• Journal of Korean Society of Water and Wastewater
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• v.11 no.1
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• pp.81-87
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• 1997

Coagulation is very important process in water works. The subsequent processes are directly affected by this process. Many factors such as turbidity, alkalinity, pH, hardness, total organic carbon(TOC), velocity gradient and flocculation time effect on coagulation process. Among these factors, specially TOC is being concerned target substance to be removed due to trihalomenthanes(THMs) precursor and alkalinity is being one of the major parameter for removing TOC. We have researched the consumption of coagulant with TOC alkalinity concentration of water and removal efficiency of residual TOC and turbidity with alkalinity. Furthermore we have investigated particle size distributions with velocity gradient and alkalinity. The consumption of coagulant was proportionally increased to TOC and alkalinity concentration and the removal of TOC in Nakdong river water was very difficult more than 150 mg/l in alkalinity but large morecular weight organic such as humic acid could be removed easily. Coagulation of low alkalinity water was more rapidly occured than of high alkalinity water by analyzing the particle size distributions. High alkalinity water needed higher mixing energy for a good coagulation within limited flocculation time.

• Proceedings of the Korean Geotechical Society Conference
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• 2006.03a
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• pp.1155-1158
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• 2006

This paper presents a study on the construction condition and environmental effect of deep soil mixing. Construction condition means the difference in unconfined compressive strength with respect to the depth and location of samples. Environmental effect means alkalinity diffused from soil stabilizer. The experimental results indicate that the unconfined compressive strength vary with respect to the depth, and doesn't show consistency pattern. So, in field application we must decide a mixing ratio enough to satisfy the least unconfined compressive strength. The difference in unconfined compressive strength with respect to the location of samples is negligible. The generation of alkalinity from soil stabilizer is reduced by permeating in non-improved soil and it is expected that the diffusion of alkalinity has no environmental effect on soil and ground water.

• Applied Microscopy
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• v.42 no.3
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• pp.136-141
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• 2012

Diversification and individualization are pursued to fulfill the increasing human desire for beauty. There are many methods to change human appearances; of these, a permanent wave is often applied to improve beauty. A permanent wave uses physical and chemical methods to break and reform the bonds of natural hair. Thus, research into the optimized conditions for permanent waves is necessary to minimize hair damage and improve the efficiency of the treatment. The object of this study is to examine the effect of varying the alkalinity (8%, 12%, and 16%) of the permanent wave treatment on the wave efficiency, degree of hair damage via tensile strength, and degree of hair protein release. The results indicate that the treatment with the highest alkalinity (16%) is more effective than that with 8% alkalinity; however, the degree of hair damage when treated with the 16% alkalinity wave is higher than with the 8% alkalinity wave. Additionally, hair proteins increasingly dissolve with increasing alkalinity of the permanent wave.

• Journal of Korean Society of Water and Wastewater
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• v.9 no.3
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• pp.88-98
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• 1995

Several kinds of coagulants such as aluminum sulfate, PAC, PASS are being used to treat drinking water resulting in residual aluminum ions in the water. Recently, it has been reported that high intake of aluminum ion may cause neurological dieseases such as Alzheimer's diesease and presenile dementia. Because of the possible adverse effect, WHO and EEC recommand to regulate residual aluminum. The autorities in Korea also has plan of regulating residual alunimum from 1995. But there is not enough information about the range of residual aluminum ion concentration when the aluminum sulfate, PAC or PASS has been used as a coagulant. Therefore the study has been conducted to find out the range of residual aluminum ion concentration after using aluminum sulfate, PAC, and PASS. Furthermore the effect of turbidity and alkalinity have been investigated. The experimental results are summarized as; 1. Most of the residual aluminum ion concentrations were within $10^{-6}$ and $10^{-5}mole/l$. Three coagulants have not showed any considerable difference in the residual aluminum concentration up to 50 NTU. However PAC has showed the least residual aluminum in high turbidity water over 100 NTU. 2. The low alkalinity water having 25mg/l as $CaCO_3$ has showed less residual aluminum than the water having 50mg/l alkalinity. However, the difference was not significcant. 3. Even the lowest residual aluminum concentration was over 0.05mg/l. Therefore the process to reduce residual aluminum would be necessary in water treatment plants.

• Journal of Environmental Health Sciences
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• v.33 no.1 s.94
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• pp.43-48
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• 2007

This study investigated the effects of pH, alkalinity, and chlorine ion which are important water quality impact factors to the corrosion in the simulated distribution system where the copper pipe is affixed. The result shows that pitting index was increased as the alkalinity and chloride ion increase in the distilled water, but there was no relation to pH. Actually the uniform corrosion rate was decreased as the pH increase with the laboratory tap water. In conclusion, it is necessary to control the pH which stands above minimum 7.5 to prevent pitting corrosion in the copper pipe. Consequently, comprehensive research about the effect of lime soda($Ca(OH)_2$) which was used as a coagulation additive in the water treatment plant to pipe corrosion must be accomplished additionally.

• Journal of the Korean Ceramic Society
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• v.31 no.10
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• pp.1107-1114
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• 1994

Although various theories have been presented on the mechanism of setting retardation of plaster in addition to organic admixtures. The purpose of this paper is that Hydration studies of plaster of paris in the presence of carboxylic acids under alkalinity are examined in the coordination chemistry. Setting of plaster of paris is retarded by the addition of carboxylic acids except oxalic acid. And setting of plaster of paris contained 5 wt% of Ca(OH)2 is also retarded by the addition of above-mentioned carboxylic acids. The degree of retarding effect under alkalinity is found to be a function of the number of the functional group and the length of carbon chain of carboxyl acids. These reasons are attributed to the soluble complex formation, that is calcium complex formation between calcium ion and carboxylic acids. The author's proposal was confirmed by the results of electrical conductivity measurement. The formation of calcium complex was surpported by IR spectra.

• Journal of Korean Society of Water and Wastewater
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• v.20 no.2
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• pp.215-223
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• 2006

The internal corrosion of water distribution systems is the main cause for the problem of the public health threat as well as water leakage in the damaged pipeline, red water, and odor and taste of the tap water. This study was examined the effect of chemicals used for pH and alkalinity control and corrosion inhibitors for producing the optimal corrosion control method. Corrosion study at different pH and alkalinity indicated that these control using alkaline chemicals was effective in corrosion rate, Fe release reduction, but examined to be increased in turbidity and corrosion-by-products(TTHMs) problems. The turbidity was slightly increased, requiring caution in controlling corrosion with $Ca(OH)_2$. At pH 9.0, TTHMs concentration is increased two times corn pared with non-control of pH. Using the pipe which had experienced 28 years of exposure, iron release was decreased with the corrosion inhibitor. Consequently, pH, Alkalinity control method using alkaline chemicals must be complemented by corrosion inhibitor application for efficient corrosion control.

• Journal of Korean Society of Environmental Engineers
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• v.33 no.8
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• pp.583-590
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• 2011

The effect of the physical parameters in the reactor (aeration depth, bubble size, and surface area) and the alkalinity of the solution on the ammonia stripping by bubbling were evaluated. When an airflow of 30 L/min was bubbled below the solution surface in the range 6-53 cm, the ammonia removal rate were observed to be the same regardless of the bubbling depths. At pH 10.0 and a temperature of $30^{\circ}C$, the average rate constant and the standard deviation were $0.178h^{-1}$ and 0.004. No appreciable changes in the ammonia removal rate were also observed with varying the bubble size and the air-contacting surface area. Alkalinity of the solution was found to affect the ammonia removal rate indirectly. This is expected because the pH of the solution would vary with dissolution of gaseous $CO_2$ by air bubbling. The real wastewaters from landfill site and domestic wastewater treatment plant were tested. In the case of domestic wastewater (pH = 7.1, alkalinity = 75 mg/L), the ammonia removal rate was poor even with the control of pH to 9.3. The raw landfill leachate (pH = 8.0, alkalinity = 6,525 mg/L), however, showed the appreciable removal rate with increasing pH during aeration. When the initial pH of the leachate was adjusted 9.4, the removal rate was significantly increased without changing the pH during aeration.

• Journal of the Korean Recycled Construction Resources Institute
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• v.6 no.3
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• pp.53-60
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• 2011

As Construction & Demolition(C&D) debris increase every year, a system has enforced for recycled aggregate made out of C&D debris, then recycled aggregate usage increased in construction field. But as environmental problem by alkalinity of recycled aggregate occurred, the study for lowering alkalinity of recycled aggregate is needed. In this study we made alkalinity reducing facility and installed in the C&D debris midterm-treat field. Then we certified effect of lowering alkalinity and quality of recycled aggregates before and after carbonation. As a result, the most effective carbonation condition is 30seconds in carbonation time, -50~100 kPa of reaction pressure with change of 3cycles. This condition made pH 9.33~9.8 of recycled aggregate possible. The quality of recycled aggregate after carbonation was better than before carbonation in terms of plasticity index, modified CBR, abrasion loss, sand equivalent, liquid limit, size distribution, density and water absorption.

• Journal of Korean Society of Water and Wastewater
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• v.18 no.2
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• pp.174-180
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• 2004

This study is a fundamental research to test the applicability of abandoned eggshell as seed material for crystallization reaction. Eggshell was calcinated at $850^{\circ}C$ and ground to lesser than 0.42mm. The calcination characteristics of eggshell were examined by X-ray diffraction (XRD). The effect of initial calcium concentration, alkalinity, reaction temperature condition, seed dosage were studied by batch test. For the low concentration sample(P concentration is under 50mg/L), more than 90% of P can be removed. The effect of initial calcium concentration(0~120mg/L) was performed. At the result of the test, more than 50mg/L calcium concentration has high removal efficiency. Alkalinity effect was studied for synthetic solution(100mg/L initial P, 50mg/L calcium, 0.025% seed dosage) with 0~300mg/L bicarbonate alkalinities. For synthetic solution(100mg/L initial P, 50mg/L calcium, 100mg/L bicarbonate alkalinity, 0.025% seed dosage), the phosphorus concentration was examined with $10{\sim}35^{\circ}C$. In addition, calcinated eggshell was injected to swine wastewater to test the applicability to actual wastewater.