biodegradable organic matter, is a promising substrate for biogas production through anaerobic fermentation. This study aims to evaluate the potential of Palm Oil Mill Effluent (POME) as a substrate for biogas production using a Continuous Stirred Tank Reactor (CSTR) under mesophilic conditions (35–37^oC). The experiment was conducted for 30 days with at a laboratory scale (10 L reactor volume). Feedstock characterization (COD, TSS, TS, VS, and pH) confirmed that POME has high organic content and slightly acidic conditions, supporting its suitability for anaerobic digestion. The results show that anaerobic fermentation of POME produced biogas with an average methane (CH₄) concentration of 66–71%, indicating stable digestion performance and relatively high efficiency. These methane levels indicate stable digestion performance and relatively high process efficiency. Overall, the findings confirm that POME is a promising feedstock for biogas production and can contribute to renewable, environmentally friendly energy supply.

Phytoremediation of Ammonia, BOD, COD, and TSS with Water Hyacinth (Eichhornia crassipes) for Wastewater

Purnomosutji Dyah Prinajati — 2025-12-10

Water hyacinth (Eichhornia crassipes) is a typical aquatic plant with several physical characteristics such as the leaves of water hyacinth are glossy and ovoid to circular in shape, with spongy petioles that provide buoyancy. The plant is widely known for its rapid proliferation, with its population being able to double in just 12 days. The Pulo Gebang Fecal Sludge Treatment Plant (STP) is a facility that treats sewage from people’s homes or centralized treatment plants. However, the treated water often does not meet quality standards. To solve this problem, a sustainable and environmentally friendly wastewater treatment method called phytoremediation was chosen. Phytoremediation involves the use of plants to remove pollutants from wastewater, offering cost efficiency, minimum energy requirements, and conservation of soil biological activity. Water hyacinth (Eichhornia crassipes) was chosen for its quality and ability to degrade penetrant substances. Phytoremediation was carried out in batch form with 3 variations of testing time, namely 5, 10 and 15 days. The study found that phytoremediation using water hyacinth significantly reduced ammonia levels, BOD, COD, and TSS parameters, with the most effective contact time being 10 days. This shows that the phytoremediation method using water hyacinth is effective in reducing contaminant levels and can be a sustainable solution for treating domestic wastewater at IPLT Pulo Gebang.

Properties and Utilization of Fly Ash for Treating Acid Mine Drainage

Nurlela — 2025-12-10

The combustion of coal in power plants (PLTU) generates fly ash containing silica dioxide (SiO?) and alumina (Al?O?), which exhibit promising properties as adsorptive materials. Fly ash, typically regarded as an industrial by-product, has been widely explored for its application as an adsorbent in wastewater purification. One of the most challenging wastewaters is acid mine drainage, characterized by strong acidity (pH < 5), residual contaminants, and elevated concentrations of heavy metal ions such as manganese (Mn) and iron (Fe). When released untreated, this effluent poses significant risks to both surface and groundwater quality in mining areas. This study focuses on the characterization and utilization of fly ash as an adsorbent to neutralize acidity and reduce Mn and Fe concentrations in acid mine drainage. The material was characterized using SEM-EDX and XRD techniques, followed by adsorption experiments. To enhance its properties, fly ash underwent physical activation through heating at 100 °C for 60 minutes. The activation process modified its structure, expanding pore volume and increasing surface area, thereby improving adsorption performance. The experimental results revealed significant differences in the properties of fly ash before and after activation. Activated fly ash effectively raised the pH of acid mine drainage to near-neutral conditions while achieving removal efficiencies of 96.61% for Mn and 83.33% for Fe using 50 g of adsorbent. These findings highlight the potential of fly ash as a low-cost and effective material for acid mine drainage treatment, both for acidity control and heavy metal removal.