• Journal of Korean Society on Water Environment
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• v.21 no.1
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• pp.29-33
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• 2005

In order to recycle the waste material and to develop the thickening unit of waste activated sludge from wastewater treatment facilities, the filtration bio-reactor equipped with a shadow mask filter module was employed for this work from which the operating properties and parameters were drawn. The sludge thickening and filtration unit is made of cylindrical acryl tank(12cm i.d. ${\times}$ 58cm height: working volume of 6L), where the flat-sheet type of shadow mask filter module(pore size: 220~250um, opening area: 34.8~39.6%) was installed and the effluent was withdrawn from the effluent port at the lowest point of the reactor, and the filtration was performed only by the hydraulic pressure. For evaluating the operating performance of this reactor, some parameters such as the solid-liquid separation of different biomass concentrations, the water quality of filtrate, the aeration cleaning time and the cleaning effect were investigated. Depending on the MLSS concentrations, the different time to withdraw 3L of filtrate was required in which the longer filtration time was necessary for the higher MLSS concentrations caused by the thicker formation of cake layer: 40 minutes for 5,000 mg/L, 70 minutes for 10,000 mg/L and 100 minutes for 15,000 mg/L, where the concentrations of SS were 8.9, 6.7 and 6.5 mg/L, respectively. Under the same operating conditions (the intensity of aeration cleaning: 80 L/min, MLSS: 10,000 mg/L), the proper aeration cleaning time was revealed 30 seconds, and the stable formation of cake layer was in the range of 10 to 15 minutes. Therefore, the shadow mask considered as a waste material can be of use as a filter material for the sludge thickening system.

• Journal of Korean Society on Water Environment
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• v.31 no.2
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• pp.151-158
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• 2015

The aim of this research is to derive an optimum operating condition for the thermal solubilization equipment that is employed to increase concentration of soluble organic materials and to assess whether it would be possible to use the waste sludge generated by thermal solubilization reaction as an external carbon source in biological denitrification process. For the purpose, we have constituted a laboratory-size thermal solubilization equipment and have assessed thermal hydrolysis efficiency based on various reaction temperature and reaction time. We have also derived SDNR using the waste sludge generated by thermal solubilization reaction through a batch experiment. As a result of research, the highest thermal hydrolysis efficiency of about 42.8% was achieved at $190^{\circ}C$ of reaction temperature and at 90 minutes of reaction time. And when SDNR was derived using the waste sludge, the value obtained was $0.080{\sim}0.094\;g\;NO_3{^-}-N/g\;MLVSS{\cdot}day$, showing SDNR that is higher than that obtained by the results of existing researches that used common wastewater as an external carbon source. Accordingly, in view of the fact that food wastes vary quite a bit in characteristics based on the area they are generated from and seasonal change, it seems that a flexible operation of thermal solubilization equipment is required through on-going monitoring of food wastes that are imported to food wastes recycling facilities.

• Journal of the Korean Geotechnical Society
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• v.36 no.8
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• pp.27-34
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• 2020

Strong alkaline waste water is generated in large quantities due to using Concrete, shotcrete and various compounds in tunnel construction sites. As the release of this alkaline waste water will contaminate the stream water, it has to be neutralized. Currently, this waste water is mainly neutralized by using sulfuric acid or hydrochloric acid, but the risks of corrosion and handling of facilities are inherent and the chemical control act requires strict management measures. Therefore, using CO₂ (carbon dioxide) as an alternative has been highlighted and various indoor experiment studies have been conducted to prove its potential. However, it is difficult to apply CO₂ to the site because it is still completely lacking in field application research and shows different characteristics from indoor experiments. In this study, the actual site applicability is verified through field testing.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2021.10a
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• pp.153-155
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• 2021

A large amount of combustible household waste are incinerated on a large scale. Incineration ashes including flooring and scattering materials are generated in the incineration facilities. The incineration materials (flooring and scattering) are generated 16.5% of the total amount ashes brought into the incinerator. The amount of incineration materials decrease the landfill period of existing landfills and increase the needs for the construction of new landfills. This study introduces technical and institutional suggestions to solve increasing incineration ash problem by recycling them. As a technical recycling method, incineration materials can be recycled by producing earthwork materials and concrete products. In addition, the government and local governments will be able to promote recycling by improving related laws such as the Waste Management Act and by preparing active institutional support measures such as incentives for recycling companies for Green New Deal strategies.

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.29 no.3
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• pp.203-209
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• 2023

The increasing saturation challenges in storage facilities for Low- and Intermediate-Level Radioactive Waste call for a more efficient storage approach. Consequently, we have developed a square-structured container that features a storage capacity approximately 20% greater than that of conventional drum-type containers. Considering the need to contain various radioactive wastes from nuclear power usage securely until they no longer pose a threat to human health or the environment, this study focuses on evaluating the sealing efficacy of the newly designed rectangular container using finite element analysis. Since radioactive waste containers typically do not experience external forces except under special circumstances, our analysis simulated the impact of an external force, assuming a fall scenario. After fastening the bolts, we examined the vertical stress distribution on the container by applying the calculated external force. The analysis confirms the container's stable seal.

• Journal of the Korea Organic Resources Recycling Association
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• v.29 no.4
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• pp.67-76
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• 2021

Biogasification is a technology that produces environmentally friendly fuel using methane gas generated in the process of stably decomposing and processing organic waste. Biogasification is the most used method for energy conversion of organic waste with high moisture content, and is a useful method for organic waste treatment following the prohibition of direct landfill (2005) and marine dumping (2013). Due to African Swine Fever (ASF), which recently occurred in Korea, recycling of wet feed is prohibited, and consumers such as dry feed and compost are negatively recognized, making it difficult to treat food waste. Accordingly, biogasification is attracting more attention for the treatment and recycling of food waste. Korea's energy consumption amounted to 268.41 106toe, ranking 9th in the world. However, it is an energy-poor country that depends on foreign imports for about 95.8% of its energy supply. Therefore, in Korea, the Renewable Energy Portfolio Standard (RPS) is being introduced. The domestic RPS system sets the weight of the new and renewable energy certificate (REC, Renewable energy certificate) of waste energy lower than that of other renewable energy. Therefore, an additional incentive system is required for the activation of waste-to-energy. In this study, the operation of an anaerobic digester that treats food waste, food waste Leachate and various organic wastes was confirmed. It was intended to be used as basic data for preparing the waste-to-energy incentive system through precise monitoring for a certain period of time. Four sites that produce biogas from organic waste and use them for power generation and heavy gas were selected as target facilities, and field surveys and sampling were conducted. Basic properties analysis was performed on the influent sample of organic waste and the effluent sample according to the treatment process. As a result of the analysis of the properties, the total solids of the digester influent was an average of 12.11%, and the volatile solids of the total solids were confirmed to be 85.86%. BOD and CODcr removal rates were 60.8% and 64.8%. The volatile fatty acids in the influent averaged 55,716 mg/L. It can be confirmed that most of the volatile fatty acids were decomposed and removed with an average reduction rate of 92.3% after anaerobic digestion.

• Journal of the Korean Society of Marine Environment & Safety
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• v.16 no.3
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• pp.269-274
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• 2010

Present state of nationwide marine facilities reported to Minister of Land, Transport and Maritime Affairs{MLTM} in Korea for two years 2008 and 2009 was analyzed, and management plan was proposed in this study. As of the end of 2009, total number of nationwide marine facilities was reported to be 672 and to be scattered along the coasts all over the nation. 124 marine facilities reported to Masan regional maritime affairs and port office occupied 18.5% of total nationwide number. 69 marine facilities reported to Mokpo regional office and 69 marine facilities reported to Pohang regional office occupied 10.3%, respectively. 181 marine facilities reported to Busan and Masan regional offices occupied 26.9%, meaning that about a quarter of total nationwide marine facilities concentrated in Southeastern Sea of Korea centering around Busan and Masan. 320 oil and noxious liquid substances storage facilities occupied 47.6% of total nationwide number. 11 pollutant storage facilities occupied 1.6%. 178 ship construction, repair and scrap facilities occupied 26.5%. 7 cargo handling facilities occupied 1.0%. 12 waste storage facilities occupied 1.8%. none of marine facilities for tourism, housing and restaurant were reported. 88 water intake and outlet facilities occupied 13.1%. 37 fishing spots at play occupied 5.5%. 13 other marine facilities occupied 1.9%. 6 integrated marine science base facilities occupied 0.9% of total nationwide number. The guidance and the public relation for national report system of marine facilities, the improvement of national report system and management plan, the advancement and complement of national report affairs-handling guides, and the voluntary participation in national report system and the performance of duties by the owners of marine facilities were proposed for better management plan of marine facilities.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.12 no.3
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• pp.217-233
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• 2014

Securing the radiological safety is a prerequisite for the safe management of the naturally occurring radioactive materials (NORM) which cannot be reused. This becomes a crucial focus of our R&D efforts upon the implementation of the Act on Protective Action Guidelines against Radiation in the Natural Environment. To secure the safety, the establishment of technical bases and procedures for securing radiological safety related to the disposal of NORM is required. Thus, it is necessary to analyze the characteristics, to collect the data, to have the radiological safety assessment methodologies and tools, to investigate disposal methods and facilities, and to study the effects of the input data on the safety for the NORM wastes. Here, we assess the environmental impact of the NORM waste disposal with respect to the major domestic and foreign NORM characteristics. The data associated with major industries are collected/analyzed and the status of disposal facilities and methodologies relevant to the NORM wastes is investigated. We also suggest the conceptual design concept of a landfill disposal facility and the management plan with respect to the major NORM wastes characteristics. The radionuclide pathways are identified for the atmospheric transport and leachate release and the environmental impact assessment methodology for the NORM waste disposal is established using a relevant code. The assessment and analysis on the exposure doses and excessive cancer risks for the NORM waste disposal are performed using the characteristics of the representative domestic NORM wastes including flying ash, phosphor gypsum, and redmud. The results show that the exposure dose and the excessive cancer risks are very low to consider any radiation effects. This study will contribute to development in the areas of the regulatory technology for securing radiological safety relevant to NORM waste disposal and to the implementation technology for the Act.

• Journal of Environmental Health Sciences
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• v.30 no.4
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• pp.329-343
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• 2004

We conducted to investigate citizen's attitude to the treatment of food waste in Yongin city. The respondent of $41.81\%$ throws the food waste eliminate from home and store less than 1l in Yongin. When they dump the food waste, they speak out the inconvenience of damaged envelope by animals in case of home and store. This caused troubles for reason of sanitary. So a local autonomous entity must carefully consider of expand use specially designed container as like apartment house. They give an answer that the collecting time of food waste is suitable form dawn till morning. This answer shows the satisfaction of the period time to collect the food waste. They prefer to be appointed the exclusive place to collect food waste. The service interval of collect is suitable 1 time a day. They want to increase the number of washing of the collecting container. This is good method for sanitary condition, but the care of the period time to collect the food waste is more efficient than the care of the number of washing the collecting container. The care of the period time minimizes to incur the enmity of the people and to pollute in environment. The major of respondent handled the food waste after keeping the basket or a kit. This fact shows to us almost citizen doesn't feel the seriousness to remove the moisture of the food waste. Recently, many solutions which can be disposal efficiently are getting magnified and improved owing to increase utilities channel to loss in quantities and dry the food waste. We expect the reduction of food waste is solved getting easily step by step. The results of the awareness about the facility of food waste show citizen prefer recycling facility to the other facilities. If recycle facility and incineration facility are constructed, they were worried about bed smell. When some facility of the food waste is constructed, they have to maintain and to handle not to incur the enmity of the people. The spread rate of specially designed container already increased, the citizen set a high value on the use of specially designed container more than amount-rate vinyl envelope that people have used for several years. In the cost treatment about food waste, the major respondent answered the use cost of specially designed container is suitable price. So we can know the use charge is proper level. The majority of citizen more prefer autonomous plan which voluntary atmosphere creation and public information by mass media than levy system and rising treatment cost which forced plan. The citizens have pretty positive thinking of incineration, so the government needs more efforts for a public notice, which includes the incineration is no more than abandoned thing. Each of local self government has to sort the food waste and make kind of resource system related to collecting and carrying, constructing a suitable facility, proper disposal of the food waste and producing harmless in our surrounding in order to solve the invisible problems. To do above mentioned things, we have to analyze referred several problems till now. Also, to minimize the side effect, the government will have to improve through enforce the system.

• Analytical Science and Technology
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• v.13 no.5
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• pp.675-682
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• 2000

The concentration of dioxins from flue gases of municipal waste incineration facilities with capacities over 50 tons/day are regulated by the guideline: $0.1ng-TEQ/Nm^3$ for new facilities, and $0.5ng-TEQ/Nm^3$ for existing facilities and it will be strengthened to $0.1ng-TEQ/Nm^3$ until 2003 year. Dioxins from these incineration facilities have to be measured more than 2 times annually by the Official Test Facilities of Dioxins. Seven institutions have been certified so far as the Official Test Facilities of Dioxins. These facilities have to be evaluated by the quality control program provided by National Institute of Environmental Research every year. We reported the results of quality control test performed in 1999. Four institutions certified in 1998 sampled flue gases at stack of M incineration facilitiy and analyzed dioxins by Official Methods of Air Pollution. The isokinetic coefficients, the parameter for evaluation of sampling ability were excellent for all four institutions. They were 100.9%, 102.4%, 102.1% and 99.2%, respectively. The criteria required are as follows; resolution over 10,000, mass calibration within ${\pm}5ppm$, ion abundance ratio within 15%, and the recovery of 50-120%. As results, those institutions also met these parameters of Official Method of Air Pollution.