• 상하수도학회지
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• 제19권2호
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• pp.135-143
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• 2005

It was evaluated that the effect of turbidity removal by Pore Controllable Fiber Filter(PCF) installed in NS(Naksang) small water treatmant plant(system) using under flow water as raw water in the study. The results of the study are as the followings. Firstly, the removal efficiency of turbidity by PCF without coagulation(in operation mode not using coagulants) was mostly below 20 percent. On the other hand, when operation using proper coagulants, that of turbidity was mostly over 80 percent. Secondly, slow sand filtration after PCF, total turbidity removal efficiency of final treated water was 84.3 percent, and the contribution by PCF was 57.1 percent and that of slow sand filtration was 27.7 percent. Therefore the introduction of PCF as pre-treatment process would be helpful to reduce the loading of high turbidity of slow sand filtration. Thirdly, the results of particle counter measurements showed that when operated PCF with coagulants, fine flocs captured or adsorbed at the pore of PCF were flow out into the effluents from 120 minutes after backwashing because of the increase of headloss of PCF. Therefore the decision of backwashing time should made consideration into the outflow of fine flocs from PCF. Fourth, coagulant dosages on PCF at the same turbidity was largely variable because of the effect of the raw water characteristics and the turbidity increase velocity at rainy days, therefore flexible coagulant dosages should be considered rather than fixed coagulant dosage by the influent jar-test result.

• 청정기술
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• 제15권1호
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• pp.38-41
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• 2009

적니(red mud)는 보오크싸이트로부터 수산화알루미늄/알루미나를 제조하는 Bayer 공정에서 부산물로 발생되는 폐기물이다. 본 연구에서는 적니로부터 철과 알루미늄을 염산으로 침출시켜 폐수처리용 응집제를 제조하였다. 적니응집제를 합성폐수에 투입한 후 조절된 pH가 증가함에 따라 중금속이온 제거율이 증가하였다. 적니응집제 제조 시에 적니의 양이 증가할수록 Fe의 침출효율은 낮아졌으나, 적니응집제의 pH는 적니의 양이 증가할수록 높아졌다. 적니응집제와 물을 혼합한 용액을 다시 적니와 반응시켜 Fe 및 Al의 농도가 더 증가되고, pH가 향상된 침출액을 얻었다. 이 침출액의 pH는 다른 응집제 $FeCl_3$와 $Fe_2(SO_4)_3$의 pH와 비슷한 값을 보였다.

• 대한환경공학회지
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• 제34권9호
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• pp.590-596
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• 2012

고도응집 공정은 DBP 전구물질인 NOM을 제거하는 최적기법이다. 본 연구에서는 낙동강 원수를 대상으로 $FeCl_3$, alum, PSOM 및 PACl 응집제를 대상으로 고도응집 공정의 적용시 가장 효과적인 응집제와 응집조건을 DOC, THMFP, HAAFP 및 제타전위 변화를 중심으로 평가하였다. 탁도 제거율은 고도응집을 적용시 기존응집에 비해 제거율의 상승은 없었으며, 일정 응집제 주입량 이상에서는 제거율이 더욱 저하되었으나 DOC, THMFP 및 HAAFP 제거율은 응집제 종류별로 기존응집에 비해 각각 13~18%, 9~18% 및 9~18% 정도 증가하였다. 응집 pH 변화에 따른 탁도 제거특성은 $FeCl_3$와 PACl이 pH 4~10 범위에서 비교적 높은 탁도 제거율을 나타내었고 alum과 PSOM의 경우는 pH 5~8의 범위에서 안정적인 제거율을 나타내었다. DOC는 4종의 응집제 모두 pH 5~7 범위에서 안정적인 제거율을 나타내었다. 고도응집 공정을 적용시 1 kDa 이하 및 10 kDa 이상의 용존 유기물질의 제거율은 각각 11~21% 및 16% 정도 기존응집 공정에 비해 증가하였으며, 소수성 및 친수성 유기물질의 제거율은 각각 27~38% 및 11~15% 정도 증가하였다. 낙동강 원수의 고도응집에 가장 효과적인 응집제로는 $FeCl_3$로 나타났으며, 다음으로 PSOM, PACl 및 alum 순이었다.

• Applied Biological Chemistry
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• 제46권3호
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• pp.183-188
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• 2003

수산가공 부산물인 갑오징어갑의 효율적 이용을 목적으로 고 용해성 아세트산 처리 갑오징어갑 분말을 응고제로 이용하여 보통 두부를 제조한 다음, 이의 저장성에 대하여 살펴보았다. 염화칼슘을 응고제로 하여 제조한 두부의 pH, 담금액의 탁도, 적정산도 및 생균수는 저장 6일째까지 거의 변화가 없었으나, 이후 pH 및 담금액의 탁도는 급격히 감소를, 적정산도 및 생균수는 급격히 증가하였다. 그러나 갑오징어갑 분말을 응고제로 하여 제조한 두부의 pH 담금액의 탁도, 적정산도 및 생균수는 저장 9일까지 거의 변화가 없었고, 이후 PH 및 담금액의 탁도는 미미한 감소를, 적정산도 및 생균수는 미미한 증가를 하여 염화칼슘을 응고제로 한 두부와 차이가 있었다. 한편, 백색도는 응고제의 종류 및 저장기간에 관계없이 저장 중 변화가 없었다. 조직감은 경도 및 부스러짐성의 경우 응고제의 종류에 관계없이 저장 3일째까지 감소하였고, 이후 염화칼슘으로 제조한 두부의 경우 저장 6일째까지, 갑오징어갑 분말로 제조한 두부의 경우 저장 9일째까지는 변화가 적었으나, 이후 염화칼슘으로 제조한 두부의 경우 크게 감소하였고, 갑오징어갑 분말로 제조한 두부의 경우 미미하게 감소하였다. 관능검사의 경우 응고제의 종류에 관계없이 물리화학적 분석의 결과와 유사하였다. 이상의 결과로 미루어 보아 두부의 유통기한은 갑오징어갑 분말을 응고제로 한 두부의 경우 9일, 염화칼슘을 응고제로 한 두부의 경우 6일로 판단되었다.

• 대한화학회지
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• 제53권3호
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• pp.286-292
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• 2009

청송 달기, 신촌약수의 Ca, Mg 등의 풍부한 미네랄 성분을 두부 응고제로 이용하기 위한 기초 연구를 하였다. 비교 응고제로는 많이 사용하고 있는 $CaCl_2,\;CaSO_4,\;MgCl_2,\;MgSO_4$를 이용하였다. 두유 2 mL에 일정량의 약수와 각종 응고제를 첨가하여 $80\;{^{\circ}C}$에서 전체 용액량을 10 mL로 하여 응고한 다음 여과한 상층액인 두부청의 퍼센트 투과도[T(%)]를 600 nm에서 구한 응고력 시험결과, 약수는 8 mL 이 상이 요구되었다. 비교 응고제의 경우 각각 0.4, 1, 0.8, 0.8 mL를 첨가한 경우 양호한 결과를 보였으며, Ca, Mg의 첨가량은 각각 66.14, 232.83와 95.68, 78.88 mg이다. 달기 및 신촌약수를 8 mL를 첨가한 경우 의 T(%) 값이 50.74와 58.52값을 보였으며, 첨가된 미네랄 양으로 볼 때에 Ca, Mg의 합한 양으로 2.41, 2.48 mg에 해당된다. 이 값은 비교 응고제보다 매우 적은 양임을 알 수 있으며, 적은 양에 비하여 상당한 응고력이 있음을 알 수 있다.

• 한국펄프종이공학회:학술대회논문집
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• 한국펄프종이공학회 2007년도 추계학술발표논문집
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• pp.301-306
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• 2007

• Membrane and Water Treatment
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• 제9권6호
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• pp.447-454
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• 2018

Although flotation techniques are often used for the removal of algal particles, the practicality of algae-harvesting technologies is limited owing to the complex and expensive facilities and equipment required for chemical coagulation. Here, we examined the feasibility of an approach to separating algal particles from water bodies without the need for chemical coagulants, depending on the condition of the algae, and to determine the optimal conditions. Using Anabaena sp., a cyanobacterium causes algal blooms in lakes, we stimulated auto-flocculation in algal particles without coagulants and conducted solid-liquid separation experiments of algal particles under various conditions. The six cultivation columns included in our analysis comprised four factors: Water temperature, light intensity, nutrients, and carbon source; auto-flocculation was induced under all treatments, with the exception of the treatment involving no limits to all factors, and algal particles were well-settled under all conditions for which auto-flocculation occurred. Meanwhile, flotation removal of auto-flocculated algal particles was attained only when nutrients were blocked after algae were grown in an optimal medium. However, no significant differences were detected between the functional groups of the extracellular polymeric substances (EPSs) of floated and settled algal particles in the FT-IR peak, which can cause attachment by collision with micro-bubbles.

• 상하수도학회지
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• 제12권2호
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• pp.99-105
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• 1998

This research explored the feasibility of preparing and utilizing a preformed polymeric solution of Al(III) for coagulation in water treatment. Slow base(NaOH) injection into supersaturated aluminum chloride solutions did produce high yields of the type of Al polymers useful to water treatment applications. PACl's characteristic analysis showed that the quantity of polymeric Al produced at value of $r(OH_{added}/Al)=2.2$ was 83% of the total aluminum in solution, as showing maximum contents and precipitate was dramatically increased when r was increased above 2.35. And PACl was stable during sitoring period so aging effect was negligible. Results of the coagulation of Nakdong river waters with three PACls showed that the effectiveness of the three coagulants can be considered as r = 2.2 > r = 2.0 > r = 2.35 which are also the order of higher polymeric aluminum contents. Coagulation results for synthetic water exhibited optimum dose of 0.25mM Al, for three PACls, but above optimum dose, r = 2.0 and 2.2 PACl impaired the coagulation and sedimentation of turbidity and humic acid because of the restabilization of particulate. The effect of pH for on coagulation of Nak Dong River water showed that it had much effect turbidity and TOC removal, especially near pH 7. But pH effect was little for turbidity and TOC removal when r = 2.35 PACl was used for coagulation, that PACl had much more precipitates content.

• 상하수도학회지
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• 제24권2호
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• pp.237-246
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• 2010

This study was carried out to compare the performances of hydrophobic and hydrophilic membranes in the filtration of the pretreatment waters using coagulants such as PAC and PAHCs, and to investigate the influence of NOM characteristics on the fouling of membranes. As a result, the hydrophobic fraction was more effectively removed by PAHCs, however the transphilic and hydrophilic fraction were more effectively removed by PAC on NOM removal. Raw water showed the highest response in the range of humic substances, and pre-coagulated waters with PAC and PAHCs followed. It was also observed that the fouling effect for a hydrophobic membrane was greater than that of a hydrophilic membrane with a similar pore size, due to fouling caused by adsorption. Foulants causing significant flux decline were alcoholic compounds (polysaccharide-like) and humic substances including aromatic groups. Especially, it appeared that alcoholic compounds such as polysaccharide-like substances which mostly remained after coagulation pretreatment had most influence on fouling. It was found that fouling were influenced by each fraction NOM components depending on coagulants used. And PAHCs was more efficient for membrane fouling than PAC.

• 상하수도학회지
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• 제21권3호
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• pp.273-278
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• 2007

Modern society has moved from a phosphorus recycling loop, where animal manure and human wastes were spread on farming land to recycle nutrients, to a once-through system, where phosphates are extracted from mined, non-renewable phosphate rock and end up either in landfill(sewage sludge, incinerator ash) or in surface waters. In this research, crystallization of nitrogen and phosphate with natural sources of $Mg^{2+}$ in synthetic water was tested. The operational parameters of pH, mixing time, and the magnesium molar ratio were investigated to find optimal conditions of the MAP precipitation using synthetic wastewater. The removal efficiency of phosphate increased with pH up to 11. By MAP precipitaiton of the synthetic waste water, 94% of the phosphate were eliminated at pH 11. It was found that at least 10 minutes mixing time was required and 20 minutes mixing time was recommended for efficient phosphate removal. High efficiency removal of phosphate was possible when the magnesium molar ratio was 1.0~2.0. The comparative study of different magnesium sources showed that coagulants (PAC) was the more efficient sources than only magnesium. The result showed that 97% of phosphate removal. In conclusion, coagulants (PAC) induced crystallization of struvite and hydroxyapatite was shown to be a technically viable process that could prove cost effective for removing phosphate in wastewater.