• 상하수도학회지
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• 제24권5호
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• pp.581-593
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• 2010

The objectives of this study were to investigate the effects of raw water pH and basicity of coagulants on turbidity removal with several raw waters having different level of turbidity, alkalinity and pH. Raw waters were sampled from M, S and B water treatment plants(WTP) located at Miryang, Nakdong, Han river, respectively. Six coagulants which have different levels of basicity and aluminum contents were used for this evaluation. High basicity of the coagulant helped to properly control coagulation processes for treating turbid and low alkali raw water. It was difficult for operators to determine optimum coagulant dose for high basicity coagulants, since residual turbidity tended to decrease continuously as coagulant dose increased. Turbidity removal efficiencies with high basicity coagulants(E and F) were higher than the other coagulants at ambient pH for the M WTP. Turbidity removal efficiencies, however, at adjusted pH 7.0 showed similar among six coagulants. Residual turbidity kept low at excess dosages with high basicity coagulants. Optimum coagulant dosages at adjusted pH 7.0 showed higher than those at ambient pH in M WTP. On the contrary in B WTP, optimum coagulant dosage at ambient pH were higher than that at adjusted pH 7.0.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1996년도 한국자동제어학술회의논문집(국내학술편); 포항공과대학교, 포항; 24-26 Oct. 1996
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• pp.952-955
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• 1996

It is difficult to determine the feeding rate of coagulant in water treatment process, due to nonlinearity, multivariables and slow response characteristics etc. To deal with this difficulty, the fusion of genetic algorithms and fuzzy inference system was used in determining of feeding rate of coagulant. The genetic algorithms are excellently robust in complex operation problems, since it uses randomized operators and searches for the best chromosome without auxiliary information from a population consists of codings of parameter set. To apply this algorithms, we made the look up table and membership function from the actual operation data of water treatment process. We determined optimum dosages of coagulant (PAC, LAS etc.) by the fuzzy operation, and compared it with the feeding rate of the actual operation data.

• 제어로봇시스템학회논문지
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• 제5권7호
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• pp.876-882
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• 1999

It is difficult to determine the feeding rate of coagulant in the water treatment process, due to nonlinearity, multivariables and slow response characteristics, etc. To deal with this difficulty, the genetic-fuzzy system was used in determining the feeding rate of the coagulant. The genetic algorithms are excellently robust in complex optimization problems. Since it uses randomized operators and searches for the best chromosome without auxiliary informations from a population consists of codings of parameter set. To apply this algorithms, we made the lookup table and membership function from the actual operation data of the water treatment process. We determined optimum dosages of coagulant(LAS) by the fuzzy operation, and compared it with the feeding rate of the actual operation data.

• 대한환경공학회지
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• 제28권12호
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• pp.1274-1279
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• 2006

본 연구에서는 낙동강 하류 매리원수, 부산시 회동수원지 원수 및 매리원수를 정수처리하는 pilot-plant의 급속 모래여과 처리수를 이용하여 오존 투입농도별로 $BDOC_{rapid}$4와 $BDOC_{slow}$의 생성특성에 대하여 조사하였다. $BDOC_{total}$ 농도가 최대가 되는 오존 투입 농도는 매리원수, 회동원수 및 모래여과 처리수에서 각각 0.9, 1.1 및 1.4 $mgO_3/mgDOC$로 조사되어 실험에 사용된 시료수의 특성에 따라 $BDOC_{total}$이 최대로 생성되는 오존 투입농도는 다르게 나타났다. $BDOC_{rapid}$를 최대로 생성시키는 오존 투입농도는 $BDOC_{total}$을 최대로 생성시키는 오존 투입농도 보다 낮은 $0.9{\sim}1.1\;mgO_3$/mgDOC로 나타났으며, 1 $mgO_3$/mgDOC 이상의 오존 투입농도에서는 $BDOC_{rapid}$의 농도가 오하려 낮아지는 것으로 나타났다. 또한. 오존 처리에 따른 $BDOC_{slow}$의 생성특성 조사에서 $BDOC_{slow}$는 $BDOC_{total}$과 $BDOC_{rapid}$를 최대로 생성시키는 오존 투입농도 보다 더 높은 오존 투입농도에서도 지속적으로 생성되었다. Biofiltration 공정의 전처리로 사용되는 오존의 최적 투입량을 결정할 수 있는 $BDOC_{rapid}/BDOC_{total}$비를 실험에 사용된 시료수별로 조사한 결과 $0.6{\sim}1.0\;mgO_3$/mgDOC로 조사되어 $BDOC_{total}$이 최대로 생성되는 오존 투입농도 $0.9{\sim}1.4\;mgO_3$/mgDOC보다 낮은 것으로 나타났다. 따라서 최적의 오존 투입율 결정시 BDOC 분류를 통한 접근법이 경제성 측면이나 biofiltration 공정의 효율면에서도 훨씬 효율적인 것으로 조사되었다.

• 한국환경과학회지
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• 제19권8호
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• pp.931-940
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• 2010

The Raw water from Deer Creek (DC) reservoir and Little Cottonwood Creek (LCC) reservoir in the Utah, USA were collected for jar test experiments. This study examined the removal of arsenic and turbidity by means of coagulation and flocculation processes using of aluminum sulfate and ferric chloride as coagulants for 13 jar tests. The jar tests were performed to determine the optimal pH range, alum concentration, ferric chloride concentration and polymer concentration for arsenic and turbidity removal. The results showed that a comparison was made between alum and ferric chloride as coagulant. Removal efficiency of arsenic and turbidity for alum (16 mg/L) of up to 79.6% and 90.3% at pH 6.5 respectively were observed. Removal efficiency of arsenic and turbidity for ferric chloride (8 mg/L) of up to 59.5% at pH 8 and 90.6% at pH 8 respectively were observed. Optimum arsenic and turbidity removal for alum dosages were achieved with a 25 mg/L and 16 mg/L respectively. Optimum arsenic and turbidity removal for ferric chloride dosages were achieved with a 20 mg/Land 8 mg/L respectively. In terms of minimizing the arsenic and turbidity levels, the optimum pH ranges were 6.5 and 8for alum and ferric chloride respectively. When a dosage of 2 mg/L of potassium permanganate and 8 mg/L of ferric chloride were employed, potassium permanganate can improve arsenic removal, but not turbidity removal.

• 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.

• 한국건설순환자원학회논문집
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• 제2권1호
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• pp.19-25
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• 2014

본 연구에서는 천연섬유인 양마를 섬유보강 콘크리트에 사용하기 위한 방안으로, 양마의 혼입량에 따른 콘크리트의 역학적 특성을 실험적으로 확인하였다. 양마는 표면이 거칠고 섬유의 인장력 및 부식저항성이 우수하기 때문에, 섬유보강재로 적용할 경우에 콘크리트의 인장강도 및 부착력 증대에 의한 균열저감 효과, 그리고 이산화탄소를 저감하는 친환경 재료로 기대된다. 이러한 연구를 위하여 기본배합 조건에 양마의 혼입량 4종류(0, 0.3, 0.6 및 $0.9kg/m^3$)를 대상으로 슬럼프, 공기량, 소성수축 균열 및 압축강도, 할열인장강도, 휨강도, 그리고 건조수축량 등에 대한 성능시험을 실시하였다. 실험결과, 양마의 혼입량이 증가할수록 슬럼프 저하 및 공기량 증대현상이 나타났지만, 차이는 크지 않았다. 특히, 할열인장강도 및 휨강도 증진에 매우 효과적이며, 소성수축균열 및 건조수축량 저감에도 큰 효과가 있는 것으로 나타났다. 따라서 콘크리트의 역학적 성능, 경제성 등을 고려하여 양마의 혼입량은 $0.6kg/m^3$로 사용하는 것이 가장 적합한 것으로 나타났으며, 향후 사용성 및 비교시험을 통한 현장적용성의 검토가 필요할 것으로 사료된다.

• 한국환경과학회지
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• 제1권2호
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• pp.137-144
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• 1992

Flocculation-spectrophotometry and streaming current detector( SCD ) method were investigated and compared in order to determine the optimum dosages of synthetic cationic polymers of different charge density and molecular mass for the removal of humic acid. The optimum dosage for each of the polymers was determined with the dosage at which the lowest absorbance of humic acid was shown for the formal. and was determined with the dosage required during charge neutralization of humic acid for the latter It was in good agreement between both methods and there is a strong inverse correlation between the optimum dosage and charge density of the polymers, with highly charged polymer giving the lowest optimum dosage, pointing out the importance the charge neutralization. By flocculation-spectrophotometry, it was found that the absorbance of humid acid with the amount of each of the polymers dosed, changes sharply for polymers of high charge density, but changes rather broadly for polymers of low and middle charge density, Both methods showed that a stoichiometric correlation exists between the optimum dosage of each of the cationic polymers and the negatively charged humic acid.

• Environmental Sciences Bulletin of The Korean Environmental Sciences Society
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• 제1권2호
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• pp.137-144
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• 1997

Flocculation-spectrophotometry and streaming current detector(SCD) method were investigated and compared in order to determine the optimum dosages of synthetic cationic polymers of different charge density and molecular mass for the removal of humic acid. The optimum dosage for each of the polymers was determined with the dosage at which the lowest absorbance of humic acid was shown for the former and was determined with the dosage required during charge neutralization of humic acid for the latter. It was in good agreement between both methods and there is a strong inverse correlation between the optimum dosage and charge density of the polymers, with highly charged polymer giving the lowest optimum dosage, pointing out the importance the charge neutralization. By flocculation-spectrophotometry, it was found that the absorbance of humic acid with the amount of each of the polymers dosed, changes sharply for polymers of high charge density, but changes rather broadly for polymers of low and middle charge density. Both methods showed that a stoichiometric correlation exists between the optimum dosage of each of the cationic polymers and the negatively charged humic acid.

• 한국환경과학회지
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• 제8권6호
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• pp.725-730
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• 1999

The advanced oxidation process (AOP) using ozone combined with hydrogen peroxide and ultraviolet treatment were evaluated for biodegradable dissolved organic carbon (EDOC) formation and dissolved organic carbon (DOC) removal. Oxidation treatment were conducted alone or combination with ozone, hydrogen peroxide and ultraviolet processes. Ozone dosage of ozone process was varied from $0.5mg/l{\ell}\cdot}min$ to $5mg/{\ell}{\cdot}min$. Ozone/hydrogen peroxide process was done using $20mg/{\ell}{\cdot}min$ of hydrogen peroxide concentration. Ozone/ultraviolet process was irradiated with $12mW/cm^2$ of density and 254nm. Ozone dosage was varied from $0.5mg/{\ell}{\cdot}min$ to $5mg/{\ell}{\cdot}min$ at the ozone/hydrogen peroxide and ozone/ultraviolet processes too. Contact time of all the process was 20 minutes. Oxidation treatment were performed on microfiltration effluent samples. BDOC formation was reached to an optimum at ozone dosage of $1.5mg/{\ell}{\cdot}min$ in the ozone/hydrogen peroxide process and $1mg/{\ell}{\cdot}min$ in ozone/ultraviolet process, after which BDOC formation was decreased at higher ozone dosages. But BDOC formation was increased with ozone dosages increasing in ozone process. The efficiency of DOC removal was higher AOPs than ozone process. Ozone/ultraviolet proces was the highest for DOC removal efficiency in each process. THMFP. removal efficiency by ozone/ultraviolet process was higher than that by each of ozone process and ozone/hydrogen peroxide process.