• Environmental Engineering Research
• /
• v.10 no.6
• /
• pp.316-327
• /
• 2005

Constructed wetlands provide several benefits that are not solely limited to storm water management and are becoming common in storm water management. In this research, four recently constructed wetlands underwent in situ and laboratory water sampling to determine their efficiency in removing storm water pollutants over a 5-month period. From the sampling results, it was determined that each of the wetlands was able to reduce the concentration of pollutants in the stormwater. To aid in the assessment of the wetlands against each other, a model was developed to determine the extent of removal of stormwater pollutants over the length of the wetland. The results from this model complimented the data collected from the field. Improvements, such as increased amounts of vegetation were recommended for the wetlands with the aim of increasing the effectiveness. Further investigations into the wetlands will allow for better understanding of the wetland's performance.

• Journal of Wetlands Research
• /
• v.4 no.1
• /
• pp.51-61
• /
• 2002

The wetland is a biologically integrated system consisting of water, soil, bacteria, plants, and animals. The wetland helps sustain the ecosystem, control the micro-climate and flood, maintain the ground water level, and provide fishing grounds. From the environmental standpoint, the wetland plays a vital role in reducing water pollution by filtering out sand and other polluted matters, producing oxygen, absorbing chemicals and nutrients. For these reasons, interest in restoring the wetlands has been steadily increasing. Artificial wetland, which is also referred to as created wetland or constructed wetland, is an alternative to natural wetland. Like natural wetland, artificial wetland is environmentally friendly and can effectively lower pollutant levels. The Korea government is actively reviewing the construction of artificial wetlands in mining and water supply areas to decrease nonpoint pollutant sources. This paper attempts to develop a pollutant removal model for the water quality improvement function of artificial wetlands. Artificial wetland can improve the quality of the water; however, depending on the type of water inflow, vegetation and hydrology, its effect can be different.

• Environmental Engineering Research
• /
• v.15 no.4
• /
• pp.197-205
• /
• 2010

Recent years have witnessed increasing interest in wetland constructions in Korea as a flood control measure during the flood season and for consideration of the ecology during the non-flood season. In this study, hydraulic and hydrologic analyses were performed on a wetland construction plan for use as an alternative sustainable flood defense during the flood season, as well as a wetland that can protect the ecosystem during the non-flood season. The study area was the basin of the Topyeong-cheon stream, which is a tributary of the Nakdong River, including the Upo wetland, which is registered in the Ramsar Convention and the largest inland wetland in Korea. Wetlands were to be constructed at upstream and downstream of the Upo wetland by considering and analyzing seven scenarios for their constructions to investigate the effect of flood control during the flood season; it was found the best scenario reduced the flood level by 0.56 m. To evaluate the usefulness of the constructed wetlands during the non flood season, the water balance in the wetlands was analyzed, with the best scenario found to maintain a minimum water level of 1.3 m throughout the year. Therefore, the constructed wetlands could provide an alternative measure for flood prevention as well as an ecosystem for biodiversity.

• Journal of Korean Society on Water Environment
• /
• v.26 no.5
• /
• pp.781-788
• /
• 2010

A pilot study was performed to examine the feasibility of multiple stage of constructed wetland (CW) for nutrient removal. The system is composed of six wetland cells connected with water-ways. The hydraulic of wetland cells is designed as free water surface flow. The treatment capacity was $25m^3d^{-1}$ at HRT of about one day for each cell. The magnitude of nutrient removal was related with the length of wetlands and plant density. Total N and P removal rates were 1353 and $246mg\;m^{-2}d^{-1}$ respectively. The pilot-scale reactor was model as continuous flow system containing contribution of CSTR and PFR typed-reactors. The $k-C^*$ model equation was applied to predict N and P reduction. The result indicated the equation was well guided to estimate reduction of $NO_3-N$ and $PO_4-P$.

• Journal of Environmental Science International
• /
• v.26 no.3
• /
• pp.401-410
• /
• 2017

This study analyzed the changes in the concentrations of organic matters in constructed treatment wetlands, coming from discharge water from a sewage treatment plant and non-point pollutant sources during rainfall events. At the beginning of a rainfall event, a massive amount of particulate organic matter flowed in, and was removed from the sedimentation basin (S1, S2); dissolved organic matter was removed after passing through stepwise treatment processes in the wetland. During dry period in the wetland, the removal efficiency rate for COD and TOC was -21 and -7%, respectively; during the rainfall event, the removal efficiency rate for COD and TOC were 47 and 43%, respectively. The highly-concentrated organic matters that flowd in at the beginning of the rainfall event was stabilized by various structures in the wetland before water discharge. Cyanobacteria blooms annually at the confluence of the So-ok stream and Daecheong Lake. Therefore, it is expected that the wetland will contribute significantly to reducing cyanobacteria and improving water quality in the area.

• Proceedings of the Korean Society of Agricultural Engineers Conference
• /
• 2000.10a
• /
• pp.490-499
• /
• 2000

Several studies on development of water quality treatment systems by wetlands are on going because of their benefits of low construction cost and high efficiency of waste water treatment. The objectives of this study were to review the necessary contents of survey and design factors for constructing constructed wetlands and to examine the required wetland area to treat non-point source pollution through case studies. The measurement of water quality and quantity in precipitation period is needed to analyse the inflow characteristics of the non-point pollution and to determine the amount of design flow. The design inflow for constructing constructed wetland was determined to the total runoff from 30mm of daily rainfall in the AMC(III) condition of the SCS method and is similar 70% of the annual mean runoff. The natural type wetland system with 0.1m of water depth and 5 hours of detention time was applied. From the results of the case studies, 70% of inflow could be treated and 1∼3% of wetland area of the total basin is needed.

• Korean Journal of Ecology and Environment
• /
• v.39 no.4 s.118
• /
• pp.481-488
• /
• 2006

The field scale experiment was performed to examine the performance of the constructed wetland for nonpoint source (NPS) pollution loading reduction. Four sets (0.88 ha each) of wetland and pond system were used. After three growing seasons of the wetland construction, plant coverage increased to about 90% even without plantation from bare soil surfaces at the initial stage. During the start up period of constructed wetlands, lower water levels should be maintained to avoid flooding newly plants, if wetland plants are to start from germinating seeds. The average removal rate of $BOD_5$, TSS, T-N and T-P during the first two years was 5.6%, 46.6%, 45.7%, and 54.8%, respectively. The $BOD_5$ removal rate was low and it might be attributed to the low influent concentration. The early stage of wetland performance demonstrated the effectiveness of water quality improvement and was satisfactory for treating polluted stream waters. From the first-order analysis, T-P was virtually not temperature dependent, and $BOD_5$ and TSS were more temperature dependent than T-N. A pond-wetland system was more effective than a wetland-pond or a wetland alone system in water quality improvement, particularly to reduce T-P. Overall, the wetland system was found to be an adequate alternative for treating a polluted stream water with stable removal efficiency and recommended as a NPS control measures.

• Journal of Korean Society on Water Environment
• /
• v.23 no.1
• /
• pp.155-160
• /
• 2007

Constructed wetland has been widely used for the treatment of sewage, stormwater runoff, industrial wastewater, agricultural runoff, acid mine drainage and landfill leachate. For the removal of nitrogen and phosphorus, uptake by plants and adsorption to media material are the major processes, and, therefore, the selection of media with specific adsorption capacity is the critical factor for the optimal design of wetland along with the selection of appropriate plant species. In this study, two media materials (loess bead and mixed media) possessing different adsorption characteristics for ammonium and phosphate were selected, and their adsorption characteristics were evaluated. In addition, the performance of subsurface-flow wetland systems employing these media was evaluated in both batch and continuous flow systems. With LB medium, beter phosphorus removal was observed, while better ammonia removal was obtained with MM medium. In addition, enhanced removal efficiencies were observed in the wetland systems employing both media and aquatic plants, mainly due to the better environment for microbial growth. As a result, appropriate selection or combination of media with respect to the inflow water quality maybe important factors for the successful design and operation of wetland systems.

• Journal of Korean Society on Water Environment
• /
• v.29 no.5
• /
• pp.591-597
• /
• 2013

The input emergy of an advanced treatment plant for reducing the 1 kg of TN and TP was estimated 4.14E+14 sej/kg, 5.02E+15 sej/kg, respectively. In addition, the input emergy of constructed wetland for reduction of the 1 kg of TN and TP reduction was estimated to be 2.48E+14 sej/kg, 3.38E+15 sej/kg, respectively. The cost reducing 1 kg of TN and TP for an advanced treatment plant was estimated 197,466 won and 2,388,739 won respectively and constructed wetland was estimated 117,976 won and 1,609,213 won respectively. As a result, All of the emergy source of constructed wetland for reducing non-point source is renewable resource. If we use the constructed wetland, it results in enhancing economic value by reducing of non-point pollution, controlling a flood and providing the habitat of animals or plants. Improving water quality program in the Nakdong River Basin should be changed into an ecological treatment facilities from expansion of the sewage treatment facilities and advanced treatment plant using high cost and non-renewable energies.

• Korean Journal of Ecology and Environment
• /
• v.55 no.3
• /
• pp.244-250
• /
• 2022

The changes in COD, TOC, T-P, and T-N concentrations were investigated for 2 years in the constructed wetland of Sookcheon, which was installed to improve the water quality of Daecheong reservoir in South Korea. In order to evaluate the pollution level of sediments in the wetland, settling velocity of particulate material (4 times) and sedimet material contents (6 times) were measured. COD and TOC concentrations increased slightly as they passed through wetlands, and T-N and T-P concentration tended to decrease. The material content (COD, T-P, T-N) of aquatic plants was higher in floating-leaved and free-floating macrophytes than emergent macrophytes. As a result of measuring the sedimentation rate of suspended materials, most of the suspended materials introduced into constructed wetlands were sedimented at a rapid rate in the first sedimentation site. In addition, sediment pollution of T-P and T-N in constructed wetland was in severe pollution. The sediments containing a large amount of T-P and T-N were eluted by physical and chemical environmental changes, which is likely to act as internal pollution sources in wetlands.