Estimation of greenhouse gas reduction in waste recycling sector in Cheongju-si, Korea using US EPA WARM model

The "A new climate agreement" adopted by the 21st Session of the Conference of Parties (COP) in Paris in 2015 and entered into force on November 4. For this purpose, it is mandatory to report on national greenhouse gas inventories and achievement of GHG reduction targets. In order to play a role as a countermeasure against climate change, efforts for climate change are also essential in local governments. Although in Korea, a portion of wastes sector among the total amount of greenhouse gas emissions is only 2.4% (based on 2015 year), considering the effect of substituting natural resources through material recycling, waste-to-energy conversion, and landfill gas recovery would make cumulative further reduction of greenhouse gases. The importance of recycling is increasing in recent years due to the lack of virgin material, the limitation of natural resources, increased waste management costs, limited space in landfills, and the impact of climate change resulting from the decomposition of waste from landfills. In the United States, the EPA WARM (waste reduction model) was developed and widely used to calculate greenhouse gas reductions in the waste sector. In this study, we used the WARM model to estimate the amount of GHG reduction by the recycling of household municipal waste in Cheongju city with a population of 800000, along with material flow analysis on the data of '2017 National Waste Generation and Disposal Status '. In order to calculate the greenhouse gas reduction amount obtained from recycling, baseline scenario was based on assuming that some of the recycled amount was either landfilled or incinerated, while the alternative scenario was based on the currently recycled amount of the city. According to the results of this study, greenhouse gas reductions by the waste recycling of Cheongju city calculated by the WARM model were reduced about 410,000 MTCO2eq (Metric Ton of Carbon Dioxide Equivalent) or 110,000 MTCE(Metric Ton of Carbon Equivalent) per year in 2017 and 2.74 million MBTU of energy was conserved. It should be noted that the feasibility of domestic application and to accurately understand and analyze the factors considered in the system boundary and estimation method should be examined, when applying to actual reduction of GHGs by waste recycling. The results of this study can be used as a basic data for estimating GHG reductions at the local city level in the waste sector and establishing GHG reduction policy in the future.