• Journal of the Korean Society of Environmental Restoration Technology
• /
• v.5 no.6
• /
• pp.24-29
• /
• 2002

Nitrate removal rate in three cattail wetland cells was investigated. They were a part of a pond-wetland system for stream water treatment demonstration. The system was composed of two ponds and six wetland cells. The acreage of each cell was approximately $150m^2$. The earth works for the system were finished from April 2000 to May 2000 and cattails were planted in the three cells in June 2000. Waters of Sinyang Stream flowing into Kohung Estuarine Lake were pumped into a primary pond, whose effluent was discharged into a secondary pond. The reservoir was formed by a tidal marsh reclamation project and located in southern coastal area of Korean Peninsula. Effluents from the secondary pond were funneled into the three cells. Volumes and water quality of inflow and outflow were analyzed from July 2000 through January 2001. Inflow and outflow averaged $20.2m^3/day$ and $19.8m^3/day$, respectively. Hydraulic retention time was about 1.6 days. Average influent and effluent nitrate concentration was $1.98mg/{\ell}$, $1.38mg/{\ell}$, respectively. Nitrate removal rate averaged $82.6mg\;m^{-2}\;day^{-1}$. Seasonal changes of nitrate retention rates were closely related to those of wetland cell temperatures. The average nitrate removal rate in the cells was a little lower, compared with that of $125.0mg\;m^{-2}\;day^{-1}$ for the wetlands operating in North America. This could be attributed to the initial stage of the cells and inclusion of three cold months into the seven-month study period. Root rhizosphere in wetland soils and litter-soil layers on cell bottoms could not developed. Increase of standing density of cattails within a few years will establish both root zones suitable for the nitrification of ammonia to nitrates and substrates beneficial to the denitrification of nitrates into nitrogen gases, which may lead to increase of the nitrate retention rate.

• Journal of Korean Society of Water and Wastewater
• /
• v.25 no.2
• /
• pp.265-274
• /
• 2011

Nowadays, the importance of non-point source pollution treatment is being emphasized. Especially, the easy runoff characteristic of highly concentrated pollutants in the roads makes the circumstance more complicated due to impermeability of roads. When the pollutants flow into steam it could make water quality in stream worse and it also causes a bad influence in the aquatic ecosystem because the effluents of rainfall-runoff may contain indecomposable materials like oil and heavy metals. Therefore, we tried to figure out the property of non-point source pollution when it is raining and carried out an assessment for the property of runoff for non-point source pollution and EMC (Event Mean Concentrations) of the essential pollutants during this study. As the result of the study, the EMC was BOD 5.2~21.7 mg/L, COD 7.5~35.4 mg/L, TSS 71.5~466.1 mg/L, T-N 0.682~1.789 mg/L and T-P 0.174~0.378 mg/L, respectively. The decreasing rate of non-point pollutant in Chungyang-Hongsung road indicates the maximum decrease of 80% until 5 mm of rainfall based on SS concentration; by the rainy time within 20~30 minutes, the decreasing rate of SS concentration was shown as 88.0~97.6%. Therefore it was concluded that it seems to be possibly control non-point pollutants if we install equipments to treat non-point pollutants with holding capacity of 30 min. It is supposed that the result of this study could be used for non-point pollutants treatment of roads in Chungyang-Hongsung area. We also want to systematically study and consistently prepare the efficient management of runoff from non-point source pollution and pollutant loading because the characteristics of non-point source pollution runoff changes depending on different characteristics and situations of roads and rainfall.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
• /
• v.11 no.2
• /
• pp.82-91
• /
• 2006

We investigated the possibility of using effluents from a municipal sewage treatment plant (STP) as tracers a tracer for hydrologic studies of rivers. The possibility was checked in a 12-km long reach downstream of Jeonju Municipal Sewage Treatment Plant (JSTP). Time-series monitoring of the water chemistry reveals that chemical compositions of the effluent from the JSTP are fluctuating within a relatively wide range during the sampling period. In addition, the signals from the plant were observed at the downstream stations consecutively with increasing time lags, especially in concentrations of the conservative chemical parameters (concentrations f3r chloride and sulfate, total concentration of major cations, and electric conductivity). Based on this observation, we could estimate the stream flow (Q), velocity (v), and dispersion coefficient (D). A 1-D nonreactive solute-transport model with automated optimization schemes was used for this study. The values of Q, v, and D estimated from this study varied from 6.4 to $9.0m^3/sec$ (at the downstream end of the reach), from 0.06 to 0.10 m/sec, and from 0.7 to $6.4m^2/sec$, respectively. The results show that the effluent from a large-scaled municipal STP frequently provides good, multiple natural tracers far hydrologic studies.

• Journal of Wetlands Research
• /
• v.9 no.1
• /
• pp.107-114
• /
• 2007

This study aimed to investigate the hexachlorobenzene (HCB) dechlorinating ability of sediment microbes collected from a natural canal receiving secondary effluents from an industrial estate and nearby factories. Nine sites along the stream and one in the estuary in the Gulf of Thailand into which the canal spills were specified and sampling for sediment and water. Preliminary analysis of the sediments showed that the first four sites nearest to the discharging location were contaminated by HCB within the range of 0.18 to 1.25 ppm. Apart from that, 1,3,5-trichlorobenzene which has never been commercially produced or used in any manufacturing processes except for the transformation from higher chlorinated benzene was also identified in the range of 0.16 to 0.24 ppm. This suggested a possibility of sporadically HCB contamination in this stream. Of more important, people in the community along this canal earn their living by coastal fishery; hence, posing a risk of spreading HCB and its less chlorinated congeners via food chain from caught marine creatures to human. As a result, there is an urgent need to understand the behavior of HCB dechlorination in this stream sediment which can lead to a clean-up action in the future. Serum bottles with sediment slurries (sediment to water ratio of 1:1 (v/v) and filtered to remove particles larger than 0.7 mm) from each site were inoculated with 2 mg/l of HCB, kept anaerobically in the dark at room temperature without any nourishment, and analyzed for HCB and its less-chlorinated congeners every 6 days. Total chemical oxygen demand, suspended solids, and volatile suspended solids were in the range of 21,492-73,584, 158,100-518,100 and 6,000-32,700 mg/l, respectively. It was found that all sediment slurries began to dechlorinate HCB in 12 to 30 days and the HCB was completely removed within 42 to 60 days or so. On the other hand, there was no HCB dechlorination occurred in the controlled set which was sterilized by autoclaving prior to the addition of HCB. This implies that the HCB transformation was solely due to microorganisms' activities. HCB was dechlorinated principally via pentachlolobenzene to 1,2,3,5-tetrachlorobenzene and terminated at 1,3,5-trichlorobenzene which is the major pathway as reported by many researchers. Dichlorobenzene has not been detected in any samples within the dechlorination period of 60 days. The results indicate that the microbial matrix in the sediment of this stream has an outstanding capability to dechlorinate HCB. Existing substrates and nutrients which mainly sorbed onto the solid phase and the typical temperature in Thailand were sufficient and suitable to promote the activities of these HCB-dechlorinating microbes.

• Journal of Environmental Science International
• /
• v.21 no.1
• /
• pp.57-67
• /
• 2012

The midge samples were undertaken at three streams, representing different surrounding environments, to investigate the contaminant exposure of midge. The content of heavy metals in midge collected in Singil stream were generally higher as a result of input to the industrial effluents with respect to other streams. Adsorption experiments were done to evaluate the possibility of removing contaminants from water with midge. Diazinon and heavy metals were contaminant target compounds in this study. The removal rate of diazinon in water by midge was 60-75%. In the case of Cu, the removal rate was reached around 90% at the lower initial concentration of 1.87 and 0.81 ppm rather than 4.25 ppm. The reduction of concentration of Cr and Cd according to the lapse of time was similar to the Cu, but their removal rates were shown 50% and 60-74%, respectively. The removal rate of Zn by midge represented relatively high level within the experimental condition. No change in concentration of Cr and As with time were occurred at all experimental conditions. It accounts for the fact that the reduction of Cr and As could not be achieved through the adsorption process, using midge.

• Journal of Environmental Impact Assessment
• /
• v.20 no.3
• /
• pp.357-365
• /
• 2011

The QUAL2K has the same basic characteristics as the QUAL2E model, which has been widely used in stream water quality modeling; in QUAL2K, however, various functions are supplemented. The QUAL2Kw model uses a genetic algorithm(GA) for automatic calibration of QUAL2K, and it can search for optimum water quality parameters efficiently using the calculation results of the model. The QUAL2Kw model was applied to the Gangneung Namdaecheon River on the east side of the Korean Peninsula. Because of the effluents from the urban area, the middle and lower parts of the river are more polluted than the upper parts. Moreover, the hydraulic characteristics differ between the lower and upper parts of rivers. Thus, the river reaches were divided into seven parts, auto-calibration for the multiple reaches was performed using the function of the user-defined automatic calibration of the rates worksheets. Because GA parameters affect the optimal solution of the model, the impact of the GA parameters used in QUAL2Kw on the fitness of the model was analyzed. Sensitivity analysis of various factors, such as population size, crossover probability, crossover mode, strategy for mutation and elitism, mutation rate, and reproduction plan, were performed. Using the results of this sensitivity analysis, the optimum GA parameters were selected to achieve the best fitness value.

• Journal of The Korean Society of Agricultural Engineers
• /
• v.46 no.1
• /
• pp.75-86
• /
• 2004

The objective of the research is to develop agricultural resue technologies of reclaiming the effluents from a municipal wastewater treatment plant and reusing for irrigated rice paddies. The Suwon wastewater treatment plant was selected for wastewater reuse tests. The control was the plots with groundwater irrigation (TR＃1), the treatment (TR＃2) using polluted stream water as it was, and three others using wastewater after treatment. Three levels of wastewater treatments were employed： the effluent from the wastewater treatment plant (TR＃3), sand filtering after treatment plant(TR＃4), and ultra-violet treatment after sand filtering (TR＃5). The randomized block method was applied to wastewater application to paddy rice with five treatments and six replica. The effects of various wastewater treatment levels on water quality, paddy soil, crop growth, yields, and the health hazards were investigated. The primary results indicate that cultivating rice with reclaimed wastewater irrigation did not cause a problem to adverse effects on crop growth and yields. Overall, wastewater could be used as a practical alternative measure for reclaimed wastewater irrigation. However, long-term monitoring is recommended on the effects on soil chemical characteristics and its related health concerns.

• Journal of Wetlands Research
• /
• v.10 no.2
• /
• pp.39-51
• /
• 2008

In recent days, the cases of using wetlands in treating waste water, storm events, mining leachate, and agriculture effluents are increasing. But there is the lack of the data for wetlands because of the difficulty in long term monitoring. Such an aspect makes the proper use of wetland impractical. In this study for the purpose of generating a long term hydrologic data, the time series of storage amount for Upo, Mokpo, Sajipo, and Jjokjibeol in Topyeong watershed is simulated using SWAT model. Based on the SWAT-Topyeong model involved in several scenarios for constructing new washlands in Topyeong watershed, the temporal behavior of new washlands is analyzed. It is also revealed that the constructed washland can affect the Upo in some degrees.

• Journal of Environmental Science International
• /
• v.18 no.3
• /
• pp.245-254
• /
• 2009

In recent years, environmental pollution by phannaceuticals and personal care products (PPCPs) in the aquatic environment is of great concern worldwide. Recent studies have been reported to occur in a variety of environmental organisms such as surface, drinking and ground water, soils, sediments and hospitals. The purpose of this study was to evaluate the occurrence and environmental behavior of fourteen human PPCPs in surface waters of Mankyung River in South Korea. We were conducted to field survey for water quality and PPCPs analysis at November, 2006. PPCPs were analyzed by liquid chromatograph coupled with a tandem mass spectrometer (HPLC-MS/MS). The concentration of COD was measured to be 2.37$\sim$19.71 mg/L, which was belong to 4$\sim$5 grade in water quality criteria of lake. Station 2 that there is no pollution in upper stream, was appeared to lower concentration. The concentration of TN and TP, that is cause matter of eutrophication, were found to be 7.78$\sim$35.42 mg/L and 0.08$\sim$0.95 mg/L, respectively, which were exceeding 5 grade in Lake water quality criteria. The 11 kind of PPCPs compounds except levofloxacin and triclosan were detected to Mankyung river. PPCPs concentrations of STP(Sewer Treatment Plant) effluents and aquatic environment in Mankyung river have been detected in the range from dozens of ng/L to hundreds of ${\mu}g/L$ that by order of atenolol, carbamazepine, propranolol, Ibuprofen, erythromycin, ifenprodil, clarithromycin, mefenamic acid, fluconazole, indomethacin, disopyramide. PPCPs concentration of Station 1 and 5, which was influenced by Jeonju STP and Wanju STP, was detected high values. Station 2 that there is no pollution, showed lower values. Station 3 which joined Gosan stream and Jeonju stream and station 4 which influenced by stock wastewater was detected to low values.

• Korean Journal of Ecology and Environment
• /
• v.56 no.4
• /
• pp.281-302
• /
• 2023

Carbon is not only an essential element for life but also a key player in climate change. The radiocarbon (¹⁴C) analysis using accelerator mass spectrometry (AMS) is a powerful tool not only to understand the carbon cycle but also to track pollutants derived from fossil carbon, which have a distinct radiocarbon isotope ratio (Δ¹⁴C). Many studies have reported Δ¹⁴C of carbon compounds in streams, rivers, rain, snow, throughfall, fine particulate matter (PM_2.5), and wastewater treatment plant effluents in South Korea, which are reviewed in this manuscript. In summary, (1) stream and river carbon in South Korea are largely derived from the chemical weathering of soils and rocks, and organic compounds in plants and soils, strongly influenced by precipitation, wastewater treatment effluents, agricultural land use, soil water, and groundwater. (2) Unprecedentedly high Δ¹⁴C of precipitation during winter has been reported, which can directly and indirectly influence stream and river carbon. Although we cannot exclude the possibility of local contamination sources of high Δ¹⁴C, the results suggest that stream dissolved organic carbon could be older than previously thought, warranting future studies. (3) The ¹⁴C analysis has also been applied to quantify the sources of forest throughfall and PM_2.5, providing new insights. The ¹⁴C data on a variety of ecosystems will be valuable not only to track the pollutants derived from fossil carbon but also to improve our understanding of climate change and provide solutions.