• Journal of The Korean Society of Agricultural Engineers
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• v.60 no.1
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• pp.11-20
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• 2018

This study is to calibrate the SWAT (Soil and Water Assessment Tool) water quality of SS (Suspended Solid), T-P (Total Phosphorus), and T-N (Total Nitrogen) by focusing on 2014~2015 drought periods and identify the important parameters. For Gongdo watershed ($366.5km^2$), the SWAT was calibrated for 2 cases of 2002~2006 normal year focusing calibration and 2014~2015 drought focusing calibration respectively. The parameters of N_UPDIS (Nitrogen uptake distribution parameter) and CMN (Rate factor for humus mineralization of active organic nutrients) played important roles for T-N calibration during drought periods. The SWAT SS, T-N, and T-P average $R^2$ (Coefficient of determination) results by focusing on 2014~2015 drought periods calibration showed 0.71, 0.65 and 0.62 while 2002~2006 normal year focusing calibration showed 0.63, 0.58 and 0.50 respectively. Also SWAT SS, T-N, and T-P model efficiency NSE (Nash-Sutcliffe efficiency) results by focusing on drought period (2014~2015) calibrated showed 0.76, 0.77, 0.87 respectively. Even though the SS, T-P parameters were unchanged during the calibration, the SS and T-P results were improved by the hydrological parameters (SCS-CN, SOL_K, SLSOIL) during the drought periods. The SWAT water quality calibration needs to be considered for the movement of SS and nutrients transport especially focusing on the drought characteristics.

• Journal of Environmental Health Sciences
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• v.15 no.2
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• pp.51-58
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• 1989

In order to estimate unit loading factors of N, and P for controlling eutrophication of Youngsan lake. This study was performed in 4 kinds of pollutant sources from domestic sewage, industrial waste water, livestock stall waste water and drainage of agricultural area during the period from april to october 1988. These results were as follows: 1. The sewage flow for domestic waste water was 191.2 l/capita, day and that of the gray and toilet waste water among the domestic waste water were shown 152.9 l/capita, day(80%) and 38.3 l/capita, day(20%), respectively. 2. The unit loading factor total nitrogen(T-N) for domestic waste water was 7.582g/capita, day, and that of the gray and toilet waste water among the domestic waste water were 1.826g/ capita, day(24.1%) and 5.756g/capita, day(75.9%), respectively. The other hand, the unit loading factors of total phosphorus(T-P) for domestic waste water was 0.925g/capita, day, and that of gray and toilet waste water among the domestic waste water were 0.470g/capita, day(50.8%) and 0.455g/capita, day(49.2%), respectively. 3. In offering Price per million won, the T-P loading factor for drinking manufacture, confectionery manufacture, beer-manufacture and fibre manufacture in the industrial pollutant sources estimate to be 0.350g/day, 0.099g/day, 32.351g/day and 1.536g/day, while T-N loading factor about them in the industrial pollutant sources estimate to be 4.117g/day, 2.414g/day, 106.726g/day and 60.504g/day, respectively. 4. The T-P loading factor according to wash-water of milch cow and pig were 6.735g/day and 18.526g/day, in case of T-N they were 42.397g/day and 27.226g/day, respectively. 5. The T-P loading factor for pollutants drainage in the Paddy fields, fields and forests area were 0.082g/are, day, 0.014g/are, day and 0.002g/are, day, and the T-N loading factor were 0.309g/are, day, 0.158g/are, day and 0.064g/are, day, respectively. The diffrent of the loading factor for pollutants discharges in the agricultural area were resulted from the rainful intensity, the rainful, the amount of fertilization manure, and etc.

• Journal of the Korean Geographical Society
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• v.39 no.4
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• pp.544-561
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• 2004

Weekly monitoring of discharge and water quality in forested and agricultural subcatchments were performed to understand the difference of water quality caused by land uses in Doegwollyong area. Correlations between water quality variables including discharge were analyzed for the same purpose. There was little variation of water Quality in forested subcatchment. On the other hand, the range of water quality variation in agricultural subcatchment was wide due to soil loss and the application of chemical fertilizers and livestock manure. Dissolved oxygen(DO) had strong negative correlation with discharge in both subcatchments. Total nitrogen(T-N) and potassium ion(K$^{+}$) had stronger positive correlation with discharge in forested subacatchment than in agricultural one. On the other hand, total suspended sediments(TSS), total phosphorus(T-P), and chemical oxygen demand(COD) had stronger correlation with discharge in agricultural subcatchment than in forested one. As water pollution of the Doam Lake, especially the increase of T-P is serious, soil conservation is very important to improve water quality. In particular, the loss of soil and nutrients from late June till early July were more serious than any other seasons, therefore it is necessary to apply environmentally sustainable methods of cultivation.n.

• Korean Chemical Engineering Research
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• v.55 no.6
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• pp.816-821
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• 2017

An integrated slow mixing/sedimentation and net fit fiber filtration system has been developed to reduce the high concentrations of suspended solid (SS) and total phosphorus (T-P) in the reject water from sewage/wastewater. A filtration device used in this experiment consists of coagulation, in-line mixing, air injection, slow mixing/sedimentation, and filtration processes. The performance test using this device was carried out with six operational modes for reject water from sewage treatment plant. Experimental conditions used were 16.7, 33.3, 41.7 and 50.0 ton/day of flow rate and 2~4 of Al/P molar ratio. By injection of coagulant in each operational mode, the high removal efficiencies of SS and T-P were obtained, but continuous operation time was decreased to 7.8~11.4 min in most modes. However, when the Mode 5 of the developed filtration device was applied, the continuous operation time was maintained up to 88.2 min. Also, it was found that the continuous operation time in the Mode 5 using the developed system was increased from 8 to 11.3 times longer than those in other modes. Backwashing flow rate was also very low at 5.4% of total filtered water. Therefore, it can be concluded that the Mode 5 of the developed filtration system was the most efficient treatment method for the removal of high concentrations of SS and T-P.

• Journal of The Korean Society of Agricultural Engineers
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• v.60 no.4
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• pp.123-132
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• 2018

The purpose of this study was to evaluate the reduction effect of non point source (NPS) pollution in Haean highland agricultural catchment ($62.8km^2$) for 13 BMP scenarios under RCP (Representative Concentration Pathway) 4.5 and 8.5 scenarios. Under the present climate condition, the BMP (best management practices) reduction efficiency of SS (suspended solid), T-N (total nitrogen), and T-P (total phosphorus) showed +25.7%, +4.2%, and +16.1% for VFS (vegetative filter strip), +0.1%, +15.6%, and +5.7% for FC (fertilizer control), and +6.3%, -2.9%, and +3.9% for RSM (rice straw mulching) respectively. In general, effective was the best for SS and T-P reductions, and the FC was the best for T-N reduction. The negative effect of T-N on RSM was induced by increase in infiltration and solute transport to baseflow. Under the future climate change scenarios, the SS, T-N, and T-P reduction efficiency showed the range of +1.9~+11.6%, -1.9~+0.2%, and +5.3~+11.9% respectively. The 3 BMPs (VFS, FC, and RSM) application in the future showed negative and little differences (-0.5~+1.6%) for SS and T-N reduction efficiencies while T-P reduction efficiency showed +0.3~+7.6% comparing with the baseline period. To achieve an increase in the reduction efficiency of future SS and T-N by +2~+10%, the combined application of more than two BMPs is necessary.

• Journal of Environmental Impact Assessment
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• v.20 no.1
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• pp.89-96
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• 2011

This study was carried out to assess the variations of water quality caused by the dam construction on the river. Six dams-Yongdam, Miryang, Hoengseong, Boryeong, Jangheung and Buan- constructed recently in Korea were selected for the study. Chemical oxygen demand(COD) was increased in the initial stage of water storage at dams compared to the lotic(river) environment, but after 3 years it was maintained lower and stabilized concentrations. Five dams except for Jangheung Dam were maintained Ia~Ib grade conditions under the water quality criteria of Korea. The concentrations of total nitrogen(T-N) were decreased under the lentic(reservoir) environment compared to the river status. Total phosphorus(T-P) was decreased 13~63% at the reservoir condition. We concluded that increase of COD concentration was due to the debris organic materials of the land, but temporary phenomenon. T-N and T-P concentrations were decreased at the lentic condition compared to the lotic.

• Proceedings of the Korea Concrete Institute Conference
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• 2002.05a
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• pp.717-722
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• 2002

The results of an experiment on the water purification of the porous concrete and its influence on the compressive strength are reported in this paper. Two different sizes of coarse aggregate of 5-10, and 10-20mm, and three absolute volume ratios of paste to aggregate of 30, 40 and 50 percent for a given size of aggregate were used. For the compressive strength, the concrete with the aggregate size of 5-10mm showed much higher strength than that with the aggregate size of 10-20mm. But, the compressive strength is higher when the ratio of paste to aggregate is smaller. In the water purification experiment, the amount of attached an organism on the porous concrete surface indirectly is examined by measuring the consumption of the Dissolved Oxygen (DO). The ability of the water purification is evaluated by the removal amount of the Total Phosphorus(T-P) and Total Nitrogen(T-N). The ability of the removal of the T-N and T-P in the test water is superior to a porous concrete with a smaller size of aggregate and a higher void content. These results are owing to a large specific surface area of the specimen. As a result, porous concrete using by-products has sufficient performance of water purification.

• Magazine of the Korean Society of Agricultural Engineers
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• v.42 no.4
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• pp.87-95
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• 2000

A vegetation purification system was applied to improve water quality of Masan Reservoir in Korea, which was composed of constructed wetlands in series. Five different kinds of macrophytes were planted in each wetland. The system was operated with the condition of low concentrations and high hydraulic loadings. Removal efficiencies(%) of chemical oxygen demand(COD) , total nitrogen(T-N) and total phosphorus(T-P) in this system were 9.0, 12.8, 20.1% , respectively. and removal rates(g/$m^2$/d) were 1.9(COD), 0.34(T-N) and 0.05(T-P) . Comparing this system with other wetlands operated at low hydraulic loadings, average removal efficiencies were low but removal rates were relatively high. Accordingly, this system could be applied to imporve reservoir water quality, because removal rates are more important than removal efficiencies in case of reservoir water quality improvement . However, the removal efficiencies and rates of this system are less than those of the hydroponic biofilter method which is a kind of a constructed wetland and utilize root zones of emergent macrophytes for trapping pollutants. Therefore, it is recommended that this system should be modified to utilize root zones of emergent macrophytes enough to improve reservoir water quality more efficiently.

• KSBB Journal
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• v.18 no.3
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• pp.234-238
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• 2003

Biofilm process is preferred to activated sludge process in small domestic wastewater treatment plant because of its simplicity in operation and maintenance. Column reactor filled with waste ceramics and with waste plastics was used to remove pollutants in restaurant wastewater. COD removal at 18 hours of hydraulic retention time (HRT) gave 93.7%, COD removal during the experimental period, where maximum COD removal was observed. Under same condition, average removal of total nitrogen and total phosphorus were 82.3% and 25.9%, respectively Organic and nitrogen were efficiently removed with the HRT of 18 hours or more.

• Asian-Australasian Journal of Animal Sciences
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• v.17 no.4
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• pp.523-532
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• 2004

An experiment was conducted to investigate the effect of microbial phytase ($Natuphos^{R}$) supplementation in combination with enzyme complex (composed of enzymes targeted to SBM dietary components such as $\alpha$-galactosides and galactomannans; $Endo-Power^{R}$) to diet with low nutrient levels on growth performance and ileal nutrient digestibility of weaned pigs. A total of 210 crossbred weaned pigs (Landrace$\times$Yorkshire$\times$Duroc), 6.68$\pm$0.98 kg of initial body weight, were randomly allotted to five dietary treatments, based on weight and age, according to a randomized complete block design. There were three pens per treatment and 14 pigs per pen. The dietary treatments were 1) CON (Control diet with no phytase and enzyme complex (EC)), 2) LP+EC 100 (Control diet with 0.15% unit lower available phosphorus (aP) level+0.1% phytase (500 FTU/kg diet) and 0.1% enzyme complex), 3) LP+EC 80 (Control diet with 0.15% unit lower aP level+0.08% phytase (400 FTU/kg diet) and 0.08% enzyme complex, 4) LPEA+EC 100 (Control diet with 0.15% unit lower aP and 3% lower ME and amino acid levels (lysine, methionine, threonine and typtophan)+0.1% phytase (500 FTU/kg diet) and 0.1% enzyme complex), 5) LPEA+EC 80 (Control diet with 0.15% unit lower aP and 3% lower ME and amino acid levels+0.08% phytase (400 FTU/ kg diet) and 0.08% enzyme complex). For the determination of ileal nutrients digestibility, a total of 15 T-cannulated pigs (initial body weight; 7.52$\pm$1.24 kg; 3 replicates per treatment) were used in the present study. Piglets were weighted and allotted into same dietary treatments as one in growth trial and phase I experimental diets were provided for ileal digestibility study. There was no significant difference (p>0.05) in average daily gain (ADG) and average daily feed intake (ADFI) among dietary treatments during the whole experimental period (0 to 5 weeks). However, piglets in LP+EC 100 group had a significantly higher gain/feed ratio (G:F) than piglets had in control (p<0.05). Crude protein, energy and phosphorus digestibilities were significantly improved when both of phytase and enzyme complex were supplemented at the revel of 0.1%, respectively to diets with low nutrient level (aP or (and) ME and amino acids) (p<0.05). Piglets in LP+EC 100 and LPEA+EC 100 groups showed significantly higher phosphorus content (%) in bone than that of piglets in control group (p<0.05). Supplementation of both of phytase and enzyme complex at 0.1%, respectively, to diet with low nutrient levels (aP or (and) ME and amino acids) significantly improved total ileal essential amino acid and nonessential amino acid digestibilities compared to control group (p<0.05). In conclusion, the results from the present study suggest that the simultaneous inclusion of phytase and enzyme complex to diets at recommended level is advantageous with respect to improving growth performance and nutrient digestibility of weaned pigs and may contribute to increased economic return when added to corn-soy based weaned pig diets.