• Journal of Environmental Science International
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• v.7 no.5
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• pp.679-685
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• 1998

The Soysauce wastewater removal characteristics of submerged biofilters filled with two filter media respectively were experimentally examined with constant temperature, pH value and variable BOD loading and recirculation ratio. The decreasing order of BOD removal is Netring(random plastic media), cubic wire meshes(plastic module). This is mainly due to the media characteristics such as void ratio, specific surface area and media shapes. The BOD removal ratio decreases with increasing $BOD_5$/ volumetric loading rate, and the loading rate for the BOD removal over 85% is lower than 1.5kg$BOD_5$ 5/$m^3$d for the plastic media of Netring and cubic wire meshes. The $BOD_5$ removal rate increases with the recirculation ratio, but the rate of increase become smaller as the recirculation ratio increases over 20. When $BOD_5$ volumetric loading is 1.5kg$BOD_5$/$m^3$d, the required recirculation ratio to obtain 85% BOD$_{5}$ removal is about 20 for Netring and it was about 30 for cubic wire meshes.s.

• Microbiology and Biotechnology Letters
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• v.24 no.6
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• pp.738-742
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• 1996

An efficient packed-bed type biofilm reactor charged with immobilized phototrophs was developed to treat organic wastewater at an extremely high volumetric loading rate. The packed bed reactor (PBR) charged with porous ceramic beads was superior to a fluidized-bed reactor suspended with activated carbon powders in terms of many aspects such as BOD removal efficiency, operational stability, and overall economics. For wastewater with BOD concentration as high as 20, 000mg/l, the BOD removal efficiency was maintained above 90% when the hydraulic retention time (HRT) was longer than 1 day. The allowable volumetric BOD loading rate of this reactor (20gBOD/l day) is more than ten-folds higher than that of an ordinary activated sludge method. The behaviour of the reactor was represented well by a Monod type kinetic equation with a maximum specific BOD loading rate(P) of 22.2gBOD/l day and a half saturation constant(K$_{s}$) of 1, 750 mgBOD/l.

• Journal of Environmental Health Sciences
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• v.21 no.4
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• pp.32-36
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• 1995

This study was carried out to investigate the treatment efficiency of sequencing batch reactor when the livestock nightsoil organic loading rate was varied. Sequencing batch reactor was operated with the variance of influent BOD concentration and operating cycle. The average influent BOD concentrations in this study were 150 mg/l, 200 mg/l, 250 mg/l, 300 mg/l, 350 mg/l, 400 mg/l, 450 mg/l and 500 mg/l in the condition of 1~3 cycles/day. The treatment efficiency of sequencing batch reactor is good at the volumetric loading of 0.05~0.20 kg $BOD/m^3\cdot day$. Therefore, sequencing batch reactor process would become an effective alternative for the process of small scale livestock nightsoil treatment plants.

• Journal of Korean Society of Water and Wastewater
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• v.13 no.4
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• pp.27-34
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• 1999

An experimental study on improvement of the paper-mill wastewater treatment using the pure oxygen activated sludge process was conducted. The effects of hydraulic retention time(HRT) and BOD loading on organic removal efficiency were investigated. The BOD removal efficiencies were above 90% under all examined HRTs except for HRT of 3 hours. The increase of HRT from 3 hours to 6 hours, and to 12 hours significantly improved BOD and COD removal efficiencies, respectively. However, additional increase of HRT did not affect organic removal efficiency. F/M ratio change at fixed HRT did not affect organic removal efficiency. However, F/M ratio investigated in this study(0.11~1.98kgBOD/kgMLVSS/day) was 5 times greater in maximum than that of conventional activated sludge process, which implies that pure oxygen activated sludge process can treat wastewater with high organic strength. Under the same HRT, the volumetric BOD loading change cause no effect on organic removal efficiency also.

• Journal of Environmental Health Sciences
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• v.29 no.3
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• pp.59-64
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• 2003

This study was conducted to investigate anoxic-RBC-anoxic-RBC process and its application to remove biologically organics and nitrogen. BOD and total-nitrogen(T-N) removal efficiencies were decreased as volumetric loading rate increased. But, the removal efficiency changes of T-N were little, as compared to BOD. Increase of internal recycle rate had few affect of BOD and T-N removal rates. Also, influent allocation(to 2nd anoxic reactor) had few affect of BOD removal efficiency rate. However, when the influent allocation rate was 30%, T-N removal efficiency was increased to 84.1 %. BOD/N ratio applied to 2nd anoxic reactor was increased to range of 3.65-4.37 as influent allocation rate increased to range 20∼35%. But, it might also cause adverse effect such as decrease of denitrification rate in excessive influent allocation rate.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.14 no.3
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• pp.669-678
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• 1994

The BOD removal characteristics of submerged biofilters filled with three kinds of filter media respectively were experimentally examined with constant temperature, pH value and variable BOD loading and recirculation ratio. Obtained results are as follows; 1. The BOD removal ratio decreases with the increasing $BOD_5$ volumetric loading rate, and the loading rate for the BOD removal over 90% is lower thean $1.6kg{\cdot}BOD_5/m^3{\cdot}d$ for the plastic media of Netring and cubic wire meshes. This is a much large value than $0.3{\sim}0.8kg{\cdot}BOD_5/m^3{\cdot}d$ for conventional activated sludge process. The required submerged biofilter volume is found to be much samller than that of conventional activated sludge process. 2. The decreasing order of BOD removal is Netring (random plastic media), cubic wire meshes (plastic module), and then gravel (stone media). This is mainly due to the media characteristics such as void ratio, specific surface area and media shapes. 3. The $BOD_5$ removal rate increases with the recircuration ration, but the rate of increases becomes samaller as the recirculation ratio increases over 20. When $BOD_5$ loading is $1.8kg{\cdot}BOD_5/m^3{\cdot}d$, the required recirculation rationto obtain 90% $BOD_5$ removal is about 20 for Netring and it was about 30 for cubic wire meshes. 4. Reynold's Number increases with recirculation ratio, and the Reynold's Numbers corresponding to the recircuration ratio of 10~50 are less than 52, showing laminar up flows in the filter. The settled and effluent sludges increase with increase of Reynol's Number, and there are the definite Reynold's Numbers at which the settling sludge concentrations become nearly constant respectively in each filters. 5. In this submerged biofilter system, small volume of sludge hopper can be substituted for a separated settling tank.

• Journal of environmental and Sanitary engineering
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• v.10 no.3
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• pp.67-77
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• 1995

This study was performed for minimization of excessive biofilm effects at the high strength organic wastewater treatment. As a results of biofilm attachment experiment using piggery wastewater, aggravation of water quality due to excessive biofilm showed after 15 days of operating times.4 excessive biofilm phase, the equivalent biofilm thickness and VSS contents per unit aura were observed in the range of 1,100 to $1,200{\mu}m$ and 2.5 to 3.0mg $VSS/cm^{2}$, respectively. In the aerobic fixed biofilm reactor/anoxic fixed biofilm reactor(AFBR/ANFBR) process with endogenous respiration phase, the BOD removal efficiency was obtained more than 90 percentage at the surface loading rate and volumetric loading rate of the AFBR maintained less than 17 g $BOD/m^{2}{\cdot}$day and 1.7kg $BOD/m^{3}{\cdot}$day, respectively. The removal efficiency of TKN and $NH_{3}$-N at the loading rates below 5.60g $NH_{3}-N/m^{2}{\cdot}day$ and 0.56kg $NH_{3}-N/m^{3}{\cdot}$day were above 76 percentage and 82 percentage, respectively. In order to reduced sludge production rate and aggravation of water quality, endogenous respiration phase was accepted at first AFBR reactor. As a results of this operating condition, sludge production was minimized and removal efficiency was maintained stability.

• 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.

• KSBB Journal
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• v.16 no.2
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• pp.133-139
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• 2001

To treat piggery wastewaters containing refractory compounds including nitrogen, biological treatments were investigated. In biological treatment, the removal efficiencies of organics and nitrogen by the activated sludge process and bioreactor using a BACC (Biological Activated Carbon Cartridge) media filled with granular activated carbon were examined. The results were as follows; in the biological process, when the approximate influent BOD concentration of 620 mg/L, through dilution, was treated by the activated sludge process, the process should be operated at a HRT of over 8 days to maintain an effluent BOD concentration of lower than 100 mg/L. In the treatment of piggery wastewater using a BACC bioreactor, when the HRT was 200 hours, the BOD, COD(sub)cr, and TKN removal efficiency of the effluent were 94, 75 and 64.3%, respectively. Comparing the BACC bioreactor with the activated sludge process, when the volumetric loading rate was 0.3 g BOD/L.day, the specific substrate removal rate of BOD was 0.14 g BOD removed/L.day in the activated sludge process which compared with 0.27 g BOD removed/L$.$day in the BACC bioreactor. The BACC bioreactor showed on average a 2-fold higher removal rate and was superior to the activated sludge process in wastewater treatment in terms of variations of loading time and high loading time. Therefore, the BACC process can effectively treat piggery wastewater containing high concentrations of nitrogen and organic compounds.

• Microbiology and Biotechnology Letters
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• v.24 no.6
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• pp.733-737
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• 1996

The formation of microbial films(biofilm) by a non-sulfur phototrophic bacteria, Rhodopseudomonas capsulata, on inorganic media was studied. Porous ceramic beads(PCB) were superior to other immobilizing media for the biofilm formation in a packed-bed reactor. It was found that the formation of microbial films favored a lower hydraulic retention time, showing a higher ratio of cells attatched to the media to those suspended in the solution. The cell concentration in the biofilm reactor was as high as 11,400mg/l, which is 8-folds of the cell concentration in an ordinary suspended treatment. It was observed that the formation of micribial film by R. capsulata followed a general serial process of cell attachment, microcolony formation, and biofilm formation. The microbial films thus formed was very stable even for an extremely high volumetric BOD loading rate of 15gBOD/l day. The scanning electron micrographs of the microbial films showed that the cells were attached to both the surface and pores of the media.