Potential reduction of greenhouse gas emissions from campus waste: An integrated 4R framework (reduce, reuse, recycle, replace)

Higher education institutions generate considerable waste, making campuses strategic environments for reducing greenhouse gas (GHG) emissions through improved waste management. This study evaluates the potential reduction in GHG emissions from adopting the 4R framework. The objective was to analyse student participation in 4R practices and estimate their impact on waste-related emissions. A total of 315 first-year engineering students completed a structured questionnaire measuring awareness and implementation of 4R behaviours. To validate the survey data, direct field observations of waste generation and composition were conducted across campus waste collection points. Emission estimates were calculated using a Life Cycle Assessment (LCA) approach with emission factors sourced from the Ministry of Environment and Forestry (MoEF) and the IPCC. Results show that participation in 4R practices ranged from 68% to 70%, indicating similar behavioural readiness across programs. Waste generation averaged 50 g per student per day, equivalent to 15.75 kg/day campus-wide. Plastic waste produced the highest emissions at 7.88 kg CO₂-eq/day, contributing to a total estimated baseline emission of 16.01 kg CO₂-eq/day. Based on these findings, strengthening plastic reduction, improving recycling compliance, and implementing behaviour-driven interventions are recommended to support progress toward a low-carbon, zero-waste campus.