• Journal of Korean Society of Environmental Engineers
• /
• v.28 no.1
• /
• pp.54-60
• /
• 2006

[ $MnO_2$ ]-Coated Sand(MCS) was prepared with variation of coating temperature, coating time, and dosage of initial Fe(III) with two kinds of sands such as Joomoonjin and quartz sand. An optimum condition for the preparation MCS was determined from the coating efficiency as well as the oxidation efficiency of As(III). Coating efficiency of Mn was strongly dependent on the coating temperature but quite similar over the investigated coating time, showing an increased coating efficiency at higher coating temperature. In contrast to coating efficiency, the oxidation efficiency of As(III) by MCS was severely reduced as increase of coaling temperature. By considering these results, an optimum coating temperature and time for the preparation of MCS was selected as $150^{\circ}C$ and 1-hr, respectively. Coating efficiency increased as the dosage of initial Mn(II) increased, while As(III) oxidation was maximum at 0.8 Mn(II) mol/kg sand. The solution pH was identified as an important parameter affecting stability of MCS, and dissolution of Mn from MCS increased as pH decreased. Oxidation rate of As(III) increased as the dosage of MCS increased as well as solution pH decreased.

• Proceedings of the Korean Society of Agricultural Engineers Conference
• /
• 2005.10a
• /
• pp.655-660
• /
• 2005

This study was carried out to evaluate of water purification in oxidation pond with filamentous algae mat. It is the water treatment process in the small rural streams to remove the organic materials and nutrients. We used the filamentous algae mat(FAM) which selectively predominate the filamentous algae to prevent the additional contamination by algae outflow. The removal efficiencies of COD, SS, T-N and T-P in Oxidation Pond with Filamentous Algae Mat were -2.5%, 84.7%, 63.9% and 89.2%, respectively. The removal efficiencies of T-N and T-P which are nutrients index were high. Results of this study would help us to determine the possibility of using the water treatment on the contaminated small rural streams.

• Journal of the Korean GEO-environmental Society
• /
• v.11 no.6
• /
• pp.31-37
• /
• 2010

In this study, optimization of MEK and Toluene removal was conducted by HTO(Hybrid Thermal Oxidation) system. HTO system has a multi-bed reaction plate and the plate consisted of wasted heat regeneration part and catalysis part. VOCs removal by HTO system was estimated by changing inlet flow rates with different valve changing times. Under $350^{\circ}C$ of combustion temperature, VOCs was fully converted and the equivalent conversion was 100%. The thermal oxidation efficiency, related to the amount of injected fuel into HTO system and the valve change time, was revealed at the level of 93.0~96.3%. In case of MEK removal by HTO system, the efficiency was ranged from 91.1 to 97.1%. Also, Toluene removal efficiency(93.2~97.4%) was good and stable with respect to the operating conditions. Considering above results, it was proved that HTO system could be a stable and compact system for VOCs, especially MEK and Toluene with high removal efficiency.

• Journal of Environmental Health Sciences
• /
• v.37 no.1
• /
• pp.64-72
• /
• 2011

This study was performed to assess the removal efficiency on nitrogen, phosphorus and organic carbon in wastewater by spatial separation and internal recycling in a modified oxidation ditch process (modified OD). The performances of the modified OD were evaluated via laboratory-scale experiments. The process was operated at hydraulic retention times of 6-48 hours and solid retention times of 17-38 days. We found that organic carbon removal efficiency increased after the modified OD operation period. T-N removal efficiency remained stable; average T-N concentration of effluent was 8.02 mg/l after modified OD operation. In contrast, T-P concentration of effluent was over 1 mg/l. Nitrogen and phosphorus removal efficiency of modified OD at HRT 12 hr were 83.1% and 74.1%, respectively. Also, maximum efficiency was found at SRTs from 20 to 30 days. T-N removal efficiency was 83.1% at a C/N ratio from 3.0 to 3.5. However, T-N removal efficiency decreased at C/N ratios over 3.5. Also, T-P removal efficiency increased with HRT at C/P ratios in the same condition. Maximum efficiency was 74.1% at a C/P ratio from 25 to 28. T-N removal efficiency was 79.2% and T-P removal efficiency was 65.3% after M4 mode operation (added to the internal recycle line connected to the anoxic reactor). The modified OD with spatial separation and internal recycling developed in this study is, therefore, believed to be an improvement for solving problems in the nutrient removal technologies.

• Journal of Environmental Science International
• /
• v.8 no.6
• /
• pp.725-730
• /
• 1999

The advanced oxidation process (AOP) using ozone combined with hydrogen peroxide and ultraviolet treatment were evaluated for biodegradable dissolved organic carbon (EDOC) formation and dissolved organic carbon (DOC) removal. Oxidation treatment were conducted alone or combination with ozone, hydrogen peroxide and ultraviolet processes. Ozone dosage of ozone process was varied from $0.5mg/l{\ell}\cdot}min$ to $5mg/{\ell}{\cdot}min$. Ozone/hydrogen peroxide process was done using $20mg/{\ell}{\cdot}min$ of hydrogen peroxide concentration. Ozone/ultraviolet process was irradiated with $12mW/cm^2$ of density and 254nm. Ozone dosage was varied from $0.5mg/{\ell}{\cdot}min$ to $5mg/{\ell}{\cdot}min$ at the ozone/hydrogen peroxide and ozone/ultraviolet processes too. Contact time of all the process was 20 minutes. Oxidation treatment were performed on microfiltration effluent samples. BDOC formation was reached to an optimum at ozone dosage of $1.5mg/{\ell}{\cdot}min$ in the ozone/hydrogen peroxide process and $1mg/{\ell}{\cdot}min$ in ozone/ultraviolet process, after which BDOC formation was decreased at higher ozone dosages. But BDOC formation was increased with ozone dosages increasing in ozone process. The efficiency of DOC removal was higher AOPs than ozone process. Ozone/ultraviolet proces was the highest for DOC removal efficiency in each process. THMFP. removal efficiency by ozone/ultraviolet process was higher than that by each of ozone process and ozone/hydrogen peroxide process.

• 한국생물공학회:학술대회논문집
• /
• 2000.11a
• /
• pp.524-527
• /
• 2000

An electroenzymatic system to oxidize veratryl alcohol of on electrodes with in-situ generated hydrogen peroxide was studied. We investigated hydrogen peroxide generation, current efficiency, and veratryl alcohol oxidation in the electrode system at various conditions. The reaction rates of veratryl alcohol oxidation were compared in an electrochemical, an electroenzymatic, and an usual biochemical systems to prove the concept of electroenzymatic oxidation.

• Korean Journal of Soil Science and Fertilizer
• /
• v.47 no.5
• /
• pp.362-367
• /
• 2014

This study was performed to test the applicability of the ozone/hydroxy radical reaction system, which applied advanced oxidation processes, to remove total petroleum hydrocarbon (TPH) from the fine soil in washing water of the soil washing process. Removal efficiency was tested on 40 L of washing water in a pilot reaction tank. Fine soil contaminated with $800mg\;kg^{-1}$ TPH was prepared at 5% and 10% suspended solids. Testing conditions included ozone/hydroxy radical flow rates of 40, 80, and $120L\;min^{-1}$, and processing time of 2 to 12 hours. The removal efficiency of petroleum hydrocarbon from water waster by ozone/hydroxy radical was increased with higher flow rates and lower percentages of suspended solids. Optimal efficiency was achieved at $80L\;min^{-1}$ flow rate for 4 hours for the 5% suspended solids, and $120L\;min^{-1}$ for 6 hours for the 10% suspended solids. These results verified the efficiency of hydroxy radical in removing TPH and the applicability of the ozone/hydroxy radical reaction system in the field.

• Korean Journal of Soil Science and Fertilizer
• /
• v.50 no.5
• /
• pp.489-496
• /
• 2017

This study was conducted to test the applicability of hydroxy radical reactor system, which applied advanced oxidation processes, to sterilize pathogenic bacteria for nutrient solution recycling in closed hydroponics. Removal efficiency was tested on 25 L of nutrient solution maxed with 10 mL culture solution of bacteria, E. coli, and R. solanacearum in a pilot tank. The testing conditions included various levels of hydroxy radicals resulting from air flow rates of 40, 80, and $120L\;min^{-1}$, and 12 hours processing time. The removal of bacteria, E. coli, and R. solanacearum by hydroxy radical in nutrient solution was significantly increased with an increase in the flow rate of the air from $40L\;min^{-1}$ to $120L\;min^{-1}$. The optimum removal efficiency was achieved at an air flow rate of $120L\;min^{-1}$ for 2 hours treatment. There were no significant differences in removal efficiency among bacteria, E. coli, and R. solanacearum for tested level and time of hydroxy radical. These results verified the efficiency of hydroxy radical in removing the pathogenic bacteria and the applicability of hydroxy radical reactor system in the field.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
• /
• 2002.04a
• /
• pp.26-29
• /
• 2002

We describe a modified method for effectively pretreating soil highly contaminated with ANT or BaA (both initial Conc. are 500 mg/kg soil), i.e., we apply Fenton oxidation in which ethanol is added to increase ANT and BaA removal. At least 0.5 $m\ell$ or 0.75 $m\ell$ of ethanol were added to 1 g of artificially ANT or BaA-contaminated soils (i.e., alluvial and sandy soil), respectively. This was followed by Feton oxidation in which various amounts of $H_2O$$_2$ and Fe$^{2+}$ were added. The results showed more than 98 % of ANT or BaA removal efficiency However less than 10 % of ANT and BaA removal efficiency was obtained in addition of distilled water or sodium dodecy1 sulfate. Additionally, we employ GC-MS to identify the main oxidation product generated by the optimized Fenton reaction [i.e., ANT or BaA degraded in to 69-73% 9,10-anthracenedione (ANTDI) or 43-51% 7,12-benz(a)anthracenedione (BaADI), respectively]. The biodegradability of ANTDI or BaADI are subsequently confirmed to be much more rapid than that of ANT or BaA, respectively, results suggesting that Fenton oxidation with ethanol-microbial treatment can be effectively applied to remove ANT or BaA from soil.l.

• Environmental Engineering Research
• /
• v.14 no.1
• /
• pp.32-40
• /
• 2009

In this study, we have prepared three kinds of carbon nanometer tube $CNT/TiO_{2}$ electrodes through impregnation with different concentration titanium n-butoxide (TNB) solution. The prepared electrodes were characterized with surface properties, structural crystallinity, elemental identification and photoelectrocatalytic activity. The $N_2$ adsorption data showed that the composites had decreased surface area compared with the pristine CNT. This indicated the blocking of micropores on the surface of CNT, which was further supported by observation via SEM. XRD results showed patterns for the composites and a typical single and clear anatase crystal structure. The main elements such as C, O and Ti were existed for all samples from the EDX data. The catalytic efficiency of the developed electrode was evaluated by the photoelectrodegradation of methylene blue (MB). The positive potential applied in photoelectrocatalytic (PEC) oxidation was studied. It was found that photoelectrocatalytic (PEC) decomposition of MB solution could be attributed to combination effects between $TiO_2$ photocatalytic and CNT electro-assisted. Through the comparison between photocatalytic (PC) oxidation and photoelectrocatalytic (PEC) oxidation, it was found that the PEC oxidation efficiency for MB is higher than that of PC oxidation.