• Journal of Environmental Health Sciences
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• v.26 no.3
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• pp.92-97
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• 2000

The treatment of the washout from small scale incinerator was performed physically, chemically and biologically. The results are as follows. 1. SS, FS removal efficiency of washout wastewater from incinerator was 67.4%, 37.4%, while SS, FS of sewage wastewater was removed 63.2% 35.4% respectively. 2. The optimal conditions for chemical coagulation turned out to be pH 7.5, alum(Al2O3 10%) 30ml/ι and polyelectrolyte(A-601P 0.1%) 4ml/ι. SS 86%, FS 89.5%, BOD 42.5% and CODMn, 63.5% was removed and the removal efficiency of some metals are shown as Pb 93.5%, Zn 86.5% and Fe 80.6%. The concentration of the effluent was SS 9mg/ι, BOD 98.4mg/ι, and CODMn 138.4mg/ι. 3. The removal efficiency in treating washout wastewater of incinerator through HBC-briquet media was getting higher with increasing HRT, and mixed wastewater with 1:1, 1:2 ratio could be met up to the standard limit with higher HRT than 12hr. Under the condition of 1:2 mix ratio and HRT 24 hr, removal efficiency of SS, BOD, CODMn, T-N and T-P was 92.1%, 90%, 87%, 48.2% and 48%, respectively, and the concentration of treated wastewater was SS 2.9 mg/ι, BOD 10.3mg/ι, CODMn 14.1mg/ι, T-N 11.6 mg/ι and T-P 1.3 mg/ι, respectively.

• Journal of Environmental Health Sciences
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• v.23 no.1
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• pp.34-42
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• 1997

A laboratory experiments were performed to investigate the treatment of photographic processing wastewater by chemical oxidation and biological treatment system. The effect of reaction conditions such as hydrogen peroxide dosage, ferrous sulfate dosage and pH on the COD removal in Fenton oxidation were investigated. The optimal dosage of hydrogen peroxide was 2.58 M and 3.87 M for the developing and fixing process wastewater, respectively. The Fenton oxidation was most efficient in the pH range of 3-5 and the optimal condition for initial reaction pH was 5 for a developing process wastewater. With iron powder catalyst, the COD for a developing process wastewater was removed in lower pH than with ferrous sulfate catalyst. The removal efficiency of COD for refractory compounds such as Diethyleneglycol, Benzylalcohol, Hydroxylamine Sulfate, Ammonium Thiosulfate, Ammonium Ferric EDTA and Disodium EDTA in the photogaphic wastewater was found than 90% except Potassium Carbonate. When the photographic processing wastewater after pretreatment by Fenton oxidation was treated with batch activated sludge process, the addition of $KH_2PO_4$ as a phosphorous compound improved the removal efficiency of COD. During the continuous biological treatment of developing and fixing process wastewater after pretreatment by Fenton oxidation, the effluent COD concentration less than 100 mg/l was obtained at 0.425 and 0.25 kgCOD/m$^3$.d, respectively.

• Proceedings of the Korean Environmental Sciences Society Conference
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• 2008.11a
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• pp.495-498
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• 2008

여러 가지 흡착제를 사용한 회분식 흡착성능 측정 실험에서 흡착성능은 음이온교환수지 > 입상활성탄 > Biomass > 분말활성탄 > 제올라이트 순으로 나타났으며, 모든 흡착제는 30분 안에 흡착평형 상태에 도달 하였다. 음이온교환수지를 이용한 회분식 흡착실험에서 최대흡착량은 pH 10에서 0.0483 mmol/g로 가장 높았고, 대체적으로 pH가 높은 범위에서 흡착이 잘 되는 것으로 밝혀졌다. 이것은 산화물 상태의 셀레늄이 pH 6 이하의 영역에서는 HSeO$_3^{-}$가 존재하며, PH 6$\sim$10 영역에서는 HSeO$_3^{-}$와 SeO$_3^{-2}$가 공존하며, pH 10 이상에서는 SeO$_3^{-2}$만 존재함을 알 수 있는데, 실험에서도 유사한 결과가 나온 것으로 사료된다. 입상활성탄을 이용한 흡착실험에서 최대흡착량은 pH 4.5에서 0.0574 mmol/g으로 가장 높았다. pH 4.5$\sim$6.5 범위에서는 대체적으로 비슷한 성능을 나타내었다. 입상활성탄의 표면전위 특성상 음이온으로 존재하는 셀레늄과 정전기적 반발력으로 인해 흡착이 거의 일어나지 않는 것으로 보이지만, 음이온 상태로 존재하는 셀레늄 이외의 금속간 화합물이나 물리적인 결합상태의 미세입자들이 흡착된 것으로 보인다.

• Resources Recycling
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• v.17 no.2
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• pp.70-75
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• 2008

A study on the cementation for the recovery of tin with aluminium in the hydrochloric acid solution was carried out. Parameters, such as aluminium metal equivalent, pH, reaction time, reaction temperature and the concentration of chloride ions were investigated. The experimental results showed that the cementation rate of Sn(II) ions increased with increase of the addition amount of aluminium powders, temperature, pH and the concentration of chloride ions in hydrochloric acid solution. From the results, the optinum conditions for recovery of metallic tin by cementation with aluminium metal powders were proposed.

• Resources Recycling
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• v.22 no.1
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• pp.48-54
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• 2013

A laboratory study was carried out to recover KI crystals with high purity by using fractional crystallization method from a waste solution generated from the production of polarizing film for LCD industry. The waste solution contains 1.3% KI, and other impurities such as B, Na, and PVA etc. With purity higher than 99.5% KI crystals were produced through refining process such as vacuum evaporation, fractional crystallization, filtering, and 24hr aging. Also the concentrated impurities were eliminated about 70% by recrystallization.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.10 no.4
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• pp.185-192
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• 1990

A two-phase UASB system was operated for high-rate treatment of concentrated distillery wastewater. The phase separation was obtained by adjusting pH in each reactor. When influent SS concentration was 4.1/g/l, the first phase UASB reactor was effectively operated up to the loading rate of 16.5kg $COD/m^3.day$, producing 3.9g HAc/l.day. In the methanogenic UASB reactor, loading rate up to 44kg $COD/m^3.day$ could be applied while removing 80% of influent COD with a specific gas production of 16.5 l/l. day. After the formation granular sludge in both reactors, it was possible to maintain the appropriate pH in the first phase only by recirculating the effluent from methanogenic phase without the addition of alkaline chemicals.

• Journal of Powder Materials
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• v.19 no.6
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• pp.405-411
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• 2012

Recovery of copper powder from copper chloride solution used in $MoO_3$ leaching process was carried out using a cementation method. Cementation is a simple and economical process, necessitating less energy compared with other recovery methods. Cementation utilizes significant difference in standard reduction potential between copper and iron under standard condition. In the present research, Cementation process variables of temperature, time, and added amount of iron scraps were optimized by using design of experiment method and individual effects on yield and efficiency of copper powder recovery were investigated using bench-scale cementation reaction system. Copper powders thus obtained from cementation process were further characterized using various analytical tools such as XRF, SEM-EDS and laser diffraction and scattering methods. Cementation process necessitated further purification of recovered copper powders and centrifugal separation method was employed, which successfully yielded copper powders of more than 99.65% purity and average $1{\mu}m$ in size.

• Applied Chemistry for Engineering
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• v.8 no.4
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• pp.595-601
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• 1997

The regeneration of the iron powders in the treatment of $FeCl_3$ etching solution containing nickel by ball-mill and ultrasonic treatments has been studied. When the unreacted iron powders were treated twice, the removal efficiency of nickel was 94.0% for the ball-mill treatment and 82.1% for the ultrasonic treatment. But the removal efficiency of nickel was 40.0% for the untreated iron powders. As the treatment time was increased, the particle size of iron powders was decreased for ball-mill treatment and almost not changed for ultrasonic treatment.

• Journal of Environmental Health Sciences
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• v.23 no.3
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• pp.40-49
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• 1997

In Korea, naked barley and tapioca are main raw materials for the production of fermentation ethyl alcohol, and one million drums bf 95% fermentation ethyl alcohol is produced per year by use of them. Stillage of alcoholic fermentation is mostly digested by methane fermentation process, and methane gas occured if methane fermentation process is recovered and mixed with fuel to decrease 25-30% for total fuel used in factories. In the anaerobic digestion process of naked barley stillage, supplement of nutrients is necessary to slove the problems caused by inhibitory materials contained if stillage and deficiency of nutrients. Therefore, the objective of this study was to examine why the anaerobic digesters using the naked barley distillery wastewater have shown the poor digestability frequently and how to control it. As the poor digestion was supposed to be occurred by the lack of iron as trace nutrient, the experiments were carried out to find out the optimum dosage and the way of addition of iron and to assess the quantitative evaluation of the type of iron in digesters. Initially, bottle test as batch digesters and lab-scaled continuous flow digesters were used in order to determine the digestion characteristics with tapioca and naked barley distillery wastewater. According to the results of batch tests, the poor digestion was caused by volatile fatty acids and could be improved by adding of calcium. The activity of the methanogenic bacteria were increased remarkably when the iron was added to the digester in the form of mixture with substrates.

• Clean Technology
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• v.23 no.4
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• pp.393-400
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• 2017

In this study, we have developed a process for separating and recovering Ni and Fe in solution through a new solvent instead of TBP and Alamine336, which are solvents used in the conventional solvent extraction method. Experimental conditions were optimized through lab test and a $10L\;h^{-1}$ pilot plant was constructed for commercialization. In addition, the process data for mass production were obtained through pilot experiment and it was confirmed that there is no problem in product quality that can be used through the corrosion test of ferric chloride.