본 연구에서는 인구감소에 따른 지방소멸 문제를 극복하고 물 복지 형평성 제고를 위해 충청남도의 먹는물 수질안전성 취약지역 및 소규모수도시설 현황을 조사하고, 먹는물 수질기준을 초과하는 소규모수도시설의 시⋅공간적 분포 특성을 분석하였다. 충청남도는 전체인구의 4.3%가 먹는물 수질안전성 취약지역의 소규모수도시설에서 상수도를 공급받고 있다. 충청남도 전체 소규모수도시설의 88%가 정수처리 과정이 없이 지하수를 그대로 공급하고 있으며, 정수처리공정은 막여과(역삼투), 산화흡착공정이 대부분이었고, 소독공정은 전체의 1.9%를 제외하고 자동투입기가 모두 설치되어 있는 것으로 나타났다. 충청남도 내 소규모수도시설 가운데 먹는물 수질기준(감시항목 포함)을 초과하는 시설은 전체의 7.1%를 차지하였으며, 건강상 유해영향 무기물질에 관한 기준에 속한 수질항목(불소, 비소, 질산성질소, 우라늄)이 전체의 58.3%, 미생물에 관한 기준에 속한 수질항목(일반세균, 총대장균군, 대장균/분원성 대장균군) 이 27.0%를 차지하는 것으로 나타났다. 건강상 유해영향 무기물질에 관한 기준에 속한 수질항목이 초과한 것은 변성암과 화강암이 넓게 분포하는 지질학적 특성 때문이며, 미생물에 관한 기준에 속한 수질항목이 초과한 것은 전문성이 떨어지는 주민대표 등이 대부분 소규모수도시설의 소독공정을 부적절하게 운영⋅관리하였기 때문인 것으로 판단된다.

2020년 수도시설 내에서 깔따구 유충이 발견된 사건 이후, 정수처리시설 내 유충 발생 문제는 국내에서 주요한 사회⋅환경적 이슈로 부상하였다. 본 연구는 깔따구과(Chironomidae)의 생태적 특성과 생활사를 바탕으로 국내 정수장 내 유충 발생 현황과 발생 원인을 종합적으로 분석하고, 모니터링 체계 및 대응 기술을 고찰하였다. 분석 결과, 유충 발생은 활성탄 여과지와 여과 공정을 중심으로 보고되었으며, 개방형 구조, 생물막 및 조류 축적, 여재 노후화, 역세척 효율 저하, 수온 및 유기물 증가 등 구조적⋅환경적⋅운영 요인이 복합적으로 작용하는 것으로 나타났다. 기존의 물리적⋅구조적 조치만으로는 발생 억제에 한계가 있어, 화학적 방제를 병행한 관리 전략의 필요성이 확인되었다. 특히 염소계 소독제 중심의 기존 수처리 체계와 더불어, 이산화염소(ClO2)와 같은 대체 소독제를 보조적으로 활용하는 접근이 검토될 수 있다. 본 연구는 생물학적 모니터링을 통한 조기 진단, 시설 및 공정 개선을 통한 산란⋅유입 차단, 기존 수처리제와 대체 소독제를 포함한 화학적 방제를 결합한 통합적 해충관리(IPM) 체계 구축이 정수장 운영 안정성과 수돗물 안전성 향상에 기여할 수 있음을 제시한다.

과불화화합물은 소수성, 소유성, 내열성의 우수한 물성을 기반으로 다양한 산업군에 활용되어 왔으나, 환경 내 잔류성과 생체 독성으로 인해 음용수를 통한 인체 노출이 중요한 공중보건 문제로 대두되고 있다. 본 연구는 음용수 내 과불화화합물 규제의 국제적 규제 동향을 분석하고, 규제 설정 원리와 과학적 배경을 고찰하는 데 목적을 둔다. 먼저 미국, 유럽연합 등 주요 국가의 음용수 내 과불화화합물 규제 현황을 비교하고, 각국이 채택한 규제 대상 물질, 설정 농도, 그리고 기저 규제 철학을 분석하였다. 특히 본 연구에서는 미국의 독성 및 위해성 기반 과학적 규제 체계를 근거로, 과불화화합물의 독성참고치(RfD) 및 발암계수(CSF)가 어떻게 도출되고 규제 기준으로 변환되는지 단계적으로 설명하였다. 또한, 개별 과불화화합물의 위해성을 넘어서, 혼합된 과불화화합물의 누적 위해성(HI) 산정 방식의 과학적 배경을 함께 살펴보았다. 이러한 국제적 규제 진전에도 불구하고, 현재 우리나라의 경우 3종 과불화화합물만 수질감시항목으로 지정되어 있을 뿐, 인체 위해성에 기반한 법적 수질기준은 마련되지 않은 실정이다. 또한, 현재의 국내 감시체계에서는 다종 과불화화합물의 혼합 노출로 인한 누적 위해성을 평가하지 못하는 구조적 한계가 있다. 이에 본 논문은 국제적인 규제 동향과 과학적 기준 설정 원리를 종합적으로 분석하고, 주요 국가의 모범사례를 바탕으로 국내 과불화화합물 음용수 규제 체계의 발전을 위한 시사점을 제시하였다.

From 2020, Korean Animal and Plant Quarantine Agency has reset the withdrawal time (WT) for veterinary drugs typically used in livestock in preparation for the introduction of positive list system (PLS) program in 2024. This study was conducted to reset the MRL for tiamulin (TML) in broiler chickens as a part of PLS program introduction. Forty-eight healthy Ross broiler chickens were orally administered with TML at the concentration of 25 g/L (TML-1, n=24) and 50 g/L (TML-2, n=24) for 5 days through drinking water, respectively. After the drug treatment, tissue samples were collected from six broiler chickens at 1, 2, 3 and 5 days, respectively. According to the previously established analysis method, residual TML concentrations in poultry tissues were determined using LC-MS/MS. In TML-1, TML in all tissues was detected less than LOQ at 2 days after drug treatment. In TML-2, TML in liver and kidney was detected more than LOQ at 2 days after treatment. According to the European Medicines Agency’s guideline on determination of withdrawal periods, withdrawal periods of TML-1 and TML-2 in poultry tissues were established to 0 and 2 days, respectively. In conclusion, the estimated WT of TML in poultry tissues is shorter than the current WT recommendation of 5 days for TML in broiler chickens.

Organoleptic parameters such as color, odor, and flavor influence consumer perception of drinking water quality. This study aims to evaluate the taste of the selected bottled and tap water samples using an electronic tongue (E-tongue) instead of a sensory test. Bottled and tap water's mineral components are related to the overall preference for water taste. Contrary to the sensory test, the potentiometric E-tongue method presented in this study distinguishes taste by measuring the mineral components in water, and the data obtained can be statistically analyzed. Eleven bottled water products from various brands and one tap water from I city in Korea were evaluated. The E-tongue data were statistically analyzed using multivariate statistical tools such as hierarchical clustering analysis (HCA), principal component analysis (PCA), and partial least squares discriminant analysis (PLS-DA). The results show that the E-tongue method can clearly distinguish taste discrimination in drinking water differing in water quality based on the ion-related water quality parameters. The water quality parameters that affect taste discrimination were found to be total dissolved solids (TDS), sodium (Na+), calcium (Ca2+), magnesium (Mg2+), sulfate (SO4 2-), chloride (Cl-), potassium (K+) and pH. The distance calculation of HCA was used to quantify the differences between 12 different types of drinking water. The proposed E-tongue method is a practical tool to quantitatively evaluate the differences between samples in water quality items related to the ionic components. It can be helpful in quality control of drinking water.

This study investigated ethopabate (EPB) residues in edible tissues of broiler chickens given in drinking water and established the withdrawal time (WT) of EPB in poultry tissues. Twenty-four healthy Ross broiler chickens were orally administered with EPB at the concentration of 3.8 mg/L for 14 days (EPB-1, n=24) and 15.2 mg/L for 7 days (EPB-2, n=24) through drinking water, respectively. After the drug treatment, tissue samples were collected from six broiler chickens at 0, 1, 3, and 5 days, respectively. EPB residue concentrations in poultry tissues were determined using LC-MS/MS. Correlation coefficient values ranged from 0.9980 to 0.9998, and the limits of detection and quantification (LOQ) were 0.03~0.09 and 0.1~0.3 μg/kg, respectively. Mean recoveries in muscle, liver, kidney and skin/fat tissues were 95.9~109.8, 108.7~115.3, 89.9~96.6 and 86.7~96.8%, respectively, and coefficient of variations were less than 17.11%. At the end of the drug-administration period (0 day), EPB was detected at levels under the LOQ in all tissues from both the EPB-1 and EPB-2 groups. According to the results of EPB residue in Ross broiler tissues, withdrawal periods of both EPB-1 and EPB-2 in poultry tissues were established to 0 day. In conclusion, the developed analytical method is suitable for the detection of EPB in poultry tissues, and the estimated WT of EPB in poultry tissues will contribute to ensuring the safety of Ross broiler chickens.

From 2020, Korean Animal and Plant Quarantine Agency has reset the withdrawal time (WT) for veterinary drugs typically used in livestock in preparation for the introduction of positive list system (PLS) program in 2024. This study was conducted to reset the MRL for amprolium (APL) in broiler chickens as a part of PLS program introduction. Forty-eight healthy Ross broiler chickens were orally administered with APL at the concentration of 60 mg/L (APL-1, n=24) for 14 days and 240 mg/L (APL-2, n=24) for 7 days through drinking water, respectively. After the drug treatment, tissue samples were collected from six broiler chickens at 0, 1, 3 and 5 days, respectively. Residual APL concentrations in poultry tissues were determined using LC-MS/MS. Correlation coefficient (0.99 >), the limits quantification (LOQ, 0.3~5.0 μg/kg), recoveries (81.5~112.4%), and coefficient of variations (<15.5%) were satisfied the validation criteria of Korean Ministry of Food and Drug Safety. In APL-1, APL in all tissues except for kidney was detected less than LOQ at 3 days after drug treatment. In APL-2, APL in liver and kidney was detected more than LOQ at 5 days after treatment. According to the European Medicines Agency’s guideline on determination of withdrawal periods, withdrawal periods of APL-1 and APL-2 in poultry tissues were established to 3 and 2 days, respectively. In conclusion, the developed analytical method is sensitive and reliable for detecting APL in poultry tissues. The estimated WT of APL in poultry tissues is longer than the current WT recommendation of 2 days for APL in broiler chickens.

The emergence of micropollutants in natural water sources due to the overuse of anthropogenic chemicals in industry and households has threatened the production of clean and safe tap water in drinking water treatment plants. Conventional physicochemical processes such as coagulation/flocculation followed by sand filtration are not effective for the control of micropollutants, whereas chemical oxidation processes (applying chlorine, permanganate, ozone, etc.) are known to be promising alternatives. Determining the optimum oxidant dose is important issue related to the production of disinfection by-products as well as unnecessary operating cost, and is made possible by simulations of target-micropollutant abatement based on kinetic model equation consisting of second-order rate constant (between the oxidant and the target) and oxidant exposure. However, the difficulty in determining oxidant exposure as a function of complex water quality parameters limits the field application of kinetic model equation. With respect to representative oxidants used in drinking water treatment plants, this article reviews two main approaches for determining oxidant exposure: i) direct measurement in situ and ii) prediction by empirical models based on key water quality parameters. In addition, we discussed research requirements to improve the predictive accuracy of the empirical models for oxidant exposure and to develop a rational algorithm to determine optimal oxidant dose by considering the priority of the target pollutants to be treated.

국내 Y정수처리시설에 20-40 m3/m2/h의 표면부하율을 갖는 고속 용존공기부상공정을 도입하였다. 우선, 용존공기부상공정과 입상활성탄 공정이 결합된 반응기를 일처리용량 500 m3/day의 조건으로 운전하였다. 운전결과는 두 공정이 원수내 탁도, 조류, 지오스민, 2-MIB를 감소시킬 수 있음을 증명하였다. 도출된 최적 설계요소를 활용하여 현장규모의 공정(5,000 m3/day)에 용존공기부상공정을 도입하였다. 여름철 56일간 조류와 탁도 제거율을 평가하였다. 처리수 내 조류의 개체수는 20-30 cells/mL 이하로 유지되었으며, 조류 제거효율은 80-89%를 기록하였다. 침전법 및 용존공기부상공정 처리수질의 탁도 제거효율을 비교한 결과 평균 탁도 제거효율은 77%를 나타냈다. 이러한 결과들은 고속 용존공기부상공정이 여름철 음용수의 탁도 및 조류와 같은 저밀도 고형물을 제거하는데 유의미한 방법임을 나타냈으며, GAC는 맛･냄새를 유발하는 화합물(지오스민, 2-MIB)를 제거할 수 있는 공정 옵션인 것을 확인하였다.

Most of the drinking water dams managed by the local governments in Korea are earthfill dams, and these dams have almost no geotechnical property information necessary for seismic performance evaluation. Nevertheless, in the rough planning stage for improving seismic safety for these dams, it is necessary to classify their relative seismic hazard against earthquakes and conduct an additional ground investigation. The zero seismic failure probability curve is a curve suggested in this study in which the probability of failure due to an earthquake becomes ‘0’ regardless of the geotechnical properties of the earthfill dam. By examining the method and procedure for calculating failure probability due to an earthquake suggested in previous researches, the zero seismic failure probability curves for an earthquake in 1,000-year and 2,400-year return periods in Korea were presented in the form of a hyperbola on the plane of the dam height versus freeboard ratio (ratio of freeboard to dam height), respectively. The distribution characteristics of the dam height and the freeboard ratio of 81 Korean earthfill dams were presented. The two proposed zero seismic failure probability curves are shown on the plane of the dam height versus freeboard ratio, and the relative seismic hazard of 81 dams can be classified into three groups using these curves as boundaries. This study presented the method of classifying the relative seismic hazard and the classification result.

Water treatment process simulator is the tool for predicting sequential changes of water quality in a train of unit processes. This predicts the changes through governing equations that represent physicochemical performance of each unit processes with an initial and boundary conditions. Since there is no operational data for the design of a water treatment facility, there is no choice but to predict the performance of the facility by assuming initial and boundary conditions in virtual reality. Therefore, a simulator that can be applied in the design stage of a water treatment facility has no choice but to be built as a numerical analysis model of a deductive technique. In this study, we had conducted basic research on governing equations, inter-process data-flow, and simulator algorithms for the development of simulators. Lastly, this study will contribute to design engineering tool development research in the future by establishing the water treatment theory so that it can be programmed in a virtual world and suggesting a method for digital transformation of the water treatment process.

Microplastics have become a rising issue in due to its detection in oceans, rivers, and tap water. Although a large number of studies have been conducted on the detection and quantification in various water bodies, the number of research conducted on the removal and treatment of microplastics are still comparatively low. In the current research, the inflow and removal of microplastics were investigated for various drinking water treatment plants around the world. Addition to the investigation of filed research, a survey was also conducted on the current research trend on microplastic removal for different treatment processes in the drinking water treatment plants. This includes the researches conducted on coagulation/flocculation, sedimentation, dissolved air flotation, sand filtration and disinfection processes. The survey indicated mechanisms of microplastic removal in each process followed by the removal characteristics under various conditions. Limitations of current researches were also mentioned, regarding the gap between the laboratory experimental conditions and field conditions of drinking water treatment plants. We hope that the current review will aid in the understanding of current research needs in the field of microplastic removal in drinking water treatment.

This study is focused on effects of factors that affect the formation of THMs during chlorination in drinking water treatment. During the chlorination, chlorine consumption is increased by increasing the initial chlorine dose, the pH and the total dissolved solid (TDS) concentration. Also THMs formation is increased up to 58.82 μg/L and 55.54 μg/L by increasing initial chlorine concentration and increasing pH. However, concentration of chloroform is decreased by increasing TDS concentration. This is caused the cation(Na+) of the total dissolved solids preferentially reacts with the functional groups of the organic material which influence the trihalomethane formation. But total trihalomethane formation is increased up to 127.46 μg/L by Br- contained in the total dissolved solids. DOC reduction was not influenced by any of the factors.

본 연구는 국내의 고온다습한 하절기에 산란계에 음용수 온도가 생산성, 호르몬 농도 및 혈액성상에 미치는 영향을 구명하고자 실행하였다. 52주령 하이라인 갈색종 산란계 432수를 3개 처리구와 8반복으로 반복당 18수씩 케이지 사육장(550 cm2/수)에 배치하였고, 처리구별로 14.5, 24.0 및 32.5℃의 음용 수를 4주간 급수하였다. 산란계의 생산성은 산란율과 난중을 매일 조사하여 계산하였고, 호르몬, 혈액 성상 및 계란품질은 사양실험 종료 후 채집하여 분석하였다. 본 연구결과 산란율과 1일 산란양은 14.5℃ 의 급수구에서 유의적으로 개선되었고(p<0.05), 사료섭취량과 난중은 14.5와 24.0℃ 급수구에서 32.5℃ 에 비하여 현저히 증가하였다(p<0.05). 계란의 난백높이와 호우유닛은 음용수 온도에 따른 처리구간 통계적 차이가 없었다. 난각강도는 14.5℃ 급수 처리구에서 증가하였고(p<0.05) 난각두께도 개선되는 경향을 보였지만 처리구간에 통계적 차이는 없었다. 또한 혈청과 간의 GH와 IGF-I 농도는 32.5, 24.0 및 14.5℃ 급여구 순서로 증가하였고(p<0.05), 코티코스테론은 감소되었는데 14.5℃에서 가장 개선되었다(p<0.05). 이외에도 혈중 AST와 콜레스테롤은 14.5℃의 음용수 처리구에서 24.0과 32.5℃에 비하여 유의적으로 감소하였고(p<0.05), HDL콜레스테롤, 단백질 및 글루코오스는 처리구간에 통계적 차이가 없 었지만, 혈중 중성지방은 14.5℃처리구에서 현저하게 감소되었다(p<0.05). 그러므로 여름철 14.5℃의 음용수를 급여하면 산란계에서 고온스트레스를 저감하므로서 생산성, 계란품질 및 혈액성상을 개선하였다.

The drinking water supply system applicable to the laying hen consists of air-water heat pumps, drinking water tanks, heat stroage tank, circulation pumps, PE pipes, nipples, and control panels. When the heat pump system has power of 7.7 to 8.7 kW per hour, the performance coefficient is between 3.1 and 3.5. The supply temperature from the heat pump to the heat stroage tank was stabilized at about 12±1°C, but the return temperature showed a variation of from 8 to 14°C. Stratified temperature in the storage tank appeared at 12.°C, 13.5°C and 14.4°C, respectively. The drinking water supply temperature remained set at 15°C and 25°C, and the conventional tap water showed a variation for 23°C to 30°C. As chickens grow older, the amount of food intake and drinking water increased. y = -0.0563x2 + 4.7383x + 8.743, R2 = 0.98 and the feed intake showed y = -0.1013x2 + 8.5611x. In the future, further studies will need to figure out the cooling effect on heat stress of livestock.

A Gravity-driven membrane (GDM) system is one of the promising solutions for household drinking water treatment in the developing countries. In this study, the GDM system was tested for optimizing manual cleaning protocols using three different feed water solutions. Two types of manual cleaning were performed to delay the permeability decrease, cleaning between batches and long-term cleaning. The optimized cleaning between batches protocol was 3 twisting and 10 vertical shaking. And the optimized long-term cleaning protocol was 70 vertical shaking for both the middle region of the module and near the header part. These cleaning protocols allowed the system to produce sufficient water to meet the daily minimum water requirements for a 5-person family, even for using the wastewater influent. The system produced Escherichia coli free water.