• Korean Journal of Poultry Science
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• v.31 no.1
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• pp.25-31
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• 2004

The effect of drinking rhus tree-extract on performance of broiler was performed to investigate development of natural antibiotic in process of broilers production. A total of 320 broiler chicks at 1 day of age were fed the commercial diet and water, drinking water containing 0 ppm(control), 500 ppm (T1), 1,000 ppm (T2) and 2,000 ppm (T3) of rhus tree-extract fur seven weeks. The body weight gain and fred conversion ratio were not different by drinking rhus tree-extract until 35 days of age, but body weight gain and feed conversion ratio were tend to improve by drinking rhus tree-extract over 35 days of age, the improvement was higher in both T$_1$, and T$_3$ than control group(p＜0.05) when 35 to 42 days of age. There was a decrease in the microflora population of both E. coli. end Salmonella in the cecum contents and feaces in broilers by drinking rhus tree-extract. The digestibility of dry matter, crude fat, and crude ash of feed were tend to increased in broiler drinking rhus tree-extract. Digestibility of crude protein of feed in broiler three treated groups was significantly improved (p＜0.15) as compared with those in control group. These results indicated that the drinking rhus tree-extract were effective in the body weight gain, feed conversion ratio, decreasing of microflora population of both E. coli and Salmonella in the cecum contents and feaces, and it had also effective the digestibility of nutrients in broilers.

• Membrane and Water Treatment
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• v.6 no.1
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• pp.77-94
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• 2015

Ultrafiltration membranes have several advantages over conventional drinking-water treatment. However, this technology presents major limitations, such as irreversible fouling and low removal of natural organic matter. Fouling depends heavily on the raw-water quality as well as on the operating conditions of the process, including flux, permeate recovery, pre-treatment, chemical cleaning, and backwashing. Starting with the premise that the optimisation of operating variables can improve membrane performance, different experiments were conducted in a pilot plant located in Granada (Spain). Several combinations of permeate and backwashing flow rates, backwashing frequencies, and aeration flow rates were tested for low-quality water coming from Genil River with the following results: the effluent quality did not depend on the combination of operating conditions chosen; and the membrane was effective for the removal of microorganisms, turbidity and suspended solids but the yields for the removal of dissolved organic carbon were extremely low. In addition, the threshold transmembrane pressure (-0.7 bar) was reached within a few hours and it was difficult to recover due to the low efficiency of the chemical cleanings. Moreover, greater transmembrane pressure due to fouling also increased the energy consumption, and it was not possible to lower it without compromising the permeate recovery. Finally, the intensification of aeration contributed positively to lengthening the operation times but again raised energy consumption. In light of these findings, the feasibility of ultrafiltration as a single treatment is questioned for low-quality influents.

• Journal of environmental and Sanitary engineering
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• v.23 no.2
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• pp.71-79
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• 2008

We examined 165 unchlorinated natural drinking water samples for the presence of E. coli group resistant to antimicrobial agent and chlorine in nothern Gyeongbuk area in 2007. Among 165 water samples, 21 samples(12.7%) were positive to total coliforms and Six genus, 16 strains of E. coli groups isolated from 16 samples showed resistance against more than one antimicrobial agent such as Ampicillin, Tetracycline and Chloroamphenicol. Among 16 strains, 14 strains resistant to Ampicillin, 9 strains resistant to Tetracycline and one strain resistant to Chloroampenicol. but all 16 strains did not contain any integron gene cassettes, which contribute to the spread of antimicrobial resistance alleles by lateral gene transfer of gene cassettes in a variety of enteric bacteria. The minimal inhibitory concentration(MIC) of 14 strains which showed resistant to Ampicillin was between $12{\mu}g/m{\ell}$ and $32{\mu}g/m{\ell}$, Nine strains resistant to Tetracycline showed between $32{\mu}g/m{\ell}$ and $128{\mu}g/m{\ell}$ and one strain resistant to Chloroampenicol showed $128{\mu}g/m{\ell}$. The chlorine sensitivity of 16 strains isolated from unchlorinated natural water sample did not show any difference among strains by the concentration of initial free chlorine and elapsed time after chlorine treatment. All 16 strains were killed after 1hr. exposure at $0.2mg/m{\ell}$ of free chlorine per liter or 30minutes exposure at $0.4mg/m{\ell}$ of free chlorine per liter.

• Journal of Korean Society on Water Environment
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• v.31 no.5
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• pp.563-568
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• 2015

Natural Organic Matter (NOM) is a precursor of disinfection by products. Recently, with the increase in NOM concentration caused by a large amount of algae, the creation of disinfection by-products is becoming a big issue. Therefore, in this study, PAC+Membrane+F/A hybrid process was organized to control disinfection by-products in small-scale water treatment plants. The optimal dosage of PAC was set at 20 mg/L through Lab. scale test. Also, it is judged that NOM concentration must be less than 1.0 mg/L to meet the recommended criteria of drinking water quality monitoring items of disinfection by-products during chlorination. The existing conventional water treatment process was compared to the independent F/A process and the PAC+Membrane+F/A hybrid process through pilot plant operation, and the result showed that there is a need to apply an advanced water treatment process to remove not only NOMs but also Geosmin caused by algae. Accordingly, it is considered that applying the PAC+Membrane+F/A process will help in controling a clogged filter caused by a large amount of algae and disinfection by-products created by chlorination and can be used as an advanced water treatment process to meet the recommended criteria of drinking water quality monitoring items.

• Journal of Korean Society of Water and Wastewater
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• v.22 no.3
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• pp.343-350
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• 2008

Many reports have warned of insufficient water supply in most countries in future and prospected providing safe and clean water become more difficult by lack of access to sustainable drinking water resources. Several facts and figures explained the impact by natural climate change and human activity results in the water scarcity and deterioration. Among many scientific solutions, the seawater desalination using a reverse osmosis membrane, so called SWRO (Seawater Reverse Osmosis) process, has been recognized as one of the most promising alternatives because of its stability and efficiency in producing large amount of drinking water from seawater through desalination by membrane filtration. Recently, in Korea, numerous researches are conducted to develop more productive and cost effective SWRO process for its wide implementation. The objective of this paper is to review the patents concerning SWRO technologies involving the plant engineering, maintenance including pretreatment of seawater and fouling control, module design, and mechanical units development for energy saving. The patents in Korea, U.S., Japan, Europe, and PCT were intensively researched and analyzed to provide the state of the art as well as leading edge technology on SWRO. This information can hopefully suggest meaningful guidelines on future research and development.

• Journal of Korean Society of Water and Wastewater
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• v.22 no.1
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• pp.131-140
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• 2008

The application of magnetic ion exchange resin($MIEX^{(R)}$) is effective for natural organic matter(NOM) removal and for control of the formation of disinfection byproducts(DBPs). NOM removal is also enhanced by adding $MIEX^{(R)}$ with coagulant such as polyaluminium chloride(PACl) in conventional drinking water treatment systems. In the application of $MIEX^{(R)}$, it is important to understand changes of NOM characteristics such as hydrophobicity and molecular weight distributions with $MIEX^{(R)}$ or $MIEX^{(R)}$+coagulant treatment.To observe characteristics of NOM by treatment with $MIEX^{(R)}$ or $MIEX^{(R)}$+coagulant, four major drinking water sources were employed. Results showed that the addition of $MIEX^{(R)}$ to coagulation significantly reduced the amount of coagulant required for the optimum removal of dissolved organic matter(DOC) and turbidity in the all four waters. The DOC removal was also increased approximately 20%, compared to coagulant treatment alone. The process with $MIEX^{(R)}$ and coagulant showed that complementary removal of hydrophobic and hydrophilic fraction of DOC. The combined processes preferentially removed the fractions of intermediate (3,000-10,000 Da) and low (< 500 Da) molecular weight. The microfiltration test showed that membrane cake resistance was decreased for waters with flocs from $MIEX^{(R)}$+coagulant. A porous layer was formed to $MIEX^{(R)}$ on the membrane surface and the layer consequently inhibited settling of coagulant flocs, which could act on a foulant.

• Membrane Journal
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• v.18 no.1
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• pp.65-74
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• 2008

NOM and fine particles are the main target materials in water treatment using membranes. Particularly, humic substances extracted from soils are frequently used in many fundamental studies representing natural organic matter in raw water for drinking water treatment. In this study, ultrafiltration (UF) of artificial humic water and natural river water was conducted and the characteristics of removal efficiency and permeability were compared. In the UF of river water, the transmembrane pressure increased in the same pattern with that of 5 mg/L humic water. For the removal of organic matter and fine particles, however, two types of feed water had shown different trends. Kaolin particles and humic acids added to artificial water were better removed, while colloids and organics in natural water were relatively poorly removed. From the $UV_{254}$ and GPC analyses, it seemed that the hydrophobicity and size of humic substances contributed to the greater removal of organic matter. The UF membrane applied for humic water also showed a higher flux recovery by caustic chemical cleaning than that for river water.

• Journal of Soil and Groundwater Environment
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• v.16 no.1
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• pp.12-18
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• 2011

To investigate the natural reduction characteristics of radon with a short half-life (3.82 day) in drinking Qgroundwater, we analyzed the changes of radon concentrations of groundwater, waters in storage tanks, and tap waters from the small-scale groundwater-supply systems (N = 301) by LSC (Liquid Scintillation Counter). We also analyzed the concentrations of uranium (half-life 4.5 billion years) in the waters by ICP/MS to compare with natural reduction of radon concentration. The radon concentrations of 68 groundwater-supply systems occupying 22.6% of the total samples exceeded the US EPA's Alternative Maximum Contaminant Level (AMCL : 4,000 pCi/L), with the average radon concentration of 7,316 pCi/L (groundwaters), 3,833 pCi/L (tank waters) and 3,407 pCi/L (tap waters). Compared to the radon levels of pumped groundwaters, those of tank and tap waters naturally reduced significantly down to about 50%. Especially, in case of 29 groundwater-supply systems with the groundwater radon concentrations of 4,000~6,000 pCi/L, average radon concentrations of the tank and tap waters naturally decreased down to the AMCL. Therefore this study implies that radon concentrations of drinking groundwater can be effectively reduced by sufficient storage and residence in tanks.

• Journal of Food Hygiene and Safety
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• v.12 no.1
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• pp.55-62
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• 1997

This study was carried out to investigate the microbiological and chemical properties of natural water during storage. The water samples were taken at the time of purchase and the opened bottles and unopened bottles stored at the temperature of 4$^{\circ}C$, 18$^{\circ}C$, and 3$0^{\circ}C$. The bacterial content normally rose to 2.06$\times$102 CFU/$m\ell$ for the unopened bottles and 2.91$\times$102 CFU/$m\ell$ for the opened bottles after 2 weeks of storage, and 1.21$\times$102 CFU/$m\ell$ and 2.64$\times$102, respectively, after 24 weeks of storage. The number of viable cells of bacteria peaked more rapidly at the storage temperature of 3$0^{\circ}C$ than 18$^{\circ}C$. But the total samples were found to be negative for coliforms test during the study period. The average range of pH value was from 7.39 to 7.76. The results showed that the nitrates and chlorides satisfied the Korea Drinking Water Quality Standards during the storage period of 24 weeks. However, the undesirable changes of the taste and odor were detected within 2 weeks and 3 weeks, respectively.

• Journal of Korean Society of Water and Wastewater
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• v.28 no.4
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• pp.397-409
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• 2014

Algal problem in drinking water treatment is being gradually increased by causing deterioration of water supplies therefore, especially taste and odor compounds such as geosmin and 2-MIB occur mainly aesthetic problem by its unpleasant effects resulting in the subsequent onset of complaints from drinking water consumer. Recently, geosmin and 2-MIB are detected frequently at abnormally high concentration level. However, conventional water treatment without advanced water treatment processes such as adsorption and oxidation process, cannot remove these two compounds efficiently. Moreover, it is known that the advanced treatment processes i.e. adsorption and oxidation have also several limits to the removal of geosmin and 2-MIB. Therefore, the purpose of this study was not only to evaluate full scale nanofiltration membrane system with $300m^3/day$ of permeate capacity and 90% of recovery on the removal of geosmin and 2-MIB in spiked natural raw water sources at high feed concentration with a range of approximately 500 to 2,500 ng/L, but also to observe rejection property of the compounds within multi stage NF membrane system. Rejection rate of geosmin and 2-MIB by NF membrane process was 96% that is 4% of passage regardless of the feed water concentration which indicates NF membrane system with an operational values suggested in this research can be employed in drinking water treatment plant to control geosmin and 2-MIB of high concentration. But, according to results of regression analysis in this study it is recommended that feed water concentration of geosmin and 2-MIB would not exceed 220 and 300 ng/L respectively which is not to be perceived in drinking tap water. Also it suggests that the removal rate might be depended on an operating conditions such as feed water characteristics and membrane flux. When each stage of NF membrane system was evaluated relatively higher removal rate was observed at the conditions that is lower flux, higher DOC and TDS, i.e., $2^{nd}$ stage NF membrane systems, possibly due to an interaction mechanisms between compounds and cake layer on the membrane surfaces.