Scenario-Based assessment of inorganic waste and Greenhouse Gas (GHG) emissions in Semarang City: towards circular economy transition

Abstract Population growth and urbanization in Indonesia have caused a drastic increase in waste production, especially in urban areas. Semarang City is one of Indonesia’s five largest cities, contributing to urban waste. This condition causes the Jatibarang landfill to experience a high burden due to the lack of waste management at the waste collection place level. Piles of solid waste from the household sector, traditional markets, commercial activities, and others can trigger the emergence of greenhouse gas (GHG) effects that can threaten environmental conditions. This study focuses on inorganic waste, where the composition of inorganic waste types in Semarang City reaches 39.2% of the total waste generation. This study focuses on classifying and mapping the types and amounts of inorganic waste generation at the waste collection place, then analyzing greenhouse gases (GHG) and the potential for circular economy-based mitigation. Data analysis uses the Intergovernmental Panel on Climate Change (IPCC) Tier 1 formula with the Embedded Emission Factor approach to obtain the best waste management scenario that can be applied at the waste collection place level. The results of the analysis of 4 scenarios show quite significant differences in reducing greenhouse gas (GHG) emissions in inorganic waste types. Scenario 1 refers to existing conditions producing 720,092 kg CO 2 e/day, scenario 2 with the Business-as-Usual (BAU) principle produces 746,154 kg CO 2 e/day, scenario 3 with the 50% Recycling principle produces 373,077 kg CO 2 e/day and scenario 4 with the 50% Recycling + 20% Reuse principle produces 223,846 kg CO 2 e/day. The results of the best scenario show a decrease in emissions of 68.91% against the existing conditions of inorganic waste management in Semarang City. The results of this study are still relevant to developing a sustainable management model while maintaining increased economic benefits.