• Journal of Industrial Technology
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• v.27 no.B
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• pp.221-227
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• 2007

This research investigates the turbidity and flow of river for an year, 2005, in order to examine the relation of the generation of turbidity according to the outflow of min water. For this research, the region of Jawoon river where is the area of high land vegetable growing in the upper Soyang Reservoir is selected to observe actual floating materials that generate negative nutrition and turbidity of the Reservoir water and the changes of water quality by raining of each month. In addition, the researcher has conducted statistical inspection methods, such as correlation analysis and regression analysis on strength of raining force, and rain continuance time among the elements affecting the outflow of floating materials.

• Journal of Korean Society of Water and Wastewater
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• v.22 no.1
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• pp.93-103
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• 2008

This study was conducted to optimize a unidirectional flushing program in distribution pipes by analysis of water pressure, velocity, quality, and other parameters during flushing. As a result, correlation coefficient between flushed pipe length and the flushing duration was obtained $R^2=0.83$ and the equation $Y_{Time}=0.0571{\cdot}X_{Pipe\;length}+4.7648$ for 10 pipes. The averaged flushing velocity in the pipes, 1.1 m/s, was enough to remove loose deposits on the inner wall of the pipes. 3 of 92 water samples taken during flushing met the National Drinking Water Quality Standard for Fe and Mn, but not for Al. Turbidity less than 1 NTU is suggested for the appropriate criteria to finish flushing in pipes. The coefficient of determination ($R^2$) between turbidity and TSS was 0.95 and the equation was induced as $Y_{TSS}=1.2068{\cdot}X_{Turbidity}$. The amount of removed deposits could be estimated from the turbidity data of discharged water in field because turbidity and TSS in the discharged water is highly correlated.

• Journal of Environmental Health Sciences
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• v.19 no.2
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• pp.1-9
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• 1993

In public water supply systems, Alum and/or PAC being used as a coagulant. It is well known that their use increased frequently the concentration of residual aluminum in filtered water upon operating conditions. This study was conducted to find the optimum conditions that both the concentration of residual aluminum and turbidity are minimized by changing such factors as pH, temperature, alum dosage, mixing rate, alkalinity and hardness. The results can be summarized as follows: The pH values for the minimum concentration of residual aluminum and turbidity as a given experimental condition were found at pH 6 and pH 7 respectively, the apparent clarity was best at pH 8. The floc settling rate was the greatest at pH 6.5, but the turbidity was high at the same condition. The more alum dosage, the higher the concentration of residual aluminum. However the alum dosage less than 15 mg/l tend to decrease in turbidity. Restabilization and enmeshment occurred near 15 mg/l and 20 mg/l of alum dose respectively. With the increase of mixing rate (rapid and slow), the concentration of residual aluminum and turbidity are increased and the same trend was found in increment of mixing time. At low water temperature, the concentration of residual aluminum was decreased, but turbidity was increased. It was confirmed that alkalinity had an effect on the coagulation efficiency, but hardness did not.

• Journal of Korean Society of Water and Wastewater
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• v.24 no.5
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• pp.581-593
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• 2010

The objectives of this study were to investigate the effects of raw water pH and basicity of coagulants on turbidity removal with several raw waters having different level of turbidity, alkalinity and pH. Raw waters were sampled from M, S and B water treatment plants(WTP) located at Miryang, Nakdong, Han river, respectively. Six coagulants which have different levels of basicity and aluminum contents were used for this evaluation. High basicity of the coagulant helped to properly control coagulation processes for treating turbid and low alkali raw water. It was difficult for operators to determine optimum coagulant dose for high basicity coagulants, since residual turbidity tended to decrease continuously as coagulant dose increased. Turbidity removal efficiencies with high basicity coagulants(E and F) were higher than the other coagulants at ambient pH for the M WTP. Turbidity removal efficiencies, however, at adjusted pH 7.0 showed similar among six coagulants. Residual turbidity kept low at excess dosages with high basicity coagulants. Optimum coagulant dosages at adjusted pH 7.0 showed higher than those at ambient pH in M WTP. On the contrary in B WTP, optimum coagulant dosage at ambient pH were higher than that at adjusted pH 7.0.

• Journal of Environmental Science International
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• v.19 no.1
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• pp.89-96
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• 2010

The separation of $TiO_2$ wastewater carried out by an electrocoagulation/flotation process, which had various operating parameters. The effect of electrode material (aluminum and four dimensionally stable electrode), applied current (0.07~0.5 A), electrolyte concentration (0~1 g/L), solution pH (3~11), initial turbidity (1000~20000 NTU) and suspended solid concentration (5000~25000 mg/L) were evaluated. Turbidity removal efficiency of the soluble anode (aluminum), which could produce metal ions, was higher than that of the dimensionally stable electrode. Considering operation time, turbidity removal and electric power, optimum current was 0.19 A. The more NaCl dosage was high, the less electric power was required. However, optimum NaCl concentration was 0.125 g/L considered removal efficiency, operation time and cost. Initial $TiO_2$ concentration did not affected turbidity removal on the electrocoagulation/flotation operation. The electrocoagulation/flotation process was proved to be a very effective separation method in the removal of $TiO_2$ from wastewater.

• Korean Journal of Ecology and Environment
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• v.47 no.2
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• pp.82-90
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• 2014

To assess the adverse effects of suspended solids on fishes, the hatching rate of embryo, and survival and growth of larvae were measured with common fish species of river such as crusian carp (Carassius auratus), common carp (Cyprinus carpio) and medaka (Oryzias latipes). Bioassay on hatching rate of embryo was conducted with a range of turbidity as 10 levels from 0.2 to 8,080 NTU. Another bioassay on 4-day larval survival and 21-day larval growth were also conducted with a range of turbidity as 8 levels from 0.1 to 8,260 NTU, and 6 levels from 0.7 to 2,030 NTU, respectively. The hatching rate of C. auratus was not significantly different from that of control at turbidity below 4,040 NTU, whereas it decreased when turbidity was 8,080 NTU (p<0.05). The hatching rate of C. carpio was not affected by concentration of suspended solids. For O. latipes, the hatching rate significantly decreased from 254 NTU (p<0.001) and it was zero when turbidity was 8,080 NTU. The 4-day survival of larvae of all 3 species was not affected by turbidity, while the larval growth of all 3 species was significantly affected. The turbidity effect on the growth of C. auratus and C. carpio was observed from 7 days after the exposure at turbidity level of 145, 143 NTU, respectively. The turbidity effect on the growth of O. latipes was observed from 14 days after the exposure at turbidity level of 254 NTU. The results of this study will provide the basic information for the derivation of water quality criteria on suspended solids for the protection of aquatic ecosystem and the quantitative ecological risk assessment of freshwater environment.

• Korean Journal of Community Nutrition
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• v.17 no.2
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• pp.205-214
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• 2012

This study examined intakes of nutrients, carotenoids and polyphenols according to lens turbidity levels among adults visiting a cataract clinic. A total of 102 males and females aged 40 years or higher agreed to participate in the study, and a face-to-face survey interview was conducted to obtain information on general characteristics, health behaviors, and dietary intakes of each participant. The dietary data were collected by a food frequency questionnaire which was previously validated in a Korean population. In addition to essential nutrients, intakes of a total of 10 carotenoids and polyphenols were calculated based on the tables of food functional composition developed by National Academy of Agricultural Science. The subjects were divided into 3 groups according to turbidity levels (< 16, ${\geq}16$ and < 25, ${\leq}25$), and health behaviors and dietary intakes were compared among the turbidity groups. Data showed seemingly higher energy intake and lower dietary antioxidant (i.e., vitamin A, ${\beta}$-carotene, lutein, zeazanthin, lycopene, cryptozanthin) intakes in the highest turbidity group. However, no statistically significant findings were found in all the comparative analysis on characteristics of health behavior and intakes of nutrients, carotenoids and polyphenols. The current study findings should be cautiously interpreted in consideration of several limitations including a cross-sectional study design, a small sample size, uneven sample size distribution across turbidity groups, and limited generalizability due to using a convenience sample. Therefore we cannot conclude that the risk of cataract is unrelated with dietary antioxidant intakes based solely on the results of this study.

• Proceedings of the Korea Water Resources Association Conference
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• 2005.05b
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• pp.1312-1316
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• 2005

Due to the Typhoon MAEMI on Sep. of 12 in 2003, the turbidity value of IMHA Dam was recorded more than 213NTU until now. The natural zeolite located in the east coast of Korean peninsula was applied to reduce turbidity with ion exchange Process. The result of this technique, the value of turbidity was reduced less than 1NTU. Also the value of pH showed stable state compare to before and after.

• Journal of Korean Society on Water Environment
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• v.22 no.5
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• pp.933-942
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• 2006

In this study, temperature, turbidity, suspended paniculate matter (SPM) distribution and mineral characteristics were investigated to explain spatial distribution of the turbid-water environment of Yongdam reservoir in July, 2005. Six stations were selected along a longitudinal axis of the reservoir and sampling was conducted in four depths of each station. Water temperature was showed the typical stratified structure by the effects of irradiance and inflow. Content of inorganic matter in suspended particles increased with the concentration of suspended particulate matter (SPM) due to the reduction of ash-free dry matter (AFDM). Turbidity ranged from 0.6 to 95.1 NTU and the maximum turbidity value of each station sharply increased toward downstream from upstream. The high turbidity layers were located at the depth between 12~16 m. Particle size ranged from 0.435 to $482.9{\mu}m$. day and silt-sized particles corresponded 91.9~98.9% and 1.1~8.0% in total numbers of SPM, respectively. Turbidity showed high correlations with clay (r=0.763, p<0.05) and silt content (r=0.870, p<0.05).Inorganic matter content (r=0.960, p<0.01) was more correlated with turbidity than organic matter (r=0.823, p<0.05). Mineral characterization using x-ray diffraction and electron probe microanalyzer demonstrated that the major minerals contained in the SPM were kaolinite, illite, vermiculite and smectite. As results of this study, surface water discharge as well as small size of the SPM were suggested as long-term interfering factors in settling down the turbid water in the reservoir.

• Journal of Korean Society on Water Environment
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• v.18 no.3
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• pp.253-260
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• 2002

The purpose of this research was to describe the mechanisms and prevention of initial degradation in turbidity of the sand filter effluent. The method used was by adding a coagulant (PAC) to the sand filter after backwashing as a means of reducing turbidity. It was found that adding 80 mg/L of PAC solution to the sand filter was very effective in improving the initial effluent turbidity. A turbidity removal efficiency of 99 % was observed in the initial term period as compared to a 70% efficiency without PAC addition. The PAC solution added to the sand filter resulted in high aluminum concentration at the upper layer as compared with the bottom layer of the sand filter column. A change in the zeta potential to a strong positive-ions at upper layer was observed at this time but only a small change was obtained at the bottom. This result showed that the zeta potential of the sand was changed to positive with PAC coating. The effect of pH on zeta potential with PAC addition was also investigated. Zeta potential was greatly changed to positive-ion at pH 4~6. A series of experiments was then conducted in this study to optimize the pH of the PAC solution to be added to the sand filter after backwashing. The removal efficiency of turbidity was found to be highest at pH 5. This result suggested that hydrolyzed aluminium species attached to the surface of the sand enhanced the removal of turbidity of the effluent.