• KSBB Journal
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• v.22 no.4
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• pp.191-196
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• 2007

This study used biofilm process, which needs simple operation, maintenance and smaller facility area than conventional activated sludge process with the small plant operation, in the treatment of increasing sewage with the rapid industrial growth. The reactor used in this study consists of one anaerobic and one aerobic chamber filled with waste ceramic and waste vinyl as media and the treated sewage was from restaurant source. The experiment was scaled up from lab. to pilot scale and lasted for about 100 days. We focused on the removal efficiency of organics, nitrogen and phosphorus with constant HRT and continuous aeration. The removal efficiency of $BOD_5$ and SS were 94.33% and 87.77% respectively, which was a satisfaction level. However the removal efficiency of $COD_{Cr}$ was 81.46% somewhat below the desired level of 90%, and that of T-N and T-P showed 71.92% and 21.10% respectively, that was below the expected value. The removal efficiency of $COD_{Cr}$ and T-N in the pilot scale was about 10% low compared with the lab.-scale.

• KSBB Journal
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• v.21 no.1 s.96
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• pp.28-33
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• 2006

A sewage was treated using a horizontal flow zeolite-filled reed bed. The sewage from the student dormitory of Changwon National University was fed into the reed bed for 10 minutes every 6 hours at the hydraulic load of $314L/m^2$ day. The filtering height of the reed bed was 100 cm and the zeolite mixture was filled in the reed bed. The mixture consisted of the same volume of two types of zeolite : $0.5{\sim}1mm$ and $1{\sim}3mm$ in diameter. Annual average removal efficiency was SS $88.5%,\;COD_{cr},\;86.1%,\;COD_{Mn}\;81.0%,\;T-N\;48.6%,\;NH_4^+-N\;97.1%$ and T-P 42.8%. T-N of effluent was mostly $NO_3^--N$ and the concentration of $NO_2^--N$ in effluent was lower than 0.1 mg/L. All removal efficiencies did not show a remarkable seasonal change.

• Journal of Korean Society of Environmental Engineers
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• v.32 no.8
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• pp.767-773
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• 2010

In recent years, there has been considerable concern over the release of methyl tert-butyl ether (MTBE), a gasoline additive, into the aquifers used as potable water sources. MTBE readily dissolves in water and has entered the environment via gasoline spills and leaking storage tanks. In this study air stripping and ozonation of MTBE in aqueous solution were performed in a laboratory scale batch reacter. The mass transfer rate (N) was evaluated and a values about $1.24{\times}10^{-6}\;mol{\cdot}sec^{-1}$ was found. In the ozonation of MTBE a 8.3% decrease of the COD and a 6.5% decrease of the TOC lead to BOD/COD = 0.03. The peudo first-order rate constants of the ozonation of MTBE was $3.75{\times}10^{-5}\;sec^{-1}$. The resulting Ea of 4.80 kcal；mol-1 was observed for molecular ozone reactions.

• Korean Chemical Engineering Research
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• v.43 no.4
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• pp.487-494
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• 2005

Nowadays a large amount of wastewater containing metal working fluids and cleaning agents is generated during the cleaning process of parts working in various industries of automobile, machine and metal, and electronics etc. In this study, aqueous or semi-aqueous cleaning wastewater contaminated with soluble or nonsoluble oils was treated using ultrafiltration system. And the membrane permeability flux and performance of oil-water separation (or COD removal efficiency) of the ultrafiltration system employing PAN as its membrane material were measured at various operating conditions with change of membrane pore sizes and soil concentrations of wastewater and examined their suitability for wastewater treatment contaminated with soluble or insoluble oil. As a result, in case of wastewater contaminated with soluble oil and aqueous or semi-aqueous cleaning agent, the membrane permeability increased rapidly even though COD removal efficiency was almost constant as 90 or 95％ as the membrane pore size increased from 10 kDa to 100 kDa. However, in case of the wastewater contaminated with nonsoluble oil and aqueous or semi-aqueous cleaning agent, as the membrane pore size increased from 10 kDa to 100 kDa and the soil concentration of wastewater increased, the membrane permeability was reduced rapidly while COD removal efficiency was almost constant. These phenomena explain that since the membrane material is hydrophilic PAN material, it blocks nonsoluble oil and reduces membrane permeability. Thus, it can be concluded that the aqueous or semi-aqueous cleaning solution contaminated with soluble oil can be treated by ultrafiltration system with the membrane of PAN material and its pore size of 100 kDa. Based on these basic experimental results, a pilot plant facility of ultrafiltration system with PAN material and 100 kDa pore size was designed, installed and operated in order to treat and recycle alkaline cleaning solution contaminated with deep drawing oil. As a result of its field application, the ultrafiltration system was able to separate aqueous cleaning solution and soluble oil effectively, and recycle them. Further more, it can increase life span of aqueous cleaning solution 12 times compared with the previous process.

• Journal of the Korea Organic Resources Recycling Association
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• v.25 no.4
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• pp.41-50
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• 2017

The design of proper agitation system is requisite in biological waste treatment and energy generation plant, which is affected by viscosity, impeller types, and power consumption. In the present work, hydrogen fermentation of food waste was conducted at various operational pHs (4.5~6.5) and substrate concentrations (10~50 g Carbo. COD/L), and the viscosity of fermented broth was analyzed. The $H_2$ yield significantly varied from 0.51 to $1.77mol\;H_2/mol\;hexose_{added}$ depending on the pH value, where the highest performance was achieved at pH 5.5. The viscosity gradually dropped with shear rate increase, indicating a shear thinning property. With the disintegration of carbohydrate, the viscosity dropped after fermentation, but it did not change depending on the operational pH. At the same pH level, the $H_2$ yield was not affected much, ranging $1.40{\sim}1.86mol\;H_2/mol\;hexose_{added}$ at 10~50 g Carbo. COD/L. The zero viscosity and infinite viscosity of fermented broth increased with substrate concentrations, from 10.4 to $346.2mPa{\cdot}s$, and from 1.7 to $5.3mPa{\cdot}s$, respectively. There was little difference in the viscosity value of fermented broth at 10 and 20 g Carbo. COD/L. As a result of designing the agitation intensity based on the experimental results, it is expected that the agitation intensity can be reduced during hydrogen fermentation. The initial and final agitation intensity of 30 g Carbo. COD/L in hydrogen fermentation were 26.0 and 10.0 rpm, respectively. As fermentation went on, the viscosity gradually decreased, indicating that the power consumption for agitation of food waste can be reduced.

• Journal of Korean Society of Environmental Engineers
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• v.29 no.3
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• pp.304-310
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• 2007

The purpose of this research was to investigate the effects of the co-treatment of municipal wastewater with microwave-irradiated excess sludge on the treatment efficiency and excess sludge production of the activated sludge process. When 250 mL of excess sludge with a MLSS concentration of approximately 2,000 mg/L was microwave-irradiated at $20^{\circ}C$ for $40\sim300$ sec by a microwave oven (2,450 MHz, 700 W), the temperature of the sludge increased at a rate of approximately $20^{\circ}C/min$ and the SCOD, TKN and T-P concentrations of the sludge showed the highest increase in the irradiation time of $40\sim130$ sec. And, the oxygen uptake rate measurement of the sludge microorganism suggested most of the microorganisms in the sludge were destroyed at an irradiation time above 130 sec(above $65^{\circ}C$). When the municipal wastewater and microwave-irradiated excess sludge was co-treated by the activated sludge process, almost no effect was observed in the pH and alkalinity of both the influent and effluent, but the influent concentrations of SS, COD, T-N and T-P increased. Even though the effluent SS, BOD and T-P concentrations showed almost no effect, the COD and TKN concentrations increased. The microbial yield coefficient decreased at a rate of 0.91 g SS/g COD removed as the irradiation ratio increased at a rate of 1 g SS/g SS-day.

• Journal of the Korean GEO-environmental Society
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• v.1 no.1
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• pp.79-85
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• 2000

The environmental assessment on the open dumping landfill of small scale which was situated in local small city was carried out to reuse the landfill site as the residental, commercial and other purposes through the analysis of the leachate of landfill, extracted solution from landfill waste. The waste was landfilled at 5.5~8m depth and the covered layer so poor as 20~50cm thickness. The biodegradable organic matters were almost degraded and the result of the leachate of landfill showed that the BOD/COD ratio were measured as 0.079, pH 7.2~7.6, SS 47736mg/L, COD 6193.8mg/L, T-N 596mg/L, and T-P 123.9mg/L respectively. These results were higher than those of extracted solution of landfill waste as the COD and BOD were measured as low values and T-N 7.77mg/L and T-P as 0.20mg/L lower concentrations the landfill appears the maturation phase. As the result of the assessment on the open dumping landfill of small scale, if appears that this landfill is maturation phase and the formation leachate is reduced. If the treatment facility of leachate from landfill and the layer which protects the inflow/infiltration is prepared, it can be safely used as this landfill site.

• Proceedings of the Korea Water Resources Association Conference
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• 2006.05a
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• pp.1083-1087
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• 2006

과거 50 년 동안 국내 보 설치 수는 매년 증가하여 왔으나, 그 증가비율은 근래 들어 감소하는 추세로, 이는 보 보다는 용수공급능력이 큰 양수장, 저수지 등 타 시설물에 의존하는 것으로 판단 할 수 있다. 더욱이 인구의 도시 집중화에 따른 농경지의 도시화, 경작 방식의 변화에 의한 비닐하우스 단지로의 변화, 시설의 노후화 등으로 매년 $50{\sim}150$개 정도의 보가 폐기되고 있다. 그러나 이렇게 폐기되는 보는 하천에 그대로 존치되어 하천생태통로의 단절, 수질악화, 수변 서식처 악화 등의 문제를 지속적으로 야기 시키고 있다. 실험은 문산천 검전보, 안양천 안양대교보, 기철거된 경안천 무명보에서 자연시료를 채취하여 실행 하였다. 문산천 검전보는 하천환경이 안정되고 양호한 대조구간으로 선정하였다. 안양 대교보는 도심화로 인하여 원기능을 상실하였으며 수차례에 걸친 개수가 이루어졌고 수년전까지만 해도 러브보로 인한 수질정화장치가 있었으나 효능이 약화되어 철거할 계획을 가지고 있는 것으로 알려져 있다. 경안천 무명보는 현재는 완전 철거된 상태이다. 경안천 무명보는 기 철거된 보의 대조구간으 로 선정하였다. 보 상류의 수질 오염도가 높은 것은 정체구역에 의한 용존산소 부족과 오염저니에 의한 것으로 판단되므로, 각각의 대상보의 퇴적물 오염도를 조사하였다. 각각의 조사 지점은 검전보의 경우, 만장교를 최상류 지점으로, 검전보 상/하류, 광탄교를 최하류 지점으로 선정하여, 총 4 지점에서 채취했으며, 안양대교보의 경우 최상류지점, 보 상/하류 지점으로 총 3지점, 무명보의 경우 보 상/하류로 총 2 지점에서 채취했으며, 실험은 $\ulcorner$Soil Method$\lrcorner$에 준하여, 각각 입도분포, 함수율, 강열감량, COD, T-N, T-P 등을 시행하였다. 문산천 검전보 퇴적물 오염도 조사 결과, 강열감량, COD, T-N, T-P 항목에서 보 상류가 보 하류에 비해 높게 나타났으며, 각각 하류에 비해 상류가 30.76%, 16.69%, 73.13%, 18.91% 더 높게 나타났다. 안양대교보 퇴적물 조사 결과, 검전보와 마찬가지로, 강열감량, COD, T-N, T-P 항목에서 보 상류가 보 하류에 비해 33.33%, 9.23%, 24.78%, 18.56% 높게 나타났다. 기 철거된 무명보의 경우, 무명보 상류, 무명보 하류 2개 지점을 채취하였으며, 강열감량, COD, T-N 항목에서 보 상류가 보 하류에 비해 18.75%, 412.6%, 25.75% 높게 나타났다. 퇴적물 조사 결과, 강열감량, COD, T-N 항목에서 검전보, 안양대교보, 무명보 모두 보 상류의 오염도가 높게 나타났으며, 무명보를 제외한 검전보, 안양대교보는 T-P 항목에서도 보 상류의 오염도가 높게 나타나, 보 상류의 퇴적물 오염농도가 심화된 것으로 나타났다. 그러나 기철거된 무명보의 경우, 강열감량, COD, T-N, 항목에서 보 상류가 높게 나타났으나, 철거되지 않은 검전보나 안양대교보에 비해 그 차이가 크지 않은 것으로 나타났다.

• Korean Journal of Environmental Agriculture
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• v.16 no.2
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• pp.156-160
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• 1997

The combination of biological wastewater treatment process and membrane separation has many advantages such as better effluent quality and system stability over the conventional biological wastewater treatment process. In this study, direct membrane separation using nonwoven fabric was applied to biological wastewater treatment. A nonwoven fabric module was submerged in the aerated bioreactor. And accumulated biomass in the bioreactor was separated by suction. The system was operated with various condition to investigate pollutant removal efficiencies and flux. After formation of biomass layer on nonwoven fabric surface, a day, the stable effluent water quality was obtained. The flux decreased at a high suction pressure faster than a low pressure. The stable flux was obtained at the pressure of $21{\sim}25cmHg$. In spite of variation of hydraulic retention time, organic loading rate, the removal efficiencies of BOD, $COD_{Cr}$. $COD_{Mn}$ were very high as follows : $95.2%(0.14{\sim}0.97\;BODKg/m^3/day)$, $86.0%(0.17{\sim}1.39\;COD_{Cr}Kg/m^3/day)$, $90.0%(0.097{\sim}0.61\;COD_{Mn}Kg/m^3/day)$.

• Journal of the Korean Society of Marine Environment & Safety
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• v.15 no.2
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• pp.91-98
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• 2009

The long-term water-quality change of Asan Bay by the influx of polluted disposal water was predicted through a simulation with an Eco-hydrodynamic model. Eco-hydrodynamic model is composed of a multi-level hydrodynamic model to simulate the water flow and an ecosystem model to simulate water quality. The water quality simulation revealed that the COD(Chemical Oxygen Demand), dissolved inorganic nitrogen(DIN) and dissolved inorganic phosphorus(DIP) are increased at 5 stations for the subsequent 6 months after the influx of the effluent. COD, DIN and DIP showed gradual decreases in concentration during the period of one to two years after the increase of last 6 months and reached steady state for next three to ten years. Concentration levels of COD, DIN, and DIP showed the increase by the ranges of $11{\sim}67%$, $10{\sim}67%$, and $0.5{\sim}7%$, respectively, which represents that the COD and DIN are the most prevalent pollutants among substances in the effluent through the sewage treatment plant. The current water quality of Asan Bay based on the observed COD, TN and TP concentrations ranks into the class II of the Korean standards for marine water quality but the water quality would deteriorate into class III in case that the disposal water by the sewage plant is discharged into the Bay.