• 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.

• 한국환경과학회지
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• 제25권3호
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• pp.425-438
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• 2016

This study carried out zeta potential measurements of the Microcystis sp. under various solutions condition and investigated the characteristics of Microcystis sp. through the size control of microbubbles to eliminate algae that causes problems in aquatic ecosystems and human activities. DAF process was adopted and several coagulants were used to remove the Microcystis sp. CCD Camera was used to measure and analyze the size of microbubble, and fluorescent microscope was used to observe the particle, algae species and community. Zeta potential behavior of the algae was analyzed by using ELS-Z. Lab-scale and pilot-scale experiments were conducted to test flotation process. Polyaluminium chloride(PAC) coagulant was used, and the removal efficiency of the algae was assessed through Chlorophyll-a analysis. In the Lab-scale experiment, 2.2 ppm, 11 ppm, 22 ppm, and 44 ppm of polyaluminium chloride was injected to coagulate the algae. The coagulated algae was floated by the microbubble. The microbubbles in the experiments were generated at a air pressure of 450 ~ 550 kPa. The microbubble size was controlled in $36{\mu}m$, $100{\mu}m$, and $200{\mu}m$, respectively by using different diffuser. The results of lab-scale experiments on flotation plant indicated that the average removal rate was about 90% or above for 11 ppm, 22 ppm, and 44 ppm of polyaluminium chloride. On the other hand, in the pilot-scale experiment, the removal efficiency was in the range of 85% to 95% in all dose ranges of polyalumium chloride and aluminium sulfate coagulants.

• 상하수도학회지
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• 제12권3호
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• pp.30-40
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• 1998

Increasing water consumption produced sludge problems of the water treatment plants. The objective of this study is to investigate aluminium coagulants recovery n acidic and alkaline conditions. Water treatment plant sludge produced in Pusan Metropolitan City were tested for the aluminium extraction process. Experiment samples were obtained in summer from water treatment plants of Deoksan and Myongjang. Aluminium coagulants used in these plants during the test period were polyaluminium chloride(PAC), polyaluminium sulfate organic(PSO), polyaluminium sulfate silicate(PASS). Aluminium contents of water treatment sludge were in the range of 7.2~10.9% of the total solids. The recovery percentages for aluminium and iron by acidic extraction method was evaluated to 88% and 42% respectively. Extracted mass variation for other materials such as iron, manganese, total organic carbon was observed during the extraction operation. Alkaline extraction produced more than two times amount of total organic carbon than that in the acidic extraction process.

• 한국잠사곤충학회지
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• 제43권1호
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• pp.37-40
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• 2001

This study was carried out to investigate the optimum condition for silk sericin collection from degumming solution using some aluminium salts with various treatment conditions and examine the thermal properties of silk sericin collected from degumming solution. Silk sericin was precipitated by treatment of aluminium metal compound from degumming solution. The best optimum collecting conditions of silk sericin from degumming solution are the concentration of 2 $m\ell$/l of polyaluminium chloride (PAC), pH range of 5~7 and room temperature. The reduction of water pollution was evaluated by decreasing the chemical oxygen demand (COD) and nitrate ion (NO$_3$￣). Thermal stability of silk sericin collected from degumming solution was a little lower than that of hot water.

• Journal of Forest and Environmental Science
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• 제14권1호
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• pp.101-111
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• 1998

본 연구에서는 우유팩을 이용하여 재생용 화장지를 만드는 제지공장의 제지폐수를 이용하여 폐수의 침강특성 및 SS, $BOD_5$, 제거 효율을 검토하고, Jar-tester를 이용하여 급속교반시간, 완속교반 시간에 따른 탁도, SS, S-$BOD_5$ 및 최적 응집제 주입량을 결정하였다. 각종 응집제 첨가 및 침강 특성에 의한 탁도제거의 효율을 측정하였다. 적정 응집제 첨가량, 급속교반 및 완속교반의 시간에 따른 처리 효율의 이론식을 제시하였다. 또한 응집제 Polyaluminium chloride(PAC) 및 Aluminium sulfate의 응집 비교 실험을 행하였다.

• Membrane and Water Treatment
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• 제12권2호
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• pp.83-93
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• 2021

In this study, defluoridation efficiency by aluminium sulphate (alum) and polyaluminium chloride (PACl) were compared for recommended Nalgonda dose (100%) and 80% of this dose in both batch and continuous modes. The residual turbidity was found to be higher in case of alum as compared to PACl with 80% dose representing lesser efficient settling of suspensions, which primarily comprise alumino-fluoro complexes that result in high residual aluminium in the treated water and this was confirmed by TEM and Zeta analysis. Moreover, the application of PACl also resulted in much lesser addition to the TDS and also required lesser lime for pH compensation due to its lower acidity. Hence this reduced dose was recommended for defluoridation. It was also observed that in case of alum, residual aluminium in treated water was 0.88 mg/L (100% dose) & 0.72 mg/L (80% dose) and in case of PACl, it was 0.52 mg/L(100% dose) & 0.41 mg/L(80% dose). After subsequent microfiltration, residual aluminium was 0.28 & 0.21 mg/L for 100% & 80% dose respectively and in case of alum and in case of PACl, it was 0.16 & 0.11 for 100% & 80% dose respectively, which conform to the Al standards(<0.2 mg/L).

• 한국환경과학회지
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• 제7권3호
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• pp.409-413
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• 1998

Polyamine was synthesized for the drinking water treatment. Polyamine was produced by the two step polycondensation of dimethytamine(DMA) and epichlorohydrin(EPI) and its properties were characterized. The effects of mole ratio of (DMA1/1EPl), reaction temperature and reaction time on synthesis of polyamine were investigated. Polyamine flocculant was applied to Nak-dong river raw water to examine its efficiency in reducing turbidity. The synthesized polyamine was effective as flocculant for drinking water treatment. The addition of 1 mg/L of polyamlne flocculant caused the reduction of 50% PAC (polyaluminium chloride).

• 상하수도학회지
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• 제24권1호
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• pp.15-24
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• 2010

Coagulation can be used for pretreatment of NF membrane filtration. Foulants such as organic matter and particulate can be removed effectively with the process while high flux recovery is maintained. Recently various types of polyaluminium coagulants including polyaluminium chloride(PAC) are commercially available for water treatment. This study examines effects of polymeric Al and hydrolysis products of PAC on nanofiltration membrane performance. Dominant hydrolysis products were polymeric Al, $Al(OH)_3$, and ${Al(OH)_4}^{-1}$ at acidic, neutral, and alkaline pH conditions, respectively. Under acidic pH condition, flux decline was increased with increasing PAC concentrations, possibly due to polymeric Al adsorption on membrane pore and/or surfaces. For neutral and alkaline pH conditions, little flux decline was observed with increasing PAC concentrations except the highest ${Al(OH)_4}^{-1}$ concentration, with which rapid flux decline was shown. Removal of ionic matters was also varied with pH conditions in this study. Especially, conductivity removal was substantially low and $Ca^{2+}$ concentration in the permeate was quite high at neutral pH condition.

• 한국환경과학회지
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• 제7권5호
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• pp.687-692
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• 1998

Poly(DADM) was synthesized for the drinking water treatment. Poly(DADM) was produced by the free radical polymerization of diallyldimethylammonium chloride(DADM) monomer and its properties were characterized. The effects of monomer concentration, initiator concentration and reaction time on synthesis of poly(DADM) were investigated. Poly(DADM) flocculant was applied to Nak-dong river water to examine its efficiency in reducing turbidity. The synthesized poly(DADM) was effective as flocculant for drinking water treatment. The addition of 1 mg/L of poly(DADM) flocculant caused the reduction of 50% PAC(polyaluminium chloride).

• Environmental Sciences Bulletin of The Korean Environmental Sciences Society
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• 제2권2호
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• pp.115-121
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• 1998

Train of chemical and biological processes was investigated to treat leachate from industrial waste landfill. Organics and nitrogen concentrations of landfill leachate studied in this research were high and their BOD/COD ratio was 0.3. Biological process should be combined with chemical process for optimum treatment of leachate. PAC(Polyaluminium chloride) was the best coagulant among three chemicals tested, and the optimum condition of PAC coagulation was pH 6 and 1,250 mg/L of dosage. When SBR was operated for simultaneous removal of organics and nitrogen, removal efficiency of COD and T-N reached over $82\%,\;71\%,$ respectively and time distribution of 2/4/2/1 was most effective for one cycle of anoxic/aerobic/anoxic/aerobic.