• Journal of Korean Society of Environmental Engineers
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• v.22 no.2
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• pp.251-264
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• 2000

Organic removal from synthetic wastewater by electrochemical methods was investigated with various operating parameters, such as current density, retention time, electrode gap and $Cl^-/COD_{Cr}$ ratio. In electrolysis, dioxide iridium coated titanium ($IrO_2/Ti$) and stainless steel plate were used for anode and cathode respectively. The $COD_{Cr}$ removal efficiencies between plate type anode and net type anode were about same effect, but electrolytic power using net type anode is low than plate type anode. The $Cl^-/COD_{Cr}$ ratio was about $1.3kgCl^-/kgCOD_{Cr}$ when organic removal obtained 70 %, $Cl^-/COD_{Cr}$ ratio needs $2.2kgCl^-/kgCOD_{Cr}$ so as to organic completely remove. The removal efficiency of organics increased with current density, retention time and $Cl^-/COD_{Cr}$ ratio, but decreased with increasing electrode gap. The relationship of operating conditions and $COD_{Cr}$ removal efficiencies are as follows. $$COD_{Cr}(%)=80.0360(Current\;density)^{0.4451}{\times}(HRT)^{0.8102}{\times}(Gap)^{-0.4915}{\times}(Cl^-/COD_{Cr})^{0.5805}$$ There existed a competition between the removals for $COD_{Cr}$ and ammonium during electrolysis, the removal of ammonium was shown to be dominant and $COD_{Cr}$ removal was low. But $COD_{Cr}$ removal was raised as addition of alkalinity.

• Proceedings of the Korean Environmental Sciences Society Conference
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• 2004.05a
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• pp.312-315
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• 2004

염색가공 공정에서 배출되는 염색폐수는 염색 가공공정이나 사용하는 염료등에 따라 폐수량과 성상의 변화가 심하기 때문에 처리에 많은 어려움이 있다. 일반적인 염색폐수 처리방법으로는 물리화학절인 응집침전법과 생물학적인 활성슬러지법을 단독 또는 조합하여 주로 사용하여 왔다. 그러나 최근에는 기존시설의 처리 향상을 위한 다각적인 기술개발이 시도되고 있으며 그 일환으로 본 연구에서는 활성탄을 담지한 폴리우레탄 담체를 개발하여 염색폐수를 처리하고자 하였다. 본 연구에서는 담체를 이용한 염색폐수의 생물학적 처리 시 여러 인자들, 즉 COD/N 비, DO 농도, 담체의 충진율 등의 영향을 조사하기 위하여 회분식 실험을 수행하였다. 또한 회분식 실험에서 얻은 최적조건을 이용하여 파일럿 실험도 함께 수행하였다. COD/N 비가 COD 제거에 미치는 영향을 살펴보기 위해 COD/N 비를 조절하지 않은 경우와 COD/N 비를 2-3으로 조절한 경우에 대해서 비교하였다. 실험결과 염색폐수의 초기 COD 농도가 1,000 ppm일 때, 처리 후 COD 농도는 COD/N 비를 조절하지 않았을 경우 860 ppm (제거효율 ＝ 18%), COD/N 비가 2일 경우 550ppm (제거효율 ＝ 52%), COD/N 비가 3의 경우 390 ppm (제거효율 ＝ 57%)으로 각각 나타났다. DO 농도가 COB 제거에 미치는 영향을 알아보고자 DO 농도를 1, 6, 7 mg/L로 변화시켰다. 그 결과 DO의 농도가 1 mg/L일 경우 COD 제거효율은 20% 정도였으나, DO 농도가 6 mg/L이상에서는 모두 80%에 가까운 제거효율을 나타내었다. 담체 충진율의 경우, 10% 충진시 40%, 20% 충진시 50%, 30% 충진시 70%의 제거효울을 각각 나타내었다. 회분식 실험에서 얻은 최적조건으로 파일럿 반응기를 100일 이상 운전한 결과 염색폐수의 COD 농도변화는 1,000ppm에서 380ppm로 평균 60%이상 제거되는 높은 효율을 보였다. 또 담체 첨가의 영향을 살펴보기위해, 담체를 충진하지 않은 조건에서 파일럿 반응기를 운전한 결과 평균 COD 제거율은 50%로 비교적 낮은 효율을 보였다.

• Korean Journal of Environmental Agriculture
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• v.21 no.2
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• pp.144-148
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• 2002

This study was carried out to investigate sewage treatment efficiencies using water hyacinth (Eichhornia crassipes) and watercress (Oenanthe Javanica). In the hyacinth system about 30% of COD introduced was removed during 2 days of hydraulic retention time, and about 30$\sim$50% of COD was removed in the watercress system during 1.2$\sim$2 days of hydraulic retention time. Therefore, COD loading of $76\sim170$ kg $COD/ha{\cdot}day$ was removed during 2$\sim$3 days of hydraulic retention time at the 0.18 $m^2$ area in the water hyacinth-watercress continuous system. Also 40$\sim$50% of N and P in the sewage were removed in the tested water hyacinth-watercress system Although COD, N and P concentrations in the final effluent were still higher than the limits of waste discharge, applicability of this waste water treatment system should be further investigated as an alternative method far small scale sewage treatments.

• Proceedings of the Korean Environmental Sciences Society Conference
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• 2008.11a
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• pp.350-354
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• 2008

전기/UV 공정에 사용하기 위해 일반적인 살균 램프인 UV-C 램프와 오존도 같이 발생하는 오존 등의 RhB 분해능을 고찰한 결과 오존 램프의 RhB 제거율이 UV-C램프보다 높은 것으로 나타났다. 전해질을 첨가하지 않은 전기/UV 공정에서 최적 전류는 1 A로 나타났다. 전기/UV 공정에서 RhB 제거의 경우 전기분해 공정과 UV 공정의 단일 공정의 RhB 농도감소와 전기/UV 복합 공정의 RhB 제거는 같아 공정의 시너지 효과는 관찰되지 않았다. 그러나 COD의 경우 전기분해 공정과 오존 램프에 의한 단일 공정의 COD 제거보다는 전기/UV 공정의 COD 제거농도가 높아 시너지 효과가 나타나는 것으로 사료되었다.

• KSBB Journal
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• v.24 no.4
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• pp.353-360
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• 2009

This study was accomplished using Anaerobic/Anoxic/Oxic upflow packed-bed column reactors with fixed media and Loop Reactor with fluidized media instead of Oxic reactor. The objectives of this study was to investigate the characteristics of organics, nitrogen and phosphorus removal from sewage with the HRT. The average removal efficiencies of $BOD_5$ and SS increase as increasing the hydraulic retention time (HRT) until 16 h of the HRT, and they were constant over 16 h of the HRT. The removal efficiency of $BOD_5$ in case of packed-bed reactor and Loop Reactor was about 86.6% and 90.9% respectively at 16 h of the HRT. The removal efficiency of SS in packed-bed reactor and Loop Reactor was about 78.0% and 88.2% respectively at 16 h of the HRT. The average removal efficiencies of $COD_{Cr}$ and $COD_{Mn}$ showed similar trends as those of $BOD_5$ and SS. At the HRT of 16 h, the removal efficiency of $COD_{Cr}$ in case of packed-bed reactor and Loop Reactor was 63.5%, 75.2% and that of $COD_{Mn}$ was 60.7%, 73.6% respectively. The average removal efficiencies of T-N and T-P increase as increasing the HRT. The removal efficiencies of T-N and T-P in Loop Reactor were 33.6% and 54.5% respectively at 16 h of the HRT and T-N and T-P were better removed in Loop Reactor. From this result, it was found that the performance of Loop Reactor was much higher than the performance of packed-bed reactor and the optimum HRT was 16 h.

• Korean Chemical Engineering Research
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• v.53 no.1
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• pp.71-77
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• 2015

A fluidized biofilter was filled with Pseudomonas sp. and Bacillus cereus/thuringiensis-fixed waste-tire crumb media and was run to treat authentic textile-dyeing wastewater mixed with alkaline polyester-weight-reducing wastewater. As a result, its removal efficiency of $COD_{Cr}$ and color were 75~80% and 67%, respectively. In addition, upon constructing hybrid-recirculating system composed of the fluidized biofilter and a 450 W-UV/photocatalytic reactor, only fluidized biofilter was run bypassing UV/photocatalytic reactor at stage I. Subsequently, the hybrid system was continuously run at stage II-i, ii and iii. At stage II-i, the total removal efficiency of $COD_{Cr}$ was enhanced to be 80~85%, compared to 75% at stage I, owing to 20~30% removal efficiency of the UV/photocatalytic reactor. However, at stage II-i, the total removal efficiency of color was enhanced to be 65~70%, compared to 45~65% at stage I, even though the removal efficiency of the UV/photocatalytic reactor was tantamount to merely 0~5%. As far as the removal efficiency of fluidized biofilter of the hybrid-recirculating system is concerned, its removal efficiency of color was enhanced by the synergy effect of the hybrid-recirculating system unlike $COD_{Cr}$. Besides, despite of the increase of hybrid-recirculating system-recycle ratio, the deactivation of photo-catalytic activity was scarcely observed to eliminate the color while its irreversible deactivation was observed to eliminate $COD_{Cr}$.

• KSBB Journal
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• v.18 no.3
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• pp.234-238
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• 2003

Biofilm process is preferred to activated sludge process in small domestic wastewater treatment plant because of its simplicity in operation and maintenance. Column reactor filled with waste ceramics and with waste plastics was used to remove pollutants in restaurant wastewater. COD removal at 18 hours of hydraulic retention time (HRT) gave 93.7%, COD removal during the experimental period, where maximum COD removal was observed. Under same condition, average removal of total nitrogen and total phosphorus were 82.3% and 25.9%, respectively Organic and nitrogen were efficiently removed with the HRT of 18 hours or more.

• Applied Chemistry for Engineering
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• v.16 no.5
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• pp.693-697
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• 2005

We researched in the optimization of unit process and the stabilization of discharged water quality through the treatment of the occurrence of wastewater classified by place of production which has high COD load and non degradable COD load in paper industry. As the result, using polymer, inorganic flocculants and alum at the same time is effective to advance the COD value through the colloid material removal with SS in the first treatment process. Moreover, it is determined to keep optimum of $FeCl_2/H_2O_2$ in the concentration of 1000 ppm in the ratio of 1/1. Because It is confirmed that to input excess chemicals using Fenton oxidation method gives adverse effect to water quality.

• Journal of Korean Society of Environmental Engineers
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• v.22 no.3
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• pp.429-439
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• 2000

Various wastewater treatment technologies were applied for decolorization and disposal of the wastewater containing the pigments, which consist of Lake Red C(Barium) or/and Lithol Rubine(Calcium) pigments. In an application of ozonation $COD_{Mn}$ was generally decreased with an increase of amounts of ozone applied, however, the decolorization effect was not that good except for Lithol Rubine series. In an application of Fenton oxidation and electrochemical process, a good $COD_{Mn}$ removal effect for all the pigment wastewater and a slight decolorization effect for a part of Lithol Rubine series were observed. In an application of ultra filtration(UF) and reverse osmosis(RO), an excellent $COD_{Mn}$ removal and decolorization(almost 100%) effects of all the pigment wastewater were observed. Thus the water treated by the UF and RO could be reusable and thus save operating costs of the pigment manufacturing plants.

• Clean Technology
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• v.25 no.4
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• pp.302-310
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• 2019

A constructed wetland with the aerobic tank and anaerobic/anoxic tank connected in series was employed in order to treat highly polluted stream water. The aerobic tank was maintained aerobic with a continuous supply of air through the natural air draft system. Five pilot plants having different residence times were employed together to obtain parameters for the best performances of the wetland. BOD and COD removals at the aerobic tank followed the first order kinetics. COD removal rate constants were slightly lower than BOD. The temperature dependence of COD (θ = 1.0079) and BOD (θ = 1.0083) was almost the same, but the temperature dependence (θ_N) of T-N removal was 1.0189. The SS removal rate was as high as 98% and the removal efficiency showed a tendency to increase with increasing hydraulic loading rate (Q/A). The main mechanism of BOD and COD removal at the anaerobic/anoxic tank was entirely different from that of the aerobic tank. BOD and COD were supplied as the carbon source for biological denitrification. T-P was believed to be removed though the cation exchange between orthophosphate and gravels within the anaerobic and anoxic tanks. The wetland could successfully be operated without being blocked by the filtered solid which subsequently decomposed at an extremely fast rate.