Evaluation of the eco-efficiency of waste treatment facilities in Korea.

As waste treatment facilities become old, their operation and maintenance costs could increase, which translates to higher treatment costs and environmental burden. This study applies the concept of eco-efficiency to evaluate waste treatment facilities considering the various conditions of waste treatment operations based on the case of Korea. In Korea, waste treatment methods were largely divided into five categories, and facilities for each treatment method were chosen based on their size, location, and waste properties for data collection. The method for evaluating the facilities' eco-efficiencies were developed using the concepts of environmental and economic performances. The results of the eco-efficiency evaluation showed that landfills were most environmentally efficient, followed by the organic waste biogasification facilities, food waste recycling facilities, incineration facilities, and, lastly, combustible waste-to-fuel facilities. The results of the eco-efficiency evaluation were further reviewed in terms of three factors which assess the status of existing facilities as well as to identify the environmental and economic indicators which significantly affect the eco-efficiency of waste treatment facilities by treatment method and propose strategic policies for promoting better waste treatment operations.

Economic analysis to promote the resource circulation of end-of-life vehicles in Korea.

This study explores how Korea's ELV recycling policy can be improved to meet the targeted ELV recycling rate by reviewing the characteristics of the recycling policies adopted in Korea and abroad and conducting an economic analysis of each step of the ELV recycling process, namely, dismantling (including waste gas treatment), shredding, and ASR recycling. The costs and revenues of each ELV treatment process was computed using the data from operators in Korea to estimate their economic feasibility. The findings indicated that, in the case of Korea, dismantling accounted for the largest portion of the ELV recycling process, pointing to the need for policies providing financial support to ELV dismantlers to enhance the overall ELV recycling rate. At the post-dismantling stage, it was found that greater attention to the ELV shredding stage and diversifying the treatment methods for recycled automotive shredder residue (ASR) can be valid measures to reduce Korea's current reliance on dismantling. However, institutional or financial support will be essential to assist with the initial investment costs for developing ASR treatment technologies and constructing new facilities.

Valorization of synthetic textile waste using CO2 as a raw material in the catalytic pyrolysis process.

Since an invention of synthetic fibers (textiles), our life quality has been improved. However, the cumulative production and disposal of them have perceived as significant since they are not biodegradable and hard to be upcycled/recycled. From washing textiles, microplastics are released into the environment, which are regarded as emerging contaminants. As a means for source reduction of microplastics, this study proposed a rapid disposal platform for waste textiles (WTs), converting them into value-added products. To this end, catalytic pyrolysis of WT was studied. To offer more environmentally sound process, CO2 was used as a raw material for WT pyrolysis. Thermal cracking of WT led to the production of syngas and CH4 under the CO2 environment. CO2 resulted in additional CO production via gas phase reaction with volatile compounds evolved from pyrolysis of WT. To expedite the reaction kinetics for syngas formation, catalytic pyrolysis was done over Co-based catalyst. Comparing to non-catalytic pyrolysis, CO2-assisted catalytic pyrolysis had 3- and 8-times higher production of H2 and CO, respectively. This process also suppressed catalyst deactivation, converting more than 80 wt% of WT into syngas and CH4. The more generation of CO from the use of CO2 as a raw material offers an effective means to minimize the formations of harmful chemical species, such as benzene derivatives and polycyclic aromatic hydrocarbons.

Resource recovery potentials by landfill mining and reclamation in South Korea.

In the existing paradigm for waste management, landfills are the final disposal site for waste with no control over the waste being sent to the sites. However, the expanding number of landfills that are at the end of their lifespans and the increasing amount of waste disposed of to landfills have presented a growing need for a shift in this paradigm, which can be achieved by the active promotion of landfill mining and resource recovery. In this study, we analyze the landfill resource recovery potentials to understand the effects on landfill lifespan extension, reduction in landfill disposal rate, energy saving, and reduction in greenhouse gas (GHG) emissions. Simulations based on material flow analysis were conducted on existing landfills, which were categorized into four different types based on their remaining capacities and availability of nearby incineration or SRF facilities. The resource recovery potentials, GHG reduction effect, and energy saving effect were higher for Type 2-1 and Type 2-2 landfills with higher ratios of combustible waste. The landfill lifespan extension effect was the highest for Type 2-2 landfill which receives a relatively smaller amount of waste than the other landfills. The reduction in landfill disposal rate was highest for Type 3, which does not have an incinerator or SRF facilities nearby. On the other hand, the overall effects, including the effect on reducing the landfill disposal rate, are the lowest for Type 1 because the chosen landfill only covers a significantly small proportion of the total waste generated in the city compared to the other landfills. The findings of this study suggest that appropriate landfill mining and reclamation operations are integral to prolonging the lifespans of existing landfills and present insights for building future landfill management strategies.

Quantifying and managing regional greenhouse gas emissions: waste sector of Daejeon, Korea.

A credible accounting of national and regional inventories for the greenhouse gas (GHG) reduction has emerged as one of the most significant current discussions. This article assessed the regional GHG emissions by three categories of the waste sector in Daejeon Metropolitan City (DMC), Korea, examined the potential for DMC to reduce GHG emission, and discussed the methodology modified from Intergovernmental Panel on Climate Change and Korea national guidelines. During the last five years, DMC's overall GHG emissions were 239 thousand tons CO2 eq./year from eleven public environmental infrastructure facilities, with a population of 1.52 million. Of the three categories, solid waste treatment/disposal contributes 68%, whilst wastewater treatment and others contribute 22% and 10% respectively. Among GHG unit emissions per ton of waste treatment, the biggest contributor was waste incineration of 694 kg CO2 eq./ton, followed by waste disposal of 483 kg CO2 eq./ton, biological treatment of solid waste of 209 kg CO2 eq./ton, wastewater treatment of 0.241 kg CO2 eq./m(3), and public water supplies of 0.067 kg CO2 eq./m(3). Furthermore, it is suggested that the potential in reducing GHG emissions from landfill process can be as high as 47.5% by increasing landfill gas recovery up to 50%. Therefore, it is apparent that reduction strategies for the main contributors of GHG emissions should take precedence over minor contributors and lead to the best practice for managing GHGs abatement.

Characteristics of MSW and heat energy recovery between residential and commercial areas in Seoul.

This paper analyzes the amount and characteristics of municipal solid waste (MSW) according to the inhabitant density of population and the business concentration in 25 districts in Seoul. Further, the heat energy recovery and avoided CO(2) emissions of four incineration plants located in residential and commercial areas in Seoul are examined. The amount of residential waste per capita tended to increase as the density of inhabitants decreased. The amount of commercial waste per capita tended to increase as the business concentration increased. The examination of the heat energy recovery characteristics indicated that the four incineration plants produced heat energy that depended on residential or commercial areas based on population and business. The most important result regarding avoided CO(2) emissions was that commercial areas with many office-type businesses had the most effective CO(2) emission savings by combusting 1 kg of waste. Assuming the full-scale operation of the four incineration plants, the amount of saved CO(2) emissions per year was 444 Gg CO(2) and 57,006 households in Seoul can be provided with heat energy equivalent to 542,711 Nm(3) of LNG.