FRP 소화수조의 부재간 결속으로 슬로싱 방지를 위한 구조해석 연구

허동필(Heo, Dongpil),민세홍(Min, Sehong) 한국방재학회 2022 한국방재학회논문집 Vol.22 No.2

소방시설의 내진설계 기준의 개정으로 소화수조 본체의 내진 안전성을 반드시 검증하게 되었다. 그럼에도 불구하고, 소화수조로 지금까지 현장에 많이 설치된 물성이 취약한 FRP 물탱크는 구조 안전성을 확인할 수 있는 방법이 없다는 현실에 직면하고 있다. 본 연구에서는 FRP 물탱크의 구조적 안전성 확보를 위한 FRP의 물리·화학적 특성 인자 값에 대해 국가공인시험기관을 통해 데이터를 추출 및 축적함으로서 구조해석의 신뢰성 제고에 대해 연구하였다. 또한 물성이 취약한 FRP 물탱크의 내진 안전성을 보강하는 방법을 외부 보강 방법이 아닌, 물탱크 부재간의 결속을 통한 자체 구조 개선으로 물탱크의 파손 원인을 제공하는 슬로싱 및 물탱크 하부 유체 유동 현상을 저감할 수 있음을 확인하였으며, 이로 인해 ｢지진에 의한 슬로싱 방지 구조를 갖는 물탱크｣를 개발하였다. 더불어 개발된 소화수조를 Solidworks Simulation 해석을 통해서 내진 안전성이 향상되었음을 검증하였다. 이러한 결과로 소화수조의 내진 안전성을 개선함으로써, 물성이 취약한 FRP 소화수조를 내진 소화수조로 사용하기 위한 기초연구 자료로 사용하고자 한다. The seismic safety of a fire extinguishing water tank must be verified because of the revision of the seismic design standard of fire protection systems. Although, the FRP water tank has weak physical properties, it is often used as a fire extinguishing water tank, confronting the reality that there is no way of checking its structural safety. This study focuses on a reliable structural analysis by extracting and accumulating data on the physical and chemical characteristics of FRP through the National Certification Testing Agency to ensure the structural safety of an FRP water tank. It has been found that sloshing causes the breakage of a water tank and the fluid movement in the lower part of a water tank can be reduced not by using the external reinforcement method but by improving the internal structure through binding of the water tank members. This method can be employed for reinforcing the seismic safety of an FRP water tank with weak physical properties. Accordingly, a water tank with a structure that prevents sloshing caused by an earthquake has been developed. The improvement in the seismic safety of the developed fire extinguishing water tank has been verified through a Solidworks simulation analysis. Therefore, the proposed strategy for the improvement of the seismic safety of a fire extinguishing water tank can be employed as the basic study material for using an FRP water tank with weak physical properties as the seismic fire extinguishing water tank.

The Numerical Simulation Analysis of Flow Field in Level Control Valve of Water Storage Tank

Yaping Wang,Lei Gao,Jianghua Ge,Han Gao,Jing Zhang 보안공학연구지원센터 2014 International Journal of Control and Automation Vol.7 No.10

Level control valve of water storage tank is installed in the outlet of tank, which control the water level of water storage tank by adjusting the water emissions, which make great significance for the safe operation of the super (super) criticality thermal power unit boiler . Complete the simulation analysis of internal flow field by the method of numerical simulation ,in order to achieve structure improvements of level control valve of water storage tank, that make level control valve of water storage tank better meet the work requirements. Establish flow channel model and mesh models of level control valve of water storage tank in various stages of the open process. Make three dimensional viscous numerical simulation of the internal complex flow field by the computational fluid dynamics software of ANSYS CFX. The error between the simulation values of the flow coefficient and the theoretical values , trial values is less than 5% ,which verifies the correctness of the simulation results . Get pressure contour , velocity streamline diagrams and outlet mass flow of level control valve of water storage tank in various stages of the open process. According to the pressure contours and velocity streamline diagrams, make detailed analysis of the flow field of level control valve of water storage tank. According to the dates of outlet mass flow, fit the flow characteristic curve of level control valve of water storage tank. Provide a theoretical basis for the structural design of level control valve of water storage tank.

저수조 내 잔류염소 감소에 미치는 주요 영향 인자에 관한 문헌연구

노유래(Yoorae Noh),김상효(Sang-Hyo Kim),최성욱(Sung-Uk Choi),박준홍(Joonhong Park) 한국방재안전학회 2016 한국방재안전학회 논문집 Vol.9 No.2

약안전한 수돗물 공급을 위해 정수처리장부터 최종 단계인 수도꼭지까지 일정 수준 이상의 잔류염소농도가 유지되어 야 한다. 하지만 국내 문헌에 따르면 상수공급의 전체 과정 중에 30-60%의 잔류염소가 소실되고, 이에 대한 주요 원인으로 정수처리 과정에서 염소 사용량 감소 추세, 급수배관 내에서 염소분해 손실, 여름철의 높은 온도에 의한 잔류염소 분해 속 도 증가, 급수배관의 노후화에 따른 잔류염소 손실, 저수조 내 저장 시 잔류염소 감소 발생 등이 파악되었다. 이러한 이유로 저수조를 거치는 급수 방식의 경우 최종 수도꼭지의 잔류염소 농도가 기준치보다 낮아질 개연성이 높고, 용량과 체류시간을 단순히 고려하는 기존의 저수조 설계 방식으로 인해서 수돗물 공급의 안전성에 대한 우려가 존재한다. 이의 개선 방안 도출 을 위해서 본 연구에서는 저수조 내 잔류염소 감소에 관여하는 주요 기작들인 수체 내 잔류염소 분해, 벽체 표면 흡착, 그리 고 증발에 의한 물질전달을 수학적으로 묘사하는 공식들과 계수 값들을 문헌을 통해서 획득하고, 일반적 저수조 조건에서 모델 시뮬레이션을 수행하였다. 그 결과 저수조에 유입되는 수돗물 내 유기물 농도, 수돗물이 저수조에 유입되는 수리학적 조건(난류 정도), 그리고 저수조 벽체 표면 재질의 흡착능 등이 저수조 내 잔류염소 감소에 주요 영향 인자들임을 알 수 있 었다. 본 연구에서 획득된 결과들은 잔류염소 감소를 최소화하여 안전한 수돗물 공급을 가능하게 하는 새로운 저수조 설계 기법이나 기술 개발에 유용하게 활용될 것이다. For safe water supply, residual chlorine has to be maintained in tap-water above a certain level from drinking water treatment plants to the final tap-water end-point. However, according to the current literature, approximately 30-60% of residual chlorine is being lost during the whole water supply pathways. The losses of residual chlorine may have been attributed to the current tendency for water supply managers to reduce chlorine dosage in drinking water treatment plants, aqueous phase decomposition of residual chlorine in supply pipes, accelerated chlorine decomposition at a high temperature during summer, leakage or losses of residual chlorine from old water supply pipes, and disappearances of residual chlorine in water storage tanks. Because of these, it is difficult to rule out the possibility that residual chlorine concentrations become lower than a regulatory level. In addition, it is concerned that the regulatory satisfaction of residual chlorine in water storage tanks can not always be guaranteed by using the current design method in which only storage capacity and/or hydraulic retention time are simply used as design factors, without considering other physico-chemical processes involved in chlorine disappearances in water storage tank. To circumvent the limitations of the current design method, mathematical models for aqueous chlorine decomposition, sorption of chlorine into wall surface, and mass-transfer into air-phase via evaporation were selected from literature, and residual chlorine reduction behavior in water storage tanks was numerically simulated. The model simulation revealed that the major factors influencing residual chlorine disappearances in water storage tanks are the water quality (organic pollutant concentration) of tap-water entering into a storage tank, the hydraulic dispersion developed by inflow of tap-water into a water storage tank, and sorption capacity onto the wall of a water storage tank. The findings from this work provide useful information in developing novel design and technology for minimizing residual chlorine disappearances in water storage tanks.

입자성 고형물을 제거하기 위한 침전조 일체형 무 환수 수조 시스템에서 수질 특성

김광석,김우항,정정조,이영식 한국환경기술학회 2019 한국환경기술학회지 Vol.20 No.6

In order to remove particulate from tank of fish farms, an all-in-one breeding and sedimentation tank was designed and its effects were investigated. Space of the water tank were partitioned into an eel breeding part on the left and a sedimentation tank on the right, and water on breeding part was moved from the breeding part to a sedimentation tank by airlift pump located on the right side of breeding part. In the sedimentation tank, the particulate in water was naturally precipitated and the water that the particulate was removed moved into an eel breeding part through hole of partition which is located top layer and then removed from bottom of sedimentation tank naturally. Concentration of particulate was decreased from 10.0 mL/L to 5 mL/L (removal efficiency: 50 %) in 1.5 hours and to 0.1 mL/L (removal efficiency: 99 %) in 6 hours. An all-in-one tank in this study is expected to be able to replace the drum screen function used in the existing eel fish farms. In existing eel fish farms, water in several fish tanks are sent to one drum screen to remove particulate, so disease in one tank can easily spread to other tank. On the other hand in this study, disease can not easily spread from tank to tank because of no water flow. Therefore, it is expected to have easier control of the disease than the drum screen method.

百濟山城用水施設에 대한 檢討

최병화(Choi, Byunghwa) 한국상고사학회 2010 한국상고사학보 Vol.69 No.-

본고에서는 연못, 지당, 집수정, 우물 등 여러 명칭으로 혼용되는 산성 용수시설에 대한 개념정리와 기능을 파악하고자 백제산성 용수시설을 검토하였다. 검토결과 백제산성 용수시설은 지하수를 사용한 우물, 지표수를 사용한 집수지(저지대 계곡부)와 저수조(정상부 평탄면)등 세 가지로 정리할 수 있었다. 그리고, 백제산성은 지하수원인 우물은 거의 사용하지 않고, 대부분 지표수원을 사용한 집수지와 저수조를 사용하였음을 알 게 되었다. 한편, 지표수인 집수지와 저수조는 입지에 따라 입수방식과 기능이 뚜렷이 구분된다. 첫째, 집수지는 저지대 계곡부에 위치하여 성내 高地의 ?水를 모으며, 주로 장마와 같은 집중 폭우기간 성내의 물길을 잡아 성밖으로 배출하는 기능을 하였다. 둘째, 저수조는 정상부 평탄면에 위치하며, 입수방식은 직접 물을 길어다 붓는 형태로서 선별된 양질의 食水를 저장할 수 있는 물탱크 같은 기능을 하였다. 이러한 기능에 따라 집수지는 성내의 고저차가 큰 대규모 산성에서만 설치되었고, 고저차가 작고 협소한 소규모 산성에서는 설치되지 않았다. 반면, 저수조는 산성의 대·소규모 상관없이 모든 성내에서 필수적으로 설치되어 식수를 공급하였다. 이 같은 현황은 백제만이 아니라 고구려 및 신라산성에서도 확인되며, 검토결과 삼국시대 산성의 일반적인 현황임을 알 수 있었다. 이외에도 백제산성에서는 저수조 가운데, 성벽 및 문지와 접하여 소규모 저수조(평면 5.2㎡이하)를 별도로 설치한 특징이 살펴졌다. 이 같은 특징은 王城을 포함한 대부분의 백제산성에서 확인되는데, 검토결과 성벽 및 문지 주변에 설치하여 적의 화공에 대비한 소화수 기능을 하였던 것으로 파악되었다. 이 같은 특징은 고구려 및 신라산성에서 볼 수 없는 것으로서 백제산성만이 지니는 독특한 특징이라 할 수 있다. The purpose of this study was to definitely arrange a concept and grasp function on the water facilities of fortress, which are used by being mixed into several names such as pond, Jidang(池塘), collecting well and a well. Thus, examination was progressed targeting the water facilities in Baekje Mountian fortress. As a result of examining, the water facilities of fortress could be arranged a concept with three kinds such as a well of using underground water, receiving reservoir(valley part of the lowland) of using surface water, and water tank(flat side of the top part). Baekje Mountian fortress could be known to have used receiving reservoir and water tank of using mostly surface water source without almost using a well, which is underground water source. On the other hand, receiving reservoir and water tank were definitely divided a method of getting water and the function according to location. First, receiving reservoir was located in the valley part of lowland, thereby having collected the flowing water of high ground, and functioned as discharging it to the outside of fortress by grasping a waterway within the fortress mainly during the torrential downpours like rainy season. Second, Water tank is located in the flat side of the top part. A method of getting water is a form of directly carrying to pour water. It functioned like water tank available for storing drinking water in good quality that was selected. According to this function, Receiving reservoir is installed only in large fortress with big difference in high and low within the fortress, and wasn't installed in the narrowly small fortress with small difference in high and low. On the other hand, water tank was installed necessarily within all the fortresses regardless of large·small fortress, thereby having supplied drinking water. This present status is confirmed even in Goguryeo and Silla fortress as well as Baekje. As a result of examining, it could be known to be the general present status of fortress in the period of the Three States. Even in addition to this, in Baekje Mountian fortress, the characteristic was examined that installed separately small water tank(ground plan in under 5.2㎡) by being close to fortress wall and door hinges in the middle of water tank. This characteristic is confirmed in most of Baekje Mountian fortress including a castle of a kingdom(王都, 王城). As a result of examining, it was grasped to have functioned as fire?extinguishing water in preparation for fire attack by being installed around the fortress wall and the door hinges. This characteristic cannot be seen in Goguryeo and Silla fortress, thereby being able to be said to be unique feature that only Baekje Mountian fortress has.

고용량 방사성옥소 치료병실의 오.폐수 저감화를 위한 연구

류재광,정우영,신상기,조시만,Ryu, Jae-Kwang,Jung, Woo-Young,Shin, Sang-Ki,Cho, Shee-Man 대한핵의학기술학회 2008 핵의학 기술 Vol.12 No.1

목적: 방사성옥소 치료병실로부터 발생한 오 폐수는 반드시 전용 정화조에서 일정시간 자연 감쇄(decay)시켜 수중 방사능 농도치가 $8.1{\times}10^{-13}$ Ci/ml 이하가 될 때에만 비로소 방류를 하여야 한다. 현재까지 서울아산병원에서는 60 ton 용량의 전용정화조 3개를 구비하여 운영하고 있었지만 2005년 10월부터 방사성옥소 치료병실을 2병상에서 4병상으로 증설 운영함에 따라 급격히 늘어난 방사성 오.폐수량으로 인하여 본원의 정화조 용량으로는 충분한 감쇄(약 125일 이상)여력이 부족하게 되었다. 따라서 본 연구에서는 치료병실 정화조의 오 폐수 유입유량에 기여하는 원인 및 요인들을 밝혀내어 합리적인 개선 조치를 함으로써 정화조 용량 부족 문제를 해결하여 1차적으로는 엄청난 병원의 경제적 손실을 유발시키는 새로운 정화조의 증설을 피하고 방사성 물질의 인위적 배출로 인한 사회적 문제 유발에 따른 대형의료기관의 신뢰도 추락의 예방에 큰 목적이 있다. 대상 및 방법: 2006년 1월부터 10월까지 고용량 옥소 치료 환자 중 150~200 mCi 이상을 투여 받고 2박3일간 입원치료를 하는 환자 402명을 대상으로, 환자 1인당 평균 물 사용량 (변기사용량, 샤워량, 세면량, 기타 등등)을 측정하였으며, 본원의 정화조 60 ton 3개의 만수 후 배출까지의 감쇄 기간을 측정하였다. 또한 본원의 치료 업무 절차를 단계별로 분석하여 정화조 유입유량의 증가 요인을 찾아보았다. 결과: 다음과 원인에 대한 개선을 통하여 본원의 방사성 오 폐수 보관일수를 정화조 1개당 84일에서 2005년 12월말 현재 약 130일로 증가시킬 수 있었다. (1) 기존 변기의 과다한물 소모량 개선 $\rightarrow$ 절수형 변기로 교체 (2) 불필요한 샤워 및 세탁 방지 $\rightarrow$ 샤워 노즐 사용 자제 및 세면대 이용 교육 (3) 치료기간 중 잦은 배뇨를 유발하는 이뇨제 복용 중지 (4) 수분 섭취량과 퇴원시 체내 잔류선량과의 상관관계 분석 (5) 입실 후 치료 전까지의 대기시간에는 외부 화장실 사용 교육 (6) 정화조 만수위 용량 한계치를 최대 85%에서 90%로 증대 운용 결론: 근래에 들어 급격하게 증가된 갑상선질환 관련 환자로 인하여 전국적으로 거의 모든 의료기관에서 방사성옥소치료의 대기일 수가 크게 증가되고 있다. 이러한 시점에 발생된 방사성 오 폐수 관련 문제는 비단 어느 한 의료기관의 문제가 아닌 관련 우리 모두가 해결해야 하는 큰 과제임에 틀림 없을 것이다. 따라서 본 개선 활동은 그 시작을 알리는 신호탄이 될 것이라 생각되며 방사성 치료병실을 운영하고 있는 타 의료기관에서도 이와 관련된 유사상황이 발생된다면 합리적인 정화조운영의 모델방안으로 제시 될 수 있을 것으로 기대된다. Purpose: In general, We discharged radioactive wastewater and sewages less than $8.1{\times}10^{-13}$ Ci/ml in a exclusive water-purifier tank. Our hospital operating three exclusive water-purifier tank for radioactive wastewater and sewages of 60 tons capacity respectively. In order to meet the criteria it need a enough decay more than 125 days per each exclusive tank. However, recently we fell into the serious situation that decay period was decreased remarkably, owing to the wastewater amount increased rapidly by enlarge the therapy ward. For that reason, in this article, I'd like to say the way that reducing of radioactive wastewater and sewages rationally. Materials and Methods: From January, 2006 to October, four hundred and two cases were analyzed. They were all hospitalized during 3 days and 2 nights. We calculated the average amount of water used (include toilet water used, shower water used, washstand water used, $\cdots$), each exclusive water-purifier tank's decay period, as well as try to search the increased factors about water-purifier tank inflow flux by re-analysis of the procedure of radioisotope therapy step by step. Results: We could increase each exclusive water-purifier tank's decay period from 84 days to 130 days through the improvement about following cause: (1) Improvement of conventional toilet stool for excessive water waste $\rightarrow$ Replacement of water saving style toilet stool (2) Prevention of unnecessary shower and wash (3) Stop the diuretics taking during hospitalization (4) Analysis of relationship between water intakes and residual dose of body (5) Education about outside toilet utilization before the administration (6) Changed each water-purifier tank's maximum level from85% to 90% Conclusion: The originality of our efforts are not only software but hardware performance improvements. Incidentally the side of software's are change of therapy procedures and protocols, the side of hardware's are replacement of water saving style toilet stool and change of each water-purifier tank's maximum level. Thus even if a long lapse of time, problem such as return to the former conditions may not happen. Besides, We expect that our trials become a new reasonable model in similar situation.

광주지역 바닥분수의 수질특성 평가

김종민,김하람,장서은,최영섭,강유미,정숙경,조영관,김은선 한국환경보건학회 2017 한국환경보건학회지 Vol.43 No.2

The purpose of this study was to investigate water quality through a field survey at six floor fountain sites. The floor fountain facilities were designed and operated in such a way that tap water was stored in a water tank and recycled repeatedly. The water tank was cleaned once or twice per week in the summer. The number of facility users was low during the day due to sweltering heat, but up to 40 people, mainly children, were using them around 8 pm. Since the operation time was as short as 30 minutes, it is considered necessary to extend it for at least one hour for the number of users. As a result of the water quality test of the reservoir tank prior to operation after cleaning, it was measured to be within drinking water quality standards at the six facilities. As a result of the water quality test after use, ammonia nitrogen was measured to be 1.45 mg/L at Site IV. This exceeded the drinking water quality standard of 0.5 mg/L. In the case of turbidity, two cases exceed at 7.38 and 4.52 NTU when applying 4 NTU as the water quality standard for waterscape facilities. Twenty-eight cases exceed the standard of drinking water quality. The result of microbiological tests, at five sites excepting Site I, where disinfectant was injected, was that the maximum total colony count was 180,000 CFU/mL, total coliforms was 2,100,000 CFU/100 mL, fecal coliforms was 4,600 CFU/100 mL, Escherichia coli was 170 MPN/100 mL and Enterococcus was 100 CFU/100 mL. This exceeded the water quality standards of drinking water. Children are very likely to inhale because the water spews from below and falls from above, so it is necessary to apply water quality standards for ammonia nitrogen, turbidity and microbes. Current floor fountain facilities are highly susceptible to disease caused by microbial contamination because of water cycling and reuse, so it is necessary to change the water every day, clean the water tank, and perform chlorination. Therefore, it is necessary to inject calcium hypochlorite according to the free chlorine water quality standard of swimming pools with a different water tank capacity. In addition, facilities should be improved to prevent the reuse of water by installing the water tank at a separate location.

SMC 소화수조의 지진안전성 설계 시 구조해석에 의한 체크리스트 적정성 연구

김길중,허동필,오흥규,정석환,민세홍 한국화재소방학회 2023 한국화재소방학회논문지 Vol.37 No.1

Recently, in seismic design analysis, some non-structural elements have been defined and analyzed as rigid bodies, whichmakes it difficult to ensure the safety of non-structural elements against earthquakes. In the recently revised “Seismic DesignStandards for Fire-Fighting Facilities,” the seismic design of fire-fighting facilities for seismic load and structural safetyprioritizes the seismic design of each connection. In particular, in a tank vibrating due to an earthquake, pressure from fluidflow is exerted on the tank wall due to the interaction between the liquid and structure; in fact, this pressure may increasethe stress of the tank and cause structural damage. In addition, the frequency of the water tank and connecting pipe is different,which may alter each other’s wavelength. The water tank is crucial for supplying water, which acts as a fire-extinguishingagent, to the fire-extinguishing facility. In terms of earthquake damage to the water tank, the risk increases when water cannotbe supplied during a fire due to damage to the continuous section of the tank wall and damage to the pipe connectorconnected to the tank. In this study, criteria for review items are presented such that the “Structural Safety Checklist forSeismic Design of Water Tanks” can be reviewed and compared by item in a structural review of the water tank duringseismic design. Structural calculation via numerical calculation cannot adequately account for the structure of the water tank. Therefore, calculations for the structure are verified, a quantitative design that addresses the limitations of numerical calculationis considered, and a three-dimensional design that includes the relative displacement of connections is established. Structuralsafety is confirmed by examining the structural members and connections through modeling and structural analysis simulation. 최근에 내진설계 해석에서 비구조요소의 일부를 강체로 규정하고 해석하는 경우가 있으며, 이에 비구조요소의 지진에 대한 안전성을 확보하기 어렵다. 근래에 개정된 ‘소방시설의 내진설계기준’에서 소방시설의 지진하중과 구조안전성에 대한 내진설계에서 각 연결부위에 대한 내진설계를 중요시하고 있는 추세이다. 특히, 지진으로 인해 진동하는 수조는 액체와 구조물의 상호작용으로 수조 벽체에 유체유동의 압력이 작용하며, 이러한 압력은 수조의 응력을증가시키고 구조적인 손상을 일으키는 원인이 될 수 있다. 또한 수조와 연결배관 등의 주파수가 상이하여 서로의파장에 의한 원인으로 손상을 초래할 수 있다. 수조는 소화설비에 물이라는 소화약제를 공급하기 위한 설비로서 중요성이 있다. 이러한 수조에 대한 지진피해 사례로는 수조 벽체 연속부위의 파손 및 수조와 연결된 배관 커넥터 등의파손으로 화재 시 수원을 공급할 수 없는 경우가 발생하여 위험성을 증가시켰다. 본 연구에서는 내진설계 시 수조의구조검토에서 ‘수조의 내진설계를 위한 구조적 안전성 체크리스’를 항목별로 검토 및 비교할 수 있도록 검토 항목의기준을 제시하였다. 수계산에 의한 구조계산은 수조의 충분한 구조적 보완이 어려우므로 구조계산에 대한 검증과수계산에 대한 한계를 보완한 정량적인 설계를 고려하고, 연결부위에 대한 상대변위를 포함한 설계를 할 수 있도록3D Modelling과 구조해석 시뮬레이션을 통하여 구조부재와 연결을 검토하여 구조안전성을 확인하였다.

百濟城郭 內 우물의 登場과 造成過程에 대한 硏究

최병화 한국고대학회 2018 先史와 古代 Vol.- No.55

In Baekje castle there are three types of water facilities such as a water tank, a collecting basin, and a well. Water tank(rainwater and fill directly with water) and a collecting basin(rainwater and collection of flowing water) are facilities that store and use surface water. Wells are facilities to find and use ground water. Among these water facilities, a water tank and a collecting basin were always made, but a wells were rarely made. The hydrological environment in which the wells are built is a natural aquifer (alluvial aquifer) or an alluvial land, where the groundwater collects. Therefore, Pungnap Earthen Fortification and Gongsanseong Fortress, Busosanseong Fortress located on the rivers could be wells including alluvial deposits containing groundwater. On the other hand, the acid which is located on a high mountain like a Chuseongsanseong Fortress does not have an alluvial land and water flows down the mountain without gathering underground. Therefore, fortresses located in high mountain did not make a well when they were built. However, wells are built in the high fortresses. All of the wells of the mountain fortress wall are located in the valley and are based on valley sediments that cover a collecting basin. As a collecting basin was covered(disuse), water was stored in the inner soil layer and turned into an environment where the well could be used. Hydrologically, it corresponds to perched aquifer. For example, the well of the Chuseongsanseong Fortress is located in the valley, Below the well is a layer of mud accumulated in the facilities that existed before making the well. Maro-sanseong Fortress is Baekje period Fortress, but well of Koryo period is confirmed. There is a collecting basin under the well. In other words, the fortress on the high mountain was not an environment to make a well when it was first made, so I built a Water tank and a collecting basin, When the collecting basin is covered, the environment changes into an environment where water can be stored in the internal soil, creating a well. It can be seen that the wells were not formed in the small-scale Teemoeic a mountain fortress without valley, but only in the Fogogcic a mountain fortress. On the other hand, when building a mountain fortress, it is possible to live only by a water tank and a collecting basin. Nevertheless, it has been confirmed that the making of the well is due to the function of the well. Wells are facilities that get the cleanest water from the mountain fortress with the least amount of labor. It does not get dirty because it collects running water like a collecting basin, and it does not have to carry water directly like a water tank. And the risk of water quality deterioration due to exposure to the surface in the hot season is low. Wells are naturally collected in the basement, filtered and clarified in the course of reaching the aquifer. And it is disconnected from the surface and stored at low temperature, and is least likely to be deteriorated and contaminated. Therefore, the well was a facility that used the most needed water in the castle. In the future, if wells are identified in ancient mountain fortress, including Baekje fortress, and excavation studies on wells are carried out, it is important to clearly identify the presence of previously a collecting basin. 백제 성곽에는 貯水槽, 集水池, 우물(井) 등의 세가 형태의 用水施設이 존재한다. 저수조(雨水 및 직접 길어다 貯藏)와 집수지(雨水 및 流水를 集水)는 지표수를 모아 사용하는 시설이며, 우물은지하수를 찾아 사용하는 시설이다. 이들 용수시설 중 저수조와 집수지는 반드시 조성하지만 우물은 거의 조성하지 않는다. 우물이 조성되는 수문학적인 환경은 지하수가 모이는 자연 대수층(충적 대수층), 즉 충적지에 해당한다. 따라서 강변에 위치한 풍납토성, 공산성, 부소산성은 지하수가저장된 충적지를 포함하여 우물이 조성될 수 있다. 반면 추성산성과 같이 높은 산에 위치한 산성은 충적지가 없어 물이 지하에 모이지 않고, 산 아래로 흘러 내려간다. 따라서 높은 산에 위치한 산성은 축성 초기 우물을 조성하지 않았다. 하지만 高地의 산성에도 우물이 축성된다. 산성 안의 우물은 모두 곡부에 위치하며, 집수지를덮고있는 곡부 퇴적층을 기반으로 한다. 집수지가 복토(폐기)되면서 내부 토양에 물이 저장되어우물을 사용할 수 있는 환경으로 변모되었기 때문이다. 수문학적으로는 부유 대수층에 해당한다. 일예로 추성산성의 우물은 곡부에 위치하고, 우물 아래 토층에는 우물이 만들어지기 전에 존재하던 유구에 퇴적된 개흙층이 두껍게 확인된다. 마로산성은 백제 산성이지만 고려시대 우물이 확인되며, 우물 아래 토층에는 석축 집수정이 자리한다. 즉, 高地의 산성은 축성 초기 우물 조성환경이형성되지 않아, 지표수원을 사용하는 집수지와 저수조를 시설하였고, 곡부 내 집수지가 폐기 및퇴적된 다음에는 지하수가 모일 수 있는 환경으로 변화되어 우물을 조성하게 된 것이다. 우물이곡부가 없는 소규모 테뫼식 산성에서는 조성되지 않고, 포곡식 산성에서만 조성된 것은 이와 같은조성환경에서 비롯된 것을 알 수 있다. 한편, 축성 초기 지표수를 사용한 저수조와 집수지만으로 성 내 생활이 가능했음에도 굳이 우물을 조성한 이유는 우물의 기능에서 비롯된 것으로 확인된다. 우물은 성내에서 良質의 食水를 적은 노동력으로 공급할 수 있는 시설이다. 집수지와 같이 流水를 모으기 때문에 수질이 탁해질 위험성도 없고, 저수조와 같이 힘들여 물을 운반할 필요가 없다. 그리고 더운 계절에 지표에 노출되어 수질이 변질될 위험성이 적기 때문이다. 즉, 우물은 지하에 자연스레 물이 모이고, 대수층까지 도달하는 과정에서 여과되어 맑게 정화되며, 지표와 단절되어 저온으로 보관되면서 변질 및 오염될 가능성이 가장 적다. 따라서 우물이야말로 성곽 내 구비되는 시설가운데 가장 선호했던 용수시설이었음을 알 수 있다. 앞으로 백제산성을 포함한 고대산성에서 우물을 확인하고, 우물에 대한 발굴조사가 이루어진다면 그 아래층에이전 시기의 集水 관련 유구가 존재했는지에 대해서 명확히 확인해야 할 것이다.

Assessment of microbial quality in household water tanks in Dubai, United Arab Emirates

Munawwar Ali Khan,Asma Mohammad Abdulrahman Ahma 대한환경공학회 2017 Environmental Engineering Research Vol.22 No.1

Provision of safe, accessible, and good water quality in the community is an important step towards reducing various waterborne illnesses. However, improving the quality of water should include spreading awareness to the public regarding the importance of cleaning their household water tanks. The aim of this study was to investigate the microbial quality of water of household water tanks in Dubai. The water samples from household water tanks were collected from forty houses, and a questionnaire was given to the residents to determine the history of the water tanks. The membrane filtration technique was used to quantify heterotrophic and total coliform bacteria on plate count agar and the violet red bile agar respectively. The overall results of this study have shown that 18 out of total 40 household water tanks contained different types of bacteria concentration level beyond local and widely accepted international standards. The overall results of this study indicated that there is a lack of awareness among residents regarding the importance of maintaining proper sanitation and hygiene of the household water tanks.