• 상하수도학회지
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• 제13권1호
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• pp.125-133
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• 1999

The objective of present work is to evaluate the optimum coagulation conditions in order to decrease dissolved organic carbon(DOC) and turbidity at different polyaluminum chloride dosage and pH from Nakdong River water. This studies were carried out to examine distribution on apparent molecular weight(AMW) of DOC in the Nakdong River water and its coagulation-sedimentation water. On the basis of jar tests, at the optimum coagulation pH in order to decrease DOC and turbidity were pH 5.0~6.0 and optimum dosage of polyaluminum chloride were 10~15mg $Al_2O_3/L$. The removal percentage of DOC and UV-254 absorbance were 35~40%, 45~60%, respectively. In pilot plant, at the optimum coagulation pH in order to decrease DOC and turbidity were 5.0-6.5, and the removal percentage of DOC were 30~45%. Distributions of AMW in the Nakdong River, less than 6,800dalton were 60.7% 6,800~11,000dalton were 32.8%, more than 11,000dalton were 6.4%. When the polyaluminum chloride dosage was 12~20mg/L, the removal percentages of each AMW for AMW of Nakdong River water, less than 6,800dalton were 25~28%, 6,800~11,000dalton were 65~68% more than 11,000dalton were 10~60%.

• 대한환경공학회지
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• 제22권3호
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• pp.441-451
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• 2000

정수장에서 발생하는 슬러지에는 처리과정에서 주입되는 응집제로 인하여 다량의 알루미늄 성분이 함유되어 있으며, 정수장에서 널리 사용되고 있는 폴리염화알루미늄(PACI) 응집제의 원료는 전량 수입되고 있는 실정이다. 본 연구는 정수 슬러지의 효과적인 재활용을 목적으로 수행되었다. 슬러지내의 알루미늄 성분을 염산(HCI)으로 용출하고 HCI 가스를 주입하여 염화알루미늄수화물($AlCl_3{\cdot}6H_2O$)을 제조하였다. 그리고 저온($180^{\circ}C$)에서 열분해시켜 고체상태의 염기성 염화알루미늄 [$Al(OH)_xCl_{3-x}$]을 얻은 후 이것을 물에 용해시켜 PACl(Polyaluminum chloride)을 제조하였다. 슬러지 용출 실험 결과 반응시간 10분, 반응온도 $105^{\circ}C$, 염산농도 27.65wt%에서 최적 용출율을 얻을 수 있었으며, KS 규격실험 결과 순도 98.7% 이상의 염화알루미늄수화물($AlCl_3{\cdot}6H_2O$)을 제조할 수 있었다. 제조된 PACl 응집제($PACl_{re}$)는 KS 규격을 모두 만족하였고, 열분해시 최적 열분해 온도는 $180^{\circ}C$이며 이때 염기도는 열분해율에 의해 결정되었다. 제조된 PACI 응집제($PACl_{re}$)와 기존의 PACI 응집제(PACI)의 성능비교 실험 결과, 탁도, DOC, $UV_{254}$ chlorophyll-a에서 유사한 효과를 보이는 것으로 나타났다.

• KSBB Journal
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• 제13권3호
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• pp.272-278
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• 1998

Cell recovery from high cell density broths of Alcaligenes eutrophus by pretreatment with aluminum-based coagulants such as aluminum sulfate, polyaluminum hydrooxide chloride silicate (PACS), and polyaluminum hydrooxide chloride (Hi-PAX) was carried out. Cells coagulated with coagulants could be successfully recovered above 95-99% by centrifugation or filtration. The optimum initial pH of fermentation broths for cell recovery was in the range of 10 to 12. Optimum coagulants dosage for cell recovery increased with increasing of cell concentrations (21-160 g/L). The optimum coagulant dosages to recover cells with more than 95% cell recovery by centrifugation for the cell concentrations ranged 21-160 g/L were as follows: aluminum sulfate, 416-1708 mg Al/L; PACS, 211-826 mg Al/L; Hi-PAX, 320-960 mg Al/L. At optimum conditions for the coagulation of cells, centrifugal forces for 95% of cell recovery were dependent on the cell concentration. The centrifugal forces at 82 g/L and 160 g/L of cell concentration were only 45${\times}$g and 1600${\times}$g, respectively.

• KSBB Journal
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• 제29권3호
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• pp.220-224
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• 2014

Flocculation is known one of the effective methods for harvesting microalgae. This study was aimed to optimize the flocculation condition for decreasing the amounts of flocculant and obtaining the highest yield of algal biomass. To achieve this goal, it was optimized the flocculant concentration, reaction pH and the concentration of cell density for harvest using response surface methodology (RSM). The flocculation of microalgae, Spirogyra varians, was carried out using inorganic flocculant polyaluminium chloride. By the RSM result, the optimal flocculation condition was calculated 5 ppm of polyaluminum chloride, pH 7.5 and 0.33 of optical cell density at $OD_{640}$. The obtained recovery yield of S. varians was 97.6% at the optimal condition.

• 상하수도학회지
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• 제26권2호
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• pp.295-302
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• 2012

The coagulation of combined sewer overflows ($CSO_{s}$) was investigated by jar-testing with several commercial coagulants. $CSO_{s}$ sample showed different characteristics of coagulation from secondary wastewater with three common coagulants, aluminum sulfate, ferric chloride and polyaluminum chloride (PACl). Jar-tests showed that relatively wide range of optimal SS and T-P removal yielded with alum and ferric chloride compared with cationic polymers, though efficient SS and T-P removal can be achieved with all three coagulants. The decrease of pH was caused by the increase in dosage of aluminum sulfate, ferric chloride and PACl as coagulants. The pH was changed from 7.0 to 4.7 with the dosages of ferric chloride 25 mL/L. Aluminum sulfate revealed pH of 5.0 and PACl was highest pH of 5.4 after dosing of coagulants. The optimal pH to treat $CSO_{s}$ with aluminum sulfate were 6-6.5; with PACl 6-7, and with ferric chloride higher than 7.

• 한국펄프종이공학회:학술대회논문집
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• 한국펄프종이공학회 1999년도 Pre-symposium of the 10th ISWPC Recent Advances in Paper Science and Technology
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• pp.390-393
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• 1999

In this paper, a series of PAC (polyaluminum chloride) samples were prepared for rosin neutral sizing system. Some characters of PAC were discussed in detail. The experimental results show that it is possible to achieve neutral sizing when PAC is compounded with DRS (dispersed rosin size) instead of alum (aluminum sulfate).

• 한국건설순환자원학회논문집
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• 제8권2호
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• pp.245-253
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• 2020

본 연구는 OPC-slag-FA의 삼성분계 시멘트에 PAC을 혼합하여 강도 특성에 대한 특성을 살펴보는 실험적 연구이다. 결합재는 80% OPC+10% slag+10% FA, 60% OPC+20% slag+20%FA, and 40% OPC+30% slag+30% FA의 세 종류이다. PAC은 mixing-water 중량의 0, 2, 4, 6, 8, and 10%를 사용하였다. 실험결과 PAC은 OPC의 양에 관계없이 압축강도를 향상시킨다. PAC은 portlandite를 소비하고 Friedel's salt를 형성하며 공극의 직경을 감소시켜 matrix를 치밀하게 만들어 압축강도 향상에 기여한다. 그러나 다공성의 FA 입자는 초기수화단계에서 PAC을 흡수하여 수화작용을 지연시키는 효과가 있었다. 따라서 FA의 사용은 수화지연효과를 고려하여 치환율을 결정할 필요가 있다.

• 한국환경과학회지
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• 제32권10호
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• pp.731-739
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• 2023

In this study, lab-scale phosphorus coagulation/precipitation experiments were performed using three types of polyaluminum chloride (PAC) with different Al contents (10%, 12%, and 17%). The PO₄-P removal efficiencies at various operating conditions, such as initial PO₄-P concentration, initial pH, and Al/P molar ratio, were evaluated, and correlations among the operating factors affecting phosphorus coagulation/precipitation with PAC were derived to optimize the process efficiency. When the initial PO₄-P concentration was 0.065 and 0.161 mmol P/L under an initial pH of 8-10, the optimal PAC dose was 0.126-0.378 and 0.189-0.667 mmol Al/L, respectively. Under these conditions, the Al/P molar ratio was 2.16-6.18 and 1.28-4.30, respectively, and the PO₄-P removal efficiency was in the range of 40.2-92.5%. When the Al/P molar ratio was 2 or less under an initial pH condition of 6-8, the PO₄-P removal efficiency was approximately ≤40% owing to insufficient Al³⁺ ions. However, when the Al/P molar ratio is 3-5, the PO₄-P removal efficiency improved to approximately 80-90%. Thus, the optimal Al/P molar ratio to achieve a PO₄-P removal efficiency of over 90% was determined to be approximately 4 in the PO₄-P coagulation/precipitation process using PAC.

• Membrane and Water Treatment
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• 제9권4호
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• pp.205-210
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• 2018

In this study, we investigated coagulants such as polyaluminum chloride (PACl) and ferric chloride ($FeCl_3$) and the combination of a coagulant and powdered activated carbon (PAC) for the removal of dissolved organic matter (DOM) from fish processing effluent to reduce membrane fouling in microfiltration. The efficiency of each pretreatment was investigated through analyses of dissolved organic carbon (DOC) and ultraviolet absorbance at 254 nm ($UVA_{254}$). Membrane flux and silt density index (SDI) analyses were performed to evaluate membrane fouling; molecular weight distributions (MWD) and fluorescence excitation-emission matrix (FEEM) spectroscopy were analyzed to assess DOM characteristics. The results demonstrated that $FeCl_3$ exhibited higher DOC and $UVA_{254}$ removals than PACl for food processing effluent and a combination of $FeCl_3$ and PAC provided comparatively better results than simple $FeCl_3$ coagulation for the removal of DOM from fish processing effluent. This study suggests that membrane fouling could be minimized by proper pretreatment of food processing effluent using a combination of coagulation ($FeCl_3$) and adsorption (PAC). Analyses of MWD and FEEM revealed that the combination of $FeCl_3$ and PAC was more efficient at removing hydrophobic and small-sized DOM.

• 상하수도학회지
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• 제7권2호
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• pp.39-46
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• 1993

In this experimental study, it is concerned to develop a simple equation using jar-test results in order to predict the optimum dosage of coagulant, PAC(polyaluminum chloride). Considering the relationships with the reactions of coagulation and flocculation, the four independent variables (e.g. turbidity, temperature, pH and alkalinity) are selected out of many parameters and they are put into calculations to develop an equation by means of multi-regression method. As the result, the dosing rate of PAC is proportional to turbidity, pH and alkalinity, but in inverse to temperature. And the developed equation is as follow, $$D_c=\frac{3.2{\cdot}T^{0.37}{\cdot}A^{0.04}{\cdot}P^{0.5}}{t^{0.1}},\;(R^2=0.9443)$$ And also, comparing between the estimated value from the equation and the real dosing rate in the plant, Kwangam and Tdukdo, during 1988~1991, it is represented an agreement having a relative error of 16.4%, 17.8%, respectively.