- Email: [email protected]
The status of waste management and waste to energy for district heating in South Korea
Waste Management 85 (2019) 304–316
Contents lists available at ScienceDirect
Waste Management journal homepage: www.elsevier.com/locate/wasman
The status of waste management and waste to energy for district heating in South Korea A.C. (Thanos) Bourtsalas a,⇑, Yoonjung Seo a,b, Md Tanvir Alam b, Yong-Chil Seo b a b
Earth Engineering Center, Columbia University, NY, USA Department of Environmental Engineering, Yonsei University, Wonju, South Korea
a r t i c l e
i n f o
Article history: Received 4 March 2018 Revised 16 December 2018 Accepted 1 January 2019
Keywords: Municipal solid waste Waste composition Waste-to-energy District heating S. Korea
a b s t r a c t This paper focuses on waste management and waste to energy (WTE) for district heating in S. Korea. The chemical formula for the materials disposed of in volume base waste fee (VBWF) bags that are processed in WTE plants was calculated as: C6H9.9O2.3, with a heat of formation of 27.6 MJ/kg. The average heating value for the 35 WTE plants was 9.7 MJ/kg, and the average amount of energy recovered was calculated at 1.5 MWh/ton waste processed. 22 of the 35 WTE plants comply with the limits of the R1 formula for energy recovery plants (R1 > 0.61), as introduced by the EU. It was estimated that 8% of the district heating demand is provided by WTE in S. Korea. WTE plants can contribute to about 0.6% to the total electricity demand of S. Korea and aid the efforts of the nation to phase out the dependence on fossil fuels. The average dioxin emissions of all WTE plants were 0.005 ng TEQ/Nm3 (limit:0.1 ng TEQ/Nm3), and most of the other pollutants examined indicated a ten-fold to hundred-fold lower emissions than the national and the EU standards. S. Korea indicated an improved performance in sustainable waste management, with combined recycling/ composting and WTE rates of about 80%, as compared to the average of the EU-28 with 65%, and the US with 36.5%, even if the EU and the US had higher GDP/capita (PPP) than S. Korea. Ó 2019 Elsevier Ltd. All rights reserved.
1. Introduction The proper and efficient management of municipal solid waste (MSW) is vital to achieving sustainable development as poor waste management impacts on public health and the environment and affects the development and improvement of future generations. For this purpose, the waste management hierarchy (Kaufman et al., 2008, Nixon et al., 2013) is used in various forms and widely accepted by organizations and legislative bodies across the world. Countries operating the most sustainable MSW management typically use integrated systems that achieve maximum, commercially viable, extraction and recycling of valuable materials. The post recycled MSW is recovered for energy production in waste-toenergy (WTE) facilities that meet appropriate environmental operating standards, such as the EU Waste Incineration Directive (WID). WTE facilities should ideally recover the low-pressure steam for district heating/cooling and/or industrial uses, in addition to the electricity production (Nixon et al., 2013; Themelis et al., 2013; Ulloa, 2007). District Heating (DH) is defined as the distribution of thermal energy from a central heat source to many residential, ⇑ Corresponding author. E-mail address: [email protected] (A.C. (Thanos) Bourtsalas). https://doi.org/10.1016/j.wasman.2019.01.001 0956-053X/Ó 2019 Elsevier Ltd. All rights reserved.
commercial and/or industrial areas, by conveying steam or hot water through a network of insulated pipes (Ulloa, 2007). A significant advantage of a DH system fueled by MSW is the potential for reducing environmental pollution. For example, the carbon dioxide savings from WTE plants co-generating 1 MWh of electricity are approximately 0.5 ton of CO2-eq, as compared to a power plant that uses coal (Ulloa, 2007). Hot water DH systems are used widely in Europe and in S. Korea and gaining in popularity in the U.S. The development of DH systems is associated with the fuel dependence of a country. For example, the Danish government provided strong incentives for the production of energy from alternative sources, including WTE, as a result of the oil crisis of the 1970s. The generation of heat relied only on imported oil and heat budgets multiplied within few months (Ulloa, 2007, Danish Energy Agency and Danish Board of District heating, 2015). In 2015, in Denmark, WTE provided to the district heating network about 35% of the total heating demand. During summer, the heat is provided for district cooling purposes (Ulloa, 2007, Danish Energy Agency and Danish Board of District heating, 2015). Similar is the situation in S. Korea, where WTE contribute significantly to the DH demand of the nation, however, the energy mainly relies on imports (EIA, 2015).
A.C. (Thanos) Bourtsalas et al. / Waste Management 85 (2019) 304–316
S. Korea is divided into ten provinces and seven metropolitan areas (Seoul, Incheon, Busan, Gwangju, Daegu, Daejeon, and Ulsan) (Population and Housing Census, 2017, Seo, 2013). The population has been increased by about 0.3 to 0.4%, i.e. 150 to 200,000 people per year since 2005, with 51.09 M people living in S. Korea in 2018. This was an increase of 5.9 M people since 1995. The population density in South Korea is 524 per Km2 (total land area: 97,230 Km2). 81.4% of the population is urban (41,511,797 people in 2018). Seoul is the most populous province of S. Korea with a population of the metropolitan of about 25.6 M in 2017 and a population density of about 17,000 people per km2. Gyeonggi province indicated a significant industrialization and urbanization increase since the 1970s, with about 12.3 M people living in the area in 2017. Gyeonguam and Busan provinces had about 3.4 M inhabitants each in 2017 (Population and Housing Census, 2017, Seo, 2013). S. Korea faced a significant growth of the middle-income class, with the GDP per capita (PPP) changing from $15,761 in 1995 to $25,976 in 2017. In 2017, S. Korea was the eighth country in the world in total energy consumption, with about 4.5 metric tons (t) of oil equivalent. About 97% of this energy was imported and coal (42%), gas (24%) and nuclear (28%) accounted for about 94% of the total electricity production in 2015, similar to the 2015 levels (Korea Energy Economics Institute, 2017; EIA, 2015). A steady increase in natural gas, coal, and nuclear energy consumption is associated with the negligible use of renewable energy, from wind, solar, hydro, waste and biofuels. However, the accident at the Fukushima nuclear power plant and problems observed in S. Korea with the certification of some parts of nuclear power stations in late 2012, lead the government to reconsider the role of nuclear energy as forcefully introduced in 2008. The government implemented a directive in early 2014, the primary objectives being the reduction of the dependence on nuclear power generation and fossil fuel imports and increasing the investments in renewable energy production (Korea Energy Economics Institute, 2017; EIA, 2015). Waste management in S. Korea has been advanced since the mid-1990s with the introduction of the volume base waste fee (VBWF) system that required households, businesses, and institutions to separate MSW into two streams (Park and Lah, 2015; Yang et al., 2015; Seo, 2013; AIEES, 2012; Park, 2009; Kim, 2008; Ahn et al., 2007; Ju, 2005; Cheong, 1995). Single stream recyclables and post-recycled/combustible wastes were placed in VBWF bags, which were purchased at supermarkets, groceries, and convenience stores. Also, in 2006, the landfilling of food wastes without pre-treatment was banned by the S. Korean government, and residents were required to separate food scraps from the trash that goes into the VBWF bags. By offering a free collection service for separated food wastes as of 2006, the S. Korean government has facilitated the use of food waste for animal feed or its composting to a soil conditioner (Park and Lah, 2015; Seo, 2013; Park, 2009; Kim, 2008; Ahn et al., 2007; Ju, 2005; Cheong, 1995). Therefore, the VBWF bags are typically used for the nonrecyclable/compostable wastes that are processed in WTE facilities to produce district heating and a small amount of electricity. The S. Korean system provides an economic incentive for recycling rather than disposing materials in the VBWF bags, since the price of the VBWF bags increased by about US$0.15/bag since 2006, making the future development of WTE challenging (Park, 2009; Kim, 2008; Ahn et al., 2007; Cheong, 1995). There are a lot of studies associated with waste management and the legislative movements that lead to the advancements of sustainable waste management in S. Korea (Park et al., 2016; Park and Lah, 2015; Yang et al., 2015; Pariatamby and Tanaka, 2014; Seo, 2013; Son, 2012; Ryu, 2010; Park, 2009; Park, 2008; Kim, 2008; Ahn et al., 2007; Ju, 2005; Cheong, 1995). However, limited studies discuss the status
305
and efficiency of the WTE facilities in S. Korea, and the drivers for the extensive use of WTE for district heating (Park et al., 2016; Yang et al., 2015; Ryu, 2010; Ahn et al., 2007). The novelty of the work presented here, is that it presents for a first time the actual emissions of the WTE plants in S. Korea and indicates the importance of district heating recovery from WTE by evaluating the R1 performance of the operations with the use of primary data. It also provides a holistic understanding on the chemical composition and the associated energetic potential of the MSW combusted in these facilities. Therefore, a comprehensive evaluation on the efficiency of the operations is conducted and improvements on the systems used are suggested. The first part of the paper provides an overview of waste generation, characteristics of waste disposed in the Volume Based Waste Fee (VBWF) bags, and disposition of MSW in S. Korea. The waste management performance of S. Korea was, also, assessed in this study and compared with other advanced nations by using a simple Sustainable Waste Management Index (SWMI). 2. Data collection and analysis 2.1. MSW generation, management and characterization Data on the generation of MSW were obtained by the Ministry of Environment and the national census. Also, data were cross checked with international databases, such as World Bank, Central Intelligence Agency (CIA) and Organization of Economic Cooperation and Development (OECD). Maps for the generation of MSW and the location of WTE plants in S. Korea were produced with Arc-GIS. For evaluating various types of waste treatment options, accurate information on the chemical composition of the waste is important. Using dataset from the national waste statistic survey, the organic fractions of MSW disposed of in VBWF bags were calculated. The ultimate analysis of the MSW generated in S. Korea from studies found in the literature (Park et al., 2016; Ministry of Environment, 2015; Ryu, 2010) derived the hypothetical compound. The atomic weight (kg/mol) of the elements found in MSW is reported. The number of moles corresponding to the amount of each element in the compound is calculated by dividing the amount of each element found in the VBWF materials (kg given as % in Table 1) over the atomic weight of the element. This relates to the molar ratio, assuming that the number of carbon moles are 6, (C6), as suggested by Themelis et al., 2002. The heat of reaction of the hypothetical formula in a combustion environment was derived by the HSC software and the maximum release of heat was calculated by applying the Hess law (Themelis et al., 2002). The obtained results, in kJ/mol, were converted to MJ/kg by dividing with the molecular weight of the reactant compound (kg/mol). The results were compared with the corresponding average for New York. 2.2. Waste management performance of S. Korea The management of solid wastes in S. Korea was compared for the years 1995 to 2015. Data for recycling/ composting, waste to energy and landfilling of MSW, were obtained by the Ministry of Environment, 2015; OECD, 2015; Hoornweg and Bhada-Tata, 2012. The level of integrated sustainable waste management has been observed in many forms and has been applied mainly regarding the priorities and financial capabilities of a community. In this context, developed nations are ‘moving away from landfills’, while developing should ‘move away from open dumps’. Therefore, the challenge of sustainability is multiparameter and cannot be
306
A.C. (Thanos) Bourtsalas et al. / Waste Management 85 (2019) 304–316
Table 1 Ultimate analysis of MSW collected in VBWF bags and disposed of in WTE. % by Weight (dry basis) Component of MSW
% in MSW
Carbon
Hydrogen
Oxygen
Nitrogen
Sulfur
Chlorine
Paper Plastics Food Wood Rubber Leather Fabric Others
35.1 21.4 8.1 1.6 0.9 0.4 0.4 32.1
43.67 75.87 45.89 47.38 61.54 52.48 50.8 14.6 41.7 12.01 3.47 6
6.36 10.15 6.36 6.21 8.66 5.91 6.17 2.1 5.8 1.01 5.74 9.9
38.48 5.77 35.3 37 12.07 24.11 33.58 11.01 22.1 16 1.38 2.3
0.51 0.77 2.55 0.71 1.12 1.96 2.05 0.17 0.6 14.01 0.04 0.1
0.02 0.15 0.06 0.02 0.27 0.02 0.01 0.01 0.05 32.07 0.00 0.0
0.4 1.32 1.13 0.29 5.42 8.95 0.58 0.15 0.6 35.45 0.02 0.0
Atomic Weight (kg/mol) # of moles Molar Ratio (Assumption: C = 6) Approximate Chemical Formula C6H9.9O2.3
approached by a single method. However, an attempt was made in this study to compare the waste management performance of the nations by their economic performance, as defined by the Gross Domestic Product per capita on a Purchased Power Parity (GDP/capita (PPP)). A simple sustainable waste management index (SWMI) has been used to assess the waste management performance of different countries. The SWMI is defined as the percentage of MSW that is recycled, composted or thermally treated by a state; therefore, it is the percentage of MSW generated that is not landfilled, i.e. SWMI = (100- landfilling rate) %. The maximum attainable SWMI of 100 implies beneficial reuse of MSW with no discharge of possible resources. In the SWMI, there is no differentiation between engineered landfills with methane recovery that is a proven and successful technique for the management of the solid wastes, and the open dumping/burning of the waste, which is associated significant public health issues. In addition, the recycling/composting rates are from national or international databases. Therefore, the contribution of informal recycling is not accounted, which is significant in many developing countries (Wilson et al., 2006). In addition, the data does not include the landfilling of the WTE residues, especially fly ash, which is the main challenge in the WTE industry since it needs special treatment and disposition, often, to a hazardous landfill. The latter is associated with the legislation of each country. For example, in the UK fly ash is stabilised with cement and disposed of in a landfill. In the US, WTE fly ash and bottom ash are mixed with water and cement and disposed of in a monofill or a landfill (Nixon et al., 2013; Themelis et al., 2013). Therefore, the ‘matrix of sustainable waste management’ can only be a good estimation of the waste management performance of the advanced countries, i.e. first and second and few countries of the third and fourth quadrant. It should be noted, that in this study the main point of the ‘matrix’ is to identify countries that have managed to ‘decouple’ the advancement of sustainable waste management, i.e. ‘move away from landfills’, from the GDP/capita (PPP), as compared to the EU-28 average (Eurostat, 2015). The indicator is a simple approach and should not be used to characterize the level of sustainability of a nation. However, for the needs of the research presented here it was a sufficient metric for the comparison between the waste management statistics of nations. Advanced indicators in this context include the work by Velis et al., 2012. 2.3. Waste to energy for district heating in S. Korea Data for the actual calorific value of the MSW processed in the WTE plants, the capacity and status of waste to energy in S. Korea were obtained by several sources (Korea Energy Economics Institute, 2017; CIA, 2017; Park et al., 2016; UNSD, 2016; KCWI,
2015; Ministry of Environment, 2015; OECD, 2015; Park and Lah, 2015; Yang et al., 2015; Hoornweg and Bhada-Tata, 2012; Park et al., 2011; Ryu, 2010). Maps for the capacity and location of WTE plants were created with Arc Map 10. The average heating value of the S. Korean solid wastes was compared with the average heating value of the US (Themelis et al., 2013) and the EU MSW (CEWEP, 2016). The energy efficiency of the S. Korean WTE plants is calculated using the R1 formula, as specified in the Waste Framework Directive of the European Union (Annex II of Directive 2008/98/EC). A WTE plant is considered energy recovery facility, when the R1, is equal to or above 0.60, for plants permitted before January 2009. For plants permitted after 2010, R1 must be higher than 0.65. When the auxiliary fossil fuel use in WTE plants is negligible, as is the usual case, the R1 factor is calculated using the following simplified formula:
R1ðenergy efficiency factorÞ ¼ ð2:6kW el þ 1:1kW heat Þ=0:97kW MSW : ð1Þ where, the subscript el: denotes electricity to the grid; heat: heat provided to district heating; and MSW: chemical energy stored in the MSW combusted. The R1 formula is an established method for characterizing combustion plants in the European Union. However, some drawbacks associated with the robustness of the method are the climate of the city/ location of the plant and the size of the facility. The R1 value significantly increases with the use of heat, which depends on the climate and the site of the facility. Typically, plants located in urban or industrialized areas, where district heating demand is usually high, have the tendency to indicate higher R1 scores. These aspects were addressed by the ‘COMMISSION DIRECTIVE (EU) 2015/1127 of 10 July 2015 amending Annex II to Directive 2008/98/EC of the European Parliament and of the Council on waste and repealing certain Directives’ that introduced the climate correction factor (CCF). CCF is calculated based on the heating degree days (HDD) of the specific geographic area. The R1 formula is also dependent on the size of the plant. Plants with larger MSW capacity are often more efficient associated with the economies of scale (CEWEP, 2016; Nixon et al., 2013; Themelis et al., 2013). Data on the technologies of the WTE plants were obtained by national databases, official reports and personal contacts of the authors (KCWI, 2015; Ministry of Environment, 2015). The stack emission data of all WTE plants were obtained by the national government official database and cross checked by the operators of the plants (KCWI, 2015; Ministry of Environment, 2015; Park et al., 2011, Ryu, 2010). The compounds examined and reported are: Sulfur oxides (SOX), nitrogen oxides (NOX), hydrogen chloride (HCl),
A.C. (Thanos) Bourtsalas et al. / Waste Management 85 (2019) 304–316
carbon monoxide (CO), particulate matter (PM), and dioxins. Data were compared to the national established limits (Ministry of Environment, 2015).
3. Results and discussion 3.1. Generation and characterization of MSW The spatial distribution of the MSW generated in the various cities of S. Korea is presented in Fig. 1. The inhabitants of Seoul generate the most MSW in S. Korea, followed by Gyeonggi, Gyeonguam and Busan, as expected, considering the population of these regions (Population and Housing Census, 2017).
307
The total amount of MSW generated in S. Korea has been slightly reduced from 19 Mt in 2008, which was the highest amount generated since 1995, to 17.8 Mt in 2015, as presented in Fig. 2. The amount of MSW generated fluctuated between 16.6 Mt in 1999 to 19 Mt in 2008. The per capita MSW generation was reduced from the high of 0.39 (1995) and 0.4 t/capita per year (1996) to the low of 0.34 t/capita per year in 2015. Fig. 2 illustrates the changes in MSW composition from 1995 to 2015. The source separated recyclables remained about at the same level since 1995, 0.1 to 0.2 t per capita per year. After the segregation of food waste, the total amount of MSW disposed in VBWF bags decreased by around 40%. The combustible waste collected from the VBWF bags was significantly reduced from 0.25 to 0.3 t per capita per year from the mid-1990s to the mid-2000s to 0.15 to 0.2 t per
2015 MSW generaon distribuon in Republic of Korea
Fig. 1. Spatial distribution of MSW generation in S. Korea in 2015, in Mt/y (Ministry of Environment, 2015).
308
A.C. (Thanos) Bourtsalas et al. / Waste Management 85 (2019) 304–316
Fig. 2. Total MSW generation (million tons per year; primary y-axis) and per capita MSW generation (t per capita; secondary y-axis). Total tonnages of the MSW composition in S. Korea from 1995 to 2015 is presented in the bars (Ministry of Environment, 2015).
capita per year from the mid-2000s to the mid-2010s (Ministry of Environment, 2015). Table 1 presents the ultimate analysis of the MSW collected in VBWF and subsequently the materials that are typically combusted for the production of district heating in WTE plants. Other materials include miscellaneous combustibles and incombustible materials. Assuming that Carbon is 6, the following chemical formula for the S. Korean MSW that is disposed of in VBWF bags was calculated: C6H9.9O2.3. The chemical formula for the MSW produced in New York (NY) was calculated by Themelis et al., 2002, as: C6H10O4. Therefore, the NY MSW has slightly higher oxygen as compare to the S. Korean MSW. This difference can be explained by the higher food waste and lower plastic content in the U.S. MSW as compared to the S. Korean MSW. The theoretical chemical formula was calculated for MSW disposed in VBWF bags (Ministry of Environment, 2015; Park and Lah, 2015). HSC software provides the values of the C6H10O2 formula, which is close enough to the formula calculated for the S. Korean MSW. Therefore, in order to calculate the maximum heat release of the MSW fuel, this formula was used. The molecular weight of the C6H10O2 formula is 114.14 kg/mol, and the heat of formation, 420.2 kJ/mol. The molecular weight of the C6H10O4 formula is 146.14 kg/mol and the heat of formation, 809.7 kJ/mol. The heat of formation of O2 is 0 kg/mol, of CO2 is 393.5 kJ/mol CO 2(g), and of H2O is 241.82 kJ/mol at 298.15 K. The chemical reactions for complete combustion of the S. Korean MSW, i.e. C6H10O2, and the NY MSW, i.e., C6H10O4 are:
S:Korea MSW : C6 H10 O2 þ 7:5O2 ¼ 6CO2 þ 5H2 O þ 27:6MJ per kg of MSW
ð2Þ
NY MSW : C6 H10 O4 þ 6:5O2 ¼ 6CO2 þ 5H2 O þ 18:8MJ per kg of MSW
ð3Þ
Thus, the potential heat generated by the S. Korea’s MSW combustibles is relatively higher than that of the NY average. This was expected since the amount of oxygen in the S. Korean was lower and this is associated with the higher combustion efficiency of the fuel.
In 2015, the actual heating value of S. Korean MSW to WTE plants ranged from a low of about 7 to a high of 12 MJ/kg and the average value for the 35 large WTE plants was 9.7 MJ/kg. This value was significantly lower than the heat of formation of the S. Korean MSW chemical formula (27 MJ/kg). This is associated with the heat losses during combustion, the latent heat and the negative effect of glass and metals in the MSW stream. The heating value of the S. Korean MSW is slightly lower than the mean value of 10.3 MJ/kg for the MSW combusted in EU WTE facilities (CEWEP, 2016). However, it is significant lower as compared to the average US MSW, which is 12 to 13 MJ/kg of MSW (Themelis et al., 2013). 3.2. Waste management performance of South Korea In 2015, out of the 17.8 Mt of MSW that were generated, 10.4 Mt (58.8% of the total) were recycled or composted, as shown in Fig. 3. About 4.5 Mt (25.3%) were combusted with energy recovery, and 2.7 Mt (15.9%) were landfilled. Fig. 3 illustrates the changes in the methods of disposal of MSW between 1995 and 2015. The rate of recycling plus composting nearly tripled from only 4.1 Mt (24%) in 1995 to about 10.5 Mt in 2015. However, this number has dropped since 2009, where the total recycling and composting were 11.4 Mt (61%), and the WTE has increased from 3.8 Mt (20%) to 4.5 Mt (25.3%) during the same period. WTE also rose from only 0.7 Mt (4%) in 1995 to 4.5 Mt (25.3%) in 2015. As a result, landfilling was significantly reduced steadily from 12.6 Mt (72%) in 1995 to 2.7 Mt (15.9%) in 2009 (Ministry of Environment, 2015; UNSD, 2015; Hoornweg & Bhada-Tata, 2012). The advancements of sustainable waste management in S. Korea were mainly driven by the introduction of the district heating law in 1991, the VBWF law in 1995 and the ban of food waste in 2006. The reduction in the recycling/composting material that is beneficially used in S. Korea can be explained by the need of the secondary market that was able to absorb the new incoming materials (Park et al., 2016; Pariatamby and Tanaka, 2014; Park, 2008). Fig. 4 shows the SWMI graphed against the Gross Domestic Product (GDP) per capita of different countries. Both indicators expressed as a percentage of the EU-28 average. From this chart, it can be concluded that a group of countries exists with the high
A.C. (Thanos) Bourtsalas et al. / Waste Management 85 (2019) 304–316
309
Fig. 3. Changes in MSW management of S. Korea, 1995–2015 (Ministry of Environment, 2015).
Fig. 4. Graph of the sustainable waste management index (SWMI) vs. GDP per capita for different countries, expressed as a percentage of the EU-28 average GDP per capita (Eurostat, 2015; OECD, 2015; Hoornweg and Bhada-Tata, 2012).
SWMI and this includes Western and Northern European countries, such as Germany, Norway, Switzerland, the Netherlands, Denmark, Austria, Belgium and Sweden, plus Singapore and Japan. All these countries have high GDP per capita (PPP) and have negligible landfill due to their investment in infrastructure over recent decades to deliver sustainable MSW management. South Korea is particularly interesting because it is the only country with a high SWMI that
has relatively GDP per capita (PPP). Therefore, S. Korea has managed to ‘decouple’ the growth of the country with the sustainable waste management development. The nation showed improved SWMI as compared to the EU-28 average (about 20% higher), even if S. Korea had lower GDP/ capita (PPP) (about 10% lower). In addition, S. Korea indicated a significant lower SWMI compared to the US (about 50% lower). S. Korea has 63% lower GDP/capita (PPP)
310
A.C. (Thanos) Bourtsalas et al. / Waste Management 85 (2019) 304–316
than the US. This advancement of S. Korea as compared to other countries was associated with the development of strong national policies that aimed the decentralized communities (Park et al., 2016; Yang et al., 2015; Son, 2012; Ryu, 2010). The government established strict federal legislations that the municipalities obliged to follow. Also, the direction of the government aimed the construction of WTE plants within the city boundaries to provide district heating for the community. A very important factor was the citizens’ participation. Similar characteristics have been observed in Europe, where the European Guidelines and Directives, had main objective the obligation of the nation members of the union. However, different geopolitical characteristics enabled the advancement of SWM in the Western and Northern European part, i.e. countries in the first quadrant of the ‘matrix’. Therefore, the centralized models that aim the decentralized communities are strongly recommended. However, it should be noted, that public
and political will are important factors in the successful implementation of sustainable systems, and typically this type of a legislative approach needs a lot of time for fruition. 3.3. Waste to energy status in South Korea The nation has 172 operating ‘‘incinerators” with capacities of over 100 tpd of which only 35 are combustion plants that export mainly heat or, in few cases, electricity (WTE) and mostly located in metropolitan areas. Fig. 5 shows the locations of these WTE power plants. Most of these plants are in the most populous and densest regions of S. Korea, that are in the Northern Eastern part of S. Korea, Seoul and Gyeonggi (KCWI, 2015). The 2015 capacity of the 35 WTE facilities was 4.5 Mt and accounted for about 90% of the total incinerator capacity in S. Korea. Fig. 6 shows the energy generated (primary y-axis) and
Fig. 5. Areas of WTE plants in S. Korea in 2015 (using ArcMap 10) (KCWI, 2015).
A.C. (Thanos) Bourtsalas et al. / Waste Management 85 (2019) 304–316
311
Fig. 6. Energy generation and use in 35 WTE plants in 2015 (KCWI, 2015; Ministry of Environment, 2015).
Fig. 7. R1 factor of the 35 S. Korean WTE plants in 2015 (KCWI, 2015; Ministry of Environment, 2015; Nixon et al., 2013; Park et al., 2011).
the t of MSW received (secondary y-axis) by each of the 35 WTE plants in 2015 (KCWI, 2015; Ministry of Environment, 2015). The average amount of energy recovered for the production of energy in S. Korea is 1.5 MWh/ton, which is slightly lower than the usual amount of energy recovered in WTE operations in the EU. It was observed that 12 WTE facilities, 34.2% of total number of facilities, in S. Korea processed less than 120,000 tpy and produced less than 1 MWh of energy/ton of MSW. Excluding these facilities, the average energy produced is about 1.8 MWh/ton. In S. Korea, only 7 facilities out of the 35 combust more than 130,000 tpy of MSW, with the largest facility, Kangnam, combusting about 265,000 t of MSW. Subsequently, in Kangnam WTE the highest amount heat energy is produced that amount at 2.3 MWh of energy/t of MSW. As a similar comparison, in Denmark the energy for district heating/cooling is on an average 2 MWh/ton of MSW and an
additional 0.5 to 0.6 MWh/ton of MSW for electricity (Nixon et al., 2013; Themelis et al., 2013; Ulloa, 2007). The power supplied to the district heating network amounted to 4,600 GWh in 2015 (1 MWh/ton of MSW), which is about 8% of the total district heating production in S. Korea (57,600 GWh). About 60% of the eleven businesses operating 24 plants in the district heating sector owned by the government, which initiated the advancement of district heating in S. Korea when enacted the ‘Integrated Energy Support Act’ in 1991 (Park et al., 2016; Yang et al., 2015; Park et al., 2011; Ahn et al., 2007). Hot water allows the transmission of heat over long distances, with relatively low heat loss, less than 10%. The central control system for the heat supply from the power plant is more economic than the conventional single building approach. On the average, district heating operates with 80% fixed cost and 20% variable costs. This is exactly the
312
A.C. (Thanos) Bourtsalas et al. / Waste Management 85 (2019) 304–316
opposite of the cost ratio for its gas competitors, indicating the sensitivity of the systems to interest rates and financing methods. For district heating, over a half of the capital costs are represented by the transmission and distribution network. Costs can be minimized by keeping the length of piping to a minimum. Thus, most systems are designed to serve high-use customers with specified areas. Existing S. Korean steam systems serve between 1,000 and 3,500 customers, which are similar to the US systems (Yang et al., 2015; Ryu, 2010).
WTE in S. Korea contributed about 57 GWh (0.02 MWh/ ton of MSW) to the total electricity production, which is a negligible amount compared to the total power generation in S. Korea (Korea Energy Economics Institute, 2017; EIA, 2015). The negligible contribution of WTE in the energy demand of S. Korea is associated with the high energy in-plant consumption of the WTE plants in the region and the lack of strong incentives to motivate the WTE industry to recover more electricity. In the case that the WTE plants recover electricity, then 2,700 GWh of electricity can be
Fig. 8. (a) Dioxins, (b) PM, (c) SOx, (d) HCl, (e) CO and (f) NOx emissions of WTE plants compared to national limits. All plants indicate emissions significantly lower than the national established limits (KCWI, 2015; Ministry of Environment, 2015; Park et al., 2011, Ryu, 2010).
A.C. (Thanos) Bourtsalas et al. / Waste Management 85 (2019) 304–316
Fig. 8 (continued)
313
314
A.C. (Thanos) Bourtsalas et al. / Waste Management 85 (2019) 304–316
Fig. 8 (continued)
contributed to the grid. Therefore, WTE in S. Korea can contribute about 0.6% to the total electricity production (497,000 GWh). However, as discussed earlier, WTE has significantly contributed to the sustainable solid waste management of the nation, since it reached 4.5 Mt (25.3%) in the same period,
3.4. Energy efficiency of S. Korean WTE plants Fig. 7 presents the electrical and heat energy generated (primary y-axis), and the calculated R1 factor for each plant (secondary y-axis). The average R1 in 2015 was 0.59, which is slightly below
A.C. (Thanos) Bourtsalas et al. / Waste Management 85 (2019) 304–316
the EU R1 limit for energy recovery facility (KCWI, 2015; Ministry of Environment, 2015; Nixon et al., 2013; Park et al., 2011). This relatively low value is mainly associated with the Uijeongbu and Sanbuk WTE plants that indicate a significant low R1 factor of 0.01 and 0.03, respectively. These plants recover electricity only to support the needs of the WTE facility, therefore, the technology is similar to an incinerator without energy production. Excluding these facilities, the R1 average for S. Korean WTE plants is 0.63. A drawback of the operations is associated with the high in-plant energy consumption that is at 0.67 MWh of thermal energy per ton of MSW. This can be significantly reduced by optimizing the amount of air used for combustion (Park and Lah, 2015; Lusardi et al., 2014; Ryu, 2010). Moreover, the improvement of steam parameters and the use of high-pressure steam for the production of electricity will increase the efficiency and, therefore, the revenues of the WTE plants (Nixon et al., 2013; Themelis et al., 2013). Also, the relatively low heating value of the MSW can be increased by the more efficient recovery of food waste that contributes negatively to the heating value of the MSW (Themelis et al., 2002). In this effort, however, the government should advocate the use of WTE and provide subsidies for the development of these projects, as is the case in China, EU and US. The development of WTE will be a ‘low hanging fruit’ but still aid the efforts of the government to phase out fossil fuels and to be more independent in the energy supply of the nation, as at this time about 97% of the energy consumed in S. Korea is imported.
315
S. Korea is near the top of the sustainable-waste-management nations, despite its relatively average range GDP per capita; MSW generation per capita has slightly decreased, from 0.40 t in 1996 to 0.35 t in 2015; The chemical formula for the materials disposed of in VBWF bags was calculated as: C6H9.9O2.3, with a heat of formation of 27.6 MJ/kg. The heating value of S. Korean MSW had an average value of 9.7 MJ/kg; Recycling and composting rates slightly reduced since 2008 and the WTE rates increased; 10.4 Mt of MSW (58.8% of the total) were recycled or composted in 2015; 4.5 Mt of MSW (25.3% of total) was processed, mainly for district heating. The average amount of energy recovered for the production of energy was 1.5 MWh/ton; About 8% of the district heating demand is provided by the 35 WTE; WTE has the potential to contribute up to about 0.6%; of the 35 WTE plants qualify as energy recovery plants (R1 > 0.61) Emissions of the S. Korean WTE plants are a tenfold to a hundredfold below the S. Korean and E.U. standards for most pollutants examined; The average dioxin emission of all plants was 0.005 ng TEQ/Nm3 (limit:0.1 ng TEQ/Nm3);
3.5. Air pollution control and emissions of S. Korean WTE plants Acknowledgments All WTE facilities meet the S. Korean air emission standards for the six air pollutants examined, as presented in Fig. 8 (KCWI, 2015; Ministry of Environment, 2015; Park et al., 2011, Ryu, 2010). Dioxin levels are the main concern because of their extremely high toxic potency even at trace quantities. The average dioxin emission for all plants in 2015 was 0.005 ng TEQ/Nm3 while the S. Korean standard was 0.1 ng TEQ/Nm3 (same as E.U. and U.S. standard). The total dioxins from all S. Korean WTE plants were at 0.08 g TEQ. S. Korean WTE plants operate with several processes of air pollution control equipment, able to remove the contaminants from the flue gas and allow the facility to comply with the stringent environmental standards. For example, the Kangnam plant treats flue gas generated from MSW combustion using selective noncatalytic reduction (SNCR), scrubber, semi-dry removal (SDR) type, dry flue gas desulfurization, bag filter, and selective catalytic reduction (SCR). Mapo WTE plant uses SNCR, SDR, bag filter, and SCR. The very low levels of dioxin emissions from S. Korea’s WTE plants can be attributable to the activated carbon used during the gas cleaning process. For example, the Paju plant, with MSW capacity of 200 tpd, treats the flue gas through SDR, bag filter and SCR and with 0.156 kg of activated carbon per t of MSW (KCWI, 2015; Ministry of Environment, 2015). Only two plants operate with SCR systems, a moving grate and a Circulating Fluidized Bed (CFB) (KCWI, 2015; Ryu, 2010). A study conducted on 57 WTE plants in the US, representing 84% of the total U.S. WTE capacity, concluded that the average dioxin concentration was 0.029 ng TEQ. The total amount of dioxins emitted by all the 77 U.S. WTE plants in 2012 was estimated at 2.9 g TEQ. The same study concluded that 1,300 g TEQ of dioxins were emitted in 2012 from open burning sources (Dwyer and Themelis, 2015). 4. Conclusions The main findings of the research study can be summarized as follows:
This study was supported by the Global WTERT Council (Columbia University) and was initiated based on the thesis by Y. Seo (www.wtert.org, Publications), Earth Engineering Center, Columbia University. References Ahn, H., Hwang, S., Kim, K., Lee, H., Park, S. & Suk, K., 2007. Waste Management in Korea. MBA White Paper, University of North Carolina. Available at: extranet. kenan-flagler.unc.edu/kicse/ORIG%20Shared%20Documents/Waste% 20Management%20in%20Korea.pdf (accessed: November 2017) Central Intelligence Agency (CIA): The World Factbook https://www.cia.gov/library/ publications/the-world-factbook/ (accessed: November 2017) Confederation of European Energy from Waste Plants (CEWEP) energy report, 2016. CEWEP, Bamberg. Available at: www.cewep.org (accessed: November2017) Cheong, H.S., 1995. Pricing for municipal solid waste disposal in Korea. Master’s dissertation, CSERGE. School of Environmental Sciences, University of East Anglia. Available at: www.cserge.uea.ac.uk/sites/default/files/wm_1995_04.pdf (accessed: November 2017). Danish Energy Agency and Danish Board of District heating, 2015. Joint report on District heating- Danish experiences. Available at: https://ens.dk/en/ourresponsibilities/global-cooperation/experiences-district-heating (accessed: November 2017). Dwyer, H., Themelis, N.J., 2015. Inventory of US 2012 dioxin emissions to atmosphere. Waste Manage. 46, 242–246. Energy Institute Association Statistical Energy Review 2015. Available at: www. eia.gov/international/data (accessed: November 2017) European Commission Directorate General, Guidelines on the interpretation of the R1 energy efficiency formula for incineration facilities dedicated to the processing of municipal solid waste according to Annex II of Directive 2008/ 98/EC on waste. Available at: http://ec.europa.eu/environment/waste/ framework/pdf/guidance.pdf (accessed: November 2017) Eurostat data, 2015. Available at: ec.europa.eu/eurostat/tgm/refreshTableAction. do?tab=table&plugin=1&pcode=tsdpc240&language=en (accessed: November 2017) Hoornweg, D., Bhada-Tata, P., 2012. What a waste: a global review of solid waste management. Urban Development Series Knowledge Papers 15, 1–98. Available at: openknowledge.worldbank.org/handle/10986/17388. Ju, D.Y., 2005. 3R Portfolio: good practices to promote the 3Rs (Republic of Korea). In: In ministerial conference on the 3R initiative, pp. 28–30. Available at: www. env.go.jp/recycle/3r/en/info/05_12.pdf (accessed: November 2017). Kaufman, S., Kwon, E., Krishnan, N., Castaldi, M., Themelis, N., 2008. Use of statistical entropy and life cycle analysis to evaluate global warming potential of waste
316
A.C. (Thanos) Bourtsalas et al. / Waste Management 85 (2019) 304–316
management systems. In: In 16th Annual North American Waste-to-Energy Conference. American Society of Mechanical Engineers, USA, pp. 107–112. Available at: www.seas.columbia.edu/earth/wtert/NAWTEC16-1915-Kaufman. pdf. Kim, K., 2008. Performance of Waste Management Policy in Korea. Ministry of Environment, Republic of Korea. Korea Conference on Waste Incineration (KCWI, in Korean), 2015. Current Operating Status of Waste to Energy Facilities for Municipal Solid Waste. Available at: k-inc.co.kr/board/pds1.php (accessed: November 2017) Korea Energy Economics Institute, 2017. Yearbook of Energy Statistics: Available at: https://www.keei.re.kr/main.nsf/index_en.html (accessed: November 2017). Lusardi, M., McKenzie, Kohn, Themelis, N., Castaldi, M., 2014. Technical assessment of the CLEERGAS moving grate-based process for energy generation from municipal solid waste. Waste Manage. Res. 32 (8), 772–781. Ministry of Environment, Government of the Republic of Korea. 1997 to 2015. Current status of waste generation and treatment (in Korean). Available at: http://eng.me.go.kr/eng/web/index.do?menuId=394 (accessed: November 2017) Nixon, J.D., Wright, D.G., Dey, P.K., Ghosh, S.K., Davies, P.A., 2013. A comparative assessment of waste incinerators in the UK. Waste Manage. 33 (11), 2234– 2244. OECD waste statistics, 2015 Available at: data.oecd.org/waste/municipal-waste.htm (accessed: November 2017) Pariatamby, A., Tanaka, M., 2014. Municipal solid waste management in Asia and the Pacific Islands. Environmental Science. Springer, Singapore. Park, G.S., 2008. The effective policy of extended producer responsibility. The Monthly Packaging World 177, 70–78. Park, J. W. ,2009. 3R policies of Korea. Ministry of Environment, Seoul. (accessed: November 2017) Park, S., Choi, J.H., Park, J., 2011. The estimation of N2O emissions from municipal solid waste incineration facilities: The Korea case. Waste Manage. 31, 1765– 1771. Park, S., Lah, T.J., 2015. Analyzing the success of the volume-based waste fee system in South Korea. Waste Manage. 43, 533–538. Park, S., Park, S.I., Lee, S.H., 2016. Strategy on sustainable infrastructure asset management: focus on Korea ׳s future policy directivity. Renew. Sustain. Energy Rev. 62, 710–722.
Population and Housing Census, 2017. Available at: kostat.go.kr (accessed: November 2017) Ryu, C., 2010. Potential of municipal solid waste for renewable energy production and reduction of greenhouse gas emissions in South Korea. J. Air Waste Manag. Assoc. 60 (2), 176–183. Seo, Y., 2013. Current MSW Management and Waste-to-Energy Status in the Republic of Korea. Master’s dissertation, Department of Earth and Environmental. Engineering, Columbia University. Available at: www.seas.columbia.edu/ earth/wtert/sofos/YS%20Thesis_final_Nov3.pdf. Son, C.J., 2012. A study on The Extended Producer Responsibility System as a Waste Management Policy. Doctoral Dissertation. University of Seokyeong. The Asian Institute for Energy, Environment and Sustainability (AIEES), The Volume Based Waste Fee System of Korea ,2012, The Seoul National University. Available at: archive.epi.yale.edu/indicators-in-practice/volume-based-wastefee-system-korea (accessed: November 2017) Themelis, N.J., Kim, Y.H., Brady, M.H., 2002. Energy recovery from New York City municipal solid wastes. Waste Manag Res. 20 (3), 223–233. Themelis, N.J., Barriga, M.E., Estevez, P., Velasco M.G., 2013: Guidebook for the application of Waste to Energy Technologies in Latin America and the Caribbean, EEC-Columbia sponsored by the Interamerican Development Bank. Available at: http://www.seas.columbia.edu/earth/wtert/pressreleases/ Guidebook_WTE_v5_July25_2013.pdf Ulloa, P., 2007. Potential for combined heat and power and district heating and cooling from waste-to-energy facilities in the US–learning from the Danish experience (Doctoral dissertation, Columbia University). Thesis available at: www.seas.columbia.edu/earth/wtert/sofos/ulloa_thesis.pdf United Nations Sustainable Development. Waste Management. Available at: sustainabledevelopment.un.org/dsd_aofw_ni/ni_pdfs/NationalReports/korea/ WasteManagement.pdf (accessed: November 2017) Velis, C.A., Wilson, D.C., Rocca, O., Smith, S.R., Mavropoulos, A., Cheeseman, C.R., 2012. An analytical framework and tool (‘InteRa’) for integrating the informal recycling sector in waste and resource management systems in developing countries. Waste Manage. Res. 30 (9), 43–66. Wilson, D.C., Velis, C.A., Cheeseman, C.R., 2006. Role of informal sector recycling in waste management in developing countries. Habitat Int. 30 (4), 797–808. Yang, W.S., Park, J.K., Park, S.W., Seo, Y.C., 2015. Past, present and future of waste management in Korea. J. Mater. Cycles Waste Manage. 17 (2), 207–217.
Contents lists available at ScienceDirect
Waste Management journal homepage: www.elsevier.com/locate/wasman
The status of waste management and waste to energy for district heating in South Korea A.C. (Thanos) Bourtsalas a,⇑, Yoonjung Seo a,b, Md Tanvir Alam b, Yong-Chil Seo b a b
Earth Engineering Center, Columbia University, NY, USA Department of Environmental Engineering, Yonsei University, Wonju, South Korea
a r t i c l e
i n f o
Article history: Received 4 March 2018 Revised 16 December 2018 Accepted 1 January 2019
Keywords: Municipal solid waste Waste composition Waste-to-energy District heating S. Korea
a b s t r a c t This paper focuses on waste management and waste to energy (WTE) for district heating in S. Korea. The chemical formula for the materials disposed of in volume base waste fee (VBWF) bags that are processed in WTE plants was calculated as: C6H9.9O2.3, with a heat of formation of 27.6 MJ/kg. The average heating value for the 35 WTE plants was 9.7 MJ/kg, and the average amount of energy recovered was calculated at 1.5 MWh/ton waste processed. 22 of the 35 WTE plants comply with the limits of the R1 formula for energy recovery plants (R1 > 0.61), as introduced by the EU. It was estimated that 8% of the district heating demand is provided by WTE in S. Korea. WTE plants can contribute to about 0.6% to the total electricity demand of S. Korea and aid the efforts of the nation to phase out the dependence on fossil fuels. The average dioxin emissions of all WTE plants were 0.005 ng TEQ/Nm3 (limit:0.1 ng TEQ/Nm3), and most of the other pollutants examined indicated a ten-fold to hundred-fold lower emissions than the national and the EU standards. S. Korea indicated an improved performance in sustainable waste management, with combined recycling/ composting and WTE rates of about 80%, as compared to the average of the EU-28 with 65%, and the US with 36.5%, even if the EU and the US had higher GDP/capita (PPP) than S. Korea. Ó 2019 Elsevier Ltd. All rights reserved.
1. Introduction The proper and efficient management of municipal solid waste (MSW) is vital to achieving sustainable development as poor waste management impacts on public health and the environment and affects the development and improvement of future generations. For this purpose, the waste management hierarchy (Kaufman et al., 2008, Nixon et al., 2013) is used in various forms and widely accepted by organizations and legislative bodies across the world. Countries operating the most sustainable MSW management typically use integrated systems that achieve maximum, commercially viable, extraction and recycling of valuable materials. The post recycled MSW is recovered for energy production in waste-toenergy (WTE) facilities that meet appropriate environmental operating standards, such as the EU Waste Incineration Directive (WID). WTE facilities should ideally recover the low-pressure steam for district heating/cooling and/or industrial uses, in addition to the electricity production (Nixon et al., 2013; Themelis et al., 2013; Ulloa, 2007). District Heating (DH) is defined as the distribution of thermal energy from a central heat source to many residential, ⇑ Corresponding author. E-mail address: [email protected] (A.C. (Thanos) Bourtsalas). https://doi.org/10.1016/j.wasman.2019.01.001 0956-053X/Ó 2019 Elsevier Ltd. All rights reserved.
commercial and/or industrial areas, by conveying steam or hot water through a network of insulated pipes (Ulloa, 2007). A significant advantage of a DH system fueled by MSW is the potential for reducing environmental pollution. For example, the carbon dioxide savings from WTE plants co-generating 1 MWh of electricity are approximately 0.5 ton of CO2-eq, as compared to a power plant that uses coal (Ulloa, 2007). Hot water DH systems are used widely in Europe and in S. Korea and gaining in popularity in the U.S. The development of DH systems is associated with the fuel dependence of a country. For example, the Danish government provided strong incentives for the production of energy from alternative sources, including WTE, as a result of the oil crisis of the 1970s. The generation of heat relied only on imported oil and heat budgets multiplied within few months (Ulloa, 2007, Danish Energy Agency and Danish Board of District heating, 2015). In 2015, in Denmark, WTE provided to the district heating network about 35% of the total heating demand. During summer, the heat is provided for district cooling purposes (Ulloa, 2007, Danish Energy Agency and Danish Board of District heating, 2015). Similar is the situation in S. Korea, where WTE contribute significantly to the DH demand of the nation, however, the energy mainly relies on imports (EIA, 2015).
A.C. (Thanos) Bourtsalas et al. / Waste Management 85 (2019) 304–316
S. Korea is divided into ten provinces and seven metropolitan areas (Seoul, Incheon, Busan, Gwangju, Daegu, Daejeon, and Ulsan) (Population and Housing Census, 2017, Seo, 2013). The population has been increased by about 0.3 to 0.4%, i.e. 150 to 200,000 people per year since 2005, with 51.09 M people living in S. Korea in 2018. This was an increase of 5.9 M people since 1995. The population density in South Korea is 524 per Km2 (total land area: 97,230 Km2). 81.4% of the population is urban (41,511,797 people in 2018). Seoul is the most populous province of S. Korea with a population of the metropolitan of about 25.6 M in 2017 and a population density of about 17,000 people per km2. Gyeonggi province indicated a significant industrialization and urbanization increase since the 1970s, with about 12.3 M people living in the area in 2017. Gyeonguam and Busan provinces had about 3.4 M inhabitants each in 2017 (Population and Housing Census, 2017, Seo, 2013). S. Korea faced a significant growth of the middle-income class, with the GDP per capita (PPP) changing from $15,761 in 1995 to $25,976 in 2017. In 2017, S. Korea was the eighth country in the world in total energy consumption, with about 4.5 metric tons (t) of oil equivalent. About 97% of this energy was imported and coal (42%), gas (24%) and nuclear (28%) accounted for about 94% of the total electricity production in 2015, similar to the 2015 levels (Korea Energy Economics Institute, 2017; EIA, 2015). A steady increase in natural gas, coal, and nuclear energy consumption is associated with the negligible use of renewable energy, from wind, solar, hydro, waste and biofuels. However, the accident at the Fukushima nuclear power plant and problems observed in S. Korea with the certification of some parts of nuclear power stations in late 2012, lead the government to reconsider the role of nuclear energy as forcefully introduced in 2008. The government implemented a directive in early 2014, the primary objectives being the reduction of the dependence on nuclear power generation and fossil fuel imports and increasing the investments in renewable energy production (Korea Energy Economics Institute, 2017; EIA, 2015). Waste management in S. Korea has been advanced since the mid-1990s with the introduction of the volume base waste fee (VBWF) system that required households, businesses, and institutions to separate MSW into two streams (Park and Lah, 2015; Yang et al., 2015; Seo, 2013; AIEES, 2012; Park, 2009; Kim, 2008; Ahn et al., 2007; Ju, 2005; Cheong, 1995). Single stream recyclables and post-recycled/combustible wastes were placed in VBWF bags, which were purchased at supermarkets, groceries, and convenience stores. Also, in 2006, the landfilling of food wastes without pre-treatment was banned by the S. Korean government, and residents were required to separate food scraps from the trash that goes into the VBWF bags. By offering a free collection service for separated food wastes as of 2006, the S. Korean government has facilitated the use of food waste for animal feed or its composting to a soil conditioner (Park and Lah, 2015; Seo, 2013; Park, 2009; Kim, 2008; Ahn et al., 2007; Ju, 2005; Cheong, 1995). Therefore, the VBWF bags are typically used for the nonrecyclable/compostable wastes that are processed in WTE facilities to produce district heating and a small amount of electricity. The S. Korean system provides an economic incentive for recycling rather than disposing materials in the VBWF bags, since the price of the VBWF bags increased by about US$0.15/bag since 2006, making the future development of WTE challenging (Park, 2009; Kim, 2008; Ahn et al., 2007; Cheong, 1995). There are a lot of studies associated with waste management and the legislative movements that lead to the advancements of sustainable waste management in S. Korea (Park et al., 2016; Park and Lah, 2015; Yang et al., 2015; Pariatamby and Tanaka, 2014; Seo, 2013; Son, 2012; Ryu, 2010; Park, 2009; Park, 2008; Kim, 2008; Ahn et al., 2007; Ju, 2005; Cheong, 1995). However, limited studies discuss the status
305
and efficiency of the WTE facilities in S. Korea, and the drivers for the extensive use of WTE for district heating (Park et al., 2016; Yang et al., 2015; Ryu, 2010; Ahn et al., 2007). The novelty of the work presented here, is that it presents for a first time the actual emissions of the WTE plants in S. Korea and indicates the importance of district heating recovery from WTE by evaluating the R1 performance of the operations with the use of primary data. It also provides a holistic understanding on the chemical composition and the associated energetic potential of the MSW combusted in these facilities. Therefore, a comprehensive evaluation on the efficiency of the operations is conducted and improvements on the systems used are suggested. The first part of the paper provides an overview of waste generation, characteristics of waste disposed in the Volume Based Waste Fee (VBWF) bags, and disposition of MSW in S. Korea. The waste management performance of S. Korea was, also, assessed in this study and compared with other advanced nations by using a simple Sustainable Waste Management Index (SWMI). 2. Data collection and analysis 2.1. MSW generation, management and characterization Data on the generation of MSW were obtained by the Ministry of Environment and the national census. Also, data were cross checked with international databases, such as World Bank, Central Intelligence Agency (CIA) and Organization of Economic Cooperation and Development (OECD). Maps for the generation of MSW and the location of WTE plants in S. Korea were produced with Arc-GIS. For evaluating various types of waste treatment options, accurate information on the chemical composition of the waste is important. Using dataset from the national waste statistic survey, the organic fractions of MSW disposed of in VBWF bags were calculated. The ultimate analysis of the MSW generated in S. Korea from studies found in the literature (Park et al., 2016; Ministry of Environment, 2015; Ryu, 2010) derived the hypothetical compound. The atomic weight (kg/mol) of the elements found in MSW is reported. The number of moles corresponding to the amount of each element in the compound is calculated by dividing the amount of each element found in the VBWF materials (kg given as % in Table 1) over the atomic weight of the element. This relates to the molar ratio, assuming that the number of carbon moles are 6, (C6), as suggested by Themelis et al., 2002. The heat of reaction of the hypothetical formula in a combustion environment was derived by the HSC software and the maximum release of heat was calculated by applying the Hess law (Themelis et al., 2002). The obtained results, in kJ/mol, were converted to MJ/kg by dividing with the molecular weight of the reactant compound (kg/mol). The results were compared with the corresponding average for New York. 2.2. Waste management performance of S. Korea The management of solid wastes in S. Korea was compared for the years 1995 to 2015. Data for recycling/ composting, waste to energy and landfilling of MSW, were obtained by the Ministry of Environment, 2015; OECD, 2015; Hoornweg and Bhada-Tata, 2012. The level of integrated sustainable waste management has been observed in many forms and has been applied mainly regarding the priorities and financial capabilities of a community. In this context, developed nations are ‘moving away from landfills’, while developing should ‘move away from open dumps’. Therefore, the challenge of sustainability is multiparameter and cannot be
306
A.C. (Thanos) Bourtsalas et al. / Waste Management 85 (2019) 304–316
Table 1 Ultimate analysis of MSW collected in VBWF bags and disposed of in WTE. % by Weight (dry basis) Component of MSW
% in MSW
Carbon
Hydrogen
Oxygen
Nitrogen
Sulfur
Chlorine
Paper Plastics Food Wood Rubber Leather Fabric Others
35.1 21.4 8.1 1.6 0.9 0.4 0.4 32.1
43.67 75.87 45.89 47.38 61.54 52.48 50.8 14.6 41.7 12.01 3.47 6
6.36 10.15 6.36 6.21 8.66 5.91 6.17 2.1 5.8 1.01 5.74 9.9
38.48 5.77 35.3 37 12.07 24.11 33.58 11.01 22.1 16 1.38 2.3
0.51 0.77 2.55 0.71 1.12 1.96 2.05 0.17 0.6 14.01 0.04 0.1
0.02 0.15 0.06 0.02 0.27 0.02 0.01 0.01 0.05 32.07 0.00 0.0
0.4 1.32 1.13 0.29 5.42 8.95 0.58 0.15 0.6 35.45 0.02 0.0
Atomic Weight (kg/mol) # of moles Molar Ratio (Assumption: C = 6) Approximate Chemical Formula C6H9.9O2.3
approached by a single method. However, an attempt was made in this study to compare the waste management performance of the nations by their economic performance, as defined by the Gross Domestic Product per capita on a Purchased Power Parity (GDP/capita (PPP)). A simple sustainable waste management index (SWMI) has been used to assess the waste management performance of different countries. The SWMI is defined as the percentage of MSW that is recycled, composted or thermally treated by a state; therefore, it is the percentage of MSW generated that is not landfilled, i.e. SWMI = (100- landfilling rate) %. The maximum attainable SWMI of 100 implies beneficial reuse of MSW with no discharge of possible resources. In the SWMI, there is no differentiation between engineered landfills with methane recovery that is a proven and successful technique for the management of the solid wastes, and the open dumping/burning of the waste, which is associated significant public health issues. In addition, the recycling/composting rates are from national or international databases. Therefore, the contribution of informal recycling is not accounted, which is significant in many developing countries (Wilson et al., 2006). In addition, the data does not include the landfilling of the WTE residues, especially fly ash, which is the main challenge in the WTE industry since it needs special treatment and disposition, often, to a hazardous landfill. The latter is associated with the legislation of each country. For example, in the UK fly ash is stabilised with cement and disposed of in a landfill. In the US, WTE fly ash and bottom ash are mixed with water and cement and disposed of in a monofill or a landfill (Nixon et al., 2013; Themelis et al., 2013). Therefore, the ‘matrix of sustainable waste management’ can only be a good estimation of the waste management performance of the advanced countries, i.e. first and second and few countries of the third and fourth quadrant. It should be noted, that in this study the main point of the ‘matrix’ is to identify countries that have managed to ‘decouple’ the advancement of sustainable waste management, i.e. ‘move away from landfills’, from the GDP/capita (PPP), as compared to the EU-28 average (Eurostat, 2015). The indicator is a simple approach and should not be used to characterize the level of sustainability of a nation. However, for the needs of the research presented here it was a sufficient metric for the comparison between the waste management statistics of nations. Advanced indicators in this context include the work by Velis et al., 2012. 2.3. Waste to energy for district heating in S. Korea Data for the actual calorific value of the MSW processed in the WTE plants, the capacity and status of waste to energy in S. Korea were obtained by several sources (Korea Energy Economics Institute, 2017; CIA, 2017; Park et al., 2016; UNSD, 2016; KCWI,
2015; Ministry of Environment, 2015; OECD, 2015; Park and Lah, 2015; Yang et al., 2015; Hoornweg and Bhada-Tata, 2012; Park et al., 2011; Ryu, 2010). Maps for the capacity and location of WTE plants were created with Arc Map 10. The average heating value of the S. Korean solid wastes was compared with the average heating value of the US (Themelis et al., 2013) and the EU MSW (CEWEP, 2016). The energy efficiency of the S. Korean WTE plants is calculated using the R1 formula, as specified in the Waste Framework Directive of the European Union (Annex II of Directive 2008/98/EC). A WTE plant is considered energy recovery facility, when the R1, is equal to or above 0.60, for plants permitted before January 2009. For plants permitted after 2010, R1 must be higher than 0.65. When the auxiliary fossil fuel use in WTE plants is negligible, as is the usual case, the R1 factor is calculated using the following simplified formula:
R1ðenergy efficiency factorÞ ¼ ð2:6kW el þ 1:1kW heat Þ=0:97kW MSW : ð1Þ where, the subscript el: denotes electricity to the grid; heat: heat provided to district heating; and MSW: chemical energy stored in the MSW combusted. The R1 formula is an established method for characterizing combustion plants in the European Union. However, some drawbacks associated with the robustness of the method are the climate of the city/ location of the plant and the size of the facility. The R1 value significantly increases with the use of heat, which depends on the climate and the site of the facility. Typically, plants located in urban or industrialized areas, where district heating demand is usually high, have the tendency to indicate higher R1 scores. These aspects were addressed by the ‘COMMISSION DIRECTIVE (EU) 2015/1127 of 10 July 2015 amending Annex II to Directive 2008/98/EC of the European Parliament and of the Council on waste and repealing certain Directives’ that introduced the climate correction factor (CCF). CCF is calculated based on the heating degree days (HDD) of the specific geographic area. The R1 formula is also dependent on the size of the plant. Plants with larger MSW capacity are often more efficient associated with the economies of scale (CEWEP, 2016; Nixon et al., 2013; Themelis et al., 2013). Data on the technologies of the WTE plants were obtained by national databases, official reports and personal contacts of the authors (KCWI, 2015; Ministry of Environment, 2015). The stack emission data of all WTE plants were obtained by the national government official database and cross checked by the operators of the plants (KCWI, 2015; Ministry of Environment, 2015; Park et al., 2011, Ryu, 2010). The compounds examined and reported are: Sulfur oxides (SOX), nitrogen oxides (NOX), hydrogen chloride (HCl),
A.C. (Thanos) Bourtsalas et al. / Waste Management 85 (2019) 304–316
carbon monoxide (CO), particulate matter (PM), and dioxins. Data were compared to the national established limits (Ministry of Environment, 2015).
3. Results and discussion 3.1. Generation and characterization of MSW The spatial distribution of the MSW generated in the various cities of S. Korea is presented in Fig. 1. The inhabitants of Seoul generate the most MSW in S. Korea, followed by Gyeonggi, Gyeonguam and Busan, as expected, considering the population of these regions (Population and Housing Census, 2017).
307
The total amount of MSW generated in S. Korea has been slightly reduced from 19 Mt in 2008, which was the highest amount generated since 1995, to 17.8 Mt in 2015, as presented in Fig. 2. The amount of MSW generated fluctuated between 16.6 Mt in 1999 to 19 Mt in 2008. The per capita MSW generation was reduced from the high of 0.39 (1995) and 0.4 t/capita per year (1996) to the low of 0.34 t/capita per year in 2015. Fig. 2 illustrates the changes in MSW composition from 1995 to 2015. The source separated recyclables remained about at the same level since 1995, 0.1 to 0.2 t per capita per year. After the segregation of food waste, the total amount of MSW disposed in VBWF bags decreased by around 40%. The combustible waste collected from the VBWF bags was significantly reduced from 0.25 to 0.3 t per capita per year from the mid-1990s to the mid-2000s to 0.15 to 0.2 t per
2015 MSW generaon distribuon in Republic of Korea
Fig. 1. Spatial distribution of MSW generation in S. Korea in 2015, in Mt/y (Ministry of Environment, 2015).
308
A.C. (Thanos) Bourtsalas et al. / Waste Management 85 (2019) 304–316
Fig. 2. Total MSW generation (million tons per year; primary y-axis) and per capita MSW generation (t per capita; secondary y-axis). Total tonnages of the MSW composition in S. Korea from 1995 to 2015 is presented in the bars (Ministry of Environment, 2015).
capita per year from the mid-2000s to the mid-2010s (Ministry of Environment, 2015). Table 1 presents the ultimate analysis of the MSW collected in VBWF and subsequently the materials that are typically combusted for the production of district heating in WTE plants. Other materials include miscellaneous combustibles and incombustible materials. Assuming that Carbon is 6, the following chemical formula for the S. Korean MSW that is disposed of in VBWF bags was calculated: C6H9.9O2.3. The chemical formula for the MSW produced in New York (NY) was calculated by Themelis et al., 2002, as: C6H10O4. Therefore, the NY MSW has slightly higher oxygen as compare to the S. Korean MSW. This difference can be explained by the higher food waste and lower plastic content in the U.S. MSW as compared to the S. Korean MSW. The theoretical chemical formula was calculated for MSW disposed in VBWF bags (Ministry of Environment, 2015; Park and Lah, 2015). HSC software provides the values of the C6H10O2 formula, which is close enough to the formula calculated for the S. Korean MSW. Therefore, in order to calculate the maximum heat release of the MSW fuel, this formula was used. The molecular weight of the C6H10O2 formula is 114.14 kg/mol, and the heat of formation, 420.2 kJ/mol. The molecular weight of the C6H10O4 formula is 146.14 kg/mol and the heat of formation, 809.7 kJ/mol. The heat of formation of O2 is 0 kg/mol, of CO2 is 393.5 kJ/mol CO 2(g), and of H2O is 241.82 kJ/mol at 298.15 K. The chemical reactions for complete combustion of the S. Korean MSW, i.e. C6H10O2, and the NY MSW, i.e., C6H10O4 are:
S:Korea MSW : C6 H10 O2 þ 7:5O2 ¼ 6CO2 þ 5H2 O þ 27:6MJ per kg of MSW
ð2Þ
NY MSW : C6 H10 O4 þ 6:5O2 ¼ 6CO2 þ 5H2 O þ 18:8MJ per kg of MSW
ð3Þ
Thus, the potential heat generated by the S. Korea’s MSW combustibles is relatively higher than that of the NY average. This was expected since the amount of oxygen in the S. Korean was lower and this is associated with the higher combustion efficiency of the fuel.
In 2015, the actual heating value of S. Korean MSW to WTE plants ranged from a low of about 7 to a high of 12 MJ/kg and the average value for the 35 large WTE plants was 9.7 MJ/kg. This value was significantly lower than the heat of formation of the S. Korean MSW chemical formula (27 MJ/kg). This is associated with the heat losses during combustion, the latent heat and the negative effect of glass and metals in the MSW stream. The heating value of the S. Korean MSW is slightly lower than the mean value of 10.3 MJ/kg for the MSW combusted in EU WTE facilities (CEWEP, 2016). However, it is significant lower as compared to the average US MSW, which is 12 to 13 MJ/kg of MSW (Themelis et al., 2013). 3.2. Waste management performance of South Korea In 2015, out of the 17.8 Mt of MSW that were generated, 10.4 Mt (58.8% of the total) were recycled or composted, as shown in Fig. 3. About 4.5 Mt (25.3%) were combusted with energy recovery, and 2.7 Mt (15.9%) were landfilled. Fig. 3 illustrates the changes in the methods of disposal of MSW between 1995 and 2015. The rate of recycling plus composting nearly tripled from only 4.1 Mt (24%) in 1995 to about 10.5 Mt in 2015. However, this number has dropped since 2009, where the total recycling and composting were 11.4 Mt (61%), and the WTE has increased from 3.8 Mt (20%) to 4.5 Mt (25.3%) during the same period. WTE also rose from only 0.7 Mt (4%) in 1995 to 4.5 Mt (25.3%) in 2015. As a result, landfilling was significantly reduced steadily from 12.6 Mt (72%) in 1995 to 2.7 Mt (15.9%) in 2009 (Ministry of Environment, 2015; UNSD, 2015; Hoornweg & Bhada-Tata, 2012). The advancements of sustainable waste management in S. Korea were mainly driven by the introduction of the district heating law in 1991, the VBWF law in 1995 and the ban of food waste in 2006. The reduction in the recycling/composting material that is beneficially used in S. Korea can be explained by the need of the secondary market that was able to absorb the new incoming materials (Park et al., 2016; Pariatamby and Tanaka, 2014; Park, 2008). Fig. 4 shows the SWMI graphed against the Gross Domestic Product (GDP) per capita of different countries. Both indicators expressed as a percentage of the EU-28 average. From this chart, it can be concluded that a group of countries exists with the high
A.C. (Thanos) Bourtsalas et al. / Waste Management 85 (2019) 304–316
309
Fig. 3. Changes in MSW management of S. Korea, 1995–2015 (Ministry of Environment, 2015).
Fig. 4. Graph of the sustainable waste management index (SWMI) vs. GDP per capita for different countries, expressed as a percentage of the EU-28 average GDP per capita (Eurostat, 2015; OECD, 2015; Hoornweg and Bhada-Tata, 2012).
SWMI and this includes Western and Northern European countries, such as Germany, Norway, Switzerland, the Netherlands, Denmark, Austria, Belgium and Sweden, plus Singapore and Japan. All these countries have high GDP per capita (PPP) and have negligible landfill due to their investment in infrastructure over recent decades to deliver sustainable MSW management. South Korea is particularly interesting because it is the only country with a high SWMI that
has relatively GDP per capita (PPP). Therefore, S. Korea has managed to ‘decouple’ the growth of the country with the sustainable waste management development. The nation showed improved SWMI as compared to the EU-28 average (about 20% higher), even if S. Korea had lower GDP/ capita (PPP) (about 10% lower). In addition, S. Korea indicated a significant lower SWMI compared to the US (about 50% lower). S. Korea has 63% lower GDP/capita (PPP)
310
A.C. (Thanos) Bourtsalas et al. / Waste Management 85 (2019) 304–316
than the US. This advancement of S. Korea as compared to other countries was associated with the development of strong national policies that aimed the decentralized communities (Park et al., 2016; Yang et al., 2015; Son, 2012; Ryu, 2010). The government established strict federal legislations that the municipalities obliged to follow. Also, the direction of the government aimed the construction of WTE plants within the city boundaries to provide district heating for the community. A very important factor was the citizens’ participation. Similar characteristics have been observed in Europe, where the European Guidelines and Directives, had main objective the obligation of the nation members of the union. However, different geopolitical characteristics enabled the advancement of SWM in the Western and Northern European part, i.e. countries in the first quadrant of the ‘matrix’. Therefore, the centralized models that aim the decentralized communities are strongly recommended. However, it should be noted, that public
and political will are important factors in the successful implementation of sustainable systems, and typically this type of a legislative approach needs a lot of time for fruition. 3.3. Waste to energy status in South Korea The nation has 172 operating ‘‘incinerators” with capacities of over 100 tpd of which only 35 are combustion plants that export mainly heat or, in few cases, electricity (WTE) and mostly located in metropolitan areas. Fig. 5 shows the locations of these WTE power plants. Most of these plants are in the most populous and densest regions of S. Korea, that are in the Northern Eastern part of S. Korea, Seoul and Gyeonggi (KCWI, 2015). The 2015 capacity of the 35 WTE facilities was 4.5 Mt and accounted for about 90% of the total incinerator capacity in S. Korea. Fig. 6 shows the energy generated (primary y-axis) and
Fig. 5. Areas of WTE plants in S. Korea in 2015 (using ArcMap 10) (KCWI, 2015).
A.C. (Thanos) Bourtsalas et al. / Waste Management 85 (2019) 304–316
311
Fig. 6. Energy generation and use in 35 WTE plants in 2015 (KCWI, 2015; Ministry of Environment, 2015).
Fig. 7. R1 factor of the 35 S. Korean WTE plants in 2015 (KCWI, 2015; Ministry of Environment, 2015; Nixon et al., 2013; Park et al., 2011).
the t of MSW received (secondary y-axis) by each of the 35 WTE plants in 2015 (KCWI, 2015; Ministry of Environment, 2015). The average amount of energy recovered for the production of energy in S. Korea is 1.5 MWh/ton, which is slightly lower than the usual amount of energy recovered in WTE operations in the EU. It was observed that 12 WTE facilities, 34.2% of total number of facilities, in S. Korea processed less than 120,000 tpy and produced less than 1 MWh of energy/ton of MSW. Excluding these facilities, the average energy produced is about 1.8 MWh/ton. In S. Korea, only 7 facilities out of the 35 combust more than 130,000 tpy of MSW, with the largest facility, Kangnam, combusting about 265,000 t of MSW. Subsequently, in Kangnam WTE the highest amount heat energy is produced that amount at 2.3 MWh of energy/t of MSW. As a similar comparison, in Denmark the energy for district heating/cooling is on an average 2 MWh/ton of MSW and an
additional 0.5 to 0.6 MWh/ton of MSW for electricity (Nixon et al., 2013; Themelis et al., 2013; Ulloa, 2007). The power supplied to the district heating network amounted to 4,600 GWh in 2015 (1 MWh/ton of MSW), which is about 8% of the total district heating production in S. Korea (57,600 GWh). About 60% of the eleven businesses operating 24 plants in the district heating sector owned by the government, which initiated the advancement of district heating in S. Korea when enacted the ‘Integrated Energy Support Act’ in 1991 (Park et al., 2016; Yang et al., 2015; Park et al., 2011; Ahn et al., 2007). Hot water allows the transmission of heat over long distances, with relatively low heat loss, less than 10%. The central control system for the heat supply from the power plant is more economic than the conventional single building approach. On the average, district heating operates with 80% fixed cost and 20% variable costs. This is exactly the
312
A.C. (Thanos) Bourtsalas et al. / Waste Management 85 (2019) 304–316
opposite of the cost ratio for its gas competitors, indicating the sensitivity of the systems to interest rates and financing methods. For district heating, over a half of the capital costs are represented by the transmission and distribution network. Costs can be minimized by keeping the length of piping to a minimum. Thus, most systems are designed to serve high-use customers with specified areas. Existing S. Korean steam systems serve between 1,000 and 3,500 customers, which are similar to the US systems (Yang et al., 2015; Ryu, 2010).
WTE in S. Korea contributed about 57 GWh (0.02 MWh/ ton of MSW) to the total electricity production, which is a negligible amount compared to the total power generation in S. Korea (Korea Energy Economics Institute, 2017; EIA, 2015). The negligible contribution of WTE in the energy demand of S. Korea is associated with the high energy in-plant consumption of the WTE plants in the region and the lack of strong incentives to motivate the WTE industry to recover more electricity. In the case that the WTE plants recover electricity, then 2,700 GWh of electricity can be
Fig. 8. (a) Dioxins, (b) PM, (c) SOx, (d) HCl, (e) CO and (f) NOx emissions of WTE plants compared to national limits. All plants indicate emissions significantly lower than the national established limits (KCWI, 2015; Ministry of Environment, 2015; Park et al., 2011, Ryu, 2010).
A.C. (Thanos) Bourtsalas et al. / Waste Management 85 (2019) 304–316
Fig. 8 (continued)
313
314
A.C. (Thanos) Bourtsalas et al. / Waste Management 85 (2019) 304–316
Fig. 8 (continued)
contributed to the grid. Therefore, WTE in S. Korea can contribute about 0.6% to the total electricity production (497,000 GWh). However, as discussed earlier, WTE has significantly contributed to the sustainable solid waste management of the nation, since it reached 4.5 Mt (25.3%) in the same period,
3.4. Energy efficiency of S. Korean WTE plants Fig. 7 presents the electrical and heat energy generated (primary y-axis), and the calculated R1 factor for each plant (secondary y-axis). The average R1 in 2015 was 0.59, which is slightly below
A.C. (Thanos) Bourtsalas et al. / Waste Management 85 (2019) 304–316
the EU R1 limit for energy recovery facility (KCWI, 2015; Ministry of Environment, 2015; Nixon et al., 2013; Park et al., 2011). This relatively low value is mainly associated with the Uijeongbu and Sanbuk WTE plants that indicate a significant low R1 factor of 0.01 and 0.03, respectively. These plants recover electricity only to support the needs of the WTE facility, therefore, the technology is similar to an incinerator without energy production. Excluding these facilities, the R1 average for S. Korean WTE plants is 0.63. A drawback of the operations is associated with the high in-plant energy consumption that is at 0.67 MWh of thermal energy per ton of MSW. This can be significantly reduced by optimizing the amount of air used for combustion (Park and Lah, 2015; Lusardi et al., 2014; Ryu, 2010). Moreover, the improvement of steam parameters and the use of high-pressure steam for the production of electricity will increase the efficiency and, therefore, the revenues of the WTE plants (Nixon et al., 2013; Themelis et al., 2013). Also, the relatively low heating value of the MSW can be increased by the more efficient recovery of food waste that contributes negatively to the heating value of the MSW (Themelis et al., 2002). In this effort, however, the government should advocate the use of WTE and provide subsidies for the development of these projects, as is the case in China, EU and US. The development of WTE will be a ‘low hanging fruit’ but still aid the efforts of the government to phase out fossil fuels and to be more independent in the energy supply of the nation, as at this time about 97% of the energy consumed in S. Korea is imported.
315
S. Korea is near the top of the sustainable-waste-management nations, despite its relatively average range GDP per capita; MSW generation per capita has slightly decreased, from 0.40 t in 1996 to 0.35 t in 2015; The chemical formula for the materials disposed of in VBWF bags was calculated as: C6H9.9O2.3, with a heat of formation of 27.6 MJ/kg. The heating value of S. Korean MSW had an average value of 9.7 MJ/kg; Recycling and composting rates slightly reduced since 2008 and the WTE rates increased; 10.4 Mt of MSW (58.8% of the total) were recycled or composted in 2015; 4.5 Mt of MSW (25.3% of total) was processed, mainly for district heating. The average amount of energy recovered for the production of energy was 1.5 MWh/ton; About 8% of the district heating demand is provided by the 35 WTE; WTE has the potential to contribute up to about 0.6%; of the 35 WTE plants qualify as energy recovery plants (R1 > 0.61) Emissions of the S. Korean WTE plants are a tenfold to a hundredfold below the S. Korean and E.U. standards for most pollutants examined; The average dioxin emission of all plants was 0.005 ng TEQ/Nm3 (limit:0.1 ng TEQ/Nm3);
3.5. Air pollution control and emissions of S. Korean WTE plants Acknowledgments All WTE facilities meet the S. Korean air emission standards for the six air pollutants examined, as presented in Fig. 8 (KCWI, 2015; Ministry of Environment, 2015; Park et al., 2011, Ryu, 2010). Dioxin levels are the main concern because of their extremely high toxic potency even at trace quantities. The average dioxin emission for all plants in 2015 was 0.005 ng TEQ/Nm3 while the S. Korean standard was 0.1 ng TEQ/Nm3 (same as E.U. and U.S. standard). The total dioxins from all S. Korean WTE plants were at 0.08 g TEQ. S. Korean WTE plants operate with several processes of air pollution control equipment, able to remove the contaminants from the flue gas and allow the facility to comply with the stringent environmental standards. For example, the Kangnam plant treats flue gas generated from MSW combustion using selective noncatalytic reduction (SNCR), scrubber, semi-dry removal (SDR) type, dry flue gas desulfurization, bag filter, and selective catalytic reduction (SCR). Mapo WTE plant uses SNCR, SDR, bag filter, and SCR. The very low levels of dioxin emissions from S. Korea’s WTE plants can be attributable to the activated carbon used during the gas cleaning process. For example, the Paju plant, with MSW capacity of 200 tpd, treats the flue gas through SDR, bag filter and SCR and with 0.156 kg of activated carbon per t of MSW (KCWI, 2015; Ministry of Environment, 2015). Only two plants operate with SCR systems, a moving grate and a Circulating Fluidized Bed (CFB) (KCWI, 2015; Ryu, 2010). A study conducted on 57 WTE plants in the US, representing 84% of the total U.S. WTE capacity, concluded that the average dioxin concentration was 0.029 ng TEQ. The total amount of dioxins emitted by all the 77 U.S. WTE plants in 2012 was estimated at 2.9 g TEQ. The same study concluded that 1,300 g TEQ of dioxins were emitted in 2012 from open burning sources (Dwyer and Themelis, 2015). 4. Conclusions The main findings of the research study can be summarized as follows:
This study was supported by the Global WTERT Council (Columbia University) and was initiated based on the thesis by Y. Seo (www.wtert.org, Publications), Earth Engineering Center, Columbia University. References Ahn, H., Hwang, S., Kim, K., Lee, H., Park, S. & Suk, K., 2007. Waste Management in Korea. MBA White Paper, University of North Carolina. Available at: extranet. kenan-flagler.unc.edu/kicse/ORIG%20Shared%20Documents/Waste% 20Management%20in%20Korea.pdf (accessed: November 2017) Central Intelligence Agency (CIA): The World Factbook https://www.cia.gov/library/ publications/the-world-factbook/ (accessed: November 2017) Confederation of European Energy from Waste Plants (CEWEP) energy report, 2016. CEWEP, Bamberg. Available at: www.cewep.org (accessed: November2017) Cheong, H.S., 1995. Pricing for municipal solid waste disposal in Korea. Master’s dissertation, CSERGE. School of Environmental Sciences, University of East Anglia. Available at: www.cserge.uea.ac.uk/sites/default/files/wm_1995_04.pdf (accessed: November 2017). Danish Energy Agency and Danish Board of District heating, 2015. Joint report on District heating- Danish experiences. Available at: https://ens.dk/en/ourresponsibilities/global-cooperation/experiences-district-heating (accessed: November 2017). Dwyer, H., Themelis, N.J., 2015. Inventory of US 2012 dioxin emissions to atmosphere. Waste Manage. 46, 242–246. Energy Institute Association Statistical Energy Review 2015. Available at: www. eia.gov/international/data (accessed: November 2017) European Commission Directorate General, Guidelines on the interpretation of the R1 energy efficiency formula for incineration facilities dedicated to the processing of municipal solid waste according to Annex II of Directive 2008/ 98/EC on waste. Available at: http://ec.europa.eu/environment/waste/ framework/pdf/guidance.pdf (accessed: November 2017) Eurostat data, 2015. Available at: ec.europa.eu/eurostat/tgm/refreshTableAction. do?tab=table&plugin=1&pcode=tsdpc240&language=en (accessed: November 2017) Hoornweg, D., Bhada-Tata, P., 2012. What a waste: a global review of solid waste management. Urban Development Series Knowledge Papers 15, 1–98. Available at: openknowledge.worldbank.org/handle/10986/17388. Ju, D.Y., 2005. 3R Portfolio: good practices to promote the 3Rs (Republic of Korea). In: In ministerial conference on the 3R initiative, pp. 28–30. Available at: www. env.go.jp/recycle/3r/en/info/05_12.pdf (accessed: November 2017). Kaufman, S., Kwon, E., Krishnan, N., Castaldi, M., Themelis, N., 2008. Use of statistical entropy and life cycle analysis to evaluate global warming potential of waste
316
A.C. (Thanos) Bourtsalas et al. / Waste Management 85 (2019) 304–316
management systems. In: In 16th Annual North American Waste-to-Energy Conference. American Society of Mechanical Engineers, USA, pp. 107–112. Available at: www.seas.columbia.edu/earth/wtert/NAWTEC16-1915-Kaufman. pdf. Kim, K., 2008. Performance of Waste Management Policy in Korea. Ministry of Environment, Republic of Korea. Korea Conference on Waste Incineration (KCWI, in Korean), 2015. Current Operating Status of Waste to Energy Facilities for Municipal Solid Waste. Available at: k-inc.co.kr/board/pds1.php (accessed: November 2017) Korea Energy Economics Institute, 2017. Yearbook of Energy Statistics: Available at: https://www.keei.re.kr/main.nsf/index_en.html (accessed: November 2017). Lusardi, M., McKenzie, Kohn, Themelis, N., Castaldi, M., 2014. Technical assessment of the CLEERGAS moving grate-based process for energy generation from municipal solid waste. Waste Manage. Res. 32 (8), 772–781. Ministry of Environment, Government of the Republic of Korea. 1997 to 2015. Current status of waste generation and treatment (in Korean). Available at: http://eng.me.go.kr/eng/web/index.do?menuId=394 (accessed: November 2017) Nixon, J.D., Wright, D.G., Dey, P.K., Ghosh, S.K., Davies, P.A., 2013. A comparative assessment of waste incinerators in the UK. Waste Manage. 33 (11), 2234– 2244. OECD waste statistics, 2015 Available at: data.oecd.org/waste/municipal-waste.htm (accessed: November 2017) Pariatamby, A., Tanaka, M., 2014. Municipal solid waste management in Asia and the Pacific Islands. Environmental Science. Springer, Singapore. Park, G.S., 2008. The effective policy of extended producer responsibility. The Monthly Packaging World 177, 70–78. Park, J. W. ,2009. 3R policies of Korea. Ministry of Environment, Seoul. (accessed: November 2017) Park, S., Choi, J.H., Park, J., 2011. The estimation of N2O emissions from municipal solid waste incineration facilities: The Korea case. Waste Manage. 31, 1765– 1771. Park, S., Lah, T.J., 2015. Analyzing the success of the volume-based waste fee system in South Korea. Waste Manage. 43, 533–538. Park, S., Park, S.I., Lee, S.H., 2016. Strategy on sustainable infrastructure asset management: focus on Korea ׳s future policy directivity. Renew. Sustain. Energy Rev. 62, 710–722.
Population and Housing Census, 2017. Available at: kostat.go.kr (accessed: November 2017) Ryu, C., 2010. Potential of municipal solid waste for renewable energy production and reduction of greenhouse gas emissions in South Korea. J. Air Waste Manag. Assoc. 60 (2), 176–183. Seo, Y., 2013. Current MSW Management and Waste-to-Energy Status in the Republic of Korea. Master’s dissertation, Department of Earth and Environmental. Engineering, Columbia University. Available at: www.seas.columbia.edu/ earth/wtert/sofos/YS%20Thesis_final_Nov3.pdf. Son, C.J., 2012. A study on The Extended Producer Responsibility System as a Waste Management Policy. Doctoral Dissertation. University of Seokyeong. The Asian Institute for Energy, Environment and Sustainability (AIEES), The Volume Based Waste Fee System of Korea ,2012, The Seoul National University. Available at: archive.epi.yale.edu/indicators-in-practice/volume-based-wastefee-system-korea (accessed: November 2017) Themelis, N.J., Kim, Y.H., Brady, M.H., 2002. Energy recovery from New York City municipal solid wastes. Waste Manag Res. 20 (3), 223–233. Themelis, N.J., Barriga, M.E., Estevez, P., Velasco M.G., 2013: Guidebook for the application of Waste to Energy Technologies in Latin America and the Caribbean, EEC-Columbia sponsored by the Interamerican Development Bank. Available at: http://www.seas.columbia.edu/earth/wtert/pressreleases/ Guidebook_WTE_v5_July25_2013.pdf Ulloa, P., 2007. Potential for combined heat and power and district heating and cooling from waste-to-energy facilities in the US–learning from the Danish experience (Doctoral dissertation, Columbia University). Thesis available at: www.seas.columbia.edu/earth/wtert/sofos/ulloa_thesis.pdf United Nations Sustainable Development. Waste Management. Available at: sustainabledevelopment.un.org/dsd_aofw_ni/ni_pdfs/NationalReports/korea/ WasteManagement.pdf (accessed: November 2017) Velis, C.A., Wilson, D.C., Rocca, O., Smith, S.R., Mavropoulos, A., Cheeseman, C.R., 2012. An analytical framework and tool (‘InteRa’) for integrating the informal recycling sector in waste and resource management systems in developing countries. Waste Manage. Res. 30 (9), 43–66. Wilson, D.C., Velis, C.A., Cheeseman, C.R., 2006. Role of informal sector recycling in waste management in developing countries. Habitat Int. 30 (4), 797–808. Yang, W.S., Park, J.K., Park, S.W., Seo, Y.C., 2015. Past, present and future of waste management in Korea. J. Mater. Cycles Waste Manage. 17 (2), 207–217.