Twenty-seven representatives from government agencies, academia, recycling enterprises, waste banks, community organisations and the private sector participated in a two-day capacity-building workshop on preventing plastic leakage from recycling activities.

The Department of Environmental Engineering at Universitas Sumatera Utara (USU), in collaboration with the North Sumatra Provincial Environment and Forestry Agency, hosted the workshop under the Capacity Building Programme for Reducing Recycling-Related Marine Plastic Pollution in ASEAN Cities (CaRMPAC). The programme is implemented by the Regional Resource Centre for Asia and the Pacific at the Asian Institute of Technology (AIT RRC.AP), with support from ERIA's Regional Knowledge Centre for Marine Plastic Debris and facilitation by the ASEAN Secretariat.

The opening session began with remarks by Dr. Guilberto Borongan, Director of AIT RRC.AP, followed by Keitaro Tsuji, Director for Environmental Policy and Director of ERIA's Regional Knowledge Centre for Marine Plastic Debris, and Dr. Ahmad Ari Pandi Harahap, Head of the North Sumatra Provincial Environment Agency. The session concluded with welcome remarks by Dr. Zaid Perdana Nasution, Vice Dean of USU's Faculty of Engineering.

The workshop combined technical sessions, field visits and stakeholder dialogue to strengthen participants' understanding of plastic-leakage pathways and practical prevention measures. Presentations by USU and AIT RRC.AP examined local waste-management challenges, leakage risks across formal and informal recycling operations, behavioural-change approaches, and policy and technical measures for improving recycling practices.

Participants also visited USU's Integrated Waste Treatment Facility to observe waste segregation, composting, black soldier fly cultivation and plastic treatment processes. Further visits to the Tzu Chi Foundation's community-based collection centre and Recyclo Goods demonstrated how recovered plastics can be sorted, processed and transformed into marketable products.

Through four focus group discussions, participants identified priority actions for preventing plastic leakage and illegal dumping. These included stronger enforcement of waste-management regulations, improved monitoring and public reporting systems, reliable waste collection services, and wider provision of segregated bins and 3R-based waste stations. Participants also recommended greater institutional support and incentives for waste banks, stronger partnerships between recyclers and manufacturers, and more stable markets for recovered materials.

Public education and behavioural change were identified as equally important. Participants called for sustained awareness programmes promoting household waste segregation, reduced use of single-use plastics, greater uptake of reusable products, and active public reporting of illegal dumping.

The workshop concluded that preventing plastic leakage requires coordinated action by local governments, recycling enterprises and communities. Effective policies and infrastructure must be supported by monitoring, public participation, technical capacity and viable markets for recovered materials. The recommendations generated in Medan will contribute to wider knowledge exchange and locally led action under CaRMPAC across ASEAN cities.