정수기는 일반적인 산업용 막여과 수처리 공정과 다르게 운전과 휴지를 반복하는 특성이 있다. 이러한 특징 때문 에 역삼투막을 사용하는 정수기의 경우, 재정수시에 정수수의 농도가 정상적인 값보다 높게 나오는 현상(제거율이 정상값보 다 낮게 나오는 현상)이 있는데, 이를 “TDS creep”이라고 한다. 본 연구에서는 휴지시간과 농도에 따른 TDS creep 정도를 관 찰하였다. 또한, TDS creep 현상을 저감하기 위해 원수 세척, 정수부의 부피 증가 및 정수 세척 방법 등을 시험하였고 이에 대한 실질적인 효과를 관찰하였다. 이러한 방법들 중에 정수수의 세척과 같이 역삼투막의 feed side와 permeate side의 농도차 를 최소화하는 것이 TDS creep 현상을 해소하는 궁극적인 해결책임을 확인하였다.

The point-of-use water dispenser systems are widely used because of convenience in handling and demand for high-quality drinking water. The application has been increased recently in the public places such as department stores, universities and the rest areas in express ways. Improvement of water qualities by the dispenser systems was compared with tap water in this study. The tap water is supplied to the dispenser as the influent of the dispenser system. The twelve dispensers in the public places were used. The five dispensers used reverse osmosis as the main filter and other dispensers used various filters such as ultrafiltration, nanofiltration, and alumina filter. The water quality indicators for sanitation safety, i.e., turbidity and total coliforms, were evaluated. Other water qualities such as pH, residual chlorine, heterotrophic plate count (HPC), and total cell counts were also analyzed. By the point-of-use water dispenser, the turbidity, residual chlorine and pH were decreased and the HPC and total cell counts were increased. The t-test results revealed that the HPC of the tap waters were not significantly different from the treated waters but the total cell counts of the two groups were significantly different. The low pH of the RO filter treatment was also significantly different from the tap waters. This study will contribute to understand the role of the point-of-use water dispenser in improving water quality and to identify key water quality for the proper maintenance of the dispenser systems.

본 연구에서는 사용 후 폐기되는 정수기용 역삼투(Reverse Osmosis; RO)막 필터를 세정하여 새 필터의 수준으로 복원시키는 연구를 수행하였다. 화학적 세정액으로는 수산화나트륨, 중아황산나트륨, EDTA용액을 사용하였으며 마이크로버 블 발생 장치와 함께 in-situ의 방법으로 세정하였다. EDTA를 0.1%의 농도로 제조한 뒤 마이크로버블과 함께 사용하여 30분 세정하였을 때 가장 좋은 결과를 나타내었다. 이때 폐 필터와 세정 후 폐필터의 성능을 비교해 보았을 때 투과도는 19.9%, 회수율은 49.5%증가하였으며 NaCl 100 mg/L 용액에 대한 염제거율은 2.3% 감소되었는데, 이는 새 필터와 동등한 수준으로 회복이 되었다. 또한 전자현미경 분석을 이용하여 막 표면의 오염물의 제거를 육안으로 확인하였다. 이로써 전량 매립 또는 소각 되어지는 정수기용 폐 RO막 필터의 세정을 통하여 재사용이 가능할 것으로 판단된다.

NSF developed NSF p477, which covers POU active media systems. Exact types and quantities of cyanotoxins vary. In 2015 USEPA set recommended health advisories for microcystins in drinking water at or below 0.3 μg/L for children less than 6 years old, and at or below 1.6 μg/L for older children and adults. NSF developed and characterized a natural source for microcystin compounds to be used as a contaminant challenge for the POU active media systems being tested. Analytical methodologies were refined to reliably identify and quantify microcystin at levels in the sub part per billion range. Laboratory column studies using various activated carbons were conducted to determine the relative retention of various microcystin congeners, to assess the appropriateness of various congeners for testing purposes.

요즘 IoT (Internet of things)에 대한 기술개발은 사업 전반에 걸쳐 이루어지고 있으며, 이에 따른 Big Data 분석으로 다양한 제품과 서비스가 만들어 지고 있다. 정수기를 사용함에 있어 과연 소비자는 어떠한 형태로 사용하고 있을까? 또한 정수기를 구성하고 있는 부품들은 어떻게 동작하고 있을까? 이러한 사항들을 측정하고 실사용 데이터를 수집 분석하기 위해 패널을 구축했고 가정집과 다중이용시설에 대해 각각 1년간 측정 분석하여 정수기 사용 패턴을 모니터링 하였다. 본 연구는 사용자의 사용하는 시간대와 장소, 온도와 습도, 사용자 특성 (자녀연령, 직업, 연령대, 수입) 등에 따라 나타나는 패턴을 분석하였다.

본 연구에서는 현재 전량 폐기되는 정수기용 폐 필터를 재활용하고자 폐 필터의 오염도 및 성능을 평가하였다. 성능 평가를 위해 실제 정수기에서 사용 후 폐기되는 RO 멤브레인 필터(도레이 케미칼에서 제조)를 회수하여 flux 및 rejection 을 측정하였고, 대조군으로써 새 필터도 같은 조건으로 실험을 진행하였다. 또한 주사전자현미경(SEM), 감쇠전반사-푸리에변환 적외선 분광기(ATR-FTIR), X선 광전자 분광기(XPS)를 이용하여 폐 필터의 표면 오염도를 분석하였다. 이를 통해 폐 필터 표면에 막 오염(fouling)의 요인과 정도를 확인하였고 이러한 분석 결과를 바탕으로, 폐 분리막 모듈의 재활용 및 복원 기술 연구를 통한 순환 활용 기술을 확보하고자 한다.

Development of the economy and the growing income of people interested in the leisure and health has been focused. Past the town common wells and groundwater around the water, but health is a priority these days to solve the drinking water directly from tap water, but most people work from home, through the water purifier has been resolved. Depending on seasonal changes and personal taste of coffee, if you can enjoy a snack and water purifier is a restaurant, lounge, public areas and focusing on the rapid spread of the fire, water purifier as compared to the total number of fires increased by 0.03% per year trend on, but the washrooms fire and fire-related research data and case studies with analysis of the exact cause lack of proper preventive measures are insufficient reality. In this study, focusing on electrical energy using a water cooler to understand the structure and principles of fire, the fire revealed the mechanism is vulnerable to the consideration of factors, the exact cause of the fire investigation and the Assistant, manufacturing defects, and to contribute to fire prevention review should.

A water purifiers for home-use has been popularly used as increasing distrust of the drinking tap water in views of safety. Besides, chlorination of drinking water can produce trihalomethanes known as a carcinogens. In general, a water purifier is known to remove risk factors such as infectious microorganisms, harmful chemicals and heavy metals. We compared the change of water components before and after purification by a water purifier and evaluated the results whether this purification system is reliable or not for safety of drinking water. The samples of water from 11 sites at the campus of Jeju National University were examined by physicochemical analyses, including concentration of sodium, potassium, chloride, residual chlorine, boron, nitrate nitrogen, sulfur, hexavalent chromium, copper, iron, aluminium, silicon, selenium, vanadium, manganese, molybdenum, nickel, arsenic, antimony, zinc, cadmium, lead, strontium. Microbiological analysis was performed by counting mesophilic bacterial colonies. Almost of all the physicochemical components after purification were shown to decrease tendency of their concentrations but not significantly differenty except that of residual chlorine. Mesophilic bacterial counts after purification were shown to increase when compared to those of tap water. All the tap water was met the acceptance of requirement of drinking water, but samples of the water after purification were failed (4 from 11). After draining generous amount of water from a purifier, bacterial counts were observed to show a decreased tendency. Bacterial colonies were not detected when the concentration of residual chlorine was higher than 0.2 ppm. Although seasonal factors and maintenance condition were not concerned in this study, higher bacterial counts in purified water could cause some problems in using water purifier for home-use. Considering the results obtained, regular maintenance and care including filter change and sterilizing the reservoir are absolutely required. A further study is required to examine where the bacteria are coming from.

This study characterized water quality of groundwater and purified water used for drinking water in 30 schools in Gyeongsangbukdo Province. The results of the study showed that 43% of groundwater and 45% of purified water were not suitable for drinking. Among them, microbial contaminations were the most serious problem. In raw groundwater, the exceeding rates of total colony counts was the highest in August (53.6%). Purified water samples showed higher rate of exceeding drinking water standard for total colony counts while showing lower rate of exceeding drinking water standard for total coliforms and fecal coliforms in March and August. Overall, proper managements for microbial contaminations are required for both groundwater and purified water. Furthermore, special attention should toward students not to drink water when groundwater or purified water exceeds the drinking water quality standard.

Quality test for activated carbon(AC) filter used for drinking water purifier is now an obligatory test and the standard material for valid purifying amount in water purifier performance test has been changed from residual chlorine to chloroform according to the notice of Ministry of Environment in 2006. Therefore, this study aimed to compare the ingredients of AC filters by confirming chloroform removal rate of AC filter and conducting 4 adsorption tests (Iodine, methylene blue decolorization, phenol value, ABS value) for AC filters provided by manufacturers. With water pressure of 1 kgf/cm2, 1,500 liters of prepared inflow went through to check chloroform removal rate. As a result, product with removal rate of below 60% from all products. On the other hand, 4 adsorption tests were conducted for filters in the market and filters from manufacturers. None of the products satisfied all 4 tests. In particular, they showed great shortage to the standard in phenol value and ABS value test. However, manufacturers' filter showed much better performance than filters in the market. Also, the result of valid purifying amount test for each of five products of appropriate product and inappropriate product based on filter quality test showed average 4,440 liters for appropriate product and average 2,620 liters for inappropriate product. According to the result, it is shown that the filter with good adsorption also had good chloroform removal efficiency and adsorption efficiency. Therefore, it is expected that customers can screen good quality product through obligatory conduct of filter quality test. However, it is considered that complementation in system is required for future inspection.

Antimicrobial powder was made by exchanging silver ion on calcined oyster shell. On the purpose of application to water clarifier, ball-type media mixed with antimicrobial powder and 0∼30% white kaoline were made. The sterilization effect, pore size distribution and zeta potential was tested to indicate the condition for the media of water clarifier. From these tests, it was confirmed that this media have an excellent sterilization power on G- and G+ germs. As the concentration of the exchanged silver ion increased, the surface charge density of the anions on the surface of the media also increased. The surface pore size decreased with the concentration of silver ion and 20% more white kaoline ratio.Consequently, mixing ratio of white kaoline would appear to indicate the optimun condition as media have sterilization power.