빗물의 용도결정을 위한 세균학적 안전성 및 수질 평가

곽동희,독고석,한무영 대한상하수도학회 2003 상하수도학회지 Vol.17 No.5

Recently, there has been an increasing interest to promote the utilization of rainwater. In this paper, concentration of organic compound and heavy metal in rainwater samples was analyzed to examine the hazardous level of rainwater for utilization. And an experiment for separating the opportunistic and pathogenic bacteria was also performed. Unlike the quality of ground water and surface water, only a few couple of bacteria types have found in the rainwater samples. This means that the quality of rainwater is by far safer than other water sources. Many opportunistic colony which inhabits in nature was found in the most of samples while the pathogenic bacteria was not detected. Organic compounds have not found in rainwater. Concentration of heavy metal in it also shows under the regulation of drinking water. Conclusively, on the basis of the analysis results on five samples, rainwater could be used directly for various purpose without additional water treatment process.

원수중의 천연유기물이 부상분리공정에 미치는 영향

곽동희,정팔진,이성우 全北大學校 附設 都市및環境硏究所 1997 都市 및 環境硏究 Vol.12 No.1

Many water bodies used for water supply may contain solid particles with a lower density. These solids are hardly removed in the sedimentation unit due to the own tendency of floating. In order to treat this type of water, the flotation process in known to be an effective method. A series of laboratory experiments has been performed to investigate the effect of natural organic matter(NOM) in raw water on flotation process. Foam formation potential(FFP) could be increase by NOM in raw water, alum is stimulate the trend of FFP to increase. Results of DAF treatment studies show that flotation efficiency can be increase by AOM, such as ethyl ester, sodium propionate, sodium dodecylbenzenesulfonate. Meanwhile, flotation efficiency can be decrease by AOM, such as glycerol, starch, pentane, peptone, isoamyl alcohol, humic acid etc. Also, the flotation efficiency by AOM corresponds well the tendency of FFP.

DAF 공정에서의 개체군수지에 의한 무기성 입자거동의 해석

곽동회,이재욱,한무영 대한상하수도학회 2003 상하수도학회지 Vol.17 No.2

The behavior of Inorganic clay particles in DAF (dissolved air flotation) process was analyzed by employing PBT (population balance in turbulence). For floc size range of 100-400㎛, the value of the initial collision-attachment efficiency was about 0.3 corresponding relatively low value. It was found that DAF process should be carefully operated, especially, in summer season when the inorganic clay particles are much introduced into water source due to heavy rainwater in Korea.

DAF 공정에서 무기 고형입자의 유체역학적 충돌효율과 부상특성

곽동희,김성진,이화경,정흥조,이재욱,정팔진 대한상하수도학회 2002 상하수도학회지 Vol.16 No.6

Separation characteristics of inorganic particles occurred during heavy rainwater were investigated in DAF (dissolved air flotation) process. In order to remove the inorganic particles effectively, the collision and flotation efficiencies were examined from a hydrodynamic point of view. Generally, the collision efficiency increased with floc size under the variation of fluid dynamic conditions including inertial force. However, more precise model should be required to analysis the collision efficiency expressed both the physical properties for inorganic particles and hydrodynamic conditions for a reactor.

鐵馬山地域의 Joint 硏究

朴喜斗,권동희,孫龍澤,郭永浩 동국대학교 대학원 1985 大學院硏究論集-東國大學校 大學院 Vol.15 No.-

The purpose of this research is to contribute the data for clarifying the geomorphic characteristics by comparing the joint strikes with stream directions. Joint sets, strikes, and dips are measured in the outcrops by the standards established by K,E, Lowe. The field data are illustrated by the joint map, rose diagrams, point diagram, contour diagram. To know the relation between joint patterns and stream directions Spearman’s r is adapted. The joint patterns in Chulmasan area are concentrated on the tree main strikes that range from N36W to N45W and from N56W to N65W and from N26E to N35E. These strikes represent a master joint set, 33.3% of the total frequency of this area. The stream direction frequency distribution is concentrated to the above ranges and is 40.7% in the above ranges. Spearman’ r is 0.52 and so we have come to concluded that there is amount of corelation between the joint patterns and the stream directions.

DAF공정의 궤적분석에서 유선과 운동함수의 적용이 기포와 플록의 충돌효율에 미치는 영향

김성진,곽동희,임영환 한국물환경학회 2004 한국물환경학회지 Vol.20 No.6

Many researchers have been carrying on study to figure out the exact collision efficiency between bubble and floc. Collision efficiency can has generally been quantified by using trajectory analysis which uses the hydrodynamic, the electrostatic and van der waals forces. Two types of method are considered to induce the hydrodynamic force in the trajectory analysis. One is to use stream function and the other is to use mobility function. There was some difference between stream and mobility function depending upon modelling factors and conditions in trajectory analysis.

타성상폐수의 주입이 하수처리효율에 미치는 영향

정팔진,곽동희,송탁식 全北大學校 附設 都市및環境硏究所 1996 都市 및 環境硏究 Vol.11 No.1

This study was to investigate the effects of dumping nightsoil, septage, and leachate to the activated sludge process receiving a mixture of sewage and industrial wastewater on its treatment performance. For the mixture of sewage and industrial wastewater, the overall removal efficiencies of BOD, COD and SS were 87.6%, 74.5% and 94.0% respectively. When the nightsoil and septage were dumped into the plant, the scum and foaming problems occurred at each stage of treatment unit. Direct dumping of the septage also induced the DO deficiencies in the aeration tanks, which resulted in a deflocculation problem in the secondary clarifiers. It may be favorite to pretreat it at the nightsoil treatment plant. When the leachate was dumped into the plant, the effluent qualities were highly fluctuating probably due to the presence of the toxic and inhibitory substances in it. It might be necessary to pretreat the raw leachate at the landfill site prior to dumping it into the plant.

조류와 유기화합물의 동시제거를 위한 흡착 - DAF 복합공정

이재욱,곽동희,최승필,정흥조 대한상하수도학회 2004 상하수도학회지 Vol.18 No.2

Dissolved air flotation (DAF) is an effective solid/liquid separation process for low density floc particles such as algal, color-alum and clay-alum flocs produced from low turbidity water. The removal of taste and odorcausing organics (2-mthylisoboneol and geosmin) originating from algae in drinking water is a local and worldwide concern. Although DAF has been effectively applied for the removal of suspended solid, its application for the treatment of dissolved organic carbon is very limited. In this study, a new hybrid system consisting of adsorption and DAF processes was introduced for the simultaneous removal of algae and taste and odorcausing organics. Powdered activated carbon (PAC) was used as an adsorbent. In this proposed system, the major concern of eliminating the spent PAC from the system was also addressed. It was found that zeta potential of algae and PAC was increased with coagulant dosage, and the removal efficiency in DAF was also enhanced up to 90-95% under the given experimental conditions. Based on this study, the hybrid process was found to be a promising technology for the simultaneous removal of algae and dissolved organic pollutants.

DAF에서 기포의 크기제어 및 영향분석

독고석,곽동희,김영환 대한상하수도학회 2004 상하수도학회지 Vol.18 No.2

The dissolved air flotation(DAF) process has been widely used for removing suspended solids with low density in water. It has been known as measuring the size of microbubbles precisely which move upward rapidly in contact zone is difficult. In this study particle counter monitoring (PCM) method is used to measure the rising microbubble after injection from a nozzle. Size and distribution curve of microbubbles are evaluated at different conditions such as pressure drop at intermediate valve, length of pipeline between saturation tank and nozzle and low pressure. And the efficiency is also checked when it collides with different size floc. The experimental results show the following fact. As the final pressure drop occurred closer to a nozzle, the bubble size became smaller. And small bubble collides with large floc as well as small one because of its physical characteristic. However large bubble collides well with large floc rather than small one since hydrodynamic flow in streamline interferes to collide between two. With performing computational process by mathematical model we have analyzed and verified the size effect between bubble and floc. Collision efficiency is the highest when P/B ratio shows in the range of 0.75 < P/B ratio (R_(particle/Rbubble)) < 2.0.

대청호 저질의 용출특성과 수질에 미치는 영향

정팔진,이성우,곽동희 全北大學校 附設 都市및環境硏究所 1997 都市 및 環境硏究 Vol.12 No.1

Lake eutrophication that bring about by excessive amounts of phosphorus and nitrogen becomes the main problem in Daechung Lake. To control the eutrophication like water bloom, it is important to quantify the nutrients loading and estimate the mass balance in the lake. In this paper, it was carried out to evaluate the nutrients discharging and characteristics of release in Daechung lake and investigate the effect of sediments on water quality. Also, it is suggested that the method of water quality management is required to improve it. The results of study are summarized as following ; 1. It is estimated that about 54% of input TP is accumulated in Daechung lake 2. It is surveyed that the mean range of TP release rate is 4.2∼10.1㎎/㎡·d at sampling sites of the lake 3. In order to improve the water quality of Daechung lake, it is needed the wastewater treatment plant and the sediment dredging of the lake preferentially.