• Journal of Environmental Health Sciences
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• v.21 no.4
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• pp.17-23
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• 1995

As a basic experiment to develope biological pretreatment proces~ in water treatment, the experiments on biodegradability and isothermal adsorption of activated carbon were performed on refractories such as humic acid, $NH_3-N$, phenol and ABS which caused the problems in drinking water treatment. Also, the treatabilities on humic acid were examined in the continuous flow type reactors. The removal efficiencies of humic acid, $NH_3-N$, phenol and ABS in the biodegradable experiments for 5 days were 20.1%, 73.4%, 91.7% and 97.5%, respectively. In the isothermal adsorption test of refractories on activated carbon to be used as a media in the continuous flow type reactors, ABS and phenol are adsorbed easily, but humic acid and $NH_3-N$ are difficult to be done. The removal efficiencies of humic acid in granular activated carbon(GAC) reactor were about 7-8% higher than in biological activated carbon(BAC) reactor. The removal efficiencies of humic acid in biological fluidized bed(BFB) reactor were about 30% in GAC media, but were almost zero in sea sand media.

• Journal of Environmental Health Sciences
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• v.22 no.3
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• pp.103-115
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• 1996

The purpose of this study was to establish acceptable criteria for the design of simple water treatment plant in rural areas. To develop efficient simple water treatment methods for rural areas, water quality in the study areas was investigated and rapid and slow filtrations in pilot-scale were tested under various conditions. The main results of this study are as follows. It was found that the water qualities of the study areas exceed the drinking water standards, which implies that some treatments are required in rural areas. Treatment efficiencies of both rapid sand and dual-media (sand and anthracite) filtration without pre-treatment such as flocculation and sedimentation are very low, which were turned out to be unadequate for the rural areas. Treatment efficiencies of both vertical and horizontal slow filtration without chlorination are very high for consumed $KMnO_4, NH_3-N, NO_3-N$, turbidity, and very low for coliform and bacteria. Treatment efficiencies of both vertical and horizontal slow filtration with chlorination are very high over the most pollutants. A slow filtration with chlorination is efficient for the rural areas. An adequate depth of sand layer is over 60 cm. A horizontal filtration is more economical than a vertical filtration. A horizontal filtration can be operated for a relatively long periods of time without sand washing or replacement because clogging is removed by simple back-washing.

• Journal of Environmental Science International
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• v.11 no.12
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• pp.1267-1274
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• 2002

This study was carried out to evaluate the pollutant removal efficiencies of the advanced drinking water treatment using ozonation process. For raw water, Nakdong River was used. By conducting batch test of ozonation, the following results were obtained. When ozone dosage of $5 mg/{\ell}$ was used, ozone transfer and utilization efficiencies of the ozonation were 94 to 92%, respectively. Removal efficiencies of single VOC compound or mixed VOC compounds in the raw water were 80% to 90% by the ozonation with $2 mg/{\ell}$ dosage and 10 minutes contact time. Removal efficiencies of ABS by the ozonation with $1 mg/{\ell}$, $3 mg/{\ell}$ dosage and 20 minutes contact time were 83% to 96%, respectively. Almost 67% of chlorophyll-a at the concentration of $38.4\mu\textrm{g}/{\ell}$ was removed by ozonation at ozone dosage of $1 mg/{\ell}$ for 20 min. Considering the efficiency of ozone utilization and water treatment, the most effective ozonation could be obtained with high ozone dosage and short contact time.

• Journal of The Korean Society of Agricultural Engineers
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• v.46 no.5
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• pp.131-139
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• 2004

In this study, on-site sewage treatment tests were conducted using the Absorbent Biofilter System (ABS) under different hydraulic loading rates to examine its treatment characteristics and efficiencies and to determine its feasibility as a small on-site sewage treatment system in a rural area. Results showed that the removal rates of BOD and SS were satisfactory at hydraulic loading rates of 100~150 cm/day, meeting the Korean effluent water quality standards for the riparian zone (10 mg/L). In the case of nutrients (N, P), however, the system did not perform well, necessitating further improvement for nutrient removal. A comparative analysis indicated that as a small on-site sewage treatment system, the ABS would be more suitable than other treatment systems in terms of performance stability, maintenance requirement, and cost-effectiveness and could be applied as an alternative treatment system in Korean rural areas.

• Journal of Environmental Science International
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• v.19 no.3
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• pp.371-377
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• 2010

The purpose of this study is to investigate treatment efficiency in dyeing wastewater treatment by the high rate aeration system(HRA) and a combination of the HRA with magnetized wastewater treatment system(MWS). At the hydraulic retention time of 16hr, 24hr, 30hr, BOD removal efficiencies of HRA system were 93%, 96% and 98%, combination of the HRA with MWS system were 94%, 96.8% and 98.2%, respectively. In ease of COD, at the hydraulic retention time of 16hr, 24hr, 30hr, COD removal efficiencies of HRA system were 66%, 77.1% and 83.1%, combination of the HRA with MWS system were 70.2%, 80.1% and 86.6%, respectively. The comparison of the HRA and combination of the HRA with MWS, effluent BOD of the former was 22.7mg/${\ell}$ and the latter was 19.4mg/${\ell}$, theretore biological treatment efficiency identified to increase by the MWS.

• Journal of The Korean Society of Agricultural Engineers
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• v.47 no.3
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• pp.69-76
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• 2005

An Absorbent Biofilter System (ABS) combined with the recirculation process was investigated for the feasible application in additional removing of organics (BOD, SS) as well as nutrients (TN, TP) from small Community wastewater in Korea. Polyurethane biofilter media with high porosity and large surface area were /used for the aerobic system. A part of treated wastewater was recirculated into the anoxic septic tank to promote removal of nutrients. The concentrations of BOD and SS of treated wastewater satisfied the regulations for small on-site wastewater treatment facility (10 mg/L) during the overall experimental period. The effluent concentrations of BOD and SS were decreased with enhancement of removal efficiencies of 95.7 and $96.7\%$. The nitrogen and phosphorus removal efficiencies by the recirculation increased to $52.9\%\;and\;43.2\%$ in average during the overall experimental period, respectively. With the improvement, these values were increased as much as additional 42 and $18\%$ compared with those of non-recirculation. The rates of nitrification and denitrification were enhanced showing $65\~77\%\;and\;42\~92\%$, respectively. The described process modification is a low cost and effective method of enhancing nitrogen and phosphorus removal, especially on existing systems without changing major design components of a treatment facility.

• Journal of Korean Society on Water Environment
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• v.22 no.6
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• pp.1031-1037
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• 2006

In order to improve water quality of the Juam Lake, a constructed wetland was implemented and operated for 2 years with the effluent of sewage treatment plant and diffuse pollutant discharged from agricultural area. During the summer season, average removal efficiencies for BOD and SS were 15.8% and 39.4%, respectively. Due to the mixed effect of vegetation, soil microbes and sediments, the higher nutrient removal efficiencies were obtained: average T-N and T-P removal efficiencies were 64.2% and 71.7%, respectively. The concentration of sediment was increased initially, and maintained constant throughout monitoring period. The highest nitrogen and phosphorus uptake were observed in Phragmites japonica. The nitrogen uptake was estimated as 0.235 DW mg/g while phosphorus uptake was estimated as 2.059 DW mg/g.

• Journal of Korean Society on Water Environment
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• v.21 no.4
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• pp.327-331
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• 2005

The study was conducted with two laboratory biological aerated filter (BAF) reactors: denitrification filter (DF) and nitrification BAF. The influent flow (Q) was fixed to 48 L/d and total empty bed contact time (EBCT) was 1 hr. The flow direction was upflow with NRCY of 1 to 2Q. The secondary effluent was fed to the reactors and the influent concentrations were adjusted with some stock solutions to simulate by-pass concentration during rainfall. The study results indicate that COD and SS removal efficiencies were excellent and not influenced by temperature. Nitrification efficiency was over 90% at the influent loading less than $1.12kg/media\;m^3/d$, but the efficiencies were decreased in low temperature. TN removal efficiencies were 10% to 60%.

• Journal of Korean Society on Water Environment
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• v.22 no.5
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• pp.846-850
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• 2006

The biological nutrient removal from domestic wastewater with low C/N ratio is difficult. Therefore, this study was performed to increase influent C/N ratio by ammonia stripping without required carbon source and for improving treatment efficiencies of sewerage by the combination process of ammonia stripping and BNR (StripBNR). The results of this study were summarized as follows. BOD removal efficiencies of BNR and StripBNR were 95.3% and 93.2%, respectively. T-N and T-P removal efficiencies of BNR were 53.3% and 40.8%, respectively. T-N and T-P removal efficiencies of StripBNR were 72.8% and 62.9%, respectively. Concentrations of $NH_3-N$, $NO_2-N$ and $NO_3-N$ at BNR effluent were 0.03 mg/L, 0.08 mg/L and 9.12 mg/L, respectively. On the other hands, concentrations of $NH_3-N$, $NO_2-N$ and $NO_3-N$ at StripBNR effluent were 5.79 mg/L, 0.01 mg/L and 0.14 mg/L, respectively. Consequently, influent C/N ratio of BNR process was increased by ammonia stripping. Removal efficiency of T-N and T-P was improved about 20% by the process of StripBNR.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.10
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• pp.4055-4068
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• 2010

In this study, validity of wastewater treatment system with advanced treatment processes was evaluated by studying its operational conditions by applying the advanced treatment to the wastewater treatment system which was operating for last several years. Study indicated a fair result for the removal efficiencies of BOD, T-P, and T-N for each unit operation. BOD removal efficiencies for primary clarifier, bioreactor, final effluent are 35, 87, and 48 % respectively. T-P(T-N) removal efficiencies for primary clarifier, bioreactor, final effluent are 18(23), 40(38), and 25(25) % respectively. Further investigation of bioreactor showed that various microorganism such as bacteria, protozoa, and metazoa is present in the bioreactor, and the main function of the media, adhesion (adsorption) of microorganism onto the media, is stabilized. Final effluent quality was lower than the regulation, and BOD, COD, SS, T-N, T-P were 5.5, 9.9, 4.6, 11.8, 0.99 mg/L respectively.