• 상하수도학회지
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• 제18권5호
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• pp.689-695
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• 2004

Electrocoagulation has been suggested as a promising alternative to conventional coagulation. The process is characterized by reduced sludge production, no requirement for chemical use, and ease of operation. However, this coagulation has scarcely been studied in water purifying process. This study was performed several batch experiments to compare turbidity removal between electrocoagulation and chemical coagulation. In addition, characteristics of floe were evaluated with zeta potential and particle size distributions. Electrocoagulation showed a relatively higher removal of turbidity (approximately 5%) with the same aluminum amount than conventional chemical coagulation. In addition, turbidity removal by electrocoagulation was less sensitive to pH and was greater for more extensive pH range than chemical coagulation. The results of zeta potential and floc size distributions illustrated that electrocoagulation provided the preferable conditions for coagulation such as zeta potential close to zero millivolt and increased portions of particles in the range of 40 and $100{\mu}m$.

• 한국환경과학회지
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• 제32권5호
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• pp.385-394
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• 2023

There is a need for a method that can effectively remove wastewater containing small-sized particles such as TiO₂. In this study, we attempted to remove TiO₂ wastewater using electrocoagulation-electroflotation two-step separation. The TiO₂ wastewater was effectively removed via batch electrocoagulation-electroflotation separation. However, in the batch process, the simultaneous operation of electrocoagulation and electoflotation was challenging due to the high residual turbidity. In the continuous operation, electrocoagulation and electoflotation reactors were kept separate. The turbidity removal in continuous operation was similar to that in the batch process, nevertheless, the residual Al concentration was high, leading to the conclusion that counterterm ensures against residual Al were necessary.

• Journal of Advanced Marine Engineering and Technology
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• 제25권5호
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• pp.1098-1107
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• 2001

This study is to develop the pretreatment for the excess and digested sludge by elector-coagulation and dewatering. Electrocoagulation is applied to excess and digested sludge before transferring to the pistion type for dewatering. Piston type filter press as a laboratory scale plant was used to estimate the dewaterability. MMD of excess sludge was increased from initial diameter of particles ($34.16{\mu}m$) to the 87%($64.01{\mu}m$) after electrocoagulation. Al electrode is more effective than Fe electrode for the dewaterabiltity of excess sludge Electrodewatering after electrocoagulation as pretreatment makes the water content of sludge cake 50~60 wt%.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2003년도 춘계학술대회
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• pp.1992-1997
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• 2003

This study is to develop the pretreatment for the excess and digested sludge by electro-coagulation and dewatering. Electrocoagulation is applied to excess and digested sludge before transferring to the piston type press for dewatering. Piston type filter press as a laboratory scale plant was used to estimate the dewaterability. MMD of excess sludge was increased from initial diameter of particles(34.16 ${\mu}m$) to the 87%(64.01 ${\mu}m$) after electrocoagulation. AI electrode is more effective than Fe electrode for the dewaterability of excess sludge. Electrodewatering after electrocoagulation as pretreatment makes the water content of sludge cake $50{\sim}60$ wt%.

• Journal of Electrochemical Science and Technology
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• 제13권2호
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• pp.261-268
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• 2022

In this study, electrochemical treatment of urban wastewater with electrical conductivity of 1000 μS cm^-1 and chemical oxygen demand of 250 mg L^-1 was investigated using the variables of initial pH value, current density and flow rate. Electrocoagulation was used, in which aluminum and stainless steel were selected, as the electrochemical treatment process. The electrocoagulation process was operated in continuous mode. The data obtained in experimental studies show that the best COD removal efficiency occurred in experiments where the initial pH value was 6. The increase in current density from 5 A to 15 A decreased the removal efficiency from 79 to 67%. The increase in flow rate under constant current density also reduced the efficiency of removal as expected. In experiments in which current density and flow rate were examined together, the increase in flow rate allowed the application of higher current densities. This situation led to considerable reductions in energy consumption values, even if the COD removal efficiency did not significantly increase. The high COD removal obtained with the use of high flow rate and high current density indicates that the electrocoagulation process can be used for high flow rate municipal wastewater treatment.

• 한국환경과학회지
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• 제19권1호
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• pp.89-96
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• 2010

The separation of $TiO_2$ wastewater carried out by an electrocoagulation/flotation process, which had various operating parameters. The effect of electrode material (aluminum and four dimensionally stable electrode), applied current (0.07~0.5 A), electrolyte concentration (0~1 g/L), solution pH (3~11), initial turbidity (1000~20000 NTU) and suspended solid concentration (5000~25000 mg/L) were evaluated. Turbidity removal efficiency of the soluble anode (aluminum), which could produce metal ions, was higher than that of the dimensionally stable electrode. Considering operation time, turbidity removal and electric power, optimum current was 0.19 A. The more NaCl dosage was high, the less electric power was required. However, optimum NaCl concentration was 0.125 g/L considered removal efficiency, operation time and cost. Initial $TiO_2$ concentration did not affected turbidity removal on the electrocoagulation/flotation operation. The electrocoagulation/flotation process was proved to be a very effective separation method in the removal of $TiO_2$ from wastewater.

• 한국환경과학회지
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• 제9권4호
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• pp.359-363
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• 2000

This research studied the characteristics and applicability of electrocoagulation using aluminium electrode for the color and COD removal in textile wastewater. Electrocoagulation reactor used two different electrode, Fe and Al, since in the general chemical wastewater treatment, aluminium and ferrous salts were used as coagulants. Aluminium electrode showed higher removal efficiency of color and COD than ferrous electrode did. The COD and color removal efficiency improved at the 0.192A/$dm^2$ current density. Thus, the electrocoagulation process with bipolar aluminium electrode showed better efficiency in the decolorization and COD removal rate of textile wastewater effluent than custom coagulants did.

• Membrane and Water Treatment
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• 제5권4호
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• pp.251-263
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• 2014

The study contributes in the treatment of waste generated by the textile complex cotton of Draa Ben Khedda, Algeria. The azo dye "Direct Red Solophenyle 4GE" represents the base particle of the discharges and electrocoagulation with nanofiltration are used as a means of treatment. The solar photovoltaic is suitable for electrochemical process to reduce the energy cost. Several study parameters are considered in this work. The electrocoagulation batch gives the best reduction 37% for a dye concentration of 7.21 mg/L ($[NaCl]_{added}$=1g/L; $j=25.2mA/cm^2$). Coupling methods (electrocoagulation-nonofiltration) gives a complete discoloration rejecting concentration 52.4 mg/L (pHi = 7.6, $[NaCl]_{added}$=3g/L, $j=2.13mA/cm^2$). The result shows the coupling efficiency with a reduced amount of resulting slurry at the end of treatment.

• 산업기술연구
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• 제21권A호
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• pp.351-355
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• 2001

This research was carried out to find out the possibility of using Faraday's law in analyzing the electrocoagulation system. Bench-scale reactor equipped with aluminum electrode plates was operated using synthetic wastewater which received sodium chloride for conductivity adjustment. Phosphate was added to the wastewater to induce the precipitation with Al. The amount of aluminum dissolved from the electrodes could be predicted by Faraday's law with a difference less than 5%. This difference was greater at a higher electric current, probably due to the increased solution temperature. However, effect of pH on the dissolution of the aluminum was negligible. The result of this study suggested that the operating condition of electrocoagulation system could be developed using the Faraday's law when the pollutant concentration is given.

• 대한환경공학회지
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• 제34권10호
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• pp.702-708
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• 2012

사불화탄소($CF_4$)는 반도체 제조공정에서 에칭과 화학기상증착(CVD)에서 사용되어온 가스이다. $CF_4$는 적외선을 강하게 흡수하고 대기 중 잔류시간이 길어서 지구온난화에 영향을 미치기 때문에 고효율의 분해가 필요하다. 또한 불화수소를 포함한 폐수는 지하수 오염의 원인이 된다. 과도한 불소를 포함한 물을 장기간 섭취는 치아와 뼈에 문제를 야기한다. 워터젯 플라즈마를 이용하여 $CF_4$를 분해 후 생성되는 부산물 중 HF에 의하여 폐수가 생성된다. 이 폐수를 알루미늄 전극을 사용한 전해응집을 이용하여 폐수 중 HF를 제거 할 수 있는 시스템을 개발하였다. 실험 변수로는 초기 pH 변화, 반응 시간 변화, 주입유량 변화, 전류 밀도 변화를 실험하였다. 변수 실험을 통하여 초기 pH는 3.5, 반응 시간은 10 min, 주입 유량은 10 mL/min, 전류 밀도는 $159A/m^2$일 때 HF 제거율은 최고 85%까지 도달하였다.