• Journal of environmental and Sanitary engineering
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• v.20 no.1 s.55
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• pp.32-39
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• 2005

Recently, sanitary landfill was one of the most widely used for disposal of waste in Korea. With increasing of use and public awareness of this method for disposal. there is an increased concern with respect to the pollution potential by the landfill leachate. Especially, an aged landfill leachate contained relatively large amount of the nonbiodegradable substances which could not be removed by biological treatment processes. So, this study was conducted to the removal of nonbiodegradable substances, such as Humic acid and Fulvic acid with the electrolysis. In this study, electrode materials, electrolyte concentration, electrode distance, current density, and pH value were found to have significant effect on both pollutant removal efficiency and current efficiency in electrochemical oxidation process.

• Journal of Electrochemical Science and Technology
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• v.13 no.2
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• pp.292-307
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• 2022

The study presents kinetics of degradation and mineralization of an anti-epileptic drug Lamotrigine (LAM) in the aqueous matrix by electrochemical advanced oxidation process (EAOP) on Ti/DSA (Ta₂O₅-Ir₂O₅) and Stainless Steel (SS) anodes using sodium sulphate as supporting electrolyte. On both the anodes, kinetic behaviour was pseudo-first-order for degradation as well as mineralization of LAM. On Ti/DSA anode, maximum LAM degradation of 75.42% was observed at an associated specific charge of 3.1 (Ah/litre) at a current density of 1.38 mA/cm² and 100 ppm Na₂SO₄ concentration. Maximum mineralization attained was 44.83% at an associated specific charge of 3.1 (Ah/litre) at a current density of 1.38 mA/cm² and 50 ppm concentration of Na₂SO₄ with energy consumption of 2942.71 kWh/kgTOC. Under identical conditions on SS anode, a maximum of 98.92% LAM degradation was marked after a specific charge (Q) of 3.1 (Ah/litre) at a current density of 1.38 mA/cm² and 100 ppm concentration of Na₂SO₄. Maximum LAM mineralization on SS anode was 98.53%, marked at a specific charge of 3.1 (Ah/litre) at a current density of 1.38 mA/cm² and 75 ppm concentration of Na₂SO₄, with energy consumption of 1312.17 kWh/kgTOC. Higher Mineralization Current Efficiency (MCE) values were attained for EAOP on SS anode for both degradation and mineralization due to occurrence of combined electro-oxidation and electro-coagulation process in comparison to EAOP on Ti/DSA anode due to occurrence of lone electro-oxidation process.

• Proceedings of the KSME Conference
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• 2003.04a
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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%.

• Proceedings of the Korean Environmental Sciences Society Conference
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• 2008.11a
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• pp.510-514
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• 2008

본 연구에서는 전극의 특성에 따른 돈사유래 축산폐수의 ECO 공법에 의한 처리특성을 평가하기 위해 ECO 시스템 모듈내 Fe-Fe 및 Al-Al 계열의 용해성 전극과 Al-SUS, Ir-SUS 등 불용성 전극을 대상으로 5$\sim$20mA/cm$^2$의 전류밀도하에서 축산폐수내 유기물 및 영양염류의 제거특성을 평가하여 다음과 같은 결론을 얻을 수 있었다. 1. 전기응집산화에 의한 축산폐수의 처리시 수중 유기물질 및 영양염류의 제거효율은 전류밀도의 증가에 비례하여 증가한다. 2. 불용성 전극조합 및 불용성-용해성 전극조합은 전류밀도가 높을수록 수중 유기물 및 오염물질 제거효율이 안정되고, 용해성 전극은 15mA/cm$^2$ 이하의 저 전류밀도의 조건하에서 전류밀도의 증가에 따라 안정된 제거효율 향상을 기대할 수 있다. 3. 불용성전극 조합인 Ir-SUS 전극조합을 사용하여 축산폐수를 처리할 경우 COD$_{Mn}$ 제거효율을 약 10% 향상시킬 수 있으며, TN 20mA/cm$^2$에서 Al-Al 전극조합과 TP 15mA/cm$^2$ 이하에서 Fe-Fe 전극조합은 제거효율이 저하되는 경향이 나타난다.

• Journal of Korean Society of Water and Wastewater
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• v.27 no.4
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• pp.439-444
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• 2013

Excessive phosphorus in aquatic systems causes algal bloom resulting in eutrophication, DO depletion, decline in recreational value of water and foul tastes. To treat wastewater containing phosphorus including effluent of wastewater treatment plant, the continuous experiments were performed by using electrochemical way. The spherical ZVI and silica sand which act as physical filter are packed at appropriate volume ratio of 1:2. Electric potential is applied externally which can be changed as per the operational requirement. The results indicate that optimum hydraulic retention time of 36 minutes (10 mL/min at 1 L reactor) was required to meet the effluent standards. Lower concentrations of phosphorus (<10 mg/L as phosphate) were removed by precipitation by contact with iron. Thus, additional electric potential was not required. In order to remove high concentration phosphorus around 150 mg/L as phosphate, external electric potential of 600 V was applied to the reactor.

• Environmental Engineering Research
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• v.22 no.2
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• pp.141-148
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• 2017

Globalization, industrialization, mining, and uncontrolled population growth have fostered a shortage of potable water. Therefore, it has become imperative to understand an effective and reasonable water purification technique. A renewed interest in electrocoagulation (EC) has been spurred by the search for reliable, cost-effective, water-treatment processes. This paper has elucidated a technical approach for getting rid of heavy metals and total suspended solids (TSS) from synthetic water using an aluminum electrode. The effect of operational parameters, such as current density, inter-electrode distance, operating time, and pH, were studied and evaluated for maximum efficiency. This study corroborates the correlation between current density and removal efficiency. Neutral pH and a low electrode gap have been found to aid the efficacy of the EC setup. The outcome indicates that a maximum TSS removal efficiency of 76.6% occurred at a current density of $5.3mA/cm^2$ during a contact time of 30 min. In the case of heavy metals remediation, 40 min of process time exhibited extremely reduced rates of 99%, 59.2%, and 82.1%, for Cu, Cr, and Zn, respectively. Moreover, kinetic study has also demonstrated that pollutants removal follows first-and second-order model with current density and EC time being dependent.

• Journal of Electrochemical Science and Technology
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• v.8 no.1
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• pp.35-42
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• 2017

In this study, the effect of electrolyte addition on the removal of organics and nutrients in electrochemical wastewater using a copper electrode, and the characteristics of the by-product of electrolysis were investigated. The removal of organics increased significantly as shorter reaction times upon the addition of chloride ion, and most of the electrolysis reaction was completed within 20 min. The reaction rate gradually increased in proportion to the $Cl^-$/COD ratio, whereas the highest removed mass of organic matter per mass of added electrolyte was observed at a $Cl^-$/COD ratio of 1. After the addition of electrolyte, significant removal of ammoniacal nitrogen was observed as a result of the enhanced generation of oxidizers such as hypochlorite. Excellent phosphorus removal was also achieved in a very short reaction time (within 2 min) by electro-coagulation. As the electrolysis progressed, the amount of by-product increased gradually, whereas a decrease of sludge volume index was observed after the addition of electrolyte. This indicated that the settling performance of the by-products was better, and their removal would be easily achieved.

• Polymer(Korea)
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• v.35 no.3
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• pp.254-259
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• 2011

In electrospraying of polymer solutions, metal sample collectors are often ineffective in fully removing solvent from sprayed particles and recovering redispersable sprayed particles. Herein, a novel electro spraying system, where sprayed particles were dispersed into laminar flow of dispersant (coagulation liquid), was designed for the nano-encapsulation of protein drugs. Chitosan and polyacrylic acid were used as the encapsulation materials. Aggregation of particles could be prevented by using this new electrospraying system, and unimodal size distribution was observed at an applied voltage between 4~16 kV and a low flow rate. The effects of the applied voltage on mean particle size were not significant on the other hand.

• Proceedings of the Korea Water Resources Association Conference
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• 2017.05a
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• pp.1-1
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• 2017

녹조현상은 부영양화된 호수나 유속이 느린 하천에서 부유성의 조류(식물 플랑크톤)가 대량 증식하여 수면에 집적하게 되고 물의 색을 현저하게 녹색으로 변화시킴으로써 발생된다. 최근에는 이러한 녹조 현상이 광역화, 독성화, 장기화의 특성을 띠며 빈번히 발생되고 있다. 녹조현상은 독소를 발생시키는 남조류에 의해 수생식물에 악영향을 주는 것으로 알려져 있다. 예를 들면 독소에 의한 가축에의 영향, 생태계 파괴로 인한 생태학적인 문제, 산소결핍으로 인한 물고기 및 각종 수중생물 폐사 등의 심각한 문제를 야기한다. 또한 조류는 식수에서 맛과 냄새를 유발할 뿐 아니라 Microcystin-LR과 같은 유해한 독소를 배출하여 공중 보건을 위협한다. 이에 식수원으로 사용되는 하천의 조류 번식에 따른 대응방안 마련이 절실히 요구된다. 유입되는 조류로 부터의 정수처리 설비의 처리 부하를 줄이기 위해서는 취수시스템과 연계한 고속 전처리 조류 제거 시스템을 개발이 필요하다. 기존의 전기응집부상공정(Electro-Coagulation and Flotation, ECF)은 화학 약품(응집제) 투여량이 적은 이점이 있지만 비교적 긴 전기 분해 시간이 필요하여 기존 정수처리 시스템과 연계성에 있어 한계가 있다. 이에 본 연구는 전기 분해 시간을 줄여 유입된 조류를 수 초 내에 응집하여 1분 이내에 조류를 분리하는 초고속 조류 전처리 기술을 개발하였다. 개발된 기술의 현장적용 및 실험 결과, 응집과정이 없이도 Chlo-a는 약 45 %의 제거 효율을 나타났다. 또한 응집제의 투입 및 전극에 의한 부상시스템에 의해 Chlo-a가 약 80 %로 제거되는 것으로 나타나 빈번하게 발생되는 조류로부터 안정적인 물 공급을 위한 전처리 공정으로 활용이 가능할 것으로 판단된다.

• Journal of Electrochemical Science and Technology
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• v.12 no.1
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• pp.21-32
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• 2021

This study reports for the first time the application of electrocoagulation (EC) from laboratory to pilot scales for the treatment of printing wastewater, a hazardous waste whose treatment and disposal are strictly regulated. The wastewater was taken from three real printing companies with strongly varying characteristics. The treatment process was performed in the laboratory for operational optimization and then applied in the pilot scale. The weight loss of the electrode and the generation of sludge at both scales were compared. The results show that the raw wastewater should be diluted before EC treatment if its COD is higher than about 10,000 mg/L. Pilot scale removal efficiencies of COD and color were slightly lower compared to those obtained from the laboratory scale. At pilot scale, the effluent CODs removal efficiency was 81.9 - 88.9% (final concentration of 448 - 992 mg/L) and color removal efficiency was 95.8 - 98.6% (final level of 89 - 202 Pt-Co) which proved the feasibility of EC treatment as an effective pre-treatment method for printing wastewater as well as other high colored and hard-biodegradable wastewaters.