Over the past two decades, the options for solid waste management have been changing from land disposal to recycling, waste-to-energy, and incineration due to growing attention for resource and energy recovery. In addition, the reduction of greenhouse gas (GHG) emission has become an issue of concern in the waste sector because such gases often released into the atmosphere during the waste management processes (e.g., biodegradation in landfills and combustion by incineration) can contribute to climate change. In this study, the emission and reduction rates of GHGs by the municipal solid waste (MSW) management options in D city have been studied for the years 1996-2016. The emissions and reduction rates were calculated according to the Intergovernmental Panel on Climate Change guidelines and the EU Prognos method, respectively. A dramatic decrease in the waste landfilled was observed between 1996 and 2004, after which its amount has been relatively constant. Waste recycling and incineration have been increased over the decades, leading to a peak in the GHG emissions from landfills of approximately 63,323 tCO2 eq/yr in 2005, while the lowest value of 35,962 tCO2 eq/ yr was observed in 2016. In 2016, the estimated emission rate of GHGs from incineration was 59,199 tCO2 eq/yr. The reduction rate by material recycling was the highest (-164,487 tCO2 eq/yr) in 2016, followed by the rates by heat recovery with incineration (-59,242 tCO2 eq/yr) and landfill gas recovery (-23,922 tCO2 eq/yr). Moreover, the cumulative GHG reduction rate between 1996 and 2016 was -3.46 MtCO2 eq, implying a very positive impact on future CO2 reduction achieved by waste recycling as well as heat recovery of incineration and landfill gas recovery. This study clearly demonstrates that improved MSW management systems are positive for GHGs reduction and energy savings. These results could help the waste management decision-makers supporting the MSW recycling and energy recovery policies as well as the climate change mitigation efforts at local government level.

In recent years, waste-to-energy conversion using municipal solid waste (MSW) has been gaining attention in municipalities. Such conversion can reduce the dependency of non-renewable energy such as fossil fuels by generating solid refuse fuel (SRF) and diverting landfilling of the waste, although there is debate over the efficiency and economic aspect of the practice. With a growing interest in the conversion, D city is trying to adopt all possible measures towards achieving a material-cycle society by constructing a waste-to-energy town by 2018. The waste-to-energy town will be comprised of energy recovery facilities such as a mechanical treatment facility for fluff-type SRF with a power generation plant, and anaerobic digestion of food waste for biogas recovery. In this paper, we focus on estimating the energy recovery potentials and greenhouse gas (GHG) reduction of MSW by waste-to-energy conversion under three different scenarios. The data required for this study were obtained from available national statistics and reports, a literature review, and interviews with local authorities and industry experts. The lower heating value was calculated using the modified Dulong equation. Based on the results of this study, the energy recovery potential of MSW was calculated to be approximately 14,201-51,122 TOE/y, 12,426-44,732 TOE/y, and 8,520-30,673 TOE/y for Scenarios 1, 2, and 3, respectively. The reduction of GHG by such conversion was estimated to range from 10,074-36,938 tonCO2eq/y, depending on scenario. This study would help determine the production rate of fluff-type SRF to be converted into a form of energy. In addition, this study would aid waste management decision-makers to clarify the effectiveness of recycling of MSW and their corresponding energy recovery potentials, as well as to understand GHG reduction by the conversion.

전 세계적으로 경제활동이 증가함에 따라 자원과 에너지 소비가 확대되면서, 유가 급등과 같은 자원 위기와 기후변화로 대표되는 환경위기를 동시에 겪고 있다. 이에 따라 석유나 석탄과 같은 1차 에너지를 대체할 수 있는 신･재생에너지를 확대 생산･보급함으로써 에너지의 수입 의존율을 줄여나갈 실질적인 방안 마련이 진행되고 있다. 여러 종류의 신･재생 에너지 중에서 특히 폐기물의 에너지화는 화석연료를 대체하고 온실가스 발생을 줄임으로써 지구온난화로 인한 기후변화에 대응할 수 있는 유력한 수단으로 평가받고 있다. SRF(Solid Refised Fuel)란 생활폐기물에서 폐합성수지류, 폐종이류, 폐목재류 등과 같은 가연성 고체폐기물을 원료로 하여 수분과 불연성분을 제거하고 분쇄, 분리, 선별, 건조, 성형 등의 가공 공정을 거쳐서 제조되는 고형연료이다. 현재 대전광역시의 생활폐기물 배출량은 1,469ton/일(2012년 기준)로 그 중 약 66.5%는 재활용이 되고 있다. 그리고 2017년 자원순환단지 설립을 계획하고 있으며 폐기물의 재활용을 넘어 에너지 회수, 효율적 자원순환 체계 구축이라는 전략을 내세우고 있다. 본 연구는 신규로 조성될 대전광역시 자원순환단지와 연계하여 대전광역시 생활폐기물의 에너지화에 대한 잠재량을 산정하고 이에 따른 활용방안을 모색하는 것을 목표로 하고 있다. 연구결과, 대전시 생활폐기물의 저위발열량은 3,870~3,894kcal/kg 였으며, 고위발열량은 4,417~4,441kcal로 나타났고 에너지 잠재량은 연간 33,900 TOE을 상회할 것으로 예측되었다.