• Plant Journal
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• v.7 no.1
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• pp.56-63
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• 2011

The identifying cause of leakage problems on mechanical seal in a feed water pump of power plant have been difficult because of technical limits of domestic mechanical seal manufacturer and the various conditions of power plants. This paper can get a conclusion through the consideration study and experiment test of mechanical seal characteristics of feed water pump depending on oxygen treatment as follows. The oxygen treatment increase dissolved oxygen and cause a corrosion on the mechanical seal stationary ring composed of antimony as well as leakage problems. For solving leakage problems of seal, to eliminate dissolved oxygen in the cooling water of seal with hydrazine injection can prevent leakage problems of mechanical seal in feed water pump.

• Journal of Korean Society of Water and Wastewater
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• v.14 no.2
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• pp.164-173
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• 2000

Fluoridation of drinking water to a level of about 0.8mg/l (below 1.5mg/l) for reducing the incidence of tooth decay is recommended. However, concerns about potential problems of unknown effects and overdosing hinders the fluoridation. This study describes the work performed to obtain information on the behavior of fluoride under various conditions in the process of water fluoridation. Effects of water treatment chemicals, water treatment unit, and water distribution on water fluoridation were investigated at both lab and an actual water treatment plant. Residual fluoride concentration was not affected by lime and chlorine dosage up to 20mg/l. Flocculation with PAC slightly decreased the residual fluoride concentration as PAC dosage increased. Average fluoride concentration of 0.87mg/l at an intake basin was decreased to 0.83mg/l by sedimentation, 0.81mg/l by dual media(sand+anthracite) filtration, and 0.79mg/l by granular activated carbon filtration in the water treatment plant.

• Membrane and Water Treatment
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• v.14 no.2
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• pp.85-93
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• 2023

Membrane separation is widely used for several applications such as water treatment, membrane reactors and climate change. Cross-linked organic-inorganic hybrid polyvinylidene fluoride (PVDF) / Tetraethyl orthosilicate (TEOS) was adopted for the preparation of optimized hollow membrane (HFM) for membrane distillation or other low pressure separators for mechanical properties and permeability under varying pretreatment schemes. HFMs were prepared on semi-pilot membrane fabrication system. Novel adopted post-treatment schemes involved soaking in glycerol, magnesium sulphate (MgSO₄), sodium hypochlorite (NaOCl), and isopropanol for different durations. All fibers were characterized for morphology using a scanning electron microscope (SEM), surface roughness using atomic force microscope (AFM), elemental composition by examining Energy Dispersive Spectroscopy (EDS), water contact angle (CA°) and porosity. The performance of the fibers was evaluated for pure water permeation flux (PWF). Post-treatment with MgSO₄ gave the highest both tensile modulus and flux. Assessment of properties and performance revealed comparable results with other organic-inorganic separators, HF or flat. In spite of few reported data on post treatment using MgSO₄ in presence of TEOS, this proves the potential of low cost treatment without negative impact on other membrane properties. The flux is also comparable with hypochlorite which manifests substantial precaution requirements in actual industrial use.The relatively high values of flux/bar for sample treated with TEOS, post treated with MgSO₄ and hypochlorite are 88 and 82 LMH/bar respectively.

• Proceedings of the KIEE Conference
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• 1995.07b
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• pp.766-768
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• 1995

This paper presents the applied example of "A" city about optimum of chemicals imjection rate. The water treatment plant of "A" city make raw water into drinking water according to the injection of PAC, Alkali and chlorine. Computer performs multiple regression analysis about preoperation data, DCS has been done chemicals optimun control.

• Journal of Wetlands Research
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• v.18 no.3
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• pp.267-274
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• 2016

Sewerage supply in rural community is the important for water quality protection of water system such as river, lake and wetland. And characteristic of small scale wastewater system that have wide range of inflow and concentration in sewage should be considered for stable operation of small scale wastewater treatment plant. In this research, characteristics of flow ratio (flow / designed flow), effect on treatment efficiency of small scale wastewater treatment plant and assessment of optimal flow ratio were conducted through analysis on operation result of 18 small scale wastewater treatment plant in Bong-hwa gun. As a result, flow ratio shows the higher value during summer. However pollutants concentration in sewage was shown the higher concentration during autumn and winter. Treatment of small scale wastewater treatment plant is increased when flow ratio increased, and nutrient treatment efficiency is more sensitive to change of flow ratio than organic compound and suspended solids. According to this research result, it need to be maintained flow ratio 0.8 over value for stable treatment efficiency of small scale wastewater treatment plant.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.28 no.9
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• pp.67-72
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• 2014

Inflow or outflow from the water treatment plant and the sewage water has potential energy. If this potential energy can be converted into electrical energy by water turbine generator, it can help to save energy because of the high capacity utilization. So recently, micro hydro power plant is reviewed in the water treatment facility. If generation capacity is low, induction generator is primarily used. If output capacity is low, generated power is supplied to the inside load. Induction generator can cause voltage drop by the inrush current at a start-up and requires reactive power for magnetization. In this study, we analyzed the flow of power and voltage variation against inrush current that occurs when the induction generator starts under the terms that loads of linear and non-linear of the water purification plant are used. Analysis results are that the voltage drop is within an allowable range and the power factor is slightly reduced by the need of reactive power.

• Proceedings of the Korea Water Resources Association Conference
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• 1996.05a
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• pp.631-647
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• 1996

• Journal of Korean Society of Water and Wastewater
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• v.14 no.3
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• pp.231-239
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• 2000

Water treatment processes produce sludges resulting from water clarification. Sludge production amount increases each year and its treatment and disposal is growing to social problems according to water demand increase. Water treatment plant sludges can be modified to soil cover in sanitary landfill site through the lime treatment. Compression strength of $1.0kg/cm^2$ or more is recommended for soil cover material in municipal landfilling site. Compression and shear strength properties of modified sludges showed material property improvement applicable for soil cover alternatives. Solidification effect of the modified sludge was observed through the scanning electron microscope. Extraction tests for hazardous components in sludges revealed that extraction levels of cadmium, copper, and lead were below the regulated criteria. When adding 10% calcium hydroxide to water treatment plant sludges, the modified sludges can reach material properties for cover soil after 28 days solidification reaction.

• Journal of Korean Society of Water and Wastewater
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• v.19 no.6
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• pp.781-790
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• 2005

Granular Activated Carbon(GAC) is widely used in drinking water treatment. Many of the problems occurring in the GAC process are associated with the operation goal and performance. The purpose of this study were to evaluate the design, operation, and performance of granular activated carbon process in D water treatment plant. The optimal operation conditions of GAC process such as backwashing condition, granular activated carbon replacement time were discussed. The design, operation and performance of GAC process is influenced by their raw water characteristics and placement within the treatment process sequence. A critical analysis of plants experience and the information from the literature identifies the effectiveness of GAC process and indicates where modifications in design and operation could lead to improved performance. It would be useful to evaluate and optimize the GAC process in other treatment plant.

• Journal of Korean Society of Water and Wastewater
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• v.12 no.3
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• pp.30-40
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• 1998

Increasing water consumption produced sludge problems of the water treatment plants. The objective of this study is to investigate aluminium coagulants recovery n acidic and alkaline conditions. Water treatment plant sludge produced in Pusan Metropolitan City were tested for the aluminium extraction process. Experiment samples were obtained in summer from water treatment plants of Deoksan and Myongjang. Aluminium coagulants used in these plants during the test period were polyaluminium chloride(PAC), polyaluminium sulfate organic(PSO), polyaluminium sulfate silicate(PASS). Aluminium contents of water treatment sludge were in the range of 7.2~10.9% of the total solids. The recovery percentages for aluminium and iron by acidic extraction method was evaluated to 88% and 42% respectively. Extracted mass variation for other materials such as iron, manganese, total organic carbon was observed during the extraction operation. Alkaline extraction produced more than two times amount of total organic carbon than that in the acidic extraction process.