• Journal of Environmental Health Sciences
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• v.19 no.1
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• pp.44-50
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• 1993

In order to investigate the hygienic conditions of potable water in farm area, we examined the hygienic bacteriological and chemical tests of the 159 waters in the farm areas of Kwangjugun, Namyangju-gun, Yangpyung-gun Paju-gun and Hwasung-gun.The results were as follows: 1. Of the 159 waters, the average numbers of standard plate count and coliform were 920 $\pm$ 250ml and 450 $\pm$ 380/100 ml, respectively. The average pH was 6.74 $\pm$ 0.08, KMnO$_4$ consumption 4.18 $\pm$ 0.23 mg/l, turbidity 0.74 $\pm$ 0.08 degree, NH$_3$-N 0.07 $\pm$ 0.02 mg/l, NO$_3$-N 7.76 $\pm$ 0.48 mg/l, total hardness 101.3 $\pm$ 4.7mg/l, chlorine 18.6 $\pm$ 1.3mg/l, sulfate 12.9 $\pm$ 1.0 mg/l, lead 0.036 $\pm$ 0.003 mg/l, manganese 0.017 $\pm$ 0.003 mg/l, zinc 0.064 $\pm$ 0.005 mg/l, and copper 0.010 $\pm$ 0.001 mg/l, respectively. 2. Of the 159 waters, 84 samples (52.8%) were over 100 per ml of SPC or detected coliform per 100 ml water and 63 samples (39.6%) exceed over physicochemical limited criteria for potable water. NO$_3$-N was the primary item among excess contents of potable water in farm areas. 3. The contents of total hardness, chlorine and NO$_3$-N in Hwasung-gun were higher than those in the other regions, but the numbers of SPC and coliform in Yangpyung-gun and Namyangjugun were higher than those in the other regions. 4. The correlationships among many items were highly significant (SPC, Coliform, KMnO$_4$ consumption NH$_4$-N, NO$_3$-N, KMnO$_4$, Total hardness, Chlorine, Sulfate).

• Journal of The Korean Society of Agricultural Engineers
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• v.62 no.6
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• pp.43-50
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• 2020

The Doam Lake watershed is one of the non-point source management areas announced by the Ministry of Environment, and is a constant problem for the stream ecosystem dut to Storm water. In this study, a total of 48(rainfall) and 47(non-rainfall) sites were investigated for the entire watershed (Samyangcheon, Chahangcheon, Hoenggyecheon, Yongpyeongcheon, Songcheon, Lake Doam) on August 15, 2019 and on October 18, 2019 to estimate the source of turbid water in the Doam Lake watershed. Subsequently, water quality analysis was performed on Suspended Soild (SS), Turbidity, Total Phosphorus (TP), Total Nitrogen (TN), and Biochemical Oxygen Demands (BOD) and correlation among water quality parameters was analyzed based on the analyzed samples. As a result, most of the turbid water generated during rainfall was in highland fields. During rainfall, Hoengyecheon had the highest average SS concentration among all streams, and during non-rainfall, the average SS concentration was highest in Yongpyeongcheon, so the two stream were selected as vulnerable areas. However, since Yongpyeongcheon may be a temporary phenomenon due to river construction, additional continuous monitoring is required. Therefore, in the Doam Lake watershed, intensive management is required for vulnerable areas.

• Korean Journal of Ecology and Environment
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• v.39 no.2 s.116
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• pp.271-283
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• 2006

A systematic water quality survey was conducted in August, 2005 for a drinking water supply reservoir (the Jeolgol reseuoir located in an island), which is at an early stage of impoundment, to investigate the causes of water color deterioration of the reservoir and the clogging of filter beds of a water treatment plant. The reservoir shape was simple and its average depth was 5.5 m, increasing from upreservoir toward the downreservoir end near the dam. Dissolved oxygen (DO) and chloropllyll-a (chi-a) showed a large variation while water temperature had a smaller range. Transparency ranged from 0.6 to 0.9 m (average 0.7 m). The average value of turbidity was 9.3 NTU, ranging from 8.0 ${\sim}$ 12.1 NTU. The transparency and the turbidity appear to be affected by a combination of biological and non-biological factors. The poor transparency was explained by an increase of inorganic colloids and algal bloom in the reservoir. The blockage of the filter bed was attributed to the oversupply of phytoplanktons from the reservoir. The range and the average concentration of chi-a within the reservoir were 31.6 ${\sim}$ 258.9 ${\mu}g\;L^{-1}$, 123.6 ${\mu}g\;L^{-1}$ for the upper layer, and 17.0 ${\sim}$ 37.4 ${\mu}g\;L^{-1}$, 26.5 ${\mu}g\;L^{-1}$ for the bottom layer, respectively. A predominant species contributing the algal bloom was Dinophyceae, Peridinium bipes f. occultatum. The distribution of Peridinium spp. was correlated with chi-a concentrations. The standing crop of phytoplankton was highest in the upreservoir with $8.5\;{\times}\;103\;cells\;mL^{-1}$ and it decreased toward the downresevoir. Synedra of Bacillariophyceae and Microcystis aeruginosa of Cyanophyceae appeared to contribute to the algal bloom, although they are not dominated. It is mostly likely that sloped farmlands located in the watershed of the reservoir caused water quality problems because they may contain a significant amount of the nutrients originated from fertilizers. In addition, the aerators installed in the reservoir and a shortage of the inflowing water may be related to the poor water quality. A long-term monitoring and an integrated management plan for the water quality of the watersheds and the reservoir may be required to improve the water quality of the reservoir.

• Korean Journal of Agricultural Science
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• v.24 no.2
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• pp.242-256
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• 1997

The physico-chemical properties and possible biological functionalities of commercially available persimmon vinegars were studied by measuring the specific gravity, turbidity, color, pH, total acidity, reducing sugars, alcohols, total nitrogen content, composition of organic acids and amino acids, soluble pectin, soluble tannin, ascorbic acid, acetoinic compounds, electron donating ability and nitrite scavenging ability. Persimmon vinegars had low specific gravity(1.005-1.0200) and lightness(40.03-54.95), but high turbidity (0.12-1.311, absorptivity at 660 nm), redness(1.65--0.64) and yellowness(4.54-8.14) compared to the other fruit vinegars reported. These physical property values of the individiual product differed greatly. The tested persimmon vinegars contained relatively large amount of reducing sugars(0.45-0.84%, w/v), alcohol(0.16-3.18%, w/v) and total nitrogen(30-60mg%, w/v). The pH values (average 3.70) of products were relatively high and the total acidities(average 3.04%, w/v) of the tested persimmon vinegars were lower than that($TA{\geq}4.0%$) specified by the Korean standard for fruit vinegar. The major organic acids identified in the tested products were acetic acid(17.6-72.9%) and lactic acid(25.1-74.1%). The acetic acid contents in the 5 products out of the 7 tested persimmon vinegars were lower than lactic acid content. The level of free amino acids of the persimmon vinegars were relatively high in arginine, methionine and threonine. Persimmon vinegars contained relatively large amount of soluble pectin(91.8-232.8mg%, w/v), soluble tannin(49.0-161.7mg%, w/v) and ascorbic acid(12.8-29.6mg%, w/v). The persimmon vinegars were high in 2,3-butanediol (average 166.90ppm) and acetoin(average 111.43ppm). The persimmon vinegars showed strong electron donating ability and nitrite scavenging ability.

• Korean Journal of Ecology and Environment
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• v.46 no.1
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• pp.116-127
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• 2013

At weekly intervals, we monitored continuous changes in water quality by constructed floating wetland equipped with the four different filter media (sponge, volcanic stone, activated carbon and magnesium hydroxide) in a eutrophic lake from March 2011 to May 2012. We also investigated phyto- and zooplankton communities both in the influent and the effluent water through the floating wetland. Over a 10-month time period, average turbidity (66%), suspended solids (79%) and chlorophyll-a (80%) concentrations were remarkably reduced in the effluent water compared to the influent (P<0.001). The average removal rates of $NO_2-N$ and $NH_3-N$ were 24% and 20%, respectively (P<0.05). The average removal rates of $NO_3-N$ and TN were less than 10% (P>0.05). On the other hand, the average removal rates of $PO_4-P$ and TP were more than 65% (P<0.01). Interestingly, the abundance of phytoplankton in the effluent was decreased about 2.6 times compared to that of the influent, whereas the abundance of zooplankton in the effluent was increased about 3.5 times compared to that of the influent. Overall, particulate matters (SS, Chl-a and TP) and dissolved nutrients ($NO_2-N$, $NH_3-N$ and $PO_4-P$) were particularly reduced at high rates. Therefore, application of our constructed floating wetland in a eutrophic lake improved the water quality and demonstrated a potential for algal bloom mitigation.

• Membrane Journal
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• v.17 no.2
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• pp.124-133
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• 2007

In this study, we treated lake water by 2 kinds of multichannel ceramic micro filtration membranes. We could investigate effects of $N_2-back-flushing$ time (BT) and transmembrane pressure (TMP), and find optimal operating conditions. The BT were changed in $10{\sim}60$ sec, TMP in $0.6{\sim}2.0$ bar at fixed filtration time (FT) 8 min, flow rate 2.0 L/min and back-flushing pressure 2.0 bar. Also, the optimal conditions were discussed in the viewpoints of resistance of membrane fouling $(R_f)$, dimensionless permeate flux $(J/J_o)$, permeate flux (J) and total permeate volume $(V_T)$. As result, optimal back-flushing conditions for HC04 ($0.4{\mu}m$ pore size) and HC10 membrane $(1.0{\mu}m)$ were BT=10 sec and BT=20 sec, respectively. Then, higher TMP should increase the driving force, and could produce more VT. Average rejection rates of pollutants were higher than 95.4% for turbidity, $12.7{\sim}20.1%\;for\;COD_{Mn},\;0.0{\sim}6.4%\;for\;NH_3-N,\;1.9{\sim}4.6%$ for T-N and $34.9{\sim}88.4%$ for T-P.

• Membrane Journal
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• v.19 no.1
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• pp.7-18
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• 2009

In this study, we used the hybrid module that was composed of granular activated carbons (GAC) packing between module inside and outside of tubular ceramic microfiltration membrane for advanced drinking water treatment. Instead of natural organic matters (NOM) and fine inorganic particles in natural water source, modified solution was prepared with humic acid and kaolin. We were investigated effect of water-back-flushing time (BT) and water-back-flushing period (FT) to minimize membrane fouling and to enhance permeate flux (J) in the hybrid process, and tried to find the optimal operating conditions. As a result, resistance of membrane fouling ($R_f$) was slightly decreased according to increasing BT. Also, the shorter FT was the more effective to reduce $R_f$ and to enhance J because of frequent water-back-flushing. However, the optimal BT and FT conditions were 10 sec and 8 min respectively when operating costs were considered. Then, the optimal conditions derived from our experiments of modified solution were applied to lake water treatment. As a result, average treatment efficiencies of turbidity, $UV_{254}$ absorbance, and $COD_{Mn}$ were very high as 99.11%, 91.40% and 89.34%, respectively, but that of TDS was low as 30.05%.

• Journal of Korean Society of Environmental Engineers
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• v.33 no.3
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• pp.202-211
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• 2011

In this study the seasonal and spatial pattern of mercury (Hg) concentrations in multimedia environments were investigated in Lake So-Yang. Total mercury (TM) in water column greatly enhanced as turbidity and particulate organic carbon (POC) increased due to the severe runoff, suggesting that most of Hg existed as particulate Hg in Lake Soyang. We also collected 22 species of fish in Lake Soyang and Han River, and the average total mercury in fish was 0.073 ppm, lower than both Korean (0.5 ppm) and EPA criteria (0.3 ppm). However when considering the amount of fish intake for Korean the Hg criterion in fish must be more stringent than current value, and the advisory for fish consumption should be made. Hg in fish considerably varied with sampling sites, having the highest in the upper region (Yang-gu) and the lowest in downstream (Han River). This spatial variation was possibly derived by "bloom dilution" associated with high phosphorus loading or elevated DOC concentrations, or both. Total mercury in sediment varied from 69.9 to $98.3{\mu}g/kg$, which was relatively lower than those measured in Voyageurs National Park in Minnesota in USA ($102{\sim}364{\mu}g/kg$).

• Membrane Journal
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• v.18 no.4
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• pp.325-335
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• 2008

In this study, we used multi-channels ceramic membrane having larger permeate volume per unit time rather than tubular membrane. The hybrid process for advanced drinking water treatment was composed of granular activated carbons (GAC) packing between module inside and outside of multi-channels microfiltration membrane. Instead of natural organic matters (NOM) and fine inorganic particles in natural water source, modified solution was prepared with humic acid and kaolin. Kaolin concentration was fixed at 30mg/L and humic acid was changed as $2{\sim}10\;mg/L$ to inspect effect of organic matters. As a result, both resistance of membrane fouling ($R_f$) and permeate flux (J) were highly influenced by concentration of humic acid. Also, in result of water-back-flushing period (FT) effect, the shorter FT was the more effective to reduce membrane fouling and to enhance permeate flux because of frequent water-back-flushing. However, the optimal FT condition was 8 min when operating costs were considered. Then, the hybrid process using multi-channels ceramic membrane and GAC was applied to lake water treatment. As a result, average treatment efficiencies in our experiment using the hybrid process were 98.02% for turbidity, 75.64% for $UV_{254}$ absorbance, 7.18% for TDS and 84.73% for $COD_{Mn}$.

• Korean Journal of Ecology and Environment
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• v.37 no.4 s.109
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• pp.423-430
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• 2004

This study intended to understand movements of turbid water in selective with drawal reservoirs before and after summer monsoon. Mean rainfall during November-May was low, compared to that during June-October. The reservoir water was discharged through watergates when previous rainfall and inflow exceeded 50 mm and $80\;m^3s^{-1}$, respectively. Intake towers were generally used except for the period of the high runoff. Average turbidity in gown-reservoir showed a difference of 29.9 NTU between premonsoon and postmonsoon. Diameter of particles of turbid water ranged between 0.435 and $482.9\;{\mu}m$. Fine particles such as clay were much denser than the larger particle. In the whole stations, clay component was relatively higher with a proportion of that in the particle distribution. Particle composition of turbid water showed that clay consisted of 94.4-98.9% and silt made of 1.1-5.6%. Analysis on turbid water movements derived from particle distribution showed a linear increase from the deep layer toward the surface layer in lower area of a reservoir. This was closely related with the hydraulic behavior of the reservoir, and heavily affected by the discharges through selective withdrawal towers and watergates. Turbid water originated from stream sediments in the middle area then resuspended in the down-reservoir causing a movement between the surface and middle layers of the reservoir. Therefore, such phenomenon needs to be understood for reservoir water quality management.