• Proceedings of the Korean Institute Of Construction Engineering and Management
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• 2007.11a
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• pp.408-411
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• 2007

Many studies are currently in progress concerning about recycling due to the environmental problems and the drain of the resources. Nowaday, the problems on wastes are increasing thus studies on the construction waste are necessary which is the greater part of domestic wastes. And much more studies on the waste concrete which takes a large part of construction wastes are in progress but the studies on how to handle the waste concrete economically are unsatisfactory. This study suggests the analyzation of the economical way of handling the waste concrete by processes depending on the cost which needed in the each process, and can be the fundamental data of the future construction waste recycling system.

• Journal of Soil and Groundwater Environment
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• v.15 no.6
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• pp.29-36
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• 2010

Several mines including Namil, Solim and Jungbong which are located in the Gyeonggi and Kangwon province have been abandoned and closed since 1980 due to "The promotion policy of mining industry". An enormous amount of mining wastes was disposed without proper treatment, which caused soil pollution in tailing dam and ore-dressing plant areas. However, any quantitative assessment was not performed about soil and water pollution by transporting mining wastes such as acid mine drainage, mine tailing, and rocky waste. In this research, heavy metals in mining wastes were analyzed according to leaching method which used 0.1 N HCl and total solution method which used Aqua-regia to recognize the ecological effect of distance from hot spot. We sampled tailings, rocky wastes and soils around the abandoned mine. Chemical and physical parameters such as pH, electrical conductivity (EC), total organic carbon (TOC), soil texture and heavy metal concentration were analyzed. The range of soil's pH is between 4.3 and 6.4 in the tailing dam and oredressing plant area due to mining activity. Total concentrations of As, Cu, and Pb in soil near ore dressing plant area are 250.9, 249.3 and 117.2 mg/kg respectively, which are higher than any other ones near tailing dam area. Arsenic concentration in tailing dams is 31.0 mg/kg, which is also considered as heavily polluted condition comparing with the remediation required level(RRL) in "Soil environment conservation Act".

• Clean Technology
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• v.4 no.1
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• pp.6-23
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• 1998

Recently, semiconductor industry has grown rapidly because of the large demand for electronic devices and equipment. The semiconductor industries have also played an important role on the economic growth in Korea. As the environmental regulations become strict, the proper environmental management and the well-developed waste minimization technologies in semiconductor industries are two of urgent problems to be solved. The semiconductor manufacturing process consists of a series of continuous chemical processes, such as cleaning, oxidation, diffusion, photolithography, etching and film deposition. During the processes, various environmentally hazardous wastes are produced. The wastes may be classified as wastewater, gaseous pollutants, and solid wastes. For waste minimization, the substitution of raw materials and process optimization techniques are used, while the selective destruction technologies of toxic chemicals contained in the wastes have been reported. Also, new technologies have been developed for source reduction and waste reduction, such as reduction of toxic chemical use and substitution of hazardous liquids with gaseous reactants or solvent.

• Journal of the Korean Recycled Construction Resources Institute
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• v.6 no.4
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• pp.342-348
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• 2018

The present study examined the various strength and deformation performances of molding materials recycled using film packaging wastes to ascertain the their applicability to secondary products in construction industries. The stress-strain relationships of molding materials were measured under compression, tension, and flexure in accordance with the ASTM procedure. The measured mechanical properties of recycled molding materials were comparable to typical ranges observed in low-density polyethylene and/or high-density polyethylene. However, to stabilize the properties of the molding materials, further management systems are required as follows: 1) evaluation of mechanical properties of materials with respect to various mixing proportions of waste ingredients; 2) estimation of the effect of foreign substance and moisture contents on the mechanical properties; and 3) establishment of comprehensive database including various sources such as manufacture process including applied pressure to produce the molding materials, and collection region and time of wastes.

• Analytical Science and Technology
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• v.19 no.2
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• pp.172-180
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• 2006

This study was performed to establish new methods for hazardous substances and to develop an analytical method in specified wastes for preventing the environmental pollution caused by hazardous wastes. Therefore, the trends of international management, regulatory criteria, and items of hazardous wastes in various countries were investigated. Based on this study, target priority of new hazardous substances in specified wastes was established. An analytical method was developed using the waste standard reference materials of sludge, oil, bottom ash, etc., which contain the new hazardous substances (Ba, Be, Cr(VI), F, Ni, Sb, Se, and V). A total of 37 waste samples from the representative facilities, which are emitting new hazardous substances, were analyzed.

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2006.11a
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• pp.127-128
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• 2006

• Journal of the Korean Professional Engineers Association
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• v.33 no.3
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• pp.35-36
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• 2000

The waste management system has become social problem all over the world since it is too much to control the waste generated during the economic development. Therefore Human being should minimize the dispersion of useful materials on the earth which is limited by means of recycle and reuse, and should maximize the use of solar energy which is almost infinite.

• Journal of Environmental Health Sciences
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• v.13 no.1
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• pp.17-33
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• 1987

As a result of technical advances and industrialization, the characteristics of domestic and industrial wastes are becoming more complex. Accordingly, improved treatment and disposal systems are being continuously sought to take account of complex characteristics and to comply with economic restrictions. In this study, an application of pyrolysis to the treatment of industrial wastes, including waste scrap rubber, waste raw material used in making the slipper bottom and waste PVC pipe, and the effectiveness of pyrolysis in resource recovery from these wastes were investigated. Batches of wastes were pyrolysed by external heating to a temperature of 400-800$\circ$C in a 32 mm diameter x 0.9 m long silica tube to produce combustible gases, oils and chars. Before the start of pyrolysis runs, the entire system was purged with nitrogen gas to exclude the air. The temperature inside the retort was controlled by the thermocouple in the gas stream, and referred to as the pyrolysis temperature. Under these conditions three products were separately collected and further analyzed. The results were summarized as follows. 1. More gases and less chars were produced with higher pyrolyzing temperature and with higher rates of heating, but the yields of oils tended downwards at temperatures above 700$\circ$C. Accordingly, operating conditions of pyrolysis should be varied with desired material. 2. Calorific values and sulfur contents of produced oils were sufficient and suitable for fuel use. Chars from waste rubber had high heating values with low sulfur contents, but calorific values of chars from waste PVC and waste slipper were as low as 3, 065-4, 273 kcal/kg and 942-2, 545 kcal/kg, respectively. Therefore, char from these wastes are inappropriate for fuel. 3. Soluble contents of Pb, Cd, Cu and Zn in chars from waste rubber and waste slipper were below the Specific Hazardous Waste Treatment Standards. However soluble contents of Pb and Cd in chars from waste PVC were one or two times and five or seven times exceedingly the Specific Hazardous Waste Treatment Standards, respectively. 4. Post high heating is desirable for treatment method of waste PVC which generates toxic hydrogen chloride. 5. The proportions of hydrogen, methane and ethane in produced gases were in the range of 3.99-35.61% V/V, 18.22-32.50% V/V and 5.17-5.87% V/V, respectively. 6. Pyrolysis is a useful disposal method in case of waste slipper, which was hardly combustible, and thus investigations of this kind of materials are required for effective management of industrial waste. 7. Based upon the possible market development for products, overall pyroly economics to take account of treatment values of noncombustible or hazardous materials should be evaluated.

• Management Science and Financial Engineering
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• v.14 no.2
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• pp.45-66
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• 2008

Refuse collection, one of important elements in reverse logistics, is an activity rendering recyclables or wastes and moving them to some points where further treatment is required. Among various decisions in the collection activity, we focus on network design, which is the problem of locating collection points as well as allocating refuses at demand points to collection points while satisfying the capacity restriction at each collection point. Here, the collection point is the place where recyclables or wastes near the point are gathered, and locating the collection points is done by selecting them from a given set of potential sites. The objective is to minimize the sum of fixed costs to open collection points and transportation costs to move refuses from demand points to collection points. An integer programming model is developed to represent the problem mathematically and due to the complexity of the problem, two types of heuristics, one with simultaneous and the others with separate location and allocation, are suggested. Computational experiments were done on test problems up to 500 potential sites, and the results are reported. In particular, some heuristics gave near optimal solutions for small-size test problems, i.e., 2% gaps in average from the optimal solution values.

• Journal of the Society of Disaster Information
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• v.4 no.1
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• pp.86-100
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• 2008

It is needed to classify the kinds of construction and demolition(c&d) debris to 6 catagories of waste concrete, waste asphalt concrete, waste wood, scraps, combustible waste and incombustible waste in order to properly do a separate discharge and to estimate unit generation rate in construction site. Also, in this case, the unit treating cost for mixed wastes should be applied with the unit treating cost for combustible waste. The construction standard materials estimation data is used for basic data for estimating unit generation rate. The mixed wastes in this data should be classified to waste wood, combustible waste and incombustible waste, and their ratio is obtained by using the unit generation rate of Asia Pacific Environment and Management Institute and Seoul Metropolitan Development Institute. The waste amounts generated from newly-built construction can be obtained from multiplying the loss rate by the amount of materials used from construction standard estimation data. Also, those from dismantling construction can be obtained by subtracting waste amount generated during newly-built construction from total input amount of materials in newly-built construction. Those in two cases can be used in construction site. It can be used for estimating the amount generated and establishing the treating plan in the case of setting up the policy of waste management and doing the environment impact assessment.