• Journal of Korea Water Resources Association
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• v.37 no.12
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• pp.1009-1018
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• 2004

A systematic method using an optimal estimation algorithm is presented for simultaneous estimation of diffuse pollution distributed along a stream reach and model parameters for a stream water quality model. It was applied with the QVAL2E model to the South Han River for optimal estimation of kinetic constants and diffuse loads along the river. Initial calibration results for kinetic constants selected from a sensitivity analysis reveal that diffuse source inputs for nitrogen and phosphorus are essential to satisfy the system mass balance. Diffuse loads for total nitrogen and total phosphorus were estimated solving the expanded inverse problem. Comparison of kinetic constants estimated simultaneously with diffuse sources to those estimated without diffuse loads, suggests that diffuse sources must be included in the optimization not only for its own estimation but also for adequate estimation of the model parameters. Application of optimization method to river water quality modeling is discussed in terms of the sensitivity coefficient matrix structure.

• Environmental Engineering Research
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• v.15 no.2
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• pp.85-91
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• 2010

Romania aims to adopt and implement the European Union's legislation, also including that for the field of water management. Like other countries, groundwater in Romania is locally polluted from point sources, such as leaking landfills, as well as from diffuse pollution sources, include fertilizers, pesticides and leakages from sewers, in urbanized areas. Diffuse pollution can also occur indirectly, by over-exploitation of groundwater wells, resulting in salt water intrusion, as well as from mining and exploitation of mineral aggregates. Romania has quite an intensive monitoring scheme to measure groundwater quality in phreatic and confined aquifers. The purpose of the work resumed in this paper was to derive natural background levels (NBL) for groundwater in order to distinguish the natural elevated concentrations of some substances (natural phenomena) from point and diffuse pollution (anthropogenic phenomena). Based on these NBLs, threshold values (TV) for groundwater will be set according to the requirements of the European Water Framework Directive and the related Groundwater Directive. This paper describes the results of a study for the derivation of NBL and TV in a pilot Groundwater Body. Also, the process and draft results for extrapolating this work for all Romanian groundwater bodies is explained, as well as points for future consideration with respect to monitoring and management.

• Journal of Korean Society on Water Environment
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• v.21 no.6
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• pp.617-623
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• 2005

Forestry and agricultural land uses constitute 85% of Korea and these land uses are typically mixed in many watersheds. Biological Oxygen Demand (BOD) concentration is a primary factor for managing water qualities of the water resources in Korea. BOD loadings from diffuse sources, however, not well monitored yet. This study aims to assess BOD loadings from diffuse sources and their affecting factors to conserve quality of water resources. Event Mean Concentration (EMC) of BOD was calculated based on the monitoring data of forty rainfall events at four agricultural-forestry watersheds. Exceedence cumulative probability of BOD EMCs were plotted to show agricultural activities in a watershed impacts on the magnitude of EMCs. Prediction equation for each rainfall event was proposed to estimate BOD EMCs: $EMC_{BOD}(mg/L)=EXP(0.413+0.0000001157{\times}$(discharged runoff volume in $m^3$)+0.018${\times}$(ratio of agricultural land use to total watershed area).

• Journal of Korea Water Resources Association
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• v.33 no.5
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• pp.527-536
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• 2000

This study estimates the pollution load in a basin by regional groups analyzing the relationship between the discharge and pollution load. The study area is placed in the Miho stream basin known as the main tributary of the Kum river. Four major Telemetary streamflow stations are chosen. In this research, discharge and water quality in a dry season and a flood season from the observed discharge in the stream are analyzed. The Rating-Curve and the Pollutograph are drawn analyzing discharge and water quality at the major stations. The characteristics of runoff for each stream are analyzed and the change of water quality are analyzed for rainfall period. The relationship between discharge and water quality has been investigated. The relationship between the discharge and pollution load is analyzed and a representative equation is derived. These relationships permit an estimates of the pollution load at the Miho stream basin. basin.

• Korean Journal of Soil Science and Fertilizer
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• v.49 no.5
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• pp.440-448
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• 2016

Nonpoint sources of pollution (NPS) is defined as diffuse discharges of pollutants (e.g., nutrient, pesticide, sediment, and enteric microorganism) throughout the natural environment and they are associated with a variety of farming practices. Previous studies found that water soluble anionic polyacrylamide (PAM) is one of the highly effective measures for enhancing infiltration, reducing runoff, preventing erosion, controlling nonpoint source of pollutants, and eventually protecting soil and water environment. Potential benefits of PAM treatment in agricultural soil and water environments have been revealed by many research and they include low cost, easy and quick application, and suitability for use with other Best Management Practices (BMPs) for NPS control. This study reviews the various applications of PAM and discusses its further potentials in agricultural environment.

• Journal of Korean Society for Atmospheric Environment
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• v.8 no.1
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• pp.45-51
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• 1992

A study on acidity in fog, dew and frost was carried out. Samples were taken during May 1990-February 1991 at two sites in Chongwon, Choongbook. The acidity of dew and of fog collected from grass at site A was 4.89 and 5.46, respectively. Dew in summer showed very strong acidity. The volume of dew deposited on grass was much less than the volume of rain, but dew is effective to diffuse acid predursors and acid materials. Dew and fog can remove more effectively atmospheric acid materiasl deoposited on grass by diurnal turbulent motion rather than direct absorption of acid predursors and materials in the atmosphere. In a polluted area, acidic dew and fog can be occurred by the direct absorption and oxidation of acidic predursors in the atmosphere as well as the role of wet removal on grass surface. Acidity of frost collected on teflon surface showed little difference to acidity of dew and fog on teflon surface. This suggests a similar absorption mechanism of atmospheric precursors and materials into dew and frost in the atmosphere. Strong acidity in dew, fog and frost appeared to occur from local pollution sources of several ten kilometres. In particular, strong acidity in dew, fog, and frost together with acid rain can accelerate a damage in ecosystems. Discussion is made on scientific analyses and seasonal variations of acidity of fog, dew and frost. A mechanism on acidification of fog, dew and frost is also discussed.

• Journal of Korean Society of Environmental Engineers
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• v.28 no.2
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• pp.173-177
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• 2006

Pesticides from diffuse pollution sources adsorbed in suspended particles flow into surface water and threats to the public health. In this research, dechlorination constants of Atrazine by zero valent iron were measured with addition of buffer solution for simulating buffer capacity of sediment. When initial concentration of Atrazine was 10, 30, and 50 mg/L, their dechlorination was explained using the pseudo-first order reaction. Dechlorination constants $K_{obs}$ were $3.21{\times}10^{-2}/d$ in average.

• Journal of the Korean GEO-environmental Society
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• v.8 no.3
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• pp.5-10
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• 2007

The paper presents results of qualitative analysis of non-regulated organic pollutants in municipal wastewater and treated municipal wastewater with flocculation, ozone and UV process using GC-MS. The majority of the pollutants in the influent of the municipal wastewater treatment facility were either food related or due to the diffuse discharge from products used both in households and in industry. In the case of biological treatment process removed some organic pollutants effectively. But some organic pollutants were not removed with biological treatment. Thus, additional steps to improve the quality of effluent municipal wastewater will require a more rigorous control of consumer products used in household and municipal wastewater process using advanced treatment processs. The obtained data contributed to the evaluation of pollutants discharges to the ecosystem as well as to the characterization of pollution sources in the basin.

• Journal of Wetlands Research
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• v.12 no.3
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• pp.39-47
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• 2010

Annually, the scale of agricultural areas in Korea were being reduced as the lands were converted to other land uses. While the rate of productivity were either being maintained or increased, the pollution load from these areas were still greater in magnitude. Although the levels of pollutant concentration released in the agricultural watersheds were minimal, the combined quantities mostly from diffuse sources were high. As a consequence, the Ministry of Environment (MOE) in Korea adopted the use of free water surface (FWS) flow constructed wetlands to reduce the pollutant loadings emitted from agricultural watersheds for the improvement of water quality and protection of aquatic ecosystems. In this study, a constructed wetland treating stream water in an agricultural watershed was monitored since April 2009 subsequent to its completion in December 2008. Satisfactory performance was achieved for TSS, BOD and TP with 26%, 28% and 39% pollutant removal rates, respectively. In addition, the effluent water quality was improved and achieved compliance the national water quality criteria. Results of this study can be useful to establish design parameters and employ proper removal techniques of similar natural treatment systems for future implementation in the country.

• Journal of the Korean Society for Marine Environment & Energy
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• v.16 no.2
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• pp.102-114
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• 2013

The basin of Lake Shihwa is one of highly industrialized region of Korea and a current environmental issue of study area is the operation of tidal power plant (TPP) to improve water quality. The application of water quality index (WQI) which integrates five physiochemical parameters (transparency, DO, DIN, DIP and chlorophyll-a) of water quality in Lake Shihwa and outer sea during 2011~2012 were performed not only to evaluate the spatial and temporal distribution of the water quality but also to assess the effect of water quality improvement by the operation of tidal power plant. The higher WQI values were observed in monitored sites near the industrial complexes in Lake Shihwa and the outfall of wastewater treatment plants (WWTPs) in outer sea. This indicates that the quality of seawater is influenced by diffuse non-point sources from industrial, municipal and agricultural areas in Lake Shihwa and by point sources from the effluence of municipal and industrial wastewater throughout WWTPs in outer sea. Mean WQI value decreased from 53.0 in 2011 to 42.8 in 2012 of Lake Shihwa. Water quality has improved significantly after TPP operation because enhancement of seawater exchange between Lake Shihwa and outer sea leads to improve a hypoxic condition which is primarily a problem in Lake Shihwa. Mean WQI of outer sea showed similar values between 2011 and 2012. However, the results of hierarchical cluster analysis and the deterioration of water quality in summer season indicate that the operation of tidal power plant was not improved the water quality in the upper most area of Lake Shihwa. To successfully improve overall water quality of Lake Shihwa, it is urgently necessary to manage and reduce of non-point pollution sources of the basin of Lake Shihwa.