• 상하수도학회지
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• 제18권2호
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• pp.254-269
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• 2004

Polysilicato-iron coagulant (PSI) is receiving attention in Japan as a substitute for aluminum-based coagulants. In the first part of this article, coagulation, sedimentation and filtration experiments were carried out using kaolin clay particles as the turbidizing material and four types of PSI with various molar ratios of polysilicic acid to ferric chloride (Si/Fe ratio). Results demonstrate that use of a PSI with a high Si/Fe ratio can cause a more dramatic decrease in treated water turbidity but a higher suction time ratio (STR) than when PACl is used. However, optimization by increasing the rapid agitation strength GR is found to greatly improve the STR. In addition, the series of filtration experiments verified that optimization of GR is greatly effective in controlling rapid increases in filter head loss, and also formation of a thin aging layer in the upper part of the filter bed by slow-start filtration is effective in improving filtered water turbidity over the entire filtration process. The second part of this article describes two innovative filtration techniques to increase the particle separation efficiency; (1) coagulant-coated filter medium by enhancing the electrical potential of the surface of the filter medium, and (2) coagulant dosing in influent by controlling the electrical potential of particles entering the filter layer. From the results of the various filtration experiments using a pilot plant, these two techniques were found to be very effective to reduce the effluent water turbidity from the start to the end of a filter run. Moreover, in the filtration experiments using these two methods simultaneously, higher removal efficiency of approximately 3-log (99.7%) was realized, resulting that the finished water turbidity was accordingly reduced to 0.004mg/L.

• 한국염색가공학회지
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• 제12권3호
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• pp.218-223
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• 2000

Color removal of dyeing wastewater is becoming more important due to intensive limitation on color unit of effluent water, so this study was to investigate an efficient color removal of dyeing wastewater. We found that bittern+iron chloride(II) inorganic coagulant developed by Kabool research center is much higher than any other inorganic coagulants for color removal. Optimum pH of this coagulant was 10.5 and removed more than 90% for color removal efficiency. The results showed that COD and color unit of effluent water was average 60mg/L and 200~250 units when continuous activated sludge test after coagulation with this coagulant has done. From the results of the experiments, the application of bittern+iron chloride(II) inorganic coagulant can save the operating cost of wastewater treatment plants.

• 상하수도학회지
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• 제27권4호
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• pp.439-444
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• 2013

Excessive phosphorus in aquatic systems causes algal bloom resulting in eutrophication, DO depletion, decline in recreational value of water and foul tastes. To treat wastewater containing phosphorus including effluent of wastewater treatment plant, the continuous experiments were performed by using electrochemical way. The spherical ZVI and silica sand which act as physical filter are packed at appropriate volume ratio of 1:2. Electric potential is applied externally which can be changed as per the operational requirement. The results indicate that optimum hydraulic retention time of 36 minutes (10 mL/min at 1 L reactor) was required to meet the effluent standards. Lower concentrations of phosphorus (<10 mg/L as phosphate) were removed by precipitation by contact with iron. Thus, additional electric potential was not required. In order to remove high concentration phosphorus around 150 mg/L as phosphate, external electric potential of 600 V was applied to the reactor.

• 한국광물학회지
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• 제22권3호
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• pp.249-259
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• 2009

본 연구는 황토와 황토에서 분리한 점토(clay fraction)를 이용하여 수용액 내 양이온의 종류와 농도에 따른 점토광물의 분산과 응집의 변화를 알아보고자 하였다. 본 연구를 위하여 사용한 황토는 전남 나주시 동강면 장동리 황토로 지표면으로 부터 90~130 cm 깊이에서 채취하였다. 황토와 황토에서 분리한 점토(< $2\;{\mu}m$) 그리고 이들 시료로부터 결정질 철과 비결정질 철을 제거한 황토와 점토시료를 이용하여 실험을 실시하였다. 이온의 종류와 농도에 따른 점토광물의 저면간격과 물리적 성질의 변화를 알아보기 위하여 4가지 양이온($Na^+$, $K^+$, $Mg^{2+}$, $Ca^{2+}$)과 이들 이온의 농도(0.001 M~1 M)를 변화시켰을 때 광물의 침강속도와 점토광물의 저면간격의 변화를 연구하였다. 장동리 황토의 주 구성광물은 석영이며, 황토로부터 분리한 점토는 카올리나이트, 일라이트, 버미큘라이트로 이루어져 있다. 장동리 황토의 비결정질 철과 결정질 철의 함량은 각각 16.3 mg/kg과 436 mg/kg으로 주로 결정질 철로 이루어져 있다. 이온농도가 다른 4가지 이온을 추가한 수용액에서 구성 입자의 크기가 작은 점토가 황토에 비하여 분산이 더 잘되었다. 황토광물을 코팅하고 있는 결정질 철과 비결정질 철을 제거하기 전과 제거한 후 광물의 분산실험 결과에서 철을 제거한 시료가 분산이 더 잘 일어났으며 이는 코팅된 철 산화물이 광물입자들의 분산을 방해하는 것으로 사료된다. 수용액 중 이온의 종류와 농도가 광물의 분산에 미치는 영향 실험결과에 따르면 첨가한 이온의 농도가 클수록 그리고 양이온 전하량이 클수록 침강속도가 빨랐다. X-선 회절 분석 결과에 따르면 카올리나이트와 일라이트는 양이온의 종류와 농도에 따른 저면 간격의 변화가 없었다. 하지만 버미큘라이트는 일반적으로 +2가 양이온을 첨가한 경우 저면간격이 $14.04\;{\AA}$으로 +1가 양이온의 $13.9\;{\AA}$보다 크게 나타났다. 이는 +2가 양이온들의 수화반경이 +1가 양이온보다 크기 때문으로 사료된다. 따라서 광물에 코팅된 철과 수용에 내의 이온의 종류와 농도가 광물의 분산 및 버미큘라이트와 같은 팽창성 점토광물의 저면간격에 영향을 줄 수 있음을 시사한다.

• 상하수도학회지
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• 제30권6호
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• pp.663-671
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• 2016

Coagulation/precipitation process has been widely used for the removal of phosphate within domestic wastewater. Although Fe and Al are typical coagulants used for phosphate removal, these have some shortages such as color problem and low sedimentation velocity. In this study, both Fe and Al were used to overcome the shortages caused by using single one, and anionic polymer coagulant was additionally used to enhance sedimentation velocity of the precipitate formed. Batch experiments using a jar test were conducted with real wastewater, which was an effluent of the second sedimentation tank in domestic wastewater treatment plant. Response Surface Methodology was used to examine the responsibility of each parameter on phosphate removal as well as to optimize the dosage of the three coagulants. Economic analysis was also done on the basis of selling prices of the coagulants in the field. Phosphate removal efficiency of Fe(III) was 30% higher than those of Fe(II). Considering chemical price, optimum dosage for achieving residual phosphate concentration below 0.2 mg/L were determined to be 18.14 mg/L of Fe(III), 2.60 mg/L of Al, and 1.64 mg/L of polymer coagulant.

• 대한환경공학회지
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• 제30권12호
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• pp.1262-1267
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• 2008

영가금속을 이용한 아조계 염료의 탈색연구를 수행하였다. 아조계 염료는 대부분 생물학적 독성을 갖고 있으며 생물학적 분해가 어려운 경우가 많다. 색을 제거하기 위한 가장 간단한 방법은 아조결합을 파괴하는 것이며 영가금속을 이용한 환원적 제거가 가능하다. 3종의 염료를(Cibacron Briliant Yellow 3G-P (CBY3G-P), Benzopurpurin 4b (B-4B), Chicago sky blue 6b (CSB6B)) 대상으로 연구하였으며 각 염료의 반응속도는 pH에 매우 의존적이며 낮은 pH에서 반응속도가 증가되었다. 영가철에서 용해된 철이온에 의한 응집 및 침전반응도 색도제거에 기여할 수 있으며 본 연구에서는 그 기여율을 알기 위해 철이온에 의한 제거실험을 수행하였으며 그 기여율은 대상 염료에 따라 편차가 크다는 것을 알 수 있었다. 본 연구에서는 영가철에 의한 환원반응에 의해아조계 염료가 성공적으로 탈색될 수 있음을 증명하였다.

• 한국환경보건학회지
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• 제35권1호
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• pp.58-63
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• 2009

This study investigated improvement to sludge dewaterability and coagulation for sewage treatment plant sludge by using sodium hypochlorite solution (NaOCl), ferric sulfate [$Fe_2(SO_4)_3$] and zeolite. The specific resistance to filtration(SRF), chloride, pH and turbidity were used to evaluate the sludge dewatering behaviors. The results of study were as follows: By varying the amount of NaOCl added the optimum result in terms of enhancement for pretreatment occurred when 34 mg/l of NaOCl was injected. When the total solids concentration of the sludge was 10,000 mg/l, the optimum ferric sulfate dosage for the sludge dewaterability was 150 mg/l and the corresponding SRF was $1.7{\times}10^7sec^2/g$. It was observed that injecting zeolite into sludge was effective in improving the dewaterability of sludge.

• 대한환경공학회지
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• 제35권3호
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• pp.226-232
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• 2013

역삼투기반 금속산업폐수 물재이용시스템의 전처리공정을 선정하기 위해 연수화, 응집침전, 활성탄, 이온교환 및 중화 침전공정에 대한 무기물 및 유기물 제거특성을 조사하였다. 유기물제거를 위해 DOC중 친수성 및 소수성 유기물을 분류하였으며, 이를 이용하여 조합공정을 최적화하였다. 다양한 전처리공정 중에서 연수화는 금속산업 방류수에 존재하는 칼슘경도(1,201 mg/L as $CaCO_3$)를 93.4%제거함과 동시에 소수성유기물을 모두 제거하는 것으로 나타났다. 연수화 후에 응집침전공정을 연계할 경우, 방류수에 포함된 유기물 5.1 mg DOC/L을 1.6 mg DOC/L까지 저감할 수 있었다. 또한, 금속공정 원폐수를 대상으로 가성소다를 이용한 중화침전공정을 적용하였을 때, 수중경도를 유발하지 않으면서도 철과 총용존성고형물을 효과적으로 제거할 수 있는 것으로 나타났다.

• 환경위생공학
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• 제16권4호
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• pp.55-61
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• 2001

There are many reservoirs used as the source of water supply and they show various specific characteristics in water quality depend seasonal. Especially, there were not a little variations of water quality in summer, as a natural consequence it follows that stratification occured phenomenon and changed anaerobic condition in the bottom of reservoir, and then accumulated Fe and Mn substance in soil and sediment were resolved into water, it attributes to coloration. G purification plant located in Y gun is very small plant in which coloration occurs by Fe and Mn in every summer. Using this plant as a model, the removal methods of Fe and Mn were studied. After prechlorination plus LAS coagulation, Fe, Mn, $NH_3-N$ were decreased from 7.290 mg/l to 0.080 mg/l, from 0.480 mg/l to 0.075 mg/l, from 0.55 mg/l to 0.04 mg/l. But $THM_{s}$ was increased from 0.050 mg/l to 0.044 mg/l. It shows that the prechlorination plus LAS coagulation treatment process in purification plant is effective to remove Fe and Mn ion.

• 보존과학회지
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• 제35권4호
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• pp.331-343
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• 2019

The purpose of this study was to investigate the material characteristics of black wares excavated from Yongyeon-ri, Damyang and to clarify the correlation of the factors that develop black coulor compared with black wares excavated from other regions. As a results of absorption rate, colour coordinate, compositional mineral, section analysis and contents showed high correlation between the kilns and the waste dumplings, indicating that they were made using the same materials. Second, comparing the microtextures and contents of the glaze layer with the excavated sherds from other kilns, a characteristic coagulation phenomena of iron oxides were not observed in Yongyeon-ri and Gilmyeong-ri, and it was considered that the material, mixing ratio, and firing environment were different from those of Bonggok-dong. In addition, statistical analysis using the major components revealed that the bodies of Yongyeon-ri were highly correlated with those of Bonggok-dong, which is nearest to the region, and similar to Gilmyeong-ri in the glaze layer. The characteristics of colorant were different depending on Fe₂O₃ content and K₂O content also contributed to the classification of the composition of each excavated kiln. Conclusionally, it can be seen from the scientific analysis that the colour of black wares excluded from different regions is materially different from that of iron oxide, the coloring condition, and the firing environment.