• Parasites, Hosts and Diseases
• /
• 제56권2호
• /
• pp.205-210
• /
• 2018

Waterborne parasitic protozoa, particularly Giardia lamblia and Cryptosporidium spp., are common causes of diarrhea and gastroenteritis worldwide. The most frequently identified source of infestation is water, and exposure involves either drinking water or recreation in swimming pools or natural bodies of water. In practice, studies on Cryptosporidium oocysts and Giardia cysts in surface water are challenging owing to the low concentrations of these microorganisms because of dilution. In this study, a 3-year monitoring of Cryptosporidium parvum, Giardia lamblia, and Naegleria fowleri was conducted from August 2014 to June 2016 at 5 surface water sites including 2 lakes, 1 river, and 2 water intake plants. A total of 50 water samples of 40 L were examined. Cryptosporidium oocysts were detected in 22% of samples and Giardia cysts in 32%. Water at the 5 sampling sites was all contaminated with Cryptosporidium oocysts (0-36/L), Giardia cysts (0-39/L), or both. The geometric mean concentrations of Cryptosporidium and Giardia were 1.14 oocysts/L and 4.62 cysts/L, respectively. Thus, effective monitoring plans must take into account the spatial and temporal parameters of contamination because they affect the prevalence and distribution of these protozoan cysts in local water resources.

• 한국물환경학회지
• /
• 제33권3호
• /
• pp.282-290
• /
• 2017

A long-term resuspension of small particles, called persistent turbidity, is one of the most important water quality concerns in the dam reservoirs system located in North Han River. Persistent turbidity may incur aesthetic nuisance and harmful effect on the ecosystem health, in addition to elevated water treatment costs for the drinking water supply to the Seoul metropolitan area. These sufferings have been more intensified as the strength and frequency of rainfall events increase by climate change in the basin. This study was to analyze the effect of an extreme turbidity flow event that occurred in 2006 on the serial reservoirs system (Soyang-Uiam-Cheongpyung-Paldang) in North Han River. The CE-QUAL-W2 model was set up and calibrated for the river and reservoirs system using the field data obtained in 2006 and 2007. The results showed that Soyang Reservoir released turbid water, which was classified as the TSS concentration is greater than 25 mg/L, for 334 days with peak TSS of 264.1 mg/L after the extreme flood event (592.7 mm) occurred between July 10 and 18 of 2006. The turbid water departed from Soyang Reservoir reached at the most downstream Paldang Reservoir after about 20 days and sustained for 41 days, which was validated with water treatment plant data. Since the released water from Soyang Reservoir had low water temperature and high TSS, an underflow formed in the downstream reservoirs and vertically mixed at Paldang Reservoir due to dilution by the sufficient inflow from South Han River.

• 한국수자원학회논문집
• /
• 제52권9호
• /
• pp.637-645
• /
• 2019

본 연구는 유역에서 제공하는 다양한 생태서비스 가운데 네팔의 Bagmati 유역의 물생산량(Water yield)을 산정하였다. 물 공급, 관개 수력 등 다양한 시설에 사용되는 물생산량 지도는 계획 및 관리에 도움이 되며 생태서비스의 공급과 생산에 의도하지 않은 부정적 영향을 줄일 수 있다. 여러 문헌들은 네팔 Bagmati유역에 대한 탄소저장과 식수공급과 같은 생태서비스 제공 연구에 중점을 두었으나 토양피복별 혹은 소유역별 물 생산량에 대한 연구는 매우 미흡했다. 따라서 본 연구에서는 네팔 바그 마티 유역에서 소유역 규모와 함께 유역의 총 물생산량을 계산하고 유역의 토지피복 유형별로 물생산량을 산정하기 위해 시작되었다. 이를 위해, 생태서비스 평가를 위해 가장 많이 사용되는 Budyko 수문학적 방법에 바탕을 둔 ArcGIS기반 InVEST Water Yield 모형이 사용되었다. 본 연구로부터의 결과는 단위면적(ha)e당 물 생산량이 소유역 5 ($15216.32m^3/ha$)에서 가장 높았으며 소유역 6 ($10847.15m^3/ha$)에서 가장 낮았다. 토지피복별 물생산량은 도시화지역에서 가장 높게 산정되었으며, 초원과 농경지가 도시화지역 다음으로 높게 산정되었다. 본 연구에서 산정된 소유역별, 토지피복별 물생산량은 지역 규모의 상호 관련 서비스 개발을 위한 효율적인 시나리오를 제공하고 지속 가능한 토지 이용 정책 및 상호 관련된 물 관리 서비스를 촉진시킬 것으로 기대한다.

• 상하수도학회지
• /
• 제29권4호
• /
• pp.469-479
• /
• 2015

This study have been conducted to analyze the feasibility of establishing Contamination Warning System(CWS) that is capable of monitoring early natural or intentional water quality accidents, and providing active and quick responses for domestic C_water supply system. In order to evaluate the water quality data set, pH, turbidity and free residual chlorine concentration data were collected and each statistical value(mean, variation, range) was calculated, then the seasonal variability of those were analyzed using the independent t-test. From the results of analyzing the distribution of outliers in the measurement data using a high-pass filter, it could be confirmed that a lot of lower outliers appeared due to data missing. In addition, linear filter model based on autoregressive model(AR(1) and AR(2)) was applied for the state estimation of each water quality data set. From the results of analyzing the variability of the autocorrelation coefficient structure according to the change of window size(6hours~48hours), at least the window size longer than 12hours should be necessary for estimating the state of water quality data satisfactorily.

• 환경영향평가
• /
• 제10권2호
• /
• pp.157-165
• /
• 2001

This paper presents the policy directions of total maximum daily loads(TMDL), which was recently adopted in Korea, for scientific management of water quality. The basic principles of water quality management are also discussed in this paper, along with the TMDL policy in United States as well as the previous policy in Korea. We discussed several unreasonable points out of the previous approaches, such as regulation of all point sources with equal standards, negligence of an assimilative capacity of the receiving water, and emphasis only on drinking water supply, etc.. For successful applications of the TMDL policy in Korea, the following directions are suggested: 1) the unit drainage basin for each TMDL application should be given, 2) the water body where the water quality standards should be maintained, needs to be guided, 3) the water quality parameters of TMDL should be given, 4) the technical guidances should be given for applications of water quality models, and 5) the seasonal TMDL would be allowed. In order to maximize the benefits of the TMDL policy, the local governments would need to implement the following strategies: 1) the increment of an assimilative capacity of the receiving water, 2) the effective controls of the non-point source pollution, 3) the advanced treatment of the point sources, 4) application of system optimization techniques along with effluent trade, and 5) utilization of watershed management systems.

• 한국환경과학회지
• /
• 제10권1호
• /
• pp.21-25
• /
• 2001

The Keum river has been utilized for drinking water supply of several city including Kunsan city and is deepening pollution state due to numerous municipal and industrial discharges. The concentration BOD in river is affected by the organic loading from a tributary and the algae biomass that largely happen to under eutrophication state. In the eutrophic water mass such as the Keum river, the autochthonous BOD was very important part for making a decision of water quality management, because it was accounted for majority of the total BOD. The predict of water quality has important meaning for management of water quality pollution of the Keum river. The purpose of this study will manage and predict water quality of the Keum river using QUAL-2E model considering the autochthonous BOD. The estimation of autochthonous BOD represented that the relationship between BOD and chlorophyll a. The regression equation was shown to be autochthonous BOD=$\beta$(sub)5$\times$chlorophyll a. The results of this study may be summarized as followed; The QUAL-2E model was calibrated with the data surveyed in the field of the study area in June, 1998. The calculated value by QUAL-2E model are in good agree to measured value within relative error of 7.80~20.33%. Especially, in the case of the considering autochthonous BOD, the calculated value of BOD were fairly good coincided with the observed values within relative error of 15%. But the case of not considering autochthonous BOD, relative error of BOD was shown to be 43.2%. In order to attain II grade of water quality standard in Puyo station which has a intake facility of water supply, we reduced to the pollutants loading of tributaries. In the case of removed 100% BOD of tributaries, the BOD of Puyo station was 4.07mg/$\ell$, belong to III grade of water quality standard. But in the case of removed 88% nutrient of tributaries, it was satisfied to II grade of water quality standard as below 3mg/$\ell$ of BOD. For estimation of autochthonous BOD in Keum river, we are performed simulating in accordance with reduction of nutrient load(50~100%) under conditions removal 90% organic load. Occupancy of autochthonous BOD according to nutrient loading reductions were varied from 25.97~79.51%. Occupancy of autochthonous BOD was shown to be a tendency to increasing in accordance with reduction of nutrient loading. Showing the above results, the nutrient that one of the growing factor of algae was important role in decision of BOD in the Keum river. For the water quality management of the Keum river, therefore, it is necessary to considering autochthonous BOD and to construction of advanced sewage treatment plant for nutrient removal.

• Environmental Engineering Research
• /
• 제22권2호
• /
• pp.203-209
• /
• 2017

Innovations in the biofiltration process can provide effective solutions to overcome crucial water pollution problems. The elimination of pollutants is a result of the combined effects of biological oxidation, adsorption and filtration processes. This research aims to evaluate the performance of quartz sand biofiltration for removing total suspended solids, turbidity, color, organic matter, and ammonium from polluted river water and develop an empirical model for designing quartz sand biofilters for the treatment of polluted river water. Experiments were conducted using two biofilter units filled with quartz sand as filter media. A set of experiments were performed to evaluate the effect of hydraulic retention time on biofilter performance in removing water contaminants. The kinetics of organic matter removal were also determined to describe the performance of the biofilter. The results show that biofiltration can significantly remove river water pollutants. Removal efficiency depends on the applied hydraulic retention time. At a hydraulic retention time of two hours, removal efficiencies of total organics, ammonium and total suspended solids were up to 78%, 82%, and 91%, respectively. A model for designing quartz sand biofiltration has been developed from the experimental data.

• 환경정책연구
• /
• 제4권2호
• /
• pp.57-82
• /
• 2005

본고는 다가올 미래의 대체 수자원인 지하수의 효율적인 관리 보전을 위하여 선진국인 미국(뉴욕주, 위스콘신주, 텍사스주), 오스트리아, 네덜란드, 캐나다. 일본, 영국의 지하수 수질기준과 국내의 지하수 수질기준을 상호 비교 분석함으로써 지하수 수질기준에 관한 선진화를 도모하고자 한다. 선진국에서는 음용수로써 지하수의 의존도가 70%이상에 달하며, 지하수 수질기준은 음용수 기준을 대체로 적용하고 있다. 그러나 각 국가간자연환경 및 규제의 접근방법이 달라 지하수 수질기준에 있어 큰 차이를 보이고 있다. 본고는 지표수자원의 심각한 오염과 용수공급의 부족현상으로 인해 점차 이용도와 관심이 증가하고 있는 우리나라의 지하수의 효율적인 관리와 보전을 위해 선진국들이 규제하고 있는 지하수 수질기준과 현재 국내에서 점차 지하수오염 문제를 야기할 수 있는 물질들에 관한 추가적 규제의 필요성을 제언하였다. 유류성 물질인 BITX 기준항목의 경우, 항목을 세분화하여 생활용수뿐만 아니라 농업용수와 공업용수에 대한 추가적 기준의 적용이 요구되며, 발암성을 지닌 일부 PAHs에 대한 규제도 필요하다. 산업의 고도화로 인해 유해화학물질이 다양해지고 그 양도 해마다 증가하고 있는 현실에 대응하기 위해서는 기준항목의 추가도입과 엄격한 기준치의 적용이 요구된다. 지하수오염의 주요 원인인 질소의 오염으로 인한 피해를 방지하기 위하여 질소항목 기준을 더욱 세분화하여야 할 것이며, 인간이나 생태계에 치명적인 위해를 끼치는 방사성물질인 라돈 또한 일부 선진국에서 그에 대한 기준치를 설정하고 있고 국내에서도 그로 인한 피해사례가 발생하고 있으므로 라돈에 대한 규제의 필요성을 제언한다.

• 상하수도학회지
• /
• 제21권1호
• /
• pp.13-25
• /
• 2007

The water treatment plants in Seoul Metropolitan Area, which are under Korea Water Resources Corporation(KOWACO)'s management, take water from Paldang Reservoir in Han River System for drinking water supply. There are taste and odor (T&O) problems in the finished water because the conventional treatment processes do not effectively remove the T&O compounds. As part of countermeasures for taste and odor control, KOWACO is planning to introduce advanced water treatment process such as ozone and GAC in near future. This study evaluated the removal characteristics of T&O and dissolved organic matter (DOM) to find design and operation parameters of advanced water treatment processes in a pilot-scale treatment plant. The GAC adsorption capacity for DOC in the two GAC system (GAC and $O_3$-GAC) at an EBCT of 14min was mostly exhausted after 9months. The differency of the removal efficiency of DOC between $O_3$-GAC and GAC increased with increasing operation time because the bioactivity in $O_3$-GAC process was enhanced by post-ozone process. Removal by conventional treatment was unable to reach the target TON(threshold odor number) of 3 but GAC systems at an EBCT(empty bed contact time) of 14 min were able to archive the target with few exception. During the high T&O episodes, PAC as a pretreatment together with GAC could be useful option for T&O control. However, substantial TON removal continued for more than two year (> 90,000 bed volumes). At the spiking of less concentration 26 to 61 ng/L in the influent of GAC systems, GAC absorber and $O_3$-GAC processes could meet the treatment target. The better spike control after 12 and 19 months of operation compared to that after 7 months of operation is a strong indication of biological control. The results presented in this study had shown that $O_3$-GAC process was found to be more effective for T&O control than GAC process. And the main removal mechanism in GAC systems were adsorption capacity and biodegradation.

• 상하수도학회지
• /
• 제28권1호
• /
• pp.91-101
• /
• 2014

Three water treatment plants(WTPs) in Jeju island whose source water have different characteristics from those of the mainland of Korea were investigated. Coefficients of bulk water decay($k_b$) of free chlorine at $5^{\circ}C$ for ES, GJ, NW WTPs were $-0.003hr^{-1}$, $-0.002hr^{-1}$ and $-0.001hr^{-1}$ respectively based on bottle tests. To simulate the free chlorine variations in the distribution system using EPANET, ES WTP was chosen. Free chlorine concentrations of several sites were less than the drinking water quality standards(i.e., 0.1 mg/L); E5(0.03 mg/L), E6(0.02 mg/L), W21(0.02 mg/L) and W25(0.03 mg/L). To maintain more than 0.1 mg/L of free chlorine in the distribution system, at least 1.9 mg/L of chlorine was needed at the WTP, which suggested rechlorination was needed to supply palatable tap water to customers. Two sites, one that diverged into E5 and E6 in the east-line and another located before E21 in the west-line were selected for the appropriate rechlorination locations. The recommended rechlorination dosages were 0.42 mg/L for the east and 0.27 mg/L for the west. The simulated results indicated that the free chlorine could be reduced to 0.4 mg/L at the WTP with rechlorination, and taps with excessive free chlorine could be more stabilized(i.e., 0.1~0.4 mg/L).