Sustainable Environmental Insight

Strength Evaluation of Palm Oil Fuel Ash and Rice Husk Ash as Partial Cement Replacement in Concrete for Sustainable Construction

2025-08-28T00:58:05+00:00

The construction industry's dependence on Portland cement considerably increased global carbon emissions, which highlighted the need for environmentally friendly alternatives. This research explored the application of rice husk ash (RHA) and palm oil fuel ash (POFA), two common agricultural byproducts in Malaysia, as partial cement replacements in concrete. The study examined the mechanical performance and durability of several POFA–RHA concrete mix designs with the goal of reducing environmental impact while maintaining structural integrity. A systematic approach was applied for material characterization, which included advanced methods such as Field Emission Scanning Electron Microscopy (FESEM). The workability, compressive strength, and water absorption of concrete samples with varying POFA and RHA proportions were assessed. The findings showed that a mixture containing 25% POFA and 5% RHA achieved notable improvements in strength and durability while reducing water absorption. In contrast, higher replacement levels reduced workability and performance due to increased water demand and particle aggregation. Overall, the combination of 25% POFA and 5% RHA delivered substantial enhancements in strength, durability, and water absorption.

Estimating Heavy Metal Concentrations in Landfill Leachate and the Impact of Waste Segregation in Malaysia

2025-08-28T00:58:04+00:00

Estimation of heavy metal concentrations in leachate was crucial for effective landfill management and pollution mitigation. The study aimed to estimate the volume of landfill leachate, the heavy metal content in the leachate, and their reduction through waste segregation practices. It was conducted in Malaysia and utilised municipal solid waste volume data from six states and two federal territories. A mathematical empirical model was applied to estimate the concentrations of heavy metals in the leachate. Based on the volume of landfilled waste, an estimated 565,000 cubic metres (m³) of leachate were discharged annually. Among the heavy metals analysed, Pb and Zn exhibited the highest concentrations (8.49 kg/yr). Waste segregation practices reduced heavy metal discharge in leachate, preventing approximately 7.09 × 10⁻⁴ to 5.32 × 10⁻³ kg/yr. Through mathematical modelling, this research provided a cost-effective approach for estimating heavy metal concentrations and supported strategies for addressing environmental and health impacts.

Evaluation of the Treatment Performance Over Time of Constructed Wetlands for Wastewater from Rice Noodle Handicraft Village after Biogas Process

2025-09-13T06:43:59+00:00

Constructed wetlands (CWs) offer a low-cost and sustainable treatment option. However, their performance strongly depends on hydraulic retention time (HRT), which also influences land use and construction requirements. This study aimed to determine the minimum HRT required for treating wastewater from rice noodle handicraft villages after the biogas process to meet the National Technical Regulation on Industrial Wastewater (QCVN 40:2025/BTNMT), Column B. The CW system was set up in a glass tank (50 × 30 × 50 cm) with a 40 cm substrate layer consisting of yellow sand mixed with crushed stone, limestone (1 × 2 cm), and gravel (3 × 5 cm), and was planted with Cyperus alternifolius at a density of 18 plants per CW unit. The system was operated for 70 days with daily sampling. Results showed that effluent quality met QCVN 40:2025/BTNMT, Column B standards after 4 days, with average treatment efficiencies of 89.2% for total suspended solids (TSS), 82.4% for chemical oxygen demand (COD), 54.7% for total nitrogen (TN), and 78.1% for total phosphorus (TP). Although longer HRTs improved treatment efficiencies, removal rates plateaued after the fourth day. Therefore, a 4-day HRT is recommended as an optimal balance between treatment performance and construction cost. These findings provide practical implications for scaling up CW systems to improve wastewater management in Vietnamese handicraft villages.

Assessment of Heavy Metals, Microplastics Abundance, Pollution Level, and Contamination Risk in the Ganges Downstream

2025-09-13T06:44:00+00:00

The degradation of aquatic ecosystems and their links to climate change had made microplastic (MP) contamination a significant environmental concern. The study evaluated the water quality and assessed the abundance, pollution level, and contamination risk of microplastics in the downstream of the Ganges. The analysis results revealed that biological oxygen demand, chemical oxygen demand, nitrate, and chromium levels slightly exceeded ECR-BD (2023) standards, reflecting mild pollution. Heavy metal analysis showed the following sequence of concentration: Fe > Cr > Cu > Ni > Pb > Zn > Mn > Cd, which increased gradually. Considering the water quality indices, the river water was moderately polluted. MP concentrations were higher in the pre-monsoon (17.7 particles/l) than in the post-monsoon (14.3 particles/l) season, with blue fibers <1 mm as the dominant forms. The identified MPs were polyethylene, polypropylene, polyethylene terephthalate, and polyvinyl chloride. The contamination factor (CF > 1) and the pollution load index (PLI > 1) indicated that the analyzed area was moderately contaminated with MPs. According to the study, the concentrations of Cr, Fe, and Cu increased with rising MP levels. Based on the co-occurrence of MPs and heavy metals, the Ganges River faced new ecological threats that needed to be addressed by tighter wastewater regulations, better plastic waste management, ongoing monitoring, and the implementation of transboundary policies to mitigate microplastic pollution.

Enhancing Soil and Water Quality through Microbial Bioremediation: A Sustainable Approach to Environmental Restoration

2025-09-13T06:44:01+00:00

This work focused on microbial bioremediation as a sustainable approach for improving soil and water quality affected by heavy metals, hydrocarbons, and other recalcitrant pollutants. The primary goal was to assess the efficacy of microbial consortia compared with single strains and to investigate ecological resilience and system-level dynamics that enabled long-term remediation. Unlike conventional physical or chemical treatments, microbial systems generated synergies of metabolic processes and ecological interactions that enhanced pollutant degradation. This review integrated recent advances in genomics, systems modeling, and ecological monitoring, and demonstrated how these tools were applied in biostimulation and bioaugmentation strategies. The novelty of this work lay in combining fine-grained microbial processes with system-level resilience thinking, providing new insights into the scalability and sustainability of bioremediation. While microbial systems were highly promising, challenges remained, including incomplete degradation, site heterogeneity, and biosafety concerns. The paper concluded with recommendations for the robust design of microbial consortia, the development of predictive ecological models, and the improvement of policy frameworks to ensure safe, equitable, and long-term adoption of microbial bioremediation.

Marine Protected Areas: A Literature Review of Their Conservation Effectiveness in Safeguarding Marine Biodiversity

2025-09-13T06:44:04+00:00

Marine Protected Areas (MPAs) are crucial for maintaining marine biological diversity because they safeguarded ecosystems, protected endangered or threatened species, and supported livelihoods, while social and economic security could be achieved by managing marine resources sustainably. This literature review aimed to synthesize related and relevant studies on the effectiveness of MPAs in safeguarding marine biodiversity. The study synthesized twenty (20) published peer-reviewed research articles and reports to scrutinize and provide answers to the questions surrounding the effectiveness, benefits, and challenges in enforcing this global conservation target. The outcomes of the reviewed and assessed papers revealed that well-managed MPAs significantly contributed to habitat restoration, species population recovery, and ecosystem resilience. However, issues such as weak enforcement, stakeholder conflicts, and climate change jeopardized their full potential. This review highlighted the contradictory position of this extensively used management tool at the intersection of biodiversity conservation and emphasized the necessity of adaptive management techniques to enhance MPA design, community involvement, and stronger policy enforcement.

Phorboxazole A: Comparative Synthetic Approaches, Bioactivity, and Future Green Chemistry Strategies

2025-09-13T06:44:02+00:00

Phorboxazole A is a tropical marine macrolide isolated from the sponge Phorbas sp. and has emerged as one of the most potent cytostatic agents found in nature, with nanomolar activity against diverse cancer cell lines and antifungal properties against pathogens like Candida albicans. The structural complexity of Phorboxazole A, characterized by a 46-carbon skeleton, 28 stereocenters, two oxazole rings, and a macrocyclic core, has spurred innovative synthetic campaigns since its isolation 30 years ago. This review article highlights the approaches in total synthesis strategies for phorboxazole A, emphasizing the Petasis-Ferrier union/rearrangement, tri-component coupling, convergent assembly, stereoselective cyclization, and comparative retrosynthetic analysis, followed by discussions regarding its biological activity, and the feasibility of utilizing green chemistry principles in mitigating the hazardous effects on human health and the environment.