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.

In light of recent social concerns related to issues such as water supply pipe deterioration leading to problems like leaks and degraded water quality, the significance of maintenance efforts to enhance water source quality and ensure a stable water supply has grown substantially. In this study, scan statistic was applied to analyze water quality complaints and water leakage accidents from 2015 to 2021 to present a reasonable method to identify areas requiring improvement in water management. SaTScan, a spatio-temporal statistical analysis program, and ArcGIS were used for spatial information analysis, and clusters with high relative risk (RR) were determined using the maximum log-likelihood ratio, relative risk, and Monte Carlo hypothesis test for I city, the target area. Specifically, in the case of water quality complaints, the analysis results were compared by distinguishing cases occurring before and after the onset of "red water." The period between 2015 and 2019 revealed that preceding the occurrence of red water, the leak cluster at location L2 posed a significantly higher risk (RR: 2.45) than other regions. As for water quality complaints, cluster C2 exhibited a notably elevated RR (RR: 2.21) and appeared concentrated in areas D and S, respectively. On the other hand, post-red water incidents of water quality complaints were predominantly concentrated in area S. The analysis found that the locations of complaint clusters were similar to those of red water incidents. Of these, cluster C7 exhibited a substantial RR of 4.58, signifying more than a twofold increase compared to pre-incident levels. A kernel density map analysis was performed using GIS to identify priority areas for waterworks management based on the central location of clusters and complaint cluster RR data.

Purpose: The purpose of this study was to understand the forest healing instructor's experiences of providing a forest healing program. Methods: The participants were 12 forest healing instructors who experienced managing a forest healing program at B mountain in C city. Data were collected using focus group interviews and individual in depth interviews and data were analyzed using qualitative content analysis method. Results: As the results of this study, 5 themes and 18 sub-themes were derived. The derived 5 themes were as follows; 1. Choosing a new path as a turning point in life 2. Ambiguity as a new forest healing instructor, 3. Feeling a reward as a forest healing instructor and feeling self-healing. 4. Facing difficulties in operating forest healing programs, 5. Having on-going tasks for the establishment of forest healing programs. Conclusion: In order to provide good forest healing program, we need to develop additional education programs for enhancing professionality as a forest healing instructor and continous long term economical supports and investment for forest healing instructors by the Korea Forest Service.

The purpose of this study is to evaluate the fixed wing type domestic UAV for monitoring of algae bloom in aquatic environment. The UAV used in this study is operated automatically in-flight using an automatic navigation device, and flies along a path targeting preconfigured GPS coordinates of desired measurement sites input by a flight path controller. The sensors used in this study were Sequoia multi-spectral cameras. The photographed images were processed using orthomosaics, georeferenced digital surface models, and 3D mapping software such as Pix4D. In this study, NDVI(Normalized distribution vegetation index) was used for estimating the concentration of chlorophyll-a in river. Based on the NDVI analysis, the distribution areas of chlorophyll-a could be analyzed. The UAV image was compared with a airborne image at a similar time and place. UAV images were found to be effective for monitoring of chlorophyll-a in river.

Scale formation is inevitable problem when seawater is treated by vacuum membrane distillation. The reason is the high concentration of calcium ion(Ca2+), sulfate ion(SO4 2-) and bicarbonate ion(HCO3 -). These ions form calcium sulfate(CaSO4) and calcium carbonate(CaCO3) on the membrane. The scale formed on membrane has to be removed, because the flux can be severely reduced and membrane wetting can be incurred. This study was carried out to investigate scale formation and effectiveness of acid cleaning in vacuum membrane distillation for SWRO brine treatment. It was found that permeate flux gradually declined until volume concentration factor(VCF) reached around 1.55 and membrane wetting started over VCF over 1.6 in the formation of precipitates containing CaSO4 during VMD operation. In contrast, when calcium carbonate formed on membrane, permeate flux was gradually reduced until VCF 3.0. The precipitates containing both CaSO4 and CaCO3 were formed on the membrane surface and in the membrane pore.

This study was carried out to apply the UAV(Unmanned Aerial Vehicle) coupled with Multispectral sensor for the algae bloom monitoring in river. The study acquired remote sensing data using UAV on the midstream area of Gum River, one of four major rivers in South Korea. Normalized difference vegetation index (NDVI) is used for monitoring algae change. This study conducted water sampling and analysis in the field for correlating with NDVI values. Among the samples analyzed, the chlorophyll concentration exhibited strong and significant linear relationships with NDVI, and thus NDVI was chosen for algae bloom index to identify emergence aspect of phytoplankton in river. Aerial remote sensing technology can provide more accurate, flexible, cheaper, and faster monitoring methods of detecting and predicting eutrophication and therefore cyanobacteria bloom in water reservoirs compared to currently used technology. As a result, there was high level of correlation in chlorophyll-a and NDVI. It is expected that when this remote water quality and pollution monitoring technology is applied in the field, it would be able to improve capabilities to deal with the river water quality and pollution at the early stage.

The UV/chlorine process is a UV-based advanced oxidation process for removing various organic pollutants in water. The process is becoming increasingly popular because of its effectiveness in practice. It is important to the safe and efficient operation of a UV/chlorine process that the optimal operating conditions for both target removal objective and saving energy are determined. Treatment efficiency of target compounds in UV/chlorine process was mainly affected by pH and scavenging factor. In this study, kinetic based mathematical model considering water characteristics and electrical energy dose calculations model was developed to predict of treatment efficiency and optimal operating conditions. The model equation was validated for the UV/chlorine process at the laboratory scale and in pilot tests at water treatment plants.

Pressure retarded osmosis (PRO) processes can be implemented on a number of water types, using different technologies and achieving various power outcomes. In this study, Sewage facility effluent was used for feed solution of PRO and synthetic NaCl water for draw solution. This study was conducted to investigate effect of water quality of pretreatment on power density and flux decline in PRO process. The results show that organic and particulate foulants have to be removed for more stable operation. Flourescence technique with EEM enables to investigate the chemical properties of aquatic organic matter by extracting spectral information. Humic/fulvic matters and soluble microbial by-products were analyzed as the most affecting factors on the PRO performance. As a result of analyzing the whole system based on the energy consumption of the unit process, specific energy consumption(SEC) of the applicable technology for PRO pre-treatment should be about 0.2 kWh/m3 or less.

선박에 주로 사용되는 기존 해수담수화 공정의 경우 많은 에너지가 소모 된다는 단점이 있다. 막증발법(MD)은 유입수의 삼투압으로 인한 구동력의 저하가 역삼투공정에 비해서 낮은 장점을 가지며, 비교적 낮은 온도(60 ∼ 80℃)에서 운전 가능하기 때문에 선박의 엔진 폐열, 해수열원 등을 활용하여 운전 비용을 절감할 수 있다. 본 연구에서는 실험실 규모의 진공식 막증발 장치에서 도출된 조건을 바탕으로 3 m3/일 규모의 실제 VMD 파일럿플랜트를 설계 및 제작하여 성능을 평가하였다. 운전결과, 3～5 L/㎡-hr의 플럭스와 99.99%의 염제거율을 나타냈다.

The Pressure Retarded Osmosis (PRO) is the next generation desalination technique and is considered as a eco-friendly energy. This was conducted to evaluate the effect of the temperature and pressure on the PRO performance. The flux of the permeation was measured under different operating conditions and estimated the power density. An improvement of PRO performance is depend on increasing solution temperature and optimum pressure. The effect of increasing feed solution temperature has stronger impact on the PRO performance comparing to the draw solution temperature. The reason of the results was due to the change of osmotic power, viscosity, water permeability and structure parameter(s).

본 연구는 SWRO/PRO 조합공정에서 PRO 공정 유입수로써 적합한 유입수질 조건과 전처리 기술을 알아보고자 하였다. 실험에 사용된 유입수로는 P시의 하수처리장 방류수를 사용하였으며, 유도용매는 역삼투막 농축수를 활용하였고, 이때 사용한 PRO막은 Toray사의 CTA재질막을 사용하였다. 본 연구에서 응집-침전, 모래여과, DMF, 활성탄여과, 정밀여과공정, 역삼투공정 등 총 6가지 전처리공정을 선정하여 평가하였고, PRO 공정 성능에 영향을 크게 주는 것으로 확인하였다. 향후 SWRO/PRO 조합공정에서 안정적인 에너지 절감 효과를 기대할 수 있는 최적 공정을 도출할 계획이다.