• 한국농공학회논문집
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• 제54권4호
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• pp.9-17
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• 2012

This study was aimed to characterize non-point source (NPS) pollutant runoff and estimate event mean concentrations (EMCs) from a small rural watershed located at the headwater area of the Gyeongan stream. The study watershed consists of the two major landuse, forest (72 %) and paddy field (28 %). The nine rainfall events ranging from 18.5 to 192.6 mm in amount were monitored in this study. Stream flow was measured at the watershed outlet using a water level gauge, while a number of water samples for each event were collected and analysed for water quality. Event pollutant loads varied greatly depending on rainfall events varying from 22.6 to 3,134.2 mg/L, 0.32 to 24.56 mg/L, 0.090 to 1.320 mg/L, and 2.3 to 149.8 mg/L for SS, TN, TP, and COD, correspondently. The respective mean EMCs were estimated by 104.2, 1.00, 0.168, and 7.9 mg/L. The Pearson correlation analysis showed that COD EMC was significantly correlated with those of SS, TN, and TP. Rainfall runoff ratio appeared to be negatively correlated with EMCs of SS, TP, and COD, although not statistically significant. The event loads from the largest rainfall was greater than the sum of those from the remaining eight events. The study results suggest that the appropriate management of intensified storm events are of greater importance in curbing NPS loads, while the estimated EMCs provide base data for the unit pollutant loads determination for the forest-paddy composite upstream watershed.

• 한국물환경학회지
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• 제26권3호
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• pp.413-419
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• 2010

A silica mine monitoring was conducted from March to December in 2008 to measure rainfall, runoff amounts and pollution loads. A total of 13 rainfall-runoff events were measured and analyzed with respect to runoff ratio, pollutant concentration and load, and initial flush. Over rainfall-runoff events, 95% confidence range of SS concentration was 942.5~2,056.2 mg/L. Other measured water quality indices also showed relatively large variation. This wide concentration variation was thought to be caused by the bare working ground of the mine that was used to store, process and transport the mined silica. Total pollution load of the 13 rainfall-runoff events was SS 17,901 kg/ha, $COD_{Cr}$ 160.9 kg/ha, $COD_{Mn}$ 111.24 kg/ha, BOD 79.6 kg/ha, T-N 13.8 kg/ha, T-P 3.5 kg/ha, and TOC 39.3 kg/ha. Initial flush was not well observed except SS. Very high SS concentration and load was occurred when rainfall was large. Therefore, it was recommended to manage the bare ground not to discharge excessive pollutants during wet days by covering the ground or constructing runoff treatment systems such as a sediment basin.

• 한국물환경학회지
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• 제31권6호
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• pp.653-664
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• 2015

TPLMS (Total water pollutant load management system) that is the most powerful water-quality protection program have been implemented since 2004. In the implementation of TPLMS, target water-quality and permissible discharged load from each unit watershed can be decided by water-quality modeling. And NPS (Non-point sources) discharge coefficients associated with certain (standard) flow are used on estimation of input data for model. National Institute of Environmental Research (NIER) recommend NPS discharge coefficients as 0.15 (Q₂₇₅) and 0.50 (Q₁₈₅) in common for whole watershed in Korea. But, uniform coefficient is difficult to reflect various NPS characteristics of individual watershed. Monthly NPS discharge coefficients were predicted and estimated using surface flow and water-quality from HSPF watershed model in this study. Those coefficients were plotted in flow duration curve of study area (Palger stream and Geumho C watershed) with monthly average flow. Linear regression analysis was performed about NPS discharge coefficients of BOD, T-N and T-P associated with flow, and R² of regression were distributed in 0.893~0.930 (Palger stream) and 0.939~0.959 (Geumho C). NPS Discharge coefficient through regression can be estimated flexibly according to flow, and be considered characteristics of watershed with watershed model.

• 한국물환경학회지
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• 제29권5호
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• pp.681-690
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• 2013

Watershed models have been increasingly used to support an integrated management of land and water, non-point source pollutants, and implement total daily maximum load policy. However, these models demand a great amount of input data, process parameters, a proper calibration, and sometimes result in significant uncertainty in the simulation results. For this reason, uncertainty analysis is necessary to minimize the risk in the use of the models for an important decision making. The objectives of this study were to evaluate three different uncertainty analysis algorithms (SUFI-2: Sequential Uncertainty Fitting-Ver.2, GLUE: Generalized Likelihood Uncertainty Estimation, ParaSol: Parameter Solution) that used to analyze the sensitivity of the SWAT(Soil and Water Assessment Tool) parameters and auto-calibration in a watershed, evaluate the uncertainties on the simulations of runoff and sediment load, and suggest alternatives to reduce the uncertainty. The results confirmed that the parameters which are most sensitive to runoff and sediment simulations were consistent in three algorithms although the order of importance is slightly different. In addition, there was no significant difference in the performance of auto-calibration results for runoff simulations. On the other hand, sediment calibration results showed less modeling efficiency compared to runoff simulations, which is probably due to the lack of measurement data. It is obvious that the parameter uncertainty in the sediment simulation is much grater than that in the runoff simulation. To decrease the uncertainty of SWAT simulations, it is recommended to estimate feasible ranges of model parameters, and obtain sufficient and reliable measurement data for the study site.

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2004년도 춘계학술대회 논문집
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• pp.233-239
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• 2004

Microbial activity of biofilm formed on the surface of gravels from intertidal zone was estimated using an aerobic respirometer system, and compared with that of suspended marine microorganisms contained in a near shore water. The maximum oxygen uptake rate of the suspended marine microorganisms was 0.15mg O$_2$／L／hr, indicating the potential of purification of polluted near shore water. For the gravels from the intertidal zone, the maximum uptake rate of oxygen was affected by the vertical positions, but their gross value was 0.77mg O$_2$／L／hr, which was around 5.1 times higher than the purification potential of polluted near shore water by the microorganisms contained in the near shore water. The nitrogen removed by the gravels from the intertidal zone and the marine microorganisms was about 1／20-1／39 times of the total consumption of oxygen, which was similar to that of the phosphate. The gravel intertidal zone contained lots of particulate organics, over than that in the near shore water, and this was confirmed from the large difference between total oxygen consumption and the removed soluble COD in the microbial activity test. This indicates that the gravel intertidal zone plays an important role in controlling the non-point source pollutants from land, as well as self-purification of polluted near shore water by trapping and degrading the particulate organics.

• 한국물환경학회지
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• 제33권5호
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• pp.572-579
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• 2017

Increased impervious surface caused by rapid urbanization serves to produce the discharge of non-point source pollutants such as total suspended solid (TSS). There exist various methods of removing TSS, including a filtration process using granular media (a well-known method to be practically used after the consideration of removal efficiency, clogging, and backwashing efficiency). To determine the TSS removal capability of the filter, we initially performed lab-scale experiments which assessed flow rates, influent concentrations, permeability co-efficients, the particular shapes of suspended solids and potential clogging, and also evaluated TSS removal efficiency when applied to filtration facility in a pilot-scale. In low filtration flux condition, the removal efficiency of suspended solids was more than 95 %, while decreased to 83% in high filtration flux. Regarding the clogging aspect of the experiment, total cumulative solids were loaded up to $19.15kg/m^2$, and TSS removal efficiency was noted to commence to decrease when the loaded solids exceeded $9.0kg/m^2$. It was also noted, however, that superior efficiency was maintained for six hours. In addition, for pilot-scale experiment, the removal efficiency was still high enough (83.4 %) for the solid concentration of 140 ~ 343 mg SS/L and after backwashing, head loss was recovered to 92 ~ 95 % during two hour filtration. With these results, It was confirmed that lifetime of the filter applied to the test was prolonged due to the high treatment efficiency and good backwashing efficiency for the cumulative solids load.

• 한국환경보건학회지
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• 제30권3호
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• pp.214-220
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• 2004

The microcosm type wetland systems were constructed in order to treat wastewater contaminated with parathion. The microcosm reactor consisted of marsh and pond type. The experiment was carried out using batch (marsh or pond) and continuous (marsh-pond and pond-marsh type) systems. In the batch reactor, marsh-type wetland completely removed parathion in water within 8 days, while pond reactor removed 97% of parathion during the same period. During parathion degradation, the amount of 4-nitrophenol production, one of the metabolites from parathion degradation, was higher in marsh-type batch reactor. In the continuous systems, both marsh-pond and pond-marsh combination systems effectively removed parathion from water, and the production of 4-nitrophenol was also minimal. In the extraction experiment, the parathion and its metabolite were not found in the wetland soil and the plant. In order to achieve both aerobic and anaerobic conditions, the continuous wetland system combining marsh and pond type can be the alternative for the non-point source pollutants such as parathion pesticide.

• 한국항해항만학회지
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• 제28권2호
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• pp.155-159
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• 2004

Microbial activity of biofilm formed on the surface of gravels from intertidal zone was estimated using an aerobic respirometer system, and compared with that of suspended marine microorganisms contained in a near shore water, The maximum oxygen uptake rate of the suspended marine microorganisms was 0.15mg$O_2$/L/hr, indicating the potential of purification of polluted near shore water. For the gravels from the intertidal zone, the maximum uptake rate of oxygen was affected by the vertical positions, but their gross value was 0.77mg $O_2$/L/hr, which was around 5.1 times higher than the purification potential of polluted near shore water by the microorganisms contained in the near shore water. The nitrogen removed by the gravels from the intertidal zone and the marine microorganisms was about 1/20-1/39 times of the total consumption of oxygen, which was similar to that of the phosphate. The gravel intertidal zone contained lots of particulate organics, over than that in the near shore water, and this was confirmed from the large difference between total oxygen consumption and the removed soluble COD in the microbial activity test. This indicates that the gravel intertidal zone plays an important role in controlling the non-point source pollutants from land, as well as self-purification of polluted near shore water by trapping and degrading the particulate organics.

• 한국물환경학회지
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• 제32권2호
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• pp.183-190
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• 2016

Monitored data (rainfall runoff and water quality) from 4 different paddy sites over 3 years were compared to analyze the effect of irrigation water management on irrigation supply and rainfall runoff quality in Korea. The system of rice intensification water management was adopted at one site (SRI) while the conventional water management method was used for rice culture at the other three sites (CT, SD and HD). The soil texture at SRI, CT and SD was sandy loam while that at HD was silt loam. The average reduction of irrigation supply at SRI compared with CT, SD and HD during the 3 years studied was 49%, 51% and 55%, respectively. The average event mean concentration (EMC) at SRI compared with that at CT, SD and HD was decreased by 35% (BOD), 44% (COD), 47% (SS), 19% (TN) and 38% (TP). The correlation between rainfall runoff and the measured non-point source (NPS) pollutants was very good in general. The comparison revealed that SRI water management significantly reduced both irrigation supply and EMC in rainfall runoff. Paddy NPS pollution was closely related to factors that induce runoff such as rainfall and irrigation supply. It was concluded that SRI management could be an effective and practical option to cope with both water shortage due to climate change and water quality improvement in rural watersheds. However, further studies are recommended in large irrigation districts for use in the development and implementation of NPS pollution policies since the data was collected from field sized paddies.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2015년도 학술발표회
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• pp.401-401
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• 2015

본 연구에서는 기타재배지(벚나무재배지)에서 발생하는 비점오염물질 유출 및 수질특성을 살펴보고자 2014년 5월부터 9월까지의 총 12회의 강우사상에 대해 유출특성을 분석하고 오염물질별 유량가중평균농도(Event Mean Concentration, EMC) 및 오염부하를 산정하였다. 모니터링 기간동안 2.6~95.8 mm의 강우가 발생하였으며, 조사된 총 12회의 event 중 단 2회 유출이 발생하였다. 강우강도는 0.33~5.28 mm/hr의 범위로 나타났으며, 선행무강우일수는 0.6~21.2일, 총 유출량은 $0.92{\sim}20.75m^3$, 유출율은 0.03~0.18의 범위로 나타났다. 강우모니터링 결과, EMC는 TOC 3.4~10.3 mg/L(평균 6.9 mg/L), BOD 6.3~6.9 mg/L(평균 6.6 mg/L), COD 22.0~28.8 mg/L(평균 25.4 mg/L), SS 101.8~962.8 mg/L(평균 532.3 mg/L), T-N 4.295~11.864 mg/L(평균 8.080 mg/L) 그리고 T-P 1.109~1.582 mg/L(평균 1.346 mg/L)의 범위로 나타났으며, 각 강우사상에 대한 단위면적당 오염부하는 TOC 0.08~0.58 kg/ha, BOD5 0.05~1.07kg/ha, CODMn 0.22~3.76 kg/ha, SS 0.77~164.4 kg/ha, T-N 0.090~0.734 kg/ha, T-P 0.008~0.270 kg/ha의 범위로 산정되었다. 벚나무재배지의 수질 항목간 Pearson 상관계수를 분석한 결과, 항목 중 $COD_{Mn}$가 다른 수질항목과 유의성을 갖고 높은 상관관계가 나타나 초기유출효과 분석을 위한 대표 수질항목으로 선정하였다. 벚나무재배지의 경우 초기유출 발생에 의한 오염부하의 급격한 증가는 나타나지 않았으며, 누적오염부하량비의 그래프에서는 대부분의 강우사상에서 기울기가 직선에 가깝게 나타났다. 기타재배지의 경우 대부분 투수지역으로 초기세척효과가 비교적 작은 것으로 나타났으며, 지속적으로 오염물질을 배출하는 특성을 보이는 것으로 분석되었다.