• Clean Technology
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• v.11 no.1
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• pp.29-39
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• 2005

Polychlorinated biphenyls, (PCBs) are a group of highly toxic chlorinated industrial chemicals used as dielectrics, coolants and lubricants in electrical transformers. This article reviewed the state-of-the-art on technologies for decomposition of Polychlorinated biphenyls (PCBs), one of the persistent organic materials (POPs). The purpose of this study was to evaluate the feasibility of decontaminating PCBs contaminated pollutants using treatment technologies such as chemical dechlorination, photodegradation and biological transformation.

• Membrane and Water Treatment
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• v.10 no.2
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• pp.139-148
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• 2019

In this study, the removal of MB from saline solutions was evaluated by two methods by adsorption and electrodialysis; the adsorption of the mixture dye/salt on dried orange peel waste (OPW) was studied in batch method. In this study the biosorption of cationic dye by OPW was investigated as a function of initial solution pH, and initial salt (sodium chloride) concentration. The maximal dye uptake at $pH{\geq}3.6$ in the absence and in the presence of salt and the dye uptake diminished considerably in the presence of increasing concentrations of salt up to 8 g/L. The Redlich Peterson and Langmuir were the most suitable adsorption models for describing the biosorption equilibrium data of the dye both individually and in salt containing medium. As well, this work deals with the electrodialysis application to remove the dye. Synthetic solutions were used for the investigation of the main operational factors affecting the treatment performance; such as applied voltage, pH, initial dye concentration and ionic strength. The experimental results for adsorption and electrodialysis confirmed the importance of electrostatic interactions on the dye. The electrodialysis process with standard ion exchange membranes enabled efficient desalination of cationic dye solutions; there are two main factors in fouling: electrostatic interaction between cations of dyes and the fixed charged groups of the CEM, and affinity interactions.

• Journal of Korean Society on Water Environment
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• v.39 no.1
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• pp.76-86
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• 2023

We are on the verge of paradigm shift for the design and operation of our urban water systems from treatment- and efficiency-based to recirculation- and sustainability-based. One of the most frequently suggested alternatives to embody this paradigm shift is to decentralize the currently highly centralized urban water infrastructure. However, claims for water infrastructure decentralization are often criticized due to poor economic feasibility, unstable performance, and unprofessional operation and maintenance. The current study critically reviews the literature to discuss the technical advancement needs to overcome such challenges. Firstly, decentralized water infrastructure was briefly defined and the rationale for the proposal of its introduction to the next-generation urban water systems was laid down. The main discussion focused on the following water technologies, which require special attention when working with decentralized water infrastructure: i) material collection, storage, and transport; ii) easily scalable water treatment; iii) sensor, information, and communications; and iv) system optimization. The principles, current development status, and challenges were discussed for each of the water technologies. The discussion on the water technologies has enabled the identification of future research needs for their application to the next-generation urban water systems which will be designed following decentralized water infrastructure. This paper will significantly improve the current understanding on water infrastructure decentralization and provides insight on future direction of water technology development.

• Korean Journal of Poultry Science
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• v.33 no.2
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• pp.127-131
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• 2006

This study was conducted to investigate the effects of expanding feed processing technologies on the egg characteristics and nutrient digestibility in laying hens. A total of two hundred seventy laying hens were randomly allocated into three treatments with fifteen replications for six weeks. Dietary treatments include 1) MS(mash), 2) EC(expanded crumble) and 3) EP(expanded pellet). In the egg production, the EC and EP treatments were significantly higher than MS treatment(p<0.05). However, no significant difference was founded in egg weight(p>0.05). Egg shell breaking was increased in EC and EP treatments compared with MS treatment(p<0.05), however, egg shall thickness showed no significant difference(p>0.05). Egg production and egg shell breaking were significantly higher in EC and EP treatments than MS treatment(p<0.05), but egg weight and egg shell thickness were no significantly difference among treatment(p<0.05). Yolk color was increased in EC treatment compared with other treatments(p<0.05). Also, yolk index was significantly improved in EC and EP treatments compared with MS treatment(p<0.05). Haugh unit was increased in EC treatment compared with MS treatment(p<0.05). EC treatment had improved DM, Ca and P digestibility. In conclusion, Expanded crumble and pellet processing could improve the egg characteristic and nutrient digestibility in laying hens.

• Clean Technology
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• v.13 no.1 s.36
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• pp.1-15
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• 2007

Biological treatment is a relatively recent air pollution control technology in which off-gases containing biodegradable odors and volatile organic compounds(VOCs) are vented through microbes. It is a promising alternative to conventional air pollution control methods. Bioreactors for air pollution control have found most of their success in the treatment of dilute and high flow waste air streams containing VOCs and odor compounds. They offer several advantages over traditional technologies such as incineration or adsorption. These include lower treatment costs, absence of formation of secondary pollutants, no spent chemicals, low energy demand and low temperature treatment. The three most widely used technologies are described, namely biofiltration, biotrickling filtration, bioscrubbing. The most widely used bioreactor for air pollution control is biofilter, but it has several limitations. In the past years major progress has been accomplished in the development of vapor phase bioreaction systems, for solving problems of biofilter. Biotrickling filters are more complex than biofilters, but are usually more effective, especially for the treatment of compounds which are difficult to degrade or compounds that generate acidic by-products. This, paper reviews fundamental and theoretical/practical aspect of air pollution control in biofilter, biotrickling filter and bioscrubber, focusing more extensively on biotrickling filtration. Special emphasis is given to the operating parameters and the factors influencing performance for air pollution control, and cost estimation in biotreatment technologies.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2002.04a
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• pp.54-57
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• 2002

Pretreatment technologies are defined as technologies that prepare or condition dredged material for subsequent, more rigorous treatment processes. The objectives of this study are to test the feasibility of treating dredged sediment using pretreatment process(hydrocyclone, sedimentation basin, and flotation), and to estimate design parameters for a pilot-plant design. The final goal of the project is to recycle the dredged sediment that is otherwise reused as construction materials.

• Journal of the Korean Professional Engineers Association
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• v.41 no.3
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• pp.24-29
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• 2008

Recently, the serious problems have been occurred due to the contaminated sites with heavy metals are increasing. There are several remediation technologies of the metal contaminated soil such as physical separation, washing with water or acid, biologically, electrically. Pytoremediation, ultrasonic etc. Among these technologies the physical separation can be put in a good option to solve the metal contaminated soil economically and environmental friendly. Because this technology has been already commercially certificated in the mineral processing field for a long time.

• Proceedings of the KSR Conference
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• 1998.11a
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• pp.505-511
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• 1998

Production technologies for aluminum rolling stocks are mainly related to welding of aluminum alloys. Automatic welding of extrusion profiles and control of welding deformations are the important contents of the production technologies. Another production technology other than welding is the technique for surface treatment of aluminum carbody. In this paper, problems caused during construction of the test carbody are described and the remedies for the problems are suggested. The accumulated experiences and systematic data will be helpful for the mass production of aluminum rolling stocks in the furture.

• Advances in materials Research
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• v.9 no.3
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• pp.189-202
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• 2020

The objective of the present work is to investigate the effect of cutting parameters (Vc, fz and ap) on tool life and the level of vibrations velocity in the machined part during face milling operation of hardened AISI 52100 steel. Dry-face milling has been achieved in the annealed (28 HRc) and quenched (55 HRc) conditions using multi-layer coating micro-grain carbide inserts. Statistical analysis based on the Response surface methodology (RSM) and ANOVA analysis have been conducted through a plan of experiments methodology using a reduced Taguchi table (L9) in order to obtain engineering models for tool life and vibration velocity in the workpiece for both heat treatment conditions. The results show that the cutting speed has a dominant influence on tool life for both soft and hard part. Cutting speed and feed per tooth is the most significant parameters for vibration levels. Comparing the experimental values with those predicted by the developed engineering models of tool life and levels of vibrations velocity, a good correlation has been obtained (between 97% and 99%) in annealed and hard conditions.

• Journal of Soil and Groundwater Environment
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• v.12 no.3
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• pp.1-9
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• 2007

As Total Maximum Daily Load program is being implemented, needs for the management and treatment of contaminated sediment are rising to attain cleaner water resources. In this paper, impacts and management methods of contaminated sediment were reviewed. Remediation technologies for contaminated sediment including dredging, natural attenuation, in situ solidification/stabilization, in situ biological remediation, in situ chemical remediation and capping were reviewed. Integrated remediation scheme was presented as well.