• Journal of Environmental Science International
• /
• v.12 no.12
• /
• pp.1309-1313
• /
• 2003

This study was carried out to obtain the optimal ammonia removal efficiency using pyroligenous liquid for the economical and environment-friendly odor removal at a petty livestock farmhouse. The ammonia removal efficiencies were evaluated due to changing dilution rates(${\times}$10, ${\times}$20, ${\times}$30, ${\times}$50 and ${\times}$100 times) and different spray amounts(10$m\ell$ and 20$m\ell$) of pyroligenous liquid. The wet scrubber device was used to remove odor in closed-type livestock farmhouse. According to dilution rate of the pyroligenous liquid, the optimum rate was 20 times and the removal efficiency increased by decreasing dilution rates. In the case of spray amounts with the optimum dilution, the amount was 20 me and the removal efficiency increased by increasing spray amount. Also, the removal efficiency by using wet deodorizing device was 83.0-97.0％ with 20 times diluted liquid.

• Journal of the Korean Society of Manufacturing Technology Engineers
• /
• v.9 no.5
• /
• pp.112-118
• /
• 2000

In case ESO(evolutionary structural optimization) which is one of topology optimization methods, the element removal ratio is fixed throughout topology optimization by 1 or 2%. As a result it has no flexibility for various types of structures and thus the rate of convergence might not be efficient. Thus various element removal methods were developed in order to improve the efficiency of ESO. In this paper, various element removal methods for ESO are compared with each other for a bracket and a short cantilever. In addition, a new improved bi-directional element removal method is suggested in order to obtain much better optimized topology. From the comparative results of the examples, it is verified that all of the developed various element removal methods are very effective, and the suggested element removal method is the most effective.

• Journal of Environmental Science International
• /
• v.21 no.1
• /
• pp.57-67
• /
• 2012

The midge samples were undertaken at three streams, representing different surrounding environments, to investigate the contaminant exposure of midge. The content of heavy metals in midge collected in Singil stream were generally higher as a result of input to the industrial effluents with respect to other streams. Adsorption experiments were done to evaluate the possibility of removing contaminants from water with midge. Diazinon and heavy metals were contaminant target compounds in this study. The removal rate of diazinon in water by midge was 60-75%. In the case of Cu, the removal rate was reached around 90% at the lower initial concentration of 1.87 and 0.81 ppm rather than 4.25 ppm. The reduction of concentration of Cr and Cd according to the lapse of time was similar to the Cu, but their removal rates were shown 50% and 60-74%, respectively. The removal rate of Zn by midge represented relatively high level within the experimental condition. No change in concentration of Cr and As with time were occurred at all experimental conditions. It accounts for the fact that the reduction of Cr and As could not be achieved through the adsorption process, using midge.

• Journal of Environmental Science International
• /
• v.25 no.7
• /
• pp.905-916
• /
• 2016

The characteristics of phenol removal and $UV_{254}$ matters variance were investigated and compared by the variation of operating factors (NaCl concentration, air flow rate, initial phenol concentration) in electrochemical reaction (ER) and dielectric barrier discharge plasma reaction (DBDPR), respectively. The phenol removal rate was shown as $1^{st}$ order both in ER and DBDPR. Also, the absorbance of $UV_{254}$ matters which means aromatic intermediates was analyzed to investigate the complete phenol degradation process. In ER, the phenol degradation and aromatic intermediates production rates increased by the increase of NaCl concentration. However, in DBDPR, the variation of NaCl concentration had no effect on the degradation of phenol and $UV_{254}$ matters. Air flow rate had a little effect on the removal of phenol and the variation of $UV_{254}$ matters in ER. The phenol removal rate in ER was a little higher than that in DBDPR. The produced $H_2O_2$ and $O_3$ amounts in ER were 2 times and 10 times higher than those in DBDPR. The chlorine intermediates ($ClO_2$ and free chlorine) were produced in ER, however, they were not produced in DBDPR.

• Asian Journal of Turfgrass Science
• /
• v.10 no.2
• /
• pp.159-166
• /
• 1996

To estimate removal rate of phosphorus in aquatic grassland ecosystems of Paldangho, this investigation was conducted along with the coast of a lake. The experimental results may be summarized on communities of Typha angustata, Miscanthus sacchriflorus Phragmites communis and Scirpus tabernaemontani as follows. The annual production of phosphorus for the litters in T. angustata, M saccharsflorus, P. cam-munis and S. taiernaemontani grasslands were 10.252 g /$m^2$, 3.833 g /$m^2$, , 2.656 g /$m^2$, and 5.210 g /$m^2$, respectively. The ratio of annual production of P accumulated on surface soils in a steady state provides estimates of the removal rate r, The estimated removal rates r of P were 0.58, 0.78, 0.68 and 0.59 in T. angustata, M. sacchariflorus, P. communis and S. tabernaemontani grasslands re- spectively. The removal and accumulation of 50, 95 and of 99% of its steady state level, the estimates for P of T. angustata were 1.195, 5.173 and 8.623 years, in M. sacchariflorus were 0.880, 3.842, and 6.403 years, and in P. cammunis were 1.014, 4.390, and 7.316 years respectively, In S. tabernaemontani grassland required period were 1.178,5.099 and 8.500. Key words:T. angustata, S. tabernaemantani, P. communis, S. tabernaemontani, Paldangho, Removal rate, Phosphorus.

• Journal of Korean Society of Water and Wastewater
• /
• v.10 no.4
• /
• pp.64-72
• /
• 1996

The effect of $O_3$, $O_3/pH$, and $O_3/H_2O_2$, $O_3/UV$, and $H_2O_2/UV$ advanced oxidation process(AOP) were investigated for the treatment of tetrachloroethylen(PCE) at various condition. The removal efficiency of 10, 20, and 30ppm PCE by ozonation were almost same, only about 60%. And pseudo first-order rate constants, ko for overall oxidation was about 0.097($min^{-1}$). In the $O_3/pH$ AOP experiment for the 20ppm PCE, the removal rate of PCE increased with the increase of pH. However, mineralization rate of PCE at pH 7 was higher than at pH 10. In the $O_3/H_2O_2$ AOP, the removal rate of PCE was the highest at peroxide-to-ozone dosage ratio of about 0.9, which PCE was removed over 99.95%. Despite 42% of PCE was directly photolyzed by the UV irradiation, the removal efficiency of PCE by $O_3/UV$ AOP was only about 70%. In $H_2O_2/UV$ AOP, the removal efficiency of PCE increased to about 98% in proportion to the $H_2O_2$ injection concentration at constant UV intensity of 5W/l.

• Journal of Korean Society for Atmospheric Environment
• /
• v.12 no.4
• /
• pp.449-457
• /
• 1996

The main purpose of this study was to investigate sulfur dioxide removal performance of flue gas desulfurization system utilizing a Spray Absorption/Drying Reactor. In this system, the size of droplets was considered the most significant factor and tested using a PDA system. Lime slurry flow rate, operating temperature, calcium/sulfur (Ca/S) ratio and applied air pressure were selected as major operation variables and tested/analyzed in terms of system performance. The results are as follows. 1. The $SO_2$ removal efficiencies were 49%, 74%, 85% for Ca$(OH)_2$ slurry flow rate of 10, 20, 30 ml/min, which implies that the increase of slurry flow rate improves removal efficiency. The optimum slurry flow rate in this study was, however, considered 20 ml/min because of constraints of system troubles and absorbent utilization. 2. As Ca/S ratio increased, $SO_2$ removal efficiency was observed to increase. 3. As air pressure, at the atomizing nozzole, increased from 3 to 5 $kg/cm^2, SO_2$ removal efficiency increased from 74% to 80%, because of droplet size reduction due to pressure increase during atomizing process and the increase of surface area, helping mass transfer between gas and liquid phase.

• Journal of the Korea Organic Resources Recycling Association
• /
• v.14 no.1
• /
• pp.169-177
• /
• 2006

In this study, it was studied that the removal rate of VOC by the catalytic combustion. The combustion temperature was changed by the contact type of VOC(space velocity and catalyst depth) and the space velocity(SV) was defined by the rate of gas volume flow rate(Q, $m^3/hr$) over volume(V, $m^3$) of catalyst (SV=Q/V). The space velocity of catalytic combustor is maintained $10,000{\sim}50,000hr^{-1}$. it was studied that the conversion rate of VOC by the catalytic combustion. The combustion temperature was changed by the contact type of VOC and catalyst and the space velocity was defined by the rate of gas volume flow rate over volume of catalyst. The VOC which pass thru the heat exchanger was measured by the hydro ionic detector and measured the VOC removal rate by the activated catalyst in the reaction temperature range of 373K-423K. The removal rate was measured over 100 times. In the automobile painting booth The VOC concentration was 63.37ppm and the removal rate was 70 % at 373K and 78.92% at 423K. The removal rate was increased as increased the temperature.

• Journal of Korean Society on Water Environment
• /
• v.22 no.1
• /
• pp.45-50
• /
• 2006

This study was performed to evaluate the air lift reactors (ALR) by variations of HRT and recycling rate. Air lift reactor was composed of bioreactor and clarifier above it. To remove organic matters and nitrogen through the formation of microbic film and filtration, bio-filter reactors were filled with clay, glass, bead, waste plastic, respectively. Influent wastewater was fed to biofilter reactor, and effluent wastewater from bio-filter reactor was injected ALR again, instead of adding external carbon source. Effluent BOD concentration was satisfied with lower than 10 mg/L in recycling rate 100% regardless of the variation of HRT and the kinds of media materials. In HRT 4 hr, recycling rate 100%, BOD removal efficiency rate was from about 85 to 90%, COD removal efficiency rate was higher than 90%. Effluent TN concentration was satisfied with less than 20 mg/L, if HRT was maintained by over than 6 hr regardless of recycling rate and media materials. Over than HRT was 4 hr, microbes concentration in air lift reactor was maintained over than 2,500 mg/L constantly, not sensitive to environmental condition, and organic removal was effective as it was higher.

• Journal of the Korean Crystal Growth and Crystal Technology
• /
• v.15 no.1
• /
• pp.34-38
• /
• 2005

Effects of pH level and slurry particle size on material removal rate and planarization of langasite single crystal wafer have been examined. Higher material removal rate was obtained with lower pH level slurries while the planarization was found to be determined by average particle size of colloidal silica slurries. Slurries containing 0.045 ㎛ amorphous silica particles showed the best polishing effect without any scratches on the surface. Effective particle number has a strong effect on the surface planarization and the removal rate, so that the lower effective particle numbers produced low removal rate but the better planarization results.