Time filter

Source Type

Gyeonggi do

Hong K.,Konkuk University | Kim W.,Konkuk University | Son D.,Konkuk University | Yun C.,Konkuk University | And 6 more authors.
International Journal of Electrochemical Science | Year: 2013

In this study, both bench- and pilot-scale electrochemical processes adopting copper electrode were used for the treatment of weak sewage in small-scale communities. Considerable organics removal could be achieved during very shorter detention time of 2~3 minutes by continuous electrolysis procedure, and the nitrogen removal was mostly performed at the beginning of the electrolysis. Most phosphorus was also eliminated in the shorter detention time. It seemed that the phosphorus removal could be performed from the orthophosphate into copper hydrogen phosphate (CuHPO4). The pH value also remarkably increased as electrolysis processed by higher concentration of hydroxyl ion through the electrolysis, whereas the pH value decreased to neutral ranges by additional aeration for 2 hours. In particular, total COD and total nitrogen were additionally decreased by aeration. The ORP value was gradually decreased with increasing detention time in both bench- and pilot-scale experiments. The ORP value considerably decreased in the pilot-scale experiment, which means the organics in the wastewater could be removed at more contiguous time and chance for wastewater during the electrolysis procedure. © 2013 by ESG. Source

Hong K.,Konkuk University | Chang D.,Konkuk University | Bae H.,EnviroSolution Co. | Sunwoo Y.,Konkuk University | And 2 more authors.
International Journal of Electrochemical Science | Year: 2013

Electrochemical experiment using three cathode materials such aluminum, iron, and copper operated constant voltage and low current conditions to evaluate the removal characteristics of phosphate ion in wastewater. The electrolysis experiments on synthetic wastewater with a higher concentration were also repeated 200 times for 10 minutes per each experiment under the bias voltage of 24V to estimate the stability of the copper electrode for a long time. When the copper electrode couple was used, by-products with green blue color such as copper hydroxide (Cu(OH)2) and copper phosphate (Cu3(PO4)2) were formed on the surface of the anode and bubbles of hydrogen gas were formed on the surface of the cathode. The formation of copper hydroxide could contribute to removing phosphate because the hydroxyl ion (OH-) in the copper hydroxide can be exchanged with the phosphate ion. The surface of the copper anode was relatively clean without oxidation, while the surfaces of the aluminum and iron anodes were completely changed from the initial state with severe oxidation. With such change to the anode surface such as aluminum and iron anodes, the electrolysis performance would degrade very fast. In repeated electrolysis experiment using the copper electrode on synthetic wastewater with a higher concentration, the copper anode of 1mm thickness was sufficient to remove the phosphate which was more than 19g. © 2013 by ESG. Source

Hong K.-H.,Konkuk University | Kim W.-Y.,Konkuk University | Son D.-J.,Konkuk University | Yun C.-Y.,Konkuk University | And 3 more authors.
International Journal of Electrochemical Science | Year: 2014

A novel electrolytic treatment process installed with copper electronic conductors was developed, and it was applied for the treatment of municipal wastewater under the conditions of constant voltage and adjustable current in a continuous mode. The organics could be successfully removed in very shorter reaction time through the electro-coagulation reaction. The fraction of copper hydroxide removed from the electronic conductor has been increased in the effluent as the electro-coagulation reaction progressed. The nitrogen could be reduced by the elimination of ammonia nitrogen, in early electrolysis reaction, and the phosphorus removal could be also accomplished by the formation of complicated compounds with metal such as copper phosphate. By the aeration after electrolysis reaction, the additional removal of organics by the oxidation and nitrogen by ammonia stripping could be achieved successfully. Thus, the electrolytic treatment process with copper electronic conductors would be good alternative method of conventional municipal wastewater treatment technologies for the simultaneous removal of organics and nutrients. © 2014 The Authors. Published by ESG. Source

Kim G.,Korea Institute of Energy Research | Kim W.,Konkuk University | Yun C.,Konkuk University | Son D.,Konkuk University | And 5 more authors.
International Journal of Electrochemical Science | Year: 2013

A modified electrolysis system was devised adopting a novel operation method of a low current and constant voltage, and a renewable copper electrode. The simultaneous removal of organics and nutrients in agro-industrial wastewater was evaluated, the analysis of by-product from electrolysis using copper electrode was also conducted. The total nitrogen decreased rapidly as the electrolysis was processed, and it was mostly performed by the elimination of ammonia nitrogen. The phosphate in water could be also removed by formation of copper compounds on the surface of the anode. Both pH value and alkalinity increased, because the concentration increment of hydroxyl ion by electrolysis of water. The ORP value also decreased during the electrolysis procedure by the generation of hydrogen gas, hydroxyl ion, and electron. The electrical conductivity as well as salinity was decreased through the electrolysis procedure, because of the loss of electrolyte ions in the wastewater through the formation of compounds and its sedimentation. The aeration was conducted for 2hours after the electrolysis procedure for the promotion of additional nitrogen removal, and the nitrogen removal could be successfully achieved. The pH value was controlled successfully to neutral with pH range of 6~8 by the aeration. © 2013 by ESG. Source

Yun C.-Y.,Konkuk University | Kim W.-Y.,Konkuk University | Son D.-J.,Konkuk University | Kim D.-G.,Korea Institute of Energy Research | And 4 more authors.
Ceramics International | Year: 2015

In this study, a novel tubular-type ceramic membrane with higher permeability was fabricated and its physical characteristics for microfiltration were evaluated. The membrane was composed of the support and active layer which is a coating of the support for selective permeation. Many macro pores under 1μm up to 40μm in diameter could be successfully formed in the support. Pores having a diameter less than one micrometer were generated by the melting of impurities or by contracting structures through sintering, and pore sizes above 1μm in diameter were also generated by the poly methyl methacrylate (PMMA) melted through sintering of support. The permeability of ceramic membranes could be enhanced by formation of large-diameter pores in the support. The pressurized-type ceramic membrane filter system with OUT-IN filtration direction was also devised for water and wastewater treatment. Surface flushing of the membrane was performed to solve the clogging. After 40min of operation, flux recovered to 97% of initial flux (320Lm-2 h-1) by surface flushing. To evaluate the feasibility of the ceramic membrane filter system, effluent from the electrolysis process for wastewater treatment was applied. Total suspended solids could be eliminated completely, and 99.8% of colloids causing the turbidity of water could be removed through filtration by the membrane. © 2015 Elsevier Ltd and Techna Group S.r.l. Source

Discover hidden collaborations