• Journal of Korean Society of Environmental Engineers
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• v.28 no.8
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• pp.843-851
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• 2006

Although the detected amounts of those disease-causing(oo)cysts were high at each point in 2001, the detected amounts of Cryptosporidium and Giardia had decreased at low levels below 10(oo)cysts until 2004. Considered the detection results of each season, the most highly detected amounts of(oo)cysts were mostly recorded in summer and late summer(from June to September), while the site which the biggest amount was detected, was the point at Goryeung. The relation of Cryptosporidium with the water quality items was low, but the relations of Cryptosporidium and Giardia with turbidity were high($R^2$=0.4914, $R^2$=0.6176 respectively). And the detected amounts of Cryptosporidium and Giardia were relatively high, 20(oo)cysts/20L when the turbidity was more than 20 NTU. It was also found that the relation between the distribution of Cryptosporidium and Giardia was high, $R^2$=0.8432 and the density of Giardia was generally higher than that of Cryptosporidium. And Cryptosporidium and Giardia were simultaneously detected at each point. The primary sources that affected the density of those(oo)cysts were the livestock waste water and sewage.

• Journal of Environmental Science International
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• v.4 no.1
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• pp.81-90
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• 1995

In order to provide the basic information for the water quality modeling, the water pollution indicators of Sin stream and Keumho river flowing through Taegu city were measured, and the Periodical variations of these indicators were studied under the condition of stagnating for 19 days. For this experiment, three sampling sites(Sungpook bridge, Mutae bridge and Gangchang bridge) were selected. Sungpook bridge is located most down the Sin stream, Mutae bridge and Gangchang bridge are located on the lower Keumho river. The results were as follows. 1. The values of water pollution indicators measured at Mutae bridge were pH 8.7, TSS 51mg/1, TS 383mg/1, Cl- 60.68mg/1, turbidity 32FTU, DO 8.58mg/1, oxygen deficit 2.02mg/1, COD 16.32mg/1, organic carbon 13.60mg/1. 2. At Gangchang bridge located down more than Mutae bridge, the values of these indicators were pH 8.0, TSS 26mg/1, TS 737mg/1, Cl- 90.59mg/1, turbidity 37FTU,DO 3.49mg/1, oxygen deficit 7.11mg/1, COD 28.02mg/1, organic carbon 14.28mg/1. 3. At Sungpook bridge, the values of these indicators were pH 8.3, TSS 145mg/1, TS 344mg/1, Cl- 32.51mg/1, turbidity 60FTU, DO 6.53mg/1, oxygen deficit 4.07mg/1, COD 43.79mg/1, organic carbon 11.03mg/1. 4. At Mutae bridge and Sungpook bridge of which initial DOs were high, DOs have decreased under the condition of stagnating for 7 days and increased after that time. On the contrary, at Gangchang bridge of which oxygen deficit was very high(7.11mg/l), DO have increased under the condition of stagnating for 13 days and decreased after that time 5. All the samples showed the quick decrease of CODs and organic carbons under the condition of stagnating for 19 days. Nevertheless, at Sungpook bridge ·of which initial COD was yeW high(43.79mg/1), the value of COD measured at the last day of experiment was still high(21.35mg/1) because of a large quantity of reducing inorganic matters. 6. All the samples didn't show the distinct decrease of turbidities because of a large quantity of nonbiodegradable inorganic solids.

• Korean Journal of Medicinal Crop Science
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• v.19 no.3
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• pp.198-204
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• 2011

This study was performed to enhance antifungal activity of anthracnose in chili pepper by nanopaticles of thiamine di-lauryl sulfate (TDS) through high pressure homogenization process. Yield of TDS was 79.14% by reaction of thiamine hydrochloride and sodium lauryl sulfate. TDS nanopaticle solution was manufactured through high pressure homogenization process. The turbidity of nanoparticles solution was increased with increasing the concentration of TDS, and nanoparticles solution of 100 ppm was showed the highest turbidity with absorbance of 3.212. The size of nanoparticles solution was measured as average 258.6 nm by DLS. Nanoparticles solution of 100 ppm showed growth inhibition activity with higher than about 80% compared to the control group against Colletotrichum gloeosporioides. Finally, nanoparticles solution was increased effectively the penetration of the TDS nanopaticles on attached cell membrane of hyphae and started to destruct the cells under microscope observation. Consequently, we suggested that the TDS nanoparticle solution by high pressure homogenization process might be suitable biochemical pesticides for improving the antifungal activities against anthracnose in pepper.

• Water for future
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• v.15 no.3
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• pp.23-36
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• 1982

The stochastic variations and structures of time series data on water quality were examined by employing the techniques of autocorrelation function, variance spectrum, Fourier series, autoregressive model and ARIMA model. These time series included hourly and daily observation on DO, turbidity, conductivity pH and water temperature. The measurement was made by automatic recording instrument at Noryangjin and Dook-do located in the downstream part of Han River during 1975 and 1976. Hourly water quality time series varied with the dominant 24-hour periodicity, and the 12-hour periodicity was also observed. An important factor affecting 24-hour periodic variation of DO is believed to be photosynthesis by algae. These phenomena might be attributable to periodic discharges of municipal sewage. Noryangjin site showed the more distinct 12-hour periodicity than Dook-do site did, and tidal effect might be responsible for the difference. The water quality, as measured by DO and turbidity, was better in the afternoon compared with the quality in the morning. This change can be explained by the periodic variation of DO, temperature and the amount of municipal wewage discharge. It was also observed that the water temperature at Noryangjin was higher than the temperature at Dook-do. This difference might have been caused by the pollutants that were added to the section between two sites. The correlation coefficients between some of the variables were fairly high. For example, the coefficient was -0.88 between DO and water temperature, 0.75 between turbidity and river flow, and 0.957 between water temperature and air temperature. The lag time of heat transfer from the air to the water was estimated as 24 days. The first order auto-regressive model was appropriate for explaning standardized hourly DO time series. The ARIMA model of (1, 0, 0) type provided relatively satisfactory results for daily DO time series after the removal of significant harmonic value.

• The Korean Journal of Food And Nutrition
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• v.26 no.3
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• pp.414-420
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• 2013

The aim of this study was to investigate the effects of environmental factors such as temperature, salinity, turbidity and pH on the growth of pathogenic Vibrios. In this study, we was obtained the samples from 2 different sites of the Incheon coastal area between January 2012 and December 2012. The water temperature in August and September was the high. the Incheon port changes the width of a small, wherease in the case of Hanjin harbor of changes of larger width. Salinity and turbidity showed significant differences, whereas temperature and hydrogen ion concentration was not significant. Pathogenic vibrios was determined using the real-time PCR method. Pathogenic vibrios in the Incheon port and Hanjin harbor were detected in 11 samples (91.67%) and 9 samples (75.0%) of Vibrio cholerae, 7 samples (58.3%) and 6 samples (50.0%) of V. vulnificus, 10 samples (83.3%) and 12 samples (100.0%) of V. parahaemolyticus, respectively. Pathogenic Vibrio bacteria were the highest at $26.8^{\circ}C$ of seawater in August. Quantitative results were the following: 102 $cell/m{\ell}$ in Vibrio cholerae, 7.876 $cell/m{\ell}$ in V. vulnificus, and 503.4 $cell/m{\ell}$ in V. parahaemolyticus, respectively. The enumeration of pathogenic vibrios showed a positive correlation with temperature and pH, but was negatively correlated with salinity and turbidity.

• Korean Journal of Ecology and Environment
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• v.46 no.1
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• pp.128-134
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• 2013

In the summer season (June~August) during the study period of Lake Doam, average concentrations of major water quality parameters, COD, SS, TN, and TP were 4.0, 16.2, 3.129 and $0.077mg\;L^{-1}$, respectively, and Chl-a was $11.8mg\;m^{-3}$. The result has indicated that Lake Doam was a meso-eutrotrophic lake. Lake Doam data from the summer season (June~August), precipitation from 2001 to 2012, and water quality (COD, SS, TN, TP, Chl-a etc.) of seven years (2001, 2002, 2004 and 2009~2012), were statistically analyzed for long-term trends by Mann-Kendall test and Sen's slope estimator methods. The statistical results showed that precipitation, SD, COD, TN, $NO_3-N$, $NH_3-N$ and Chl-a had decreasing trends, and EC, turbidity, SS, TP and DIP had increasing trends. Suspended solids and total phosphorus were directly affected by precipitation. In the case of suspended solids, more aggressive and constructive plans need to be implemented than the current turbidity reduction project to achieve the targeted water quality ($5mg\;L^{-1}$ of SS) in Lake Doam. In particular, we need to specify a project that considers the steep topographic characteristics of high, land farming areas and precipitation conditions of the Lake Doam watershed, which can increase the efficiency of a turbidity reduction project.

• Membrane Journal
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• v.21 no.4
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• pp.351-359
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• 2011

For advanced drinking water treatment of high turbidity water, we used the hybrid process that was composed of photocatalyst packing in space of between outside of multi-channel ceramic microfiltration membrane and membrane module inside. Photocatalyst was polypropylene (PP) beads coated $TiO_2$ powder by CVD (chemical vapor deposition) process. Instead of natural organic matters (NOM) and fine inorganic particles in natural water source, standard NOM solution was prepared with humic acid and kaolin. Water-back-flushing of 10 sec was performed per every period of 10 min to minimize membrane fouling. Resistance of membrane fouling ($R_f$) increased and J decreased as concentration of humic acid changed from 2 mg/L to 10 mg/L, and finally the highest total permeate volume ($V_T$) could be obtained at 2 mg/L. Then, treatment efficiency of turbidity and $UV_{254}$ absorbance were above 96.4% and 78.9%, respectively. As results of treatment portions by membrane filtration, photocatalyst adsorption, and photo-oxidation in (MF), (MF + $TiO_2$), (MF + $TiO_2$ + UV) processes, turbidity was treated little by photocatalyst adsorption, and photo-oxidation. However, treatment portions of $UV_{254}$ absorbance by adsorption (MF + $TiO_2$) and photo-oxidation (MF + $TiO_2$ + UV) at humic acid of 4 mg/L and 6 mg/L were above 9.0, 9.5 and 8.1, 10.9%, respectively.

• Journal of Environmental Science International
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• v.31 no.1
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• pp.1-8
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• 2022

In this study, solid-liquid separation conditions for coagulation and sedimentation experiments using inorganic coagulant (aluminum sulfate and Poly-Aluminum Chloride (PAC)) were optimized with brine wastewater discharged by the epoxy-resin process. When the turbidity and suspended solid (SS) concentration in raw wastewater were 74 NTU and 4.1 mg/L, respectively, their values decreased the lowest in a coagulant dosage of 135.0 - 270.0 mg Al³⁺/L. The epoxy resin was re-dispersed in the upper part of wastewater treated above 405.0 mg Al³⁺/L. The removal efficiencies of turbidity and SS via dosing with aluminum sulfate and PAC were evaluated at initial turbidity and SS of 74 - 630 NTU and 4.1 - 38.5 mg/L, respectively. They increased most in the range from 135.0 - 270.0 mg Al³⁺/L. The solid-liquid separation condition was quantitatively compared to the correlation of SS removal efficiency between the coagulant dosage and SS concentration based on the concentration of aluminum ions. The empirical formula, R = be^aD, shows the relationship between SS removal efficiency (R) and coagulant dosage (D) at 38.5 mg/L; it produced high correlation coefficients (r²) of 0.9871 for aluminum sulfate and 0.9751 for PAC.

• Journal of Korean Society on Water Environment
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• v.38 no.6
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• pp.275-281
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• 2022

To maintain water quality after water treatment, monitoring whether the quality of treated tap water quality changes is essential. However, current investigations are insufficient to prevent secondary contamination in drinking water supply systems. This study investigated Gyeonggi's e apartment where a red water problem occurred and monitored the water quality and corrosiveness of the overall water supply system to the apartment from June 2021 to April 2022. In a comparison of drinking water quality after water treatment and the influent of the reservoir, turbidity and heavy metal concentrations were increased and residual chlorine was decreased due to increases in temperature. Correlation analysis and principal component analysis (PCA) indicated that a low level of residual chlorine may cause the abscission of Mn²⁺ and Fe²⁺ through microorganism activation, which also causes a high level of turbidity. The corrosion index (LI) in the influent of the reservoir tank was increased due to Ca²⁺ and temperature. These results indicate that the corrosiveness of drinking water and the deterioration of drinking water quality were mainly increased between the drinking water treatment plant and the reservoir tank's influent. The findings provide clear evidence that it is essential to manage water supply systems and reservoir tanks to prevent the secondary contamination of drinking water.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.33 no.3
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• pp.205-212
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• 2000

Experimental investigations on the removal of protein, total suspended solids and turbidity from aquacultural water were carried out by using three types of foam separator: counter current air driven type foam separator (CCADFS), high speed aeration type foam separator (HSAFS) and venturi type foam separator (VFS). The decrease of flow rate by CCADFS, HSAFS and VFS were $0.4,\;66.1,\;77.2 {\%}$ respectively. Protein removal rates by three types foam separator were decreased with the increased hydraulic residence time (HRT). Bellw 0.32 minute and 0.21 minute of hydraulic residence times, protein removal rate of HSAFS and YES was higher than that of CCADFS, respectively. Protein removal rate of VFS was lower than that of HSAFS at any HRT. As increasing the HRT, protein removal efficiency of CCADFS was increased, but that of HSAFS and VES were decreased. The changes of removal rates and efficiencies of total suspended solid and turbidity were similar to proteins.