박갑성 , 백성옥 , 이선영 , 임동준 Kap Song Park , Sung Ok Baek , Sun Young Lee , Dong Joon Lim

DOI: Vol.6(No.2) 2001-2009, 1990

A survey of trihalomethane (THM) levels in Daegu city drinking water supplies was undertaken with a solvent extraction/gas chromatography technique from May, 1989 to August, 1990. Mean THM levels in the Daegu city drinking water was 19.3 ㎍/l. Highest and lowest THM levels was 48.4 ㎍/l and 3.6 ㎍/l, respectively. THM concentrations consistently increased from January, 1990 (6.5 ㎍/l) to August, 1990 (30.1 ㎍/1). The seasonal variation was apparent for Nakdong river water systems. THM concentrations from Nakdong river water systems were generally higher than those from the reservoir water systems.

김원만 , 김홍석 Won Man Kim , Hong Seog Kim

DOI: Vol.6(No.2) 2010-2018, 1990

The spape and site of baffle wall play a major role to uniformize flow pattern and to improve removal efficiency in rectangular sedimentation basin. This research has been studied on the mixing distance and time of jet flow, according to sizes, spaces and numbers of openings on baffle wall and shape of baffle wall in rectangular sedimentation basin, and has been measured flow pattern, detention time and depth of deposited particle from the inlet. As a result of this study, in the case 6% of opening area, the more small and narrow opening sizes are, the better flow pattern could be achived. The flow pattern and the deposit states of particles have been more improved when the cut -off plate is installed at the underflow of the baffle wall.

임굉 Going Yim

DOI: Vol.6(No.2) 2019-2027, 1990

The applications of zeolite have been carried out in the various aspects because of its Large cation exchange capacity, molecular sieving and adsorption characteristics. Therefore, the present paper was studied its application as adsorbent of heavy metal ions in wastewater by batch adsorption process and column flow adsorption operation. In result, the adsorption mechanism of the heavy metal ion concentration in wastewater on zeolite is generally coincided with Langmuir`s formula from the relationship between the adsorption equilibrium concentrations and the amounts of adsorbed ions. In case of sample treated with dilute sodium hydroxide solution, the amounts of adsorbed ions increased about 59 percent. To think the relation between the breakthrough capacity and ionic concentration of the influent, the use of natural zeolites were suitable for the higher order water treatment. The adequate particle size of zeolite for the column operation is approximately 12 mesh in points of easy working. The perfect removal of heavy metal ions excepted lead(II) ion could be possible when the linear flow velocity was 0.6㎝ per minute. The adsorbed cations on zeolite could be collected by elution with dilute hydrochloric acid solution, in order to obtain a higher recovery, it would be necessary to examine another eluent such as sodium chloride solution, etc. As a result, the domestic natural zeolites could be effectively used as economic adsorbent in order to treat wastewater of the environment industries.

백광욱 , 조영태 , 이준걸 , 장덕 , 정윤진 Kwang Wook Baek , Young Tai Cho , Jun Gul Lee , Duk Chang , Yoon Jin Chung

DOI: Vol.6(No.2) 2028-2033, 1990

An experimental investigation was conducted on methane fermentation for naked barley distillery waste. Digesters were operated at the hydraulic retention times of 15 to 40 days with organic loading rates of 0.53∼2.82 gCOD/L ·d. Inhibition of methane fermentation was clearly observed at the retention time of 15 days with an organic loading rate of 2.82 gCOD/L·d. Digestion efficiencies were improved with an increase of hydraulic retention time regardless of organic loading rate. It is believed that inhibition of digestion does not occur due to organic overloading and failure must be due to the inhibition material in the naked barley distillery waste. Inhibitory concentration is considered to be dependent on the retention time.

이찬기 , 윤주환 , 권재혁 , 전태성 Chan Ki Lee , Zu Whan Yun , Jae Hyuk Kwon , Tae Sung Jeon

DOI: Vol.6(No.2) 2034-2041, 1990

An efficient pretreatment of piggery wastewater would be an essential for the successful secondary treatment due to the high concentration of suspended solids(SS) and Biochemical Oxygen Demand (BOD). To evaluate an efficient pretreatment process for the diluted piggery wastewater treatment, the sedimentation process and the filtration process were considered. Results indicated that, the filtration process which adopted dried rice straw as a medium was an effective method to remove the SS and soluble BOD. In addition. the removed rice straw medium would be an adequate bulking agent for the composting process.

신응배 , 박완철 , 최용수 , 김동하 Eung Bai Shin , Wan Chul Park , Yong Soo Choi , Dong Ha Kim

DOI: Vol.6(No.2) 2042-2052, 1990

This paper presents problems and limitations inherent to the existing septic tank systems, and approaches to devise new systems. The bench-scale laboratory experiments have demonstrated that a new aerobic system yields an average organic removal efficiency of 88±5 percent at a 4-day and 95±3 percent at a 6-day hydraulic retention time(HRT), respectively. With a new anaerobic system the ranges of removal rates are 77±10 percent at a 4-day and 88±7 percent at a 6-day HRT, respectively. Even with the new anaerobic system it is anticipated that the system will meet the minimum required criterion of an average removal efficiency of 77%. These two systems were tested under the loading conditions ranging from 60 to 180㎏ BOD/1000㎥ day. The paper will also discuss sludge production rates as they relate to the frequency of sludge removal from a tank.

윤주환 Zu Whan Yun

DOI: Vol.6(No.2) 2053-2062, 1990

박영숙

DOI: Vol.6(No.2) 2063-2075, 1990

이상은

DOI: Vol.6(No.2) 2076-2078, 1990