NEWS

2025.10.23

【Report】 The AJI International Workshop on “Sustainable Wastewater Management in Southeast Asia: Natural Methods for Heavy Metal Reduction” was held!

The online International Workshop on “Sustainable Wastewater Management in Southeast Asia: Natural Methods for Heavy Metal Reduction” was held on October 4, 2025, organized by the Asia-Japan Research Institute (AJI), Ritsumeikan University. The workshop brought together seven researchers from universities across Bangladesh, Japan, Indonesia, Philippines, and Vietnam, who presented their latest studies on wastewater management in Southeast Asia. The event attracted a diverse international audience and was moderated by Dr. Nguyen Thi Thuong, Senior Researcher at AJI.

The workshop opened with a welcome speech by Professor Yasushi Kosugi, Director of the Asia-Japan Research Organization, Ritsumeikan University. Professor Kosugi warmly greeted all speakers and participants joining from Japan and abroad and introduced the mission and activities of AJI at Ritsumeikan University. In his remarks, he outlined the workshop’s objectives and program, underscoring the vital importance of wastewater management in promoting sustainable development across Asia, particularly in Southeast Asia. He concluded by expressing his sincere hopes for the workshop’s success and encouraging participants to strengthen academic networks and foster future research collaborations.

The first presentation was delivered by Mr. Abu Bakar Siddique, Research Assistant at the Institute of Tropical Ecology and Environmental Science, Visayas State University, Philippines. His presentation, titled “Heavy Metal Contamination in Urban River Sediments of the Philippines: Baseline Risk Assessment Supporting Nature-Based Remediation Strategies,” focused on assessing the ecological risks of heavy metal contamination in sediments from the Urban River, Leyte, Philippines. Using pollution indices such as the contamination factor, pollution load index, geo-accumulation index, enrichment factor, and ecological risk index, the study revealed elevated levels of Mn, Zn, Cu, Ni, Pb, and Cd, primarily originating from anthropogenic sources such as port operations and agricultural runoff. The findings provide essential baseline data underscoring the urgent need for sustainable, nature-based remediation methods, including phytoremediation, bioadsorbents, and constructed wetlands, for effective urban wastewater management in Philippines. Following his insightful presentation, participants engaged actively with several questions and comments.

Mr. Abu Bakar Siddique delivering his presentation

The second presentation was delivered by PhD candidate Abd Aziz Amin from the Graduate School of Science and Engineering, Ritsumeikan University, Japan, who presented his research titled “Unlocking the Potential of Microbial and Natural Wetlands for Heavy Metal Assessment in Aquatic Environments.” His study evaluated the use of biofilms in wetlands as a cost-effective and reliable tool for monitoring heavy metal pollution in aquatic ecosystems. By analyzing biofilm composition and metal accumulation patterns, the research explored the relationship between environmental metal concentrations and biofilm characteristics, providing insights into their suitability as biomonitoring indicators. The results showed that biofilms offer a sensitive and integrated measure of heavy metal contamination, providing a practical approach for water quality monitoring. His presentation received highly positive feedback from participants, and he responded thoughtfully to their questions during the discussion.

Mr. Abd Aziz Amin making his presentation

Next, Dr. Nguyen Thi Hai, Lecturer at the University of Science, Vietnam National University, Vietnam, presented her research titled “Zero-Waste Approaches in Removing Arsenic from Water Using an Iron-Coated Pomelo Peel Adsorbent: Adsorption Performance and Waste Management.” She began by emphasizing that arsenic contamination in drinking water remains a serious environmental and public health concern due to its high toxicity and adverse effects on human health and ecosystems. To address this issue, her study adopted a zero-waste approach by recycling agricultural by-products—pomelo peels—to synthesize an iron-coated pomelo peel biochar (PPCI) adsorbent for arsenic removal from aqueous environments. The PPCI exhibited high arsenic removal efficiency, and the spent adsorbent was further treated through stabilization and solidification using cement and lime to prevent arsenic leaching. The resulting concrete brick products demonstrated potential for safe use in construction. Overall, this research presents a sustainable and circular solution for arsenic remediation and waste management.

Dr. Nguyen Thi Hai delivering his presentation

The fourth presentation was delivered by Professor Shaibur Rahman Molla from Jashore University of Science and Technology, Bangladesh, titled “Removal of Pollutants from Groundwater Using Natural Bioadsorbents (Lemon Peel and Peanut Peel Charcoal).” He began by highlighting that groundwater contamination with heavy metals has become a major environmental issue in Bangladesh, with documented evidence of toxicity and related health risks. In his study, natural adsorbents, specifically lemon peel charcoal and peanut peel charcoal, were used to evaluate their effectiveness in removing heavy metals. He also examined the effect of contact time on the removal of As, Fe, and Mn. The findings indicated that these natural bioadsorbents show promising potential for heavy metal removal; however, further material modification is necessary to enhance their treatment performance. His presentation drew active engagement from the participants, including several comments and two questions.

Professor Shaibur Rahman Molla presenting his research

Professor Marla C. Maniquiz-Redillas from De La Salle University, Manila, Philippines, continued the workshop with a presentation titled “Nature-Based Green Infrastructure for Heavy Metal Reduction.” Her talk addressed the persistent issue of heavy metal contamination and introduced micro-scale, nature-based treatment systems designed for sustainable and adaptable pollution control. She highlighted systems such as constructed wetlands, bio-infiltration units, and sedimentation-based filters, emphasizing their design concepts, operational flexibility, and applicability under varying environmental conditions. These green infrastructure approaches can effectively capture pollutants at the source, manage both dry- and wet-weather flows, and provide cost-effective, resilient, and eco-friendly solutions for wastewater treatment in Southeast Asia and beyond. In the Q&A, the lively participants raised several comments on her presentation. Also, she clarified some questions from other speakers.

Professor Marla C. Maniquiz-Redillas making her presentation

Next, Professor Andi Kurniawan from Brawijaya University, Indonesia, presented his study titled “Biofilm Matrices as Living Platforms for Heavy Metal Biosorption and Time-Integrated Pollution Biomonitoring in Aquatic Ecosystems.” He described biofilms, microbial communities embedded in extracellular polymeric substances (EPS), as an effective nature-based approach for heavy metal removal. Their EPS-rich matrices contain abundant functional groups that bind metal ions through electrostatic attraction, complexation, and ion exchange, providing high biosorption capacity and selectivity. His research demonstrated high metal removal efficiency, and with clear diagrams and illustrations, he explained the mechanisms and pathways of heavy metal adsorption by biofilms. The study also showed that biofilms adapt to environmental changes, reinforcing their dual role as pollution sinks and environmental sentinels. By integrating biosorption and biomonitoring, biofilms provide a sustainable, self-regenerating solution for aquatic ecosystem restoration and water quality management.

Professor Andi Kurniawan giving his presentation

The final presentation was delivered by Dr. Nguyen Thi Thuong, titled “Eco-Friendly Approaches to Heavy Metal Removal Using Constructed Wetlands.” She began by highlighting the serious issue of heavy metal and wastewater pollution in Southeast Asia and reviewed existing treatment methods, emphasizing the importance of biological approaches for sustainable wastewater management, particularly the use of constructed wetlands. She presented examples from Southeast Asian countries where constructed wetlands have been applied to remove heavy metals from various wastewater sources, including landfill leachate, domestic wastewater, and industrial effluents. She also shared a case study demonstrating the use of by-product waste (clamshell) as a substrate in constructed wetlands for treating acid mine drainage, showing that constructed wetlands achieve high heavy metal removal efficiency. Furthermore, integrating by-product waste not only improves treatment performance but also reduces solid waste discharge into the environment. Following her presentation, participants actively discussed her research and provided constructive comments.

Dr. Nguyen Thi Thuong presenting her research

In his closing remarks, Professor Soda Satoshi from the Graduate School of Science and Engineering, Ritsumeikan University, expressed his heartfelt gratitude to all invited speakers, participants, and organizers for their invaluable contributions to the success of the workshop. He summarized the key discussions and findings, highlighting the critical role of effective wastewater management, particularly heavy metal treatment, in promoting sustainable development in Southeast Asia. Professor Soda emphasized that international collaboration and knowledge sharing are essential for driving innovation, developing practical solutions, and addressing the global challenges of wastewater pollution. He also encouraged participants to continue strengthening research networks and exchanging experiences across countries. Concluding his remarks, he wished all researchers continued health, success, and scientific achievements and expressed his enthusiasm for future international collaborations to advance sustainable wastewater management.