Analysis of incombustibles in the feedstock to incineration facilities in South Korea for optimum sorting and management.

Korea's Ministry of Environment has implemented the Framework Act on Resource Recirculation to activate waste resource recovery. However, industrial waste treatment facilities have some problems related to diversity of waste received for proper management of wastes. Waste incineration facilities are required to receive and process combustible waste and are forbidden to re-consign waste to other waste treatment facilities without any processing. In reality, a large amount of incombustibles is injected into the incinerator because it is impossible to completely separate the incombustible materials. Therefore, it is necessary to develop additional management criteria for optimal operation of the incineration facility. This study was conducted to improve institutional management of incineration facilities in Korea. Through a literature review and statistics study, incombustible waste management trends were investigated. The characteristics of waste entering incineration facilities were surveyed. Physical composition and proximate analysis of incoming waste were conducted, and properties of the incombustibles mixed in feedstocks to waste incineration facilities were examined. As a result of this study, incombustibles mainly consisting of the construction and demolition waste, such as soil, glass, and metals, should be separated from feed sent to incinerators. A mechanical screening technique that sorts particles of 30-40 mm in size can be used to separate the incombustibles. Also, management criteria could be proposed to sort and re-consign the incombustibles.

Analysis of incombustibles in the feedstock to incineration facilities in Republic of Korea for optimum sorting and management.

The Ministry of Environment, Republic of Korea has implemented the "Framework Act on Resource Recirculation" to activate waste resource recovery. However, industrial waste treatment facilities have some problems related to diversity of waste received for proper management of wastes. Waste incineration facilities are required to receive and process combustible waste and are forbidden to re-consign waste to other waste treatment facilities without any processing. In reality, a large quantity of incombustibles is injected into the incinerator because it is impossible to completely separate the incombustible materials. Therefore, it is necessary to develop additional management criteria for optimal operation of the incineration facility. This study was conducted to improve institutional management of incineration facilities in Korea. Through a literature review and statistics study, incombustible waste management trends were investigated. The characteristics of waste entering incineration facilities were surveyed. Physical composition and proximate analysis of incoming waste were conducted, and properties of the incombustibles mixed in feedstock to waste incineration facilities were examined. As a result of this study, incombustibles mainly consisting of the construction and demolition waste, such as soil, glass, and metals should be separated from feed sent to incinerators. A mechanical screening technique that sorts particles of 30-40 mm in size can be used to separate the incombustibles. Also, management criteria could be proposed to sort and re-consign the incombustibles.

A descriptive study of claims for occupational mental disorder: adjustment disorder.

BACKGROUND: The number of claims of Industrial Accidents Compensation Insurance (IACI) for mental illness has increased. In particular, the approval rate was higher in cases with confirmed incident circumstances such as adjustment disorder, acute stress disorder, and post-traumatic stress disorder. With increased numbers of filed IACI applications and their approval rates, the need to evaluate various work-related incidents and stressors consistently is also increasing. METHOD: In January 2015-December 2017, among the cases of industrial accidents filed for mental illness and suicide by the Korea Workers' Compensation and Welfare Service, 76 filed or approved adjustment disorder cases were included. The cases of adjustment disorder were applied in this study to the "Criteria for Recognition of Mental Disorders by Psychological Loads" established in Japan in 2011 and investigated if cases were approved/rejected consistently. Additionally, features with the greatest influence on approval/rejection were examined quantitatively. RESULTS: The number of applications more than doubled from 2015 to 2017, with the approval rate rising from 66.7% to 90.6%. Among the major categories, applications of adjustment disorder related to "interpersonal relationships" were the largest number of applications. Applications related to "sexual harassment", "interpersonal relationships", and "accidents and experiences including fires" showed relatively higher approval rate. The approval rate was the lowest in the case of "change in the amount and quality of work". CONCLUSIONS: Approved cases tend to have special precedents and strong intensity. The main reasons for the rejection were that there were no special precedents and that the intensity of the case was weak. These 2 were the most important factors in determining approval/rejection.

Carbon disulfide exposure estimate and prevalence of chronic diseases after carbon disulfide poisoning-related occupational diseases.

BACKGROUND: In Korea, Carbon disulfide (CS2) toxicity was an important social problem from the late 1980s to the early 1990s but there have been few large-scale studies examining the prevalence of diseases after CS2 exposure discontinuance. So we investigated past working exposure to CS2 characteristics from surviving ex-workers of a rayon manufacturing plant including cumulative CS2 exposure index. Furthermore, we studied the prevalence of their chronic diseases recently after many years. METHODS: We interviewed 633 ex-workers identified as CS2 poisoning-related occupational diseases to determine demographic and occupational characteristics and reviewed their medical records. The work environment measurement data from 1992 was used as a reference. Based on the interviews and foreign measurement documents, weights were assigned to the reference concentrations followed by calculation of individual exposure index, the sum of the portion of each time period multiplied by the concentrations of CS2 during that period. RESULTS: The cumulative exposure index was 128.2 ppm on average. Workers from the spinning, electrical equipment repair, and motor repair departments were exposed to high concentrations of ≥10 ppm. Workers from the maintenance of the ejector, manufacturing of CS2, post-process, refining, maintenance and manufacturing of viscose departments were exposed to low concentrations below 10 ppm. The prevalence for hypertension, coronary artery disease, cerebrovascular disease, diabetes, arrhythmia, psychoneurotic disorder, disorders of the nervous system and sensory organ were 69.2%, 13.9%, 24.8%, 24.5%, 1.3%, 65.7%, 72.4% respectively. CONCLUSIONS: We estimated the individual cumulative CS2 exposure based on interviews and foreign measurement documents, and work environment measurement data. Comparing the work environment measurement data from 1992, these values were similar to them. After identified as CS2 poisoning, there are subjects over 70 years of average age with disorders of the nervous system and sensory organs, hypertension, psychoneurotic disorder, cerebrovascular disease, diabetes, coronary artery disease, and arrhythmia. Because among ex-workers of the rayon manufacturing plant, only 633 survivors recognized as CS2 poisoning were studied, the others not identified as CS2 poisoning should also be investigated in the future.

Characteristics of PCDDs/PCDFs in stack gas from medical waste incinerators.

Toxic polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) in 45 stack gas samples were measured from 19 medical waste incinerators in South Korea using high-resolution gas chromatography equipped with a high-resolution mass spectrometer. The average concentrations of the sum of 17 toxic PCDD/PCDF congeners emitted from the medical waste incinerators ranged from 0.153 to 101.9 ng/Sm3. Based on the World Health Organization toxic equivalency factor, they ranged from 0.007 to 5.437 ng-TEQ/Sm3. The congener patterns of PCDDs/PCDFs were described using principal component analysis and presented four patterns. In the evaluation of annual average total TEQ concentrations, outlying stack gas samples were excluded. In this study, the number of chlorine substitutions was evaluated as an important factor in congener patterns. Coefficient of determination values were employed for evaluation of correlation between PCDDs and PCDFs. 1,2,3,4,6,7,8-HpCDF was measured as the most emitted congener, while 2,3,4,7,8-PeCDF was the greatest TEQ contributor.