With the upcoming enforcement of the Fundamental Law of Resource Circulation in January 2018, changes are expected to occur in waste management policies. Until now, South Korea has worked hard to prevent waste generation and improve recycling. The recycling rate has improved, but recyclables are not considered high-quality. To resolve these issues in its member states, the EU is promoting resource efficiency policies. Their plan is to integrate the environment with the economy, achieve economic growth, and create jobs. A circular economy has also been adopted as a strategy to promote the resource efficiency policies. The key content of the strategy consists of an action plan and a waste law revision. Goals for the recycling of wastes by 2030 have been set in laws revised through this strategy, which also includes recycling evaluation standards and calculation methods. For Korea to cultivate a resource circulation society in the future, the EU’s resource efficiency policies and strategies must be preemptively implemented in a manner that suits the situation in Korea, and terms must be defined and standards established for recycling.
With industrial development, the use of electrical and electronic products made of low-specific-gravity and easyprocessing plastics has increased. As these products have been abandoned, environmental problems, such as Dioxine and Furan, have begun to arise. Accordingly, through long-time reviews and discussions, the EU has implemented the Restriction of Hazardous Substances (RoHS) and Waste Electrical and Electronic Equipment (WEEE) regulations. Additionally, the Stockholm Convention was adopted in April 2011 for wastes containing brominated flame retardants. Therefore, the Basel Convention issued technical guidelines on environment-friendly treatment for wastes containing brominated flame retardants. For Korea to respond to both the conventions and changing trends in international persistent organic pollutant (POP) management, proper management and treatment plans suitable to Korean circumstances are required. In this regard, the study identified domestic and international trends in environmental regulations and usages, obtained fundamental data for the management of wastes containing brominated flame retardants, and investigated the current status of waste generation in Korea. Based on the results, six target samples were selected and evaluated to see if they were heat-treatable through content analysis, three-component analysis, element analysis, calorific value analysis, and thermogravimetric (TGA) analysis. The results of the analyses were used to make a lab-scale incineration reactor, and the results of the TGA analysis became the basis for setting the incineration temperature ranges for experiments. After incineration, five general air pollutants (O2, CO, CO2, SOx, and NOx) and three components of BRFs in the emission gas and flooring were analyzed to identify if the PBDEs in wastes can be destroyed in a stable and environmental manner during heat treatment.
In this study, gasification experiments were conducted using high calorific waste by measuring flue gas and gaseous pollutant composition. The feedstock used in this experiment was collected from industrial wastes and had a heating value more than 5,000 kcal/kg as well as low moisture and ash contents. Experiments were conducted at 1,200℃ temperature by changing equivalent ratios (ERs) to find out an optimum condition for syngas production. Results showed that at ER 0.3, the highest syngas composition (around 81%) was obtained in flue gas. In this study, gas pollutant was sampled in cold absorbent by following Korean air pollutant standard sampling method. Later, sampled solutions were analyzed by IC (Ion Chromatography) to find out gaseous pollutant concentration. Usually, after gas cleanup system, all of the gaseous pollutants are removed by wet scrubber and catalyst reactor. However, in this study, due to gaseous pollutants removed by wet scrubber, the removal efficiency of gaseous pollutants showed lower performance compared with other catalyst clean up system. Thus, it is advisable to install a cleaning unit to deal with tar and soot.
This research examined the possibility of the temperature maintenance of an anaerobic digestion reactor without external heating by the oxidation heat generated in an aerobic fermenter, considering the difficulties of anaerobic digestion because of the winter season in Korea. For the experiment, an anaerobic digestion chamber was installed inside, the device with aerobic fermentation installed outside was used, the anaerobic digestion chamber was covered, and the raw material was used in the perspective of handling livestock excretion and food waste. During 230 days of operation in total, normal operation was started after about 120 days, and during that operating time, the temperature change, degradation behavior of organisms, and digestion yield were analyzed; the results are shown below. In the situation excluding the aerobic reactor in the summer season, maintaining the temperature of the digestion chamber at 30℃ was possible through heat storage within the house, but the temperature decreased to about 20℃ because of the outside temperature in the winter season, and maintaining the temperature of the digestion chamber at 25℃ was possible as long as the aerobic fermentation chamber maintained its temperature of more than 50℃. Regarding the results for the effects of the inside and outside temperature of the house on the aerobic reactor chamber temperature, a significant effect was not examined, and it was identified that the aerobic reactor temperature relied on the degree of aerobic microorganism vitalization. When using a hot-water system with solar heat, the possibility of usage as complementary energy in the unstable winter season was checked. Even in the winter season, maintaining the temperature of the anaerobic digestion chamber without external heating was possible, and even during the time of operation, although the temperature changed from 25℃ to 38℃, methane gas was stably produced.
Powder mine wastes cause secondary environmental problems from dust flying around villages. It is necessary to recycle to prevent this secondary pollution and to use its beneficial contents. Magnesium and iron may play a role like that of aluminum in geopolymer forming. In this study, therefore, we analyzed the compressive strength of geopolymer prepared from melting slag (MS) and high-magnesium iron mine waste (MW). The compressive strength increased by increasing the mixing ratio of MS and decreasing the L/S ratio. The optimal properties were obtained at a mixing ratio of MS to MW of 5 : 5, molar ratio of SiO2/Na2O of 1.8, and L/S ratio of 0.2. Under these conditions, the compressive strength at 28 days was 112.5 MPa. According to the FT-IR analysis, a geopolymer structure was identified. As a result, we confirmed the possibility of geopolymer forming from MS and MW.
Recently, the concept of “waste minimization and a sustainable resource circulation society” has become a global issue as the key term waste management policy, the effective use of waste, has been emphasized. Research that converts wastes from incinerators into energy is actively underway as a countermeasure for this issue. The most important factor, the lower heating value (LHV), is the amount of heat (excepting the latent heat of water vapor) generated when the fuel is completely burned, and it is necessary to analyze the combustion performance and economic efficiency of waste incineration facilities. The current LHV estimation methods of the Dulong equation and calorimeter through sampling cannot produce results that reflect the operation status of the incineration facility and the waste characteristics. Consequently, an objective and quantitative LHV formula (LHVKorea) was derived based on the operating data from the domestic municipal solid waste incineration facilities in this study. Additionally, by comparing LHVKorea and LHVEU, the error range of the two formulas is analyzed. The average result of LHVKorea is 2,318kcal/kg (1,788 ~ 2,734 kcal/kg), and an error range of 5% appears between LHVKorea and LHVEU.
Among the unintentional persistent organic pollutants (UPOPs), polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDDs/PCDFs) were measured from a stack of 28 small-scale waste incinerators (SWIs) from 2013 to 2015. The emissions of PCDDs/PCDFs ranged from N.D. to 208.3 ng-TEQ/S㎥ with an average of 21.1 ng-TEQ/S㎥ based on the International Toxicity Equivalency Factor (I-TEF). The 28 stack gas samples were categorized into four types and evaluated by the score plot of principal component analysis (PCA). Furthermore, 17 PCDD/PCDF congeners were divided with the number of chlorine substitutions by a loading plot. The correlations between PCDDs and PCDFs were also estimated. The emissions of PCDDs/PCDFs from 19 SWIs were below the emission standards, while nine SWIs significantly exceeded them in this study.
Much research on Black Soldier Fly (Hermetia illucens) is underway in the disposal of food waste. In addition to food waste treatment, it has received much attention in the industrial using of by-products such as feed, compost, and antibiotics. In this study, the treatment efficiency of organic wastes and larval growth were investigated according to the amount of input. The organic wastes used in this study were chicken carcasses and food waste. In case of carcass treatment, to the exclusion of bones and feathers, it was treated about 83 percent. Food waste was completely treated in 48 hours when 50 percent of the weight of the food was put into the larvae. The maximum larval growth was observed with 10 percent injected, from 0.076 g to 0.254 g. However, there was no difference in the growth of larvae when 30 percent or more was added.
This study has focused on identifying the cause of agglomeration that occurred in a domestic commercial-scale circulating fluidized bed boiler. Solid refuse fuel (SRF) was fed into the target facility to produce electricity. Agglomeration occurred in the combustor and cyclone during commercial operation. The bed material, clinkers produced in the combustor and cyclone, and boiler ash were collected, and components that are known to cause agglomeration were analyzed. Additionally, the possibility of slagging and fouling formation was predicted using components obtained by XRF analysis. The melting temperature of the bed material was decreased by complex reactions of low-boiling-point metal, alkaline metal and sulfur, and chlorine components. Then, agglomeration was generated because the bed material and ash were melted and combined. Basicity (B/A), which can lead to slagging, was estimated to be above 1.0 (reference 0.5 < B/A < 1.0). The boiler ash had a basicity of 1.83. The slag viscosity index (SVI) was estimated to be between 18.83 and 49.78 (reference 65 < SVI < 72). The boiler ash and combustor clinker had 3.30 and 4.40 total alkali (TA) values, respectively (reference 0.3 < TA < 0.4). This condition determined that slagging and fouling formation easily progressed. This result is expected to be utilized as data for preventing agglomeration formation and clinker generation.
The most common types of refrigerants used in automobiles today usually include HCFCs and HFCs, which have the potential of ozone depletion or the greenhouse effect. Although environmentally friendly refrigerants are being developed, there is still a lack of safety and high-cost problems for new refrigerants. This study was conducted to determine the flow of refrigerants from automotive air conditioners and examine their potential problems and a proper management plan. The number of automobiles manufactured, the number of automobiles in use, and end-of-vehicle flow were examined through available statistics and reports. The material flow of refrigerants has been determined by the life cycle of automobiles and the unit requirements of the refrigerants used in automobiles. Based on the results, in 2014, there were approximately 1,017 tons of refrigerants introduced from the manufacturing stage of automobiles, and about 395 tons of refrigerants leaked from the use stage. After the use stage, only 13 tons of refrigerants were delivered to treatment facilities and 195 tons were emitted into the atmosphere during the dismantling process. As a result, in South Korea in 2014, a large amount of refrigerants (590 tons) was estimated to have been leaked into the atmosphere from automotive air conditioners during the use and dismantlement stage. Several preventive measures for refrigerants should be properly enforced by introducing economic incentives as well as a monitoring system with strengthened laws and policies.
Slag and coal ash were selected to evaluate the recyclability of waste generated during the heat treatment processes. A list of waste types and recyclable types of the two wastes were identified. A recycling environmental hazardous assessment was reviewed step by step. In addition, the hazardous properties of slag and coal ash were investigated, and the chemical components, leaching, and content of harmful substances in the waste were analyzed. The two selected wastes were classified as general wastes. As a result of chemical analysis with XRF, the two wastes did not produce toxic gases in contact with water and show leaching toxicity from the analysis of harmful substances. In addition, waste is often brought into contact with the soil when recycled, so the content of slag and coal ash is analyzed and compared with the 2 region standard of soil; two samples were within the standard. Therefore, the surveyed wastes can be recycled in nonmatrix contact types and the recycling purpose and method permitted by the new law is excluded from the recycling environmental hazardous assessment. However, to recycle wastes for new uses, the recycling environmental hazardous assessment is required.
The purpose of this study was to suggest feasible disposal methods for heavy-metal-contaminated soil or mine tailings through solidification/stabilization. To improve the compressive strength and enhance the heavy-metal stabilization after solidification/stabilization, we used the industrial wastes (oyster shell powder and waste gypsum) and indigenous bacteria as immobilization agents. Three indigenous bacteria were isolated from each heavy-metal-contaminated soil or mine tailing site, and the bacteria were identified by cellular fatty acid composition analysis. The results of cellular fatty acid composition analysis showed that the closest strains of these bacteria are Brevibacillus centrosporus, Lysinibacillus sphaericus, and Bacillus megaterium. To the best of our knowledge, this research was the first report of biomineralization by Brevibacillus centrosporus. As a result of mixing additives with the optimum mixing ratio suggested in this study, the compressive strengths of specimens were satisfied in accordance with the US Environmental Protection Agency (EPA) waste treatment standard after 28 days of aging. Additionally, the results of the Toxicity Characteristics Leaching Procedure (TCLP) and Synthetic Precipitation Leaching Procedure (SPLP) analysis showed the successful immobilization of heavy metals after 28 days of specimen formation for solidification/stabilization.