• Clean Technology
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• v.11 no.2
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• pp.57-67
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• 2005

Epoxy resins are produced by the dehydro condensated reaction with ECH (Epichlorohydrin) and BPA(Bisphenol-A) as raw reactants under sodium hydroxide(NaOH) as a catalyst, and from this reaction, salted water named of brine, which contains ECH derivatives in condition of emulsion as likely as glycidol and polymer resins, is produced as an undesired side product. This brine water is alkaline wastewater and causes process fouling problems by plugging and chemically depositing polymer particles on the surface of inner wall of reactors and pipes, and decreases the biodegradable efficiency in the wastewater process. In this study, the optimization of coagulation and sediment reactions, using inorganic and organic polymer coagulants, were performed to remove the causes occurring the process fouling phenomena. And also, based on this study, the methodologies applicable to the commercial processes including economical analysis were presented.

• Applied Chemistry for Engineering
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• v.27 no.4
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• pp.427-432
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• 2016

The purpose of the research was to examine the utilization of waste bittern from salt farm as a source for producing magnesium (Mg). In this work, a precipitation process for recovering Mg, where Mg is precipitated as $Mg(OH)_2$ by the addition of NaOH solution, was investigated. At the NaOH/Mg molar ratios of 2.70 : 1 to 2.75 : 1 and pH 9.5-10, > 99% of Mg could be precipitated from the bittern. The molar concentration of NaOH solution added as an alkaline reagent had no significant influence on the recovery efficiency of Mg precipitate. The particle size of Mg precipitate was strongly affected by the flow rate of caustic addition. The faster the flow rate of caustic addition, the smaller particles were formed. The Mg precipitate recovered was 100-120 g per 1 L of bittern and contained 94% $Mg(OH)_2$ after washing with water. Our results showed that the bittern can be used as a potential resource for Mg production.

• Journal of Soil and Groundwater Environment
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• v.9 no.2
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• pp.1-10
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• 2004

The purpose of this study is to evaluate a laboratory test on arsenic reduction efficiency for ARD (Acid Rock Drainage) using limestone and apatite, and to design an apatite drain system. As a result of the laboratory test, results of this study show that pH, arsenic removal ratio, and dissolution amount of limestone ＆ apatite are inversely proportional to flow rates, and apatite removes 100％ of arsenic at 0.6 ml/min/kg flow rate. It is supposed that dissolution rate of apatite is ten times higher than that of limestone. The arsenic compounds are assumed to be Johnbaumnite, and/or Ca-arsenic hydrate. According to the results of the laboratory test, apatite drain system is designed as follow; Sixty two tons of apatite will be needed per one year and six months, and the precipitates will be removed from the precipitation pond per 3 months.

• The Korean Journal of Mycology
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• v.20 no.1
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• pp.72-76
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• 1992

The extraction and separation methods of protein-bound polysaccharides from the mycelium and culture broth of Coriolus versicolor (Fr) Quel were investigated. The use of 2% solution of surface active agent Triton X-100, was effective for extraction of the protein-bound polysaccharides from the mycelium. For the separation and partial purification of the protein-bound polysaccharides, the column chromatography using DEAE-Cellulose and DEAE-Sephadex proved to be effective.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.8 no.8
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• pp.1732-1739
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• 2004

In this paper, we proposed a visualization system with ANN algorithm that traits the motion of particles that move colliding in the water, where we got a great deal of variable information and predicts the distribution of particles according to the flowing of water and the pattern of their precipitation. We adopted ART2 to detect sensitively the collision between particles in this visualzation. Various particles and their mutual collision influencing the force such as buoyancy force, gravitational force, and the pattern of precipitation are considered in this system. Flowing particles whose motion is changed with the environment can be visualized in the system presented here as they are in real water.

• Journal of the Korean Wood Science and Technology
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• v.44 no.3
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• pp.398-405
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• 2016

The cellulose nanofibers (CNFs) were prepared by wet disk-milling (WDM) and fractionated by settling method into supernatant, middle and sediment fractions. The diameter and its distribution of the fractionated CNFs were investigated. With increasing WDM passing number, precipitation became delayed. Weight fraction at sediment fraction was decreased, whereas those at supernatant and middle fractions were increased with increasing WDM passing number. Diameter distribution of CNFs at supernatant fraction was narrowest and became broaden at middle and sediment fraction. Filtration time was longer in order of supernatant, middle and sediment fraction.

• Journal of the Korea Organic Resources Recycling Association
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• v.21 no.2
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• pp.71-78
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• 2013

This study examined the feasibility of phosphorus removal from dewatering centrate/filtrate in wastewater treatment by struvite formation. Since dewatering centrate/filtrate obtained after anaerobic digestion contains a high content of ammonia, magesium addition and pH adjustment could remove phosphorous. The optimum magnesium dose, reaction time, settling time, and pH value was found at 2 mol Mg/mol $PO_4^{3-}$, 10 min, 120 min, and 8.5, respectively. A bench-scale continuous operation at the optimum condition showed 80% of total phosphorus removal and 82% of phosphate removal in dewatering centrate. The elemental composition and crystal structure of the chemical precipitate was similar to the reported values of struvite.

• Proceedings of the Membrane Society of Korea Conference
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• 2003.11a
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• pp.146-148
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• 2003

Bayer 공정은 가성소다를 이용하여 보오크사이트로부터 수산화알루미늄을 추출하는 공정이다. 그러나 보오크사이트 추출 후 1차 침전공정에서 반응한 보오크사이트 잔사는 침전시킴으로써 깨끗한 공정액을 분리하는 데 이때 침전되지 못한 다량의 분산성 고형물이 공정액 중에 존재하게 되는데 이를 분산성 보오크사이트(레드머드) 미립자라하며 보통 80-100mg/$\ell$의 농도를 나타낸다. 그러므로 이를 제거하기 위해 다음 공정인 입상여과필터 공정을 사용하는데 이때 필터링 효율증대를 위해 보조제로써 다량의 소석회(Ca(OH)$_2$)를 투여하여 공정액 중의 고형물을 농도를 8-100mg/$\ell$에서 5mg/$\ell$로 낮추는 공정을 사용하고 있다. 특히 국내 수산화알루미능 제조회사일 KC(주)의 경우 소석회 사용량이 일 10톤, 년간 약 3,600톤을 사용함으로써 소석회의 사용량에 따라 같은 량의 슬러지가 발생되게 된다. 따라서 여과후 발생되는 슬러지의 처리비용 문제(연간 9천만원)와 소석회의 미립자에 의한 공정액의 2차 오염과 제품 품질 저하(quality claim) 및 소석회 사용량에 따른 연간 원료비(연간 3억원) 등의 상당한 문제점을 나타내고 있는 실정이다. 아울러 최근 고품위 수산화알루미늄의 공급 요구에 따라 여과시 정제기준이 점차 낮아져 이제는 1mg/$\ell$ 이하를 유지하여야 하는 근본적인 문제에 봉착해있는 실정이다. 그러므로 본 연구에서는 소석회를 사용하는 입상여과법을 대체하기 위한 신공정개발을 추진하였으며, 그동안 카트리지여과법 등의 다양한 실험 결과로부터 최근 필터 보조제를 첨가하지 않는 물리적 여과방법인 세라믹 막 여과법의 적용 가능성을 확인하고 친환경공정인 세라믹 막 여과 실용화 공정 기술을 개발하였다. 세라믹 막 여과 법은 여과 보조제를 사용하지 않으므로 2차적인 슬러지 발생등의 환경문제를 발생하지 않으며, 공정액에 첨가제를 투입하지 않으므로 순환형 친환경공정으로 각광받을 수 있다. 본 연구에서는 고온, 고농도의 NaOH 수용액의 처리에 적합한 막소재와 발생될 수 있는 제반 문제점 등을 파악하였고, 장기간의 실험을 거쳐 최적 투과 압력(Trans membrane pressue), 세정 조건 및 주기, 막재질에 있어서 보강하여야 할 Point, 최적 운전 조건들을 토출해 내었고, 향후 실제 Plant에 적용할 계획이다.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.36 no.4 s.107
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• pp.67-76
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• 2004

Because paper industry spends lots amount of water, the recycling of water is very important in economical as well as environmental aspects. In order to optimize the process water recycling system, the efficiency of unit operation for water circulation, such as save-all system, CDS and settling tank, plays an important role in. In this study, the sedimentation efficiency of process water was evaluated by SS measurement with the different amounts of flocculent addition. 3 different kinds of process water were collected from fine paper mill, and applied in laboratory sedimentation equipment for the measurement of settling efficiency of SS materials. The addition amounts of alum and PAC were resulted in optimum efficiency of sediments in the condition of 100 ppm of alum and 500 ppm of PAC respectively. In the comparison of sedimentation efficiency between alum and PAC, alum showed more economical and efficient results. The SS of spill water and the particle size of suspended materials treated by alum flocculents were below 50 ppm and about 1 $\mu$m. It would be considered that the spill water can be substituted to superclear water grade.

• Clean Technology
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• v.6 no.1
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• pp.27-38
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• 2000

A physicochemical process called Ultra Rapid Coagulation(URC) can dramatically remove organics, metals, and phosphates in wastewater by adding weighted coagulation additive(WCA) and recycling sludge into the coagulation basin to increase the growth rate and adsorption ability of floc. Also this process can improve floc settling rate than conventional coagulation process and reduce the pollutants loaded into the receiving water for securing water source. It was evaluated that WCA and sludge added have effects on the removal efficiency and estimated the possibilities of reusing the effluent from this process.