• 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.

• 대한환경공학회지
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• 제39권4호
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• pp.201-207
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• 2017

본 연구에서는 낙동강 하류원수에 대한 응집제 주입율 자동화를 위해 stream current detector (SCD)와 charge analyzing system (CAS)의 적용성 비교 평가하였다. SCD 시스템을 이용한 경우, 원수 pH가 9.3에서 5.7로 낮아지면 pH 9.3에서 설정된 유동 전하값을 응집제 주입율로 사용할 수 없었고, pH 5.7에 맞는 유동 전하값의 재설정이 필요하였다. 원수의 pH 변화에 따른 SCD의 유동 전하값의 재설정을 하지 않을 경우, 후단의 모래여과 처리수 탁도가 증가하는 현상을 보였다. CAS 시스템의 경우는 원수 pH의 범위가 6.0~9.3의 범위일 때 polydadmac을 전하 중화제로 사용하는 것이 가능하였고, 고탁도 원수에도 poly-dadmac이 양호한 전하중화제로 평가되었다. 그러나 pH 5~11의 범위에서 polydadmac의 전하량은 거의 변화하지 않은 반면, 응집제로 사용되는 alum의 전하량은 6배 정도 차이가 발생하고, pH에 적합한 응집제 요구량을 보였다. 따라서 원수의 pH가 높은 경우는 전하 적정제로 정수장에서 사용하는 응집제를 직접 이용하는 것이 효율적이었다.

• 한국환경보건학회:학술대회논문집
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• 한국환경보건학회 2002년도 춘계 국제 학술대회
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• pp.54-64
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• 2002

This study evaluated advanced water treatment (AWT) system in Korea. There are currently 16 plants operating with AWT. However, no attempt has been made to evaluate AWT system. This study selected one water treatment plant with AWT (pre-ozonation ＋ BAC). Using the operation data from 1995 to 2001 and pilot study results, the post-evaluation of the AWT system has been conducted. The study found that AWT improved water qualities of organic, ammonia, and turbidity, as expected. However, the extent of the improvement was generally short of the pilot study expectations. Pre-ozonation failed to decrease coagulant consumption. The dosage increased rather than decreased. AWT was, however, successful to decrease chlorine consumption. The chlorine reduction was related to the change in raw water characteristics and AWT introduction. Pre-ozonation failed to decrease coagulant consumption. The dosage increased rather than decreased. AWT was, however, successful to decrease chlorine consumption. The chlorine reduction was related to the change in raw water characteristics and AWT introduction, Both operation of pre-ozonation and reduced ammonia loading were responsible for the reduction. AWT increased the operation cost. Maintenance, raw water, and power cost increased, while labor and chemical cost decreased. Manpower reduction resulting form automation caused the decrease of labor cost. The reduction of chlorine consumption caused the decrease of chemical cost.

• 한국환경과학회지
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• 제7권2호
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• pp.217-222
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• 1998

Organics matters including algae are the major contaminants of Nak-dong river and it's concentration Is more Increasing now. The use of coagulants has been Incresed for the effective treatment of drinking water, and aluminum coagulants have been the most widely used in raw water treatment. However, when inorganic metal coagulant is excessively used for long period, it would result in secondary problems, such as increasing sludge production, enhancing the cost of water treatment process, and increasing concentration of residual metal, especially aluminum. Therefore, recently. in order to reduce the use of metal coagulant and enhance the coagulation effectiveness, several alternative coagulants, such as polymeric Inorganic coagulants and organic polymers, have been used In water treatment plants. The objectives of thins research were (11 to determine optimum dosage concentration and compare the coajuiation efnciency at various pH ranees with alum alone, alum+cationic polymer, and alum+anlonlc polymer, (21 to evaluate the amount of alum reduced by using organic polymer, (31 to maximize removal officiency of organic matter and minimize the concentration of residual aluminum.

• 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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• 제30권8호
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• pp.775-780
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• 2008

슬러지 개량은 폐 슬러지의 응집성 및 탈수성을 개선하기 위해 슬러지 처리 공정에서 널리 사용되고 있다. 본 연구는 3종의 응집제(Alum, FeCl$_3$ 및 PAC)를 이용하여 응집제 주입량과 슬러지 케이크의 탈수성의 정량적인 상관관계를 도출하고자 하였다. Alum, FeCl$_3$ 및 PAC가 0.79$\sim$1.19 mmol/g, 0.61$\sim$1.25 mmol/g TSS, 및 0.21$\sim$0.39 mmol/g TSS로 주입되었을 때, 슬러지의 여과비저항은 초기값에 비해 약 95.0% 이상 감소되었다. 이 실험 결과에서 슬러지 g당 응집제 주입량(D)과 무차원 여과비저항(R)의 관계는 지수함수적인 관계로 나타낼 수 있었다.

• 환경위생공학
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• 제18권1호
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• pp.41-50
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• 2003

Traditionally the supernatant after chemical treatment of metal acid wastewater is discharged in environment. The supernatant can be used as a coagulant as it contains effective metals. The aim of this study is to investigate the feasibility of treatment of dyeing wastewater using the supernatant after treatment by magnesium hydroxide and dolomite($Ca{\cdot}Mg(CO_3)_2$), of acidic metal wastewater. In dyeing wastewater treatment with the supernatant, optimum pH and dosage were determined. COD, turbidity and color were analyzed to evaluate the performance of treatment. In the case of magnesium hydroxide, the optimum dosage was 10%(v/v) for supernatant A and 3%(v/v) for supernatant B. Color, turbidity and COD removal was 99~100%, 85~97% and 43~53%, respectively. In the case of dolomite, the optimum dosage was 10%(v/v) for supernatant A and 3% for supernatant B. Color, turbidity and COD removal was 96~99%, 62~9l% and 52~53%, respectively.

• 상하수도학회지
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• 제18권6호
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• pp.742-747
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• 2004

Solid-liquid separation of swine wastewater was conducted using bentonite as coagulant. During the separation experiment, coagulation efficiency was also investigated. To determine optimal bentonite dose, 0.1, 0.2, 0.4, 0.8, and 1.6% (w/v basis) of bentonite was dosed. Suspended solid removal efficiency was 87-98% at whole bentonite dosage. But sediment volume was increased, and settling velocity was decreased at excessive bentonite dosage. Therefore optimal bentonite dosage was evaluated around 0.2-0.4%. In the test to determine optimal pH, coagulation using bentonite was performed at pH 3, 4, 5, 6, and 7. At lower pH suspended solid removal efficiency was increased. However, sediment volume was also increased and phosphorus release was observed. Thereby optimal pH for bentonite coagulation might be appeared in the range of 6-7.

• 한국환경보건학회지
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• 제38권2호
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• pp.128-135
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• 2012

Objectives: This study was aimed at determining the optimum coagulation dosage in a high turbid kaolin water sample using streaming current detection (SCD) as an alternative to the jar test. Methods: SCD is able to optimize coagulant dosing by titration of negatively charged particles. Kaolin particles were used to mimic highly turbid water ranging from 50 to 600 NTU, and polyaluminum chloride (PAC, 17%) was applied as a titrant and coagulant. The coagulation consisted of rapid stirring (5 min at 140 rpm), reduced stirring (20 min at 70 rpm), and settling (60 min). To confirm the coagulation effect, a jar test was also compared with the SCD titration results. Results: SCD titration of kaolin water samples showed that the dose of PAC increased as the pH rose. However, supernatant turbidity less than 1 NTU after coagulation was not achieved for high turbid water by SCD titration. Instead, a conversion factor was used to calculate the optimum PAC dosage for high turbid water by correlating a jar test result with that from an SCD titration. Using this approach, we were able to successfully achieve less than 1 NTU in treated water. Conclusions: For high turbid water influent in a water treatment plant, particularly during summer, the application of SCD control by applying a conversion factor can be more useful than a jar test due to the rapid calculation of coagulation dosage. Also, the interpolation of converted PAC dose could successfully achieve turbidity in the treated water of less than 1 NTU. This result indicates that an SCD system can be effectively used in a water treatment plant even for high turbid water during the rainy season.

• 상하수도학회지
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• 제9권3호
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• pp.99-107
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• 1995

Various humic substances are widely distributed in natural water body, such as rivers and lakes and cause the yellowish or brownish color to water. The evidence that humic substances are precursors of THMs formation in chlorinated drinking water has been reported m the Jiteratures. For the reason of public health as well as aesthetics, needs for humic substances removal have been increased in the conventional water treatment processes. In this research, the characteristics of aluminium coagulation of humic acids and humic acids were investigated. The optimum pH and coagulants dosage to remove these materials simultaneously by coagulation were alto studied. The results are as followed; 1. UV-254 absorptiometry for measuring the concentration of aquatic humic acids showed good applicability and stable results. 2. The optimal pH range for humic acids removal by aluminium coagulation was 5 to 5.5, however, an increase in aluminium coagulant dosage could enhance the removal rate of humic acids in the wide pH range. 3. Coprecipitation of humic acids in the typical pH range of 6.5 to 8 in water treatment processes may require the sweep coagulation mechanism with the excess aluminium coagulant dosage. 4. Using PAC(poly aluminium chloride) or PASS(poly aluminium silica sulfate) as coagulants was able to expand the operating range for removing humic acids. 5. From the coagulation of humic substances(UV-254) and turbidity at pH range of 5.5 - 6.0 and alum dose of 86 ppm, the removal efficiency of turbidity from the reservoir water was above 90% and that of UV-254 was above 70%. 6. By using the reservoir water, the optimum condition of rapid mixing for simultaneous removal of turbidity and UV-254 absorbance was pH of 5.8 and LAS dose of 86 ppm, in this study.