• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.41 no.5
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• pp.44-49
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• 2009

Old newspaper was deinked using commercial cellulolytic enzymes and a surfactant complex at low alkalinity. The properties of the deinked pulp(DIP) were evaluated and the suspended solids content, cationic demand, turbidity, and chemical oxygen demand(COD) of the process water were measured. The results can summarized as follows, 1. The brightness and yield of the DIP were improved using enzymatic surfactant complex deinking. 2. The amount of foaming during deinking with the enzyme surfactant complex was higher than that with synthetic surfactant deinking. However, it was not sufficient to cause process problem. 3. The pH and turbidity of the white water from deinking with the enzyme surfactant complex were similar to those of the white water from surfactant deinking. 4. The suspended solids content, cationic demand, and COD of the white water from deinking with the enzyme surfactant complex were improved compared to those of the white water from surfactant deinking.

• Journal of environmental and Sanitary engineering
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• v.12 no.1
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• pp.49-58
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• 1997

A study on the synthesis of zeolite from bituminous coal ESP fly ash as a raw material, which was emitted from the power plant, was carried out to reduce environmental problems and reuse of the industrial wastes. Bituminous coal fly ash was used as the source of silica and alumina. Zeolite was synthesized by hydrothermal reaction in aqueous NaOH solution with sodium aluminate as additive. The objective of this study is to elucidate the effect of several experimental variables on the synthesis of zeolite. The effects of preroasting temperature, mixing speed, leaching alkalinity, and molar ratio of Na$_{2}$O/SiO$_{2}$ and SiO$_{2}$/Al$_{2}$O of the products were investigated. The synthesized zeolite was proved to be NaA, which is known as 4A type, by comparing with SEM images, and X-ray diffraction analysis. And also we know that the transformation of zeolite A take places into other types of zeolites, i.e. Hydroxysodalite, zeolite P, with the variation of leaching alkalinity.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2016.10a
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• pp.106-107
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• 2016

Construction waste is recycled and used for the efficient and eco-friendly disposal of construction waste increasing due to reconstruction and redevelopment project and so on. There is recycled aggregate as a typical case. And this recycled aggregate shows strong alkalinity due to calcium hydroxide, and causes many environmental problems. Therefore, this is a study on reduction in the strong alkalinity of recycled aggregate by using phosphate of ammonium in order to reduce the pH of recycled aggregate. Besides, a possibility that a pH reducing agent of recycled aggregate could be applied to a site was evaluated. As a result, it was possible to verify that pH decreased as the percentage of pH reducing agent increased. It is thought that the pH reducing agent can be applied to a site by methods such as immersion and spray using the pH reducing agent in the process of producing recycled aggregates.

• Journal of Korean Society of Water and Wastewater
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• v.7 no.2
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• pp.39-46
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• 1993

In this experimental study, it is concerned to develop a simple equation using jar-test results in order to predict the optimum dosage of coagulant, PAC(polyaluminum chloride). Considering the relationships with the reactions of coagulation and flocculation, the four independent variables (e.g. turbidity, temperature, pH and alkalinity) are selected out of many parameters and they are put into calculations to develop an equation by means of multi-regression method. As the result, the dosing rate of PAC is proportional to turbidity, pH and alkalinity, but in inverse to temperature. And the developed equation is as follow, $$D_c=\frac{3.2{\cdot}T^{0.37}{\cdot}A^{0.04}{\cdot}P^{0.5}}{t^{0.1}},\;(R^2=0.9443)$$ And also, comparing between the estimated value from the equation and the real dosing rate in the plant, Kwangam and Tdukdo, during 1988~1991, it is represented an agreement having a relative error of 16.4%, 17.8%, respectively.

• The Korean Journal of Ecology
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• v.7 no.2
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• pp.61-66
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• 1983

Seasonal changes of aquatic environmental factors, phytoplankton biomass and primary productivity were investigated in the Jido pond (a phytoplankton proliferating pond) from August 1982 to October 1983. Secchi disc transparency, pH, alkalinity and inorganic nitrogen concentration ranged 24~105cm, 7.5~10.6, 50~175mgCaCO3/l 0.1~4.0mgN/l, respectively. The minimum values of transparency, alkalinity and inorganic nitrogen concentration and the maximum value of pH were obtained during the phytoplankton proliferating season. The phytoplankton biomass changed in the range of 51~1146mgchl/m3 with considerable fluctuations but maintained fairly constant in winter. Themaximum and minimum rates of monthly carbon inflow (net primary production) of the phytoplankton community attained 1190gc/m2 in August 1982 and 68g/m2 in February 1983, respectively. The annual rates of inflow and outflow from August 1982 to July 1983 were 7.384 and 7.396kgc/m2, respectively. Turnover rate of phytoplankton carbon and efficiency of radiation of the phytoplankton community varied in the ranges of 60~130%/day (annual mean, 90%/day) and 0.9~11.2% (annual mean, 6.3%), respectively.

• Journal of Korean Society of Water and Wastewater
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• v.19 no.2
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• pp.228-237
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• 2005

The main purpose of this study was to investigate the red water reducing effects of phosphate based inhibitor when it was applied to water distribution system. The effects of pH, alkalinity, calcium concentration in the reduction of the red water also studied. The most finished water in Korea showed relatively high corrosiveness and was required to introduce some types of corrosion reducing methods such as addition of alkalinity. The precipitation of $CaCO_3$ by addition of $Ca(OH)_2$ formed porous film on the surface of the carbon steel pipes and was displaced easily from the surface of the pipes; on the other hand, addition of zinc phosphate (ZOP) formed reliable film on the surface and reduced iron release and color. Although the main function of ZOP was to suppress the release of Pb and Cu, it also reduced iron concentration released from water distribution pipes.

• Journal of Korean Society on Water Environment
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• v.27 no.4
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• pp.438-444
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• 2011

Magnesium is one of the abundant natural resources in the earth crust and seawater, which is directly related to various organisms activities interconnecting with water-rock system. In aqueous system, magnesium is known to predominantly exist in the form of $Mg^{2+}$ ion which is verified in its $E_h-pH$ diagram. When it is at equilibrium in aqueous system, temperature takes an essential role to complete equilibrium states. This study represents the change of the stable region of magnesium ion according to temperature, and how the consequences would affect aquatic organisms. It was revealed that there is a noticeable tendency shrinking the stable region of magnesium ion in a diagram as temperature increases, and as a result, aquatic bio-species presumably have difficulties to absorb the nutrient. Also, it was considered that the water system would be acidified by decreasing alkalinity.

• Environmental Engineering Research
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• v.9 no.2
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• pp.88-95
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• 2004

• Journal of Environmental Science International
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• v.22 no.1
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• pp.1-6
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• 2013

A fixed biofilm reactor system composed of anaerobic, anoxic(1), anoxic(2), aerobic(1) and aerobic(2) reactor was packed with synthetic activated ceramic (SAC) media and adopted to reduce the inhibition effect of low temperature on nitrification activities. The changes of nitrification activity at different wastewater temperature were investigated through the evaluation of temperature coefficient, volatile attached solid (VAS), specific nitrification rate and alkalinity consumption. Operating temperature was varied from 20 to $5^{\circ}C$. In this biofilm system, the specific nitrification rates of $15^{\circ}C$, $10^{\circ}C$ and $5^{\circ}C$ were 0.972, 0.859 and 0.613 when the specific nitrification rate of $20^{\circ}C$ was assumed to 1.00. Moreover the nitrification activity was also observed at $5^{\circ}C$ which is lower temperature than the critical temperature condition for the microorganism of activated sludge system. The specific amount of volatile attached solid (VAS) on media was maintained the range of 13.6-12.5 mg VAS/g media at $20{\sim}10^{\circ}C$. As the temperature was downed to $5^{\circ}C$, VAS was rapidly decreased to 10.9 mg VAS/g media and effluent suspended solids was increased from 3.2 mg/L to 12.0 mg/L due to the detachment of microorganism from SAC media. And alkalinity consumption was lower than theoretical value with 5.23 mg as $CaCO_3$/mg ${NH_4}^+$-N removal at $20^{\circ}C$. Temperature coefficient (${\Theta}$) of nitrification rate ($20^{\circ}C{\sim}5^{\circ}C$) was 1.033. Therefore, this fixed film nitrogen removal process showed superior stability for low temperature condition than conventional suspended growth process.

• Journal of environmental and Sanitary engineering
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• v.16 no.3
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• pp.96-103
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• 2001

This study was carried out to investigate the major factors for the removal of NOMs (Natural Organic Matters) by alum ferric chloride and blended coagulants that consisted of alum and ferric chloride. Investigated factors were pH, the dosage of coagulant, alkalinity, hardness and bloc strength. The particle size contained in the test water came from the Han River was also measured. DOC(Dissolved Organic Carbon) removal at pH 6 was two to three times higher than at pH 8.5. The blended coagulant showed 9 to 10 percent higher DOC removal efficiency and 2 to 4 percent higher turbidity under the same condition. Alkalinity consumption of alum, ferric chloride and blended coagulant was 81%, 90% and 86% of theoretical value, respectively. The limit concentration of alkalinity to avoid pin floe was 10 mg $CaCO_3/L$ when alum was used. Hardness had no apparent effect on coagulation. The residual turbidity and $UV_{254}$ showed a tendency of increasing with floc strength($sec^{-1}$) increase. The order of floe strength was the following; alum >blended coagulant > ferric chloride. The particle counter test showed 89 percent of the small particle size(SPS, $1~5{\;}{\mu}textrm{m}$) and 11 percent of the medium to large particle size(M.LPS, $5~125{\;}{\mu}textrm{m}$). At PH7.85, the particle removal efficiencies of SPS($1~5{\;}{\mu}textrm{m}$) and M.LPS($5~125{\;}{\mu}textrm{m}$) in the coagulation process were 81% and 95%, respectively.