• Journal of The Korean Society of Agricultural Engineers
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• v.47 no.1
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• pp.79-91
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• 2005

Wetland systems are widely accepted natural water purification systems around the world in nonpoint sources pollution control. Constructed wetlands have become a popular technology for treating contaminated surface and wastewater. In this study, the field experiment to reduce nonpoint source pollution loadings from polluted stream waters using wetland system was performed from June 2002 to March 2004, including winter performance using four newly constructed wetlands. The Dangjin stream water flowing into Seokmun estuarine lake was pumped into wetlands, and inflow and hydraulic residence time of the system was $500m^{3}{\~}1500m^{3}/day\;and\;2{\~}5$ days respectively. After 3 years operation plant-coverage was about $80~90\%$ from zero at initial stage even with no plantation. Average water quality of the influent in growing season was BOD_{5}\;3.96mg/L$, TSS 22.98 mg/L, T-N 3.29 mg/L, T-P 0.30 mg/L. The average removal rate of four wetlands for $BOD_{5},\;TSS,\;T-N\;and\;T-P$ in growing season was $24\%$, $62\%$, $54\%$, and $51\%$, respectively. And average water quality of the influent in winter season was $BOD_{5}$ 4.92 mg/L, TSS 12.47 mg/L, T-N 5.54 mg/L, and T-P 0.32 mg/L, respectively. The average removal rate of four wetlands for them was $-21\%$. $23\%$, $33\%$, and $53\%$, respectively. The reason of higher BOD_{5} effluent concentration in winter season might be that low temperature restrained microorganism activity and a organic body from the withered plant and algae was flown out. Except the result of $BOD_{5}$, the effectiveness of water quality improvement in winter season was satisfactory for treating polluted stream waters, and $BOD_{5}$ variation was within the range of background concentration. Performance of the experimental system was compared with existing data base (NADB), and it was within the range of general system performance. Overall, the wetland system was found to be satisfactory for NPS control such as improvement of polluted stream water.

• Korean Journal of Soil Science and Fertilizer
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• v.44 no.6
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• pp.1089-1094
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• 2011

To treat non-point source pollution in Juam lake, removal efficiencies of pollutants were investigated in Bongsan constructed wetlands (CWs) at different treatment time, stages and wastewater loads. The constructed wetlands consisted of forebay, $1^{st}$ and $2^{nd}$ wetlands. The concentrations of BOD, SS, T-N, and T-P in inflow were $1.87mg\;L^{-1}$, $1.62mg\;L^{-1}$, $11.47mg\;L^{-1}$, and $4.40mg\;L^{-1}$, respectively. The removal rates of BOD, SS, T-N, and T-P in Bongsan CWs were 26, 18, 16 and 9%, respectively. The removal rates of BOD and T-N were higher than those for SS and T-P. The amounts of pollutant removal in Bongsan CWs were higher in the order of forebay > $1^{st}$ wetland > $2^{nd}$ wetland for BOD, forebay > $2^{nd}$ wetland > $1^{st}$ wetland for SS, $1^{st}$ wetland > forebay > $2^{nd}$ wetland for T-N and $2^{nd}$ wetland > forebay > $1^{st}$ wetland for T-P.

• Environmental Engineering Research
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• v.20 no.1
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• pp.51-57
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• 2015

As expected, the expression of denitrifying genes in a Typha wetland (relatively stagnant compared to other ponds), showing higher nitrogen removal efficiency in summer, was affected by temperature. The abundance and gene transcripts of nitrate reductase (narG), nitrite reductase (nirS), nitric oxide reductase (norB), and nitrous oxide reductase (nosZ) genes in seasonal sediment samples taken from the Acorus and Typha ponds of free surface flow constructed wetlands were investigated using quantitative polymerase chain reaction (Q-PCR) and quantitative reverse transcription PCR (Q-RT-PCR). Denitrifying gene copy numbers ($10^5-10^8$ genes $g^{-1}$ sediment) were found to be higher than transcript numbers-($10^3-10^7$ transcripts $g^{-1}$ sediment) of the Acorus and Typha ponds, in both seasons. Transcript numbers of the four functional genes were significantly higher for Typha sediments, in the warm than in the cold season, potentially indicating greater bacterial activity, during the relatively warm season than the cold season. In contrast, copy numbers and expression of denitrifying genes of Acorus did not provide a strong correlation between the different seasons.

• Environmental Engineering Research
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• v.21 no.2
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• pp.164-170
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• 2016

Since most of the existing wastewater treatment options lack the ability to treat micro-contaminants, the increased use of pharmaceuticals and personal care products (PPCPs) and release as human waste have become a serious concern in recent years. Constructed wetlands (CWs) are a low-cost technology for wastewater treatment, however, its performance in term of PPCPs removal has not yet been fully investigated. This study aimed to characterize the removal factors and efficiency of acetaminophen (ACT) removal by CWs. The results revealed the decreased concentrations of ACT with increasing hydraulic retention times (HRT) of 0, 3, 5 days. The contribution of removal factors was found to be varied with initial ACT concentration. At the low ACT concentration (i.e. 1 ppb), plant uptake was the dominant, followed by microbial and photolytic removal. In contrast, at the high ACT concentration (i.e. 100 ppb), microbial and photolytic removal were found as dominant factors. On the other hand, hydrogen peroxide ($H_2O_2$) concentration was found at higher level in the plant shoot than in the root probably due to occurrence of the Fenton reaction resulting in PPCPs removal.

• Journal of Environmental Science International
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• v.26 no.3
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• pp.401-410
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• 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
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• 2000.10a
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• pp.490-499
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• 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.

• Ecology and Resilient Infrastructure
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• v.1 no.2
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• pp.102-108
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• 2014

Studies of non-point pollutant treatment facilities have widely been conducted for a decade, but natural non-point pollutant treatment facilities implemented on roads have not been carried out for the removal efficiency of non-point pollution sources. This study analyzed the removal efficiency of non-point pollution sources from constructed wetlands using monitoring and event mean concentration method. As a result of this study, removal efficiency of general non-point pollution sources as TSS, COD, BOD is relatively good, but removal efficiency of TN, TP, Cr, Zn, Pb is very small or nothing.

• Korean Journal of Soil Science and Fertilizer
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• v.44 no.5
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• pp.929-936
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• 2011

To treat non-point source pollution in Dongbok lake, removal efficiencies of pollutants were investigated in Dongbokcheon constructed wetlands (CWs) at different treatment time and wastewater loading. The wetlands consisted of forebay, wetlands ($1^{st}$, $2^{nd}$, $3^{rd}$, $4^{th}$, $5^{th}$, $6^{th}$, $7^{th}$, and $8^{th}$ wetlands) and sedimentation pond. The concentrations of BOD, SS, T-N, and T-P in inflow ranged $0.85{\sim}3.14mg\;L^{-1}$, $3.33{\sim}9.70mg\;L^{-1}$, $0.64{\sim}5.33mg\;L^{-1}$, and $0.03{\sim}0.10mg\;L^{-1}$ from April to October in 2008, respectively. The removal rates of BOD, SS, T-N, and T-P in Dongbokcheon CWs were 34%, 5%, 31%, and 13%, respectively. The removal rates of BOD and T-N were higher than those for SS and T-P. The amounts of pollutant removal in Dongbokcheon CWs were higher in the order of forebay > wetlands > sedimentation pond for BOD, sedimentation pond > wetlands > forebay for SS, sedimentation pond > forebay > wetlands for T-N. The amount of T-P removal in wetlands was higher than forebay and sedimentation pond.

• Journal of Wetlands Research
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• v.17 no.2
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• pp.184-192
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• 2015

This study is a basic research for low maintenance constructed wetlands which can prevent water quality deterioration due to wetland soils. The purpose of this study is to analyze water quality control mechanisms of constructed wetland on the artificial ground which installed the modular revetment structure(MRS), a device that separates water and soil. This study was then conducted with two different wetland mesocosms (a treatment plot and a control). These mesocosms were monitored to analyze effects of water quality control of the MRS. A treatment plot was built, and separated into soil and water, by filling the MRS with the decomposed granite soil in the mesocosm made of rubber material. A control plot was built where the decomposed granite soils were exposed to water by leaving the soil on the bottom of the mesocosm made of rubber material. Water quality was then analyzed by using Kolmogorov-Smirnov Z examination which then showed that pH, BOD, SS, Chl-a, T-P, T-N had statistically valid difference between a container with the MRS and one without it. According to the analysis of the water quality, the temperature and the EC level came out similarly and both mesocosm showed same level on pH and DO. A treatment plot had higher levels of BOD, SS Chl-a, and T-P. A control plot's T-N value was little lower than that of the treatment plot. This study suggests method of constructed wetlands using the MRS prevents problems occurring in wetland soils: aridity of wetlands by soil erosion, eutrophication, and algal blooms due to nutrients released from wetland soil. These functions of constructed wetland with the MRS increase aesthetic, ecologic, social, and economic value of the wetland. Outcomes of this research will later enable more proficient way of stabilizing water quality and provide data for planning low maintenance constructed wetlands.

• Journal of Environmental Impact Assessment
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• v.19 no.1
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• pp.83-89
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• 2010

The areas for agricultural purposes in Korea are decreasing every year because of urbanization. However, it is still 17.6% of the total national boundary on 2008. Most of the rice paddy fields are located near the waterbodies which require lots of water during rainy season from May to September. Also lots of nitrate and phosphate chemical fertilizers are spread on the fields every year in order to supply the nutrients for vegetation. The excess nutrients is impairs the water quality of rivers and lakes when it is washed out from the fields. The Korean Ministry of Environment (MOE) adapted the new water quality improvement program, which is the Total Daily Maximum Load, to improve the water quality and to protect the aquaecosystems. The constructed wetland is one of the possible ways to treat the agricultural runoff. The constructed wetland on this study area was constructed by MOE in 2007 to evaluate the application of the constructed wetlands. Plant growth continues to increase during the summer until it reaches its highest biomass of 6,032 g/$m^2$ in August and September. More researches about sedimentation, vegetation, water balance, etc. were performed to evaluate the removal efficiency, to find the removal mechanisms and to make the guidelines for design and maintenance.