• Progress in Superconductivity and Cryogenics
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• v.18 no.1
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• pp.23-27
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• 2016

The technologies using magnetic force control have been investigated toward application in various fields. Some of them have been put into practical use as the results of technological development. This paper introduces our technical development in the field of water processing, scale removal, magnetic drug delivery system, decontamination of radioactive substances and resources recycling.

• Journal of the Korean Applied Science and Technology
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• v.29 no.4
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• pp.653-658
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• 2012

There is an increasing interest in the use of electrochemical methods for the food waste treatment. The technologies using the electrochemical method provide ideal tools for approaching industrial and food wastes problems. Unlike other chemical treatments, the electrochemical systems do not make the volume of the secondary waste increase. The electrochemical methods can be operated with electrochemical apparatus and inorganic agent allow selective separation and recovery and even quieter than others. This study concerns design factors, electrode construction and wastewater treatment process of the electrochemical apparatus. The experiment of color, COD and BOD removal is much effective in using electrochemical method with ultrasonication and ozonation.

• Resources Recycling
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• v.6 no.4
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• pp.24-30
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• 1997

The recent trend of recycle of mold scrap is to make high quality secondary ingot which can be used as raw malerial undcr intensive control of scrap. In this study, recycle of aluminum chlp generated atter machinmg process of castings was performed by vortex melting melhod Vortex melting technique was adopted for chip mclting process. The condition far optimal vortcx depth was decided using water mndellng experiment varying the shape, location, rotating speed of stlircr and watcr levcl. Before melting, chips were preheated at room temperame, 200, 300, $ 400^{\circ}C$and then submerged in the mirldle of vortex. The lecovery rale depending on the temperature was examined. As a result vortex depth was influenccd only by shape and rotating speed of stirrer, and the hlghest recovery rate oI 97% was obta~nedw hcn the submerged chip was preheated at $300^{\circ}C.$

• Fisheries and Aquatic Sciences
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• v.1 no.2
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• pp.242-249
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• 1998

The engineering aspect of water treatment processes in the recirculating aquaculture system was studied. To recycle the water in the aquaculture system, a wastewater treatment process was required to maintain high water quality for the growth and health of the cultured fish. In this study, three different biofilm processes were used to reduce the concentration of organic matters and ammonia from the recirculating water - two phase fluidized bed, three phase fluidized bed, and trickling filter. The objectives of this research were to evaluate the optimum treatment conditions of the biofilm processes for the recirculating aquaculture system, and thereby reduce the volume of biofilm processes, which are commonly used for the recycle water treatment processes for aquaculture. The result of this study showed that the removal efficiency of organic matters by trickling filter was found to be lower than that of the fluidized bed. In the trickling filter system, anthracite showed better organic removal efficiency than crushed stone as a media. In the two phase fluidized bed, the maximum removal efficiency of either organics or ammonia was obtained when both the packing rate of media was maintained to $40\%$ of total reactor depth excepting sediment zone and the bed expansion rate was maintained to $100\%$. When 100 tilapia (Oreochromis niloticus) of each average 200g was reared, the pollutant production rate was 0.07g $NH_4\;^+-N/kg$ fish/day and 0.06g P04-3-P/kg fish/day, and sludge production rate was 0.39 g SS/kg fish/day. In the two phase and three phase fluidized bed, the volume of water treatment tank could be calculated from an empirical equation by using the relationship between the influent COD to $NH_4\;^+-N$ ratio (C/N, -), media concentration (Cm, g/L), influent ammonia nitrogen concentration (Ni, mg/L), effluent ammonia nitrogen concentration (Ne, mg/L), bed expansion rate $(E,\;\%)$, and influent flowrate $(Q,\;m^3/hr)$. The empirical equation from this study is $$V_2\;=\;10^{3.1279}\;C/N^{3.5461}\;C_m\;^{-3.7473}\;N_i\;^{4.6477}\;E^{0.0326}\;N_e\;^{-0..8849}\;Q\;(Two\;Phase\;FB) V_3\;=\;10^{11.7507}\;C/N^{-1.2330}\;C_m\;^{-6.5715}\;N_i\;^{1.5091}\;N_e\;^{-1.8489}\;Q (Three\;Phase\;FB)$$

• Proceedings of the IEEK Conference
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• 2001.10a
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• pp.715-718
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• 2001

This study uses traditional alum coagulation and sedimentation process to treat CMP wastewater from cleaning after polishing. The primary goal is to successfully recycle both solid fines and water for semiconductor manufacturing. Results indicated that CMP wastewater may be successfully treated to recover clean water and fine particles by alum coagulation. The optimum operating conditions for coagulation are as fellowing: alum dosage of 10 ppm, pH at 5, rapid mixing speed at 800 rpm, 5 min rapid mixing time, and long slow mixing time. The treated water with low turbidity and an average residual aluminum ion concentration of 0.23 ppm may be considered for reuse. The settled sludge after alum coagulation contains mainly SiO$_2$particle with a minor content of aluminum (1.7 wt%) may be considered as raw materials for glass and ceramic industry.

• Journal of Environmental Science International
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• v.15 no.1
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• pp.77-84
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• 2006

An effective technique of sludge separation is required for excess sludge of sewage or wastewater plant. The separation of bulking sludge of paper manufacturing plant was studied using DAF(Dissolved Air Flotation) system. The effects of parameters such as nozzle type, A/S(air/solid) ratio. pressure, injection time of pressured water and saturation time were examined. The results showed that the best nozzle type was flat which had small orifice hole, The optimum A/S ratio and pressure were $7.070\times10^{-3}$(recycle ratio of pressured water $20\%$) and 5atm, respectively. Injection times of pressurized water around 20-25 sesc and flotation time of 30 min appeared to be optimal for the DAF operation. The order of performance of packing was 18 mm > 22 mm > 32 mm.

• Environmental Engineering Research
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• v.11 no.5
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• pp.266-276
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• 2006

Commonly, the flocculant is dissolved in process or recycle water in industrial plant which has many ionic materials. Therefore, the polymer degradation in aqueous solution by chemical, mechanical or bacteriological may occur, sometimes rapidly. Even if the same flocculant is dissolved, the flocculation characteristics and the properties of dissolving polymer varied with the kind of dissolving water. In this study, we try to estimate the interaction between flocculants and ionic materials in dissolving water using self inversing emulsion polymer; polyacrylamide-co-trimethyl ammonium ethyl acrylate chloride flocculants which have varying molecular weights and structures at a several conditions. The polymeric flocculant is dissolved in artificial dissolving water with Potassium Chloride (PC), Calcium Chloride anhydrous (CC), Potassium Hydroxide (PH), Sodium Chloride (SC), Sodium Bromate (SB) and Iron (II) Sulfate Heptahydrate (IS) as ionic sources. Experimental results indicate that the cationic and anionic ions in dissolving water induce the hydrolysis, degradation of cationic functional group and uncoiling of polymeric flocculants, therefore, the flocculation efficiency decreased by undesired polymer. According that result, it is important to estimate not only its structures and physical properties but also the qualities of dissolving water to optimize the efficiency.

• Environmental Engineering Research
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• v.22 no.3
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• pp.277-280
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• 2017

Destablization and demulsification is a difficult task for the treatment of waste oil-in-water drilling fluid because of its "three-high" characteristics: emulsification, stabilization and oiliness. At present, China is short for effective treating technology, which restricts cleaner production in oilfield. This paper focused on technical difficulties of waste oil-in-water drilling fluid treatment in JiDong oilfield of China, adopting physical-chemical collaboration demulsification technology to deal with waste oil-in-water drilling fluid. After oil-water-solid three-phase separation, the oil recovery rate is up to 90% and the recycled oil can be reused for preparation of new drilling fluid. Meanwhile, harmless treatment of wastewater and sludge from waste oil-in-water drilling fluid after oil recycling was studied. The results showed that wastewater after treated was clean, contents of chemical oxygen demand and oil decreased from 993 mg/L and 21,800 mg/L to 89 mg/L and 3.6 mg/L respectively, which can meet the requirements of grade one of "The National Integrated Wastewater Discharge Standard" (GB8978); The pollutants in the sludge after harmless treatment are decreased below the national standard, which achieved the goal of resource recovery and harmless treatment on waste oil-in-water drilling fluid.

• 한국신재생에너지학회:학술대회논문집
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• 2008.05a
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• pp.638-641
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• 2008

Geothermal water at moderate temperature in a range between 30 to $50^{\circ}C$ exists sparse in surroundings. Mostly they are utilized as heat or water source at spar zones in Korea. However, a large portion of used water is discarded due to its poor recovery quality and inferior application technologies. In this research, an innovative heat pump system based on the hybrid concept that combinate compression cycle and absorption cycle was investigated mathematically. The hybrid heat pump aims to recycle various kind of the heat sources at moderate temperature including geothermal water effectively. The prime objective of the simulation is to design a compression/absorption hybrid heat pump system which can make high temperature above the level of $90^{\circ}C$ and low temperature of $20^{\circ}C$ as well at the same using $50^{\circ}C$ geothermal heat water. As a result, primitive data was provided as a basis to design a prototype 3 RT class hybrid heat pump.

• Journal of the Korean Ceramic Society
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• v.50 no.1
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• pp.18-24
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• 2013

This study was conducted to recycle fly ash containing an abundance of CaO generated from combustion in a circulating layer as a carbon storage medium. The study utilized XRD, TG-DTA and XRF analyses during the hydration of fly ash and identified calcium substances within fly ash that could be used in a carbonation process. $Ca^{2+}$ ions in the calcium substances were easily converted to hydrates. A carbonation experiment was done, which used the method of $CO_2$ gas injection to produce suspensions by mixing fly ash with distilled water. The results were analyzed using TG-DTA, XRD, and pH meter measurements. The study was able to verify that the reaction was completed at a $CO_2$ flow rate of 300cc/min approximately 30 minutes after an injection into a solution with a solid-liquid ratio of 1 : 10 of fly ash and distilled water. Moreover, the stirring time of the suspensions did not influence the reaction, and the reaction time was found to diminish as the portion of the fly ash became smaller. Thus, this study produced carbon storage fly ash having a $CO_2$ storage rate of about 71% through the utilization of the CaO content contained within fly ash.