• Journal of the Korean Society of Environmental Restoration Technology
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• v.25 no.1
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• pp.1-10
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• 2022

This study was conducted to investigate the germination characteristics through the temperature change treatment compared to the general room temperature immersion treatment of the native species, the Larix kaempferi, and the Berula platyphyllavar. japonica seeds, and to obtain basic data for the production of healthy seedlings with high productivity and efficiency. As a result, the germination rate of the larch seeds showed a significant difference according to room temperature and temperature immersion treatment, and the average germination days of the birch seeds showed a significant difference according to room temperature immersion and temperature immersion treatment. On the other hand, there was no significant difference in germinal uniformity. The results of the study are as follows. First, the results of the analysis of the fallen leaves were the highest germination rate in the treatment of 1.5 days of hot water and 1.5 days of cold water, the fastest germination rate, the lowest average germination day, and the highest germination uniformity. This is the best result in most items, and the change temperature immersion treatment of hot and cold baths was superior to the conventional room temperature immersion treatment. Second, the results of birch tree showed that the germination rate was the highest in 1.5 days of hot water and 1.5 days of cold water. The average germination day is 1.5 days of cold water 1.5 days of hot water 1.5 days, but the difference between 1.5 days of hot water and 1.5 days of cold water is 0.01 days. The highest germinated uniformity was found in 1.5 days of cold water and 1.5 days of hot water. As a result, in the case of larch and birch, the seed temperature immersion (1.5 days of hot water, 1.5 days of cold water) treatment is superior to the existing three-day immersion treatment in various analysis methods, and it is expected that productivity and efficiency can be improved at a low cost in a short period of time at the seedling production site through seeds.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2002.11a
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• pp.59-62
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• 2002

Recently, advanced system for water and wastewater treatment is introduced and operated because of water pollution and etc. One of this System makes use of O3(Ozone) for water and wastewater treatment. In airtight concrete structure, waterproofing phase as well as water are affected by strong oxidative O3 in the long-term. For this reason, material stability against O3 is examined. Consequently, the purpose of this study is to find out material stability an object of epoxy resin by way of accelerated O3 testing.

• Journal of Advanced Marine Engineering and Technology
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• v.34 no.3
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• pp.391-398
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• 2010

This study is currently giving priority to developing the ballast water treatment system using ozone(Ozone BWTS). The Ozone BWTS, were equipped on the real merchant vessel named as M. V. Hyundai Hong Kong to carried out shipboard tests of ballast water treatment system in accordance with orders of IMO G8 Guidelines. The study results show that the Ozone BWTS is capable of meeting the Ballast Water Performance Standard under Regulation D-.2 of the International Convention for the Control and Management of Ships’ Ballast Water and Sediments, and also the more stringent standards being proposed under US legislation.

• Journal of Korean Society of Water and Wastewater
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• v.20 no.3
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• pp.377-388
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• 2006

This paper is aimed to design for qualification structure and developing Vocational Education and Training Program of Water Treatment Plant Operator. Also job analysis was performed by the experts of education and related field though Developing A Curriculum(DACUM). The qualification structure and developing Vocational Education and Training Program of Water Treatment Plant Operator was designed and policy suggestions are made for the substantiality and activity to the government. This study is performed expert interview and job analysis The results are presented the summaries of job definitions, job models, areas of vocation activities, curriculum for education and training and guidelines for making questions in examinations.

• Journal of environmental and Sanitary engineering
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• v.21 no.3 s.61
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• pp.37-43
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• 2006

Recently, needs for reuse of sludge produced from WTP(water treatment plant) have been increased with shortage of landfill sites and difficulties of the treatment and disposal processes. Therefore, Reusing is becoming an Increasingly popular waste management alternative to divert waste from landfills. In order to research the characteristics of WTP sludges, we used the sludges of C WTP which intake the lake Dae-Cheong and the sludges of S WTP which intake Keum river, The specific surface area of C and S WTP sludges were $0.9986m^2/cc\;and\;1.874m^2/cc$, respectively. The gravity was about $2.0{\sim}2.4$ which are scope of peat or loamy clay. The major minerals of C WTP sludges were kaolinite(48.4%), muscovite(19.5%), and quartz(16.7%). Also, muscovite(31.6%), quartz(30.3%), and kaolinite(17.3%) in S WTP sludges were major minerals.

• Journal of Korean Society of Water and Wastewater
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• v.18 no.3
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• pp.312-319
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• 2004

The optimum dosage control is presumably the goal of every water treatment plant. However it is difficult to determine the dosage rate of coagulant, due to nonlinearity, multivariables and slow response characteristics, etc. To deal with this difficulty, the real number genetic-fuzzy system was used in determining the dosage rate of the coagulant. The genetic algorithms are excellently robust in complex optimization problems. Since it uses randomized operators and searches for the best chromosome without auxiliary informations from a population which consists of codings of parameter set. To apply this algorithms, we made the real number rule table and membership function from the actual operation data of the water treatment plant. We determined optimum dosages of coagulant(LAS) using the fuzzy operation and compared them with the dosage rate of the actual operation data.

• Journal of Korean Society on Water Environment
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• v.30 no.1
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• pp.95-101
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• 2014

Overall studies for the N-nitrosodimethylamine (NDMA) formation and treatment methods were conducted. In this study, occurrence in several countries and emerging treatment technologies of NDMA were generally reviewed. The NDMA formation was dependent on pH, contact time, and molar ratio (monochloramine/dimethylamine). The formation was rapidly increased when the molar ratio was greater than 1. It was likely that monochloramine could be related to stimulate NDMA formation. NDMA concentrations in water supply and wastewater plants after disinfection were approximately 10 ng/L and 100 ng/L, respectively. UV oxidation and adsorption processes are regarded as effective technologies for the NDMA removal. It is suggested that the UV oxidation with proper lamps is applied in water supply system.

• 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.10 no.2
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• pp.80-87
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• 1996

Treatment efficiencies of water quality parameters such as $KMnO_4$ Demand, $UV_{254}$, Turbidity, and LAS(Linear Alkyl Sulfonate) were compared between DAF(Dissolved Air Flotation) and CGS(Conventional Gravitational Sedimentation). The experimental results showed that DAF is much more efficient in treatment of water quality parameters than CGS. The optimum pH was about 7, and optimum alum($Al_2(SO_4)_3$) dose was about 30 ppm for DAF treatment. Economic aspects were also analyzed for bath systems. Even though production cost per ton of drinking water is slightly higher in DAF than in CGS, it turned out that construction cost and land value of CGS far surpass the production cost. DAF system is superior in removal efficiency of impurities and in production cost as a whole to CGS system.

• Korean Membrane Journal
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• v.9 no.1
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• pp.12-17
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• 2007

We performed periodic water-back-flushing using permeate water to minimize membrane fouling to enhance permeate flux in tubular ceramic microfiltration system for water treatment of high turbid source. The filtration time (FT) = 2 min with periodic 6 sec water-back-flushing showed the highest value of dimensionless permeate flux ($J/J_o$), and the lowest value of resistance of membrane fouling ($R_f$), and we acquired the highest total permeate volume $(V_T)\;=\;6.805L$. Also in the result of BT effect at fixed FT = 10 min and BT (back-flushing time) = 20 sec showed the lowest value of $R_f$ and the highest value of $J/J_o$, and we could obtain the highest $V_T\;=\;6.660\;L$. Consequently, FT = 2 min and BT = 6 sec could be the optimal condition in water treatment of high turbid source above 10 NTU. However, FT = 10 min and BT = 20 sec was superior to reduce operating costs because of lower back-flushing frequency. Then the average quality of water treated by our tubular ceramic MF system was turbidity of 0.07 NTU, $COD_{Mn}$ of 1.86 mg/L and $NH_3-N$ of 0.007 mg/L.