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조관형,우달식,황병기,이선주,박덕원,Jo, Kwan-Hyung,Woo, Dal-Sik,Hwang, Byung-Gi,Lee, Seon-Ju,Park, Duck-Weon 한국환경보건학회 2009 한국환경보건학회지 Vol.35 No.5
This study was initiated to improve the cooling water quality by chemical coagulation and sedimentation in steel mills. Due to the inefficient flocculation in the settling tanks of blast furnace cooling water systems, the solid particles in the cooling water overflow accumulate and clog the cooling system. To protect the cooling water system from such fouling, proper flocculants must be continuously used. Laboratory tests were performed for the indirect cooling water system of a plate mill. The batch test in the gas scrubbing cooling water system of a blast furnace showed that the proposed coagulant was more effective for the improvement of coagulation and sedimentation than the existing one. During the tests, cationic flocculants were more effective than use of only an anionic flocculant. The suggested combination of anionic and cationic flocculants can probably improve the turbidity removal efficiency of the cooling water. Proper control of the overflow rate by the designed residence time would help turbidity removal efficiency in the settling tank. In addition, the settling can be enhanced by adopting rapid and slow mixing alternatively. Scale problems in blast furnace cooling water system were reduced to some extent by efficient settling.
동관에서 pH, 알칼리도, 염소이온이 부식에 미치는 영향
조관형,김선일,우달식,Jo, Kwan-Hyung,Kim, Sun-Il,Woo, Dal-Sik 한국환경보건학회 2007 한국환경보건학회지 Vol.33 No.1
This study investigated the effects of pH, alkalinity, and chlorine ion which are important water quality impact factors to the corrosion in the simulated distribution system where the copper pipe is affixed. The result shows that pitting index was increased as the alkalinity and chloride ion increase in the distilled water, but there was no relation to pH. Actually the uniform corrosion rate was decreased as the pH increase with the laboratory tap water. In conclusion, it is necessary to control the pH which stands above minimum 7.5 to prevent pitting corrosion in the copper pipe. Consequently, comprehensive research about the effect of lime soda($Ca(OH)_2$) which was used as a coagulation additive in the water treatment plant to pipe corrosion must be accomplished additionally.
조관형,Jo, Kwan-Hyung 한국환경보건학회 2010 한국환경보건학회지 Vol.36 No.2
In this study, a method for river water quality evaluation by algal examination was investigated. For development of this method, algae living in small rural streams in Gwangcheon-Cheon were collected and observed by microscope. Samples were collected at six stations from May 2008 to May 2009. To elucidate the relationship between pollution and the algal species, diatom grasps were collected from the streams and used to determine the water quality grade. The numerical EC value was compared with the value of DAIpo (Diatom Assemblage Index of Organic Water Pollution), and the results showed a tendency to a mutually inverse relationship. Further, the numerical BOD and COD values were compared to the DAIpo value. The results showed that, various diatoms reside in Gwangcheon-Cheon, and water quality was found to be second-grade at all the examined points. These results indicate pollution of streams by livestock wastewater; however continuous monitoring will be necessary to more definitely determine the reason for the Gwangcheon-Cheon pollution.
활성슬러지를 이용한 질소방향족화합물의 생물학적 분해 특성
조관형,Jo, Kwan-Hyung 한국환경보건학회 2010 한국환경보건학회지 Vol.36 No.3
Biological degradation of nitrogen-containing aromatic compounds was investigated in activated sludge previously adapted to mineralize low concentrations of nitrogen-containing aromatic compounds. Normally, the time required for 95% degradation of 10 mg/l dinitrophenol (DNP) under aerobic conditions was less than 4 hours without any lag, and with mixed liquor suspended solid (MLSS) levels from 600 to 1,000 mg/l. However, when the initial DNP concentration was increased to 75 mg/l, lags and even complete inhibition of DNP degradation were observed. The length of the lag was found to increase proportionally with decreasing MLSS levels. When dilute activated sludge was incubated for extended periods (192 hours), degradation of 75 mg/l DNP did eventually occur after lag periods of 37 to 144 hours, depending on the MLSS concentration. DNP was degradable in high concentrations if MLSS concentrations were sufficiently high to allow growth of bacteria resistant to the toxic effects of DNP.
정수처리장내 급속모래 여과지의 이단복합여과시스템으로의 개량
우달식,황규원,김준언,황병기,조관형,Woo, Dal-Sik,Hwang, Kyu-Won,Kim, Joon-Eon,Hwang, Byung-Gi,Jo, Kwan-Hyung 한국환경보건학회 2011 한국환경보건학회지 Vol.37 No.2
This study aimed for developing a two stage dual media filtration system. It has a sand and activated carbon layer above the under-drain system, and a sand layer above the middle-drain system for pretreatment. When retrofitting an old sand filter bed or designing a new one, this technology can substitute the existing sand filter bed without requiring a new plant site. The removal rate of total particle is 93, and 3~7 ${\mu}m$ and 5~15 ${\mu}m$ particles are all 97%. These high removal efficiencies of each pollutant due to adsorption and biological oxidation in activated carbon filter layer. The best backwashing method of two stage dual media filtration system is ascertained by air injection, air + water injection and water injection sequence. In this study, a pilot plant of two stage and dual filtration system was operated for 4 months in water treatment plant. The stability of turbidity was maintained below 1 NTU. The TOC, THMFP and HAAFP were removed about 90% by two stage and dual media filtration system, which is almost 2 times higher than existing water treatment plant.