• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.42 no.4
• /
• pp.493-499
• /
• 2022

The standards pertaining to the quality of discharged water in sewage treatment plants are strengthening, and accordingly, facilities in sewage treatment plants are being upgraded. In addition, the discharge water quality of sewage treatment plants must be maintained at a high level, and efficient sewage treatment plant operations have thus emerged as a very important issue. For the efficient operation of sewage treatment plants, this study applied a basic blowing amount calculation method based on sewage facilities to evaluate the required oxygen amount and blowing amount according to inflow water quality by logicizing various influencing factors. As a result of calculating the amount of air blown by applying actual April water quality data from sewage treatment plant A to the blower demand calculation developed through this study, it was found that the average amount of air blown was reduced by about 12%. When the blower demand calculation developed here is applied to an actual sewage treatment plant, the amount of air blown can be controlled based on the inflow water quality. This can facilitate the realization of an autonomous control of sewage treatment plants, in contrast to the existing sewage treatment operation method that relies on operational experience of operator. In addition, it is expected that efficient sewage treatment plants can be operated by reducing blowing amounts and power costs, which will contribute to both energy and carbon savings.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2003.11a
• /
• pp.208-211
• /
• 2003

In this paper, mechanical property of electric epoxy with water aging was discussed. We studied mechanical property of elastic resin after absorption in water from 0 to 484 hour. As a result, diffusion factor of elastic epoxy showed $20-21{\times}10^{-4}mm^2/s$ and general epoxy showed $9.5{\times}10^{-4}mm^2/s$. Elastic property increased linearly according to amount of addictives and decreased elastic property according to amount of water absorption. Tensile strength was reduced to add to addictives. It was effected by water absorption of micro-void of elastic epoxy. Hardness inclined to decrease after increasing according to absorbed time.

• Proceedings of the IEEK Conference
• /
• 2003.11a
• /
• pp.393-396
• /
• 2003

This paper proposes a method to speed up the document image binarization using a water flow model. The proposed method extracts the region of interest (ROI) around characters from a document image and restricts pouring water onto a 3-dimensional terrain surface of an image only within the ROI. The amount of water to be filled into a local valley is determined automatically depending on its depth and slope. Then, the proposed method accumulates weighted water not only on the locally lowest position but also on its neighbors. Finally, the depth of each pond is adaptively thresholded for robust character segmentation. Experimental results on real document images shows that the proposed method has attained good binarization performance as well as remarkably reduced processing time compared with that of the existing method based on a water flow model.

• The Korean Journal of Food And Nutrition
• /
• v.13 no.1
• /
• pp.45-52
• /
• 2000

In order to select the optimum ethanol concentration for extraction of volatile components in cinnamon, the dried cinnamon was extracted with water and 30∼90% ethanol. The volatile components of cinnamon extracts were isolated by the simultaneous distillation extraction method using Likens and Nickerson's extraction apparatus, and analyzed by GC-MS. In cinnamon bark powder 45 components were detected and 21 components were identified. The major component of cinnamon bark powder was cinnamic aldehyde. In water extract of cinnamon, volatile components were not extracted sufficiently. The volatile components of cinnamon were increased with the increment of ethanol concentraction upto 70%. The volatile component of 70% ethanol extract showed similar pattern and amount to cinnamon bark powder. But in 90% ethanol extracts, the number and amount of volatile component were reduced. The above data suggested that 70% ethanol was the most effective solvent for volatile components extraction of cinnamon.

• Journal of Korean Society of Water and Wastewater
• /
• v.12 no.3
• /
• pp.65-74
• /
• 1998

Life cycle assessment (LCA) on two different sludge treatment systems, on-site treatment and pipe-collected intensive treatment was performed to estimate the environmental impact in the aspect of global warming effect. As a main parameter of the estimation, $CO_2$ was chosen and quantified through the whole life cycle of the treatment systems including construction, operation and dismantlement. In this study, the changes of $CO_2$ production unit (CPU) by up-scaling n currently used sludge treatment processes were also calculated. As the result, a larger amount of $CO_2$ was exhausted from the construction step of intensive treatment system than that of on-site treatment system, because an additional pipe-collection system was needed in intensive treatment system. However, the total amount of $CO_2$ exhausted from whole life cycle including not only construction and dismantlement but also 15 year-operation and maintenance was reduced by appling intensive treatment.

• Journal of Korean Society of Water and Wastewater
• /
• v.28 no.4
• /
• pp.411-417
• /
• 2014

The performance of the new aerobic digestion system combined with inorganic sludge separation unit and sludge solubilization unit, CaviTec II, is evaluated. Anaerobic digester effluent sludge is used for feed sludge of CaviTec II system. By addition of CaviTec II, the amount of cake generated is reduced by 27%, and the soluble nitrogen is reduced by 92%.

• Asian-Australasian Journal of Animal Sciences
• /
• v.18 no.1
• /
• pp.32-37
• /
• 2005

Under a typical Mediterranean environment in southern Australia, the evaporation rate increases significantly in hot summers, resulting in highly saline drinking water for grazing animals. Also in the cropping areas, dryland salinity is a problem. Grazing animals under these environments can ingest excessive amount of salt from feed, drinking water and soil, which can lead to a reduction in growth rate. To understand the impact of high salt intake on grazing deer, two experiments were conducted to assess the effect of salt levels in drinking water on feed intake and growth rate of red and fallow weaner deer. The results revealed that fallow deer did not show any abnormal behaviour or sickness when salt level in drinking water was increased from 0% to 2.5%. Feed intake was not affected until the salt content in water exceeded 1.5%. Body weight gain was not affected by 1.2% salt in drinking water, but was reduced as salt content in water increased. Compared with deer on fresh water, the feed intake of red deer on saline water was 11-13% lower when salt level in drinking water was 0.4-0.8%. An increase in salt level in water up to 1% resulted in about a 30% reduction in feed intake (p<0.01). Body weight gain was significantly (p=0.004) reduced when salt level reached 1.2%. The deer on 1% salt tended to have a higher (p=0.052) osmotic pressure in serum. The concentration of P, K, Mg and S in serum was affected when salt level in water was over 1.0%. The results suggested that the salt level in drinking water should be lower than 1.2% for fallow weaner deer and 0.8% for red weaner deer to avoid any reduction in feed intake. Deer farmers need to regularly test the salt levels in drinking water on their farms to ensure that the salt intake of grazing deer is not over the levels that deer can tolerate.

• Bulletin of the Korean Chemical Society
• /
• v.31 no.12
• /
• pp.3755-3759
• /
• 2010

A on-line SPE (solid phase extraction)-HPLC preconcentration method was developed for the determination of phenolic compounds at trace levels in environmental water sample. XAD-4 and Dowex 1-X8 were used as sorbent in the on-line SPE-HPLC method for the selective enrichment of nine phenolic compounds, which are included in the priority pollutants list of the US EPA. Also alumina prefiltering considerably reduced the amount of interfering peaks due to humic substances that could accumulated due to the preconcentration step and prevent quantification of polar phenolic compounds in environmental water samples. This method was used to determine the phenolic compounds in tap and river water and superiority to the US EPA 625 method in its enrichment factor, pretreatment time, recoveries, and detection limit. The limits of detection were in the range of $0.3-0.9\;{\mu}g/L$ in tap water sample.

• Journal of Korean Society of Water and Wastewater
• /
• v.11 no.4
• /
• pp.133-141
• /
• 1997

In order to treat the landfill leachate, $UV/TiO_2/H_2O_2$ system connected with biological treatment was investigated, and proper pretreatment methods were examined to reduce the load on the system considering economical and technical efficiency. It was more profitable to put $H_2O_2$ into the system in the early stage for the sample which was treated with $H_2SO_4$ to decrease alkalinity and with $FeCl_3-6H_2O$ flocculation. Because the required reaction time run up by increasing $H_2O_2$ input amount, though the COD was reduced slightly, the optimal $H_2O_2$ input amount should be determined for the desired COD and the economical efficiency. The appropriate way to get the lowest COD in the shortest time was the method to treat the sample which was controlled to pH 3.5 after adjusting to pH 12 and put 500 ppm $H_2O_2$ into the system. In that case, to increase $H_2O_2$ input amount was not profitable for the system efficiency. The sufficient photocatalytic excited time was required to reduce the photocatalytic decomposition time for the sample which was gone through the alkali state.

• Proceedings of the IEEK Conference
• /
• 2001.10a
• /
• pp.542-546
• /
• 2001

Converter slag has some compositional similarities to portland cement. But it has no hydration properties due to it's quite high concentrations of FeO(20-35%), MnO(4-6.5%). So it is needed to reduce the concentrations of iron and manganese of converter slag to use as cement additives by enhancing it's hydration properties. In this study, converter slag was modified it's composition by mixing of silica, alumina and quenched BF slag and reduced in induction furnace and quenched in running water. The hydraulic properties and structures of modified and quenched converter slag are significantly changed depend on the amount and kinds of additives. The addition of alumina up to 10% and BFQ slag up to 20% by weight on converter slag was effective to enhance the hydraulic properties of modified and quenched slag. The addition of reduced and quenched converter slag up to 20% by weight in replacement of portland cement in mixing of concrete mortar were shown higher compressive strength than 100% cement concrete mortar.