• Journal of environmental and Sanitary engineering
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• v.12 no.2
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• pp.1-12
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• 1997

This research aims to develop biofilm process for the nutrient removal of piggery wastewater. The developed process is the four stage anoxic-oxic biofilm process with recirculation of the final effluent. In summery, the results are as follows: 1. Nitrification in the piggery wastewater built up nitrite because of the high strength ammonia nitrogen. The nitrification of nitrobacter by free ammonia was inhibited in the total ammonia nitrogen loading rate with more than 0.2 kgNH$_{3}$-N/m$^{3}$·d. 2. The maximal total ammonia nitrogen removal rate was obtained at 22$\circ $C and without being affected by the loading rate. But total oxidized nitrogen production rate was largely affected by loading rate. 3. Autooxidation by the organic limit was a cause of the phosphorus release in the aerobic biofilm process. But the phosphorus removal rate was 90 percent less than the influent phosphorus volumetric loading rate of above 0.1 kgP/m$^{3}$·d. Therefore, the phosphorus removal necessarily accompanied the influent loading rate. 4. On the anoxic-oxic BF process, the total average COD mass balance was approximately 67.6 percent. Under this condition, the COD mass removal showed that the cell synthesis and metabolism in aerobic reactor was 42.8 percent and that the denitrification in anoxic reactor was 10.7 percent, respectively.

• Journal of Korean Society of Environmental Engineers
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• v.37 no.3
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• pp.152-158
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• 2015

This paper investigated the membrane fouling potential at the state of passive adsorption which is no permeation with the test modules on COD (Chemical oxygen demand) loading rates, examined the recovery rate and resistance on membrane fouling by three cleaning manners of hydrophobic membrane in a bioreactor. The results showed that high COD loading led to the increase of extra-cellular polymeric substances and filtration resistance. The permeability resistance from 1st day to 63rd day was getting increased, however, the value of permeability resistance after 63th day during the operation period was almost same level at three COD loading rates, it was due that the biomass adhesion on membrane surface at the state of passive adsorption reached to the critical state. Also, the final recovery rates after three cleaning manners were 78%, 72% and 69% at the COD loading concentrations of 250 mg/L, 500 mg/L and 750 mg/L respectively, and then recovery rate by physical cleaning at Run 2 and Run 3 was decreased after 40th day, it proved that biomass cake, which is not easily removed, was formed on the membrane surface because of high COD loading rate and EPS concentration.

• Journal of environmental and Sanitary engineering
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• v.12 no.3
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• pp.9-17
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• 1997

This research aims to remove nitrogen in the piggery wastewater by combined process with upflow anaerobic sludge blanket (UASB) and biofilm process. For the effective denitrification. anaerobic and anoxic reactors were connected to a reactor. The effluent of aerobix reactor was recycled equally with influent in the upper filter of anaerobic reactor for denitrification and outlet of UBF reactor was connected to the settling tank with $1.5{\;}{\ell}$ capacity and the settling sludge was repeatedly recycled to UASB zone. The organic loading rate of total reactor was operated from 0.4 to $3.1kgCOD/m^{3}/d$ and it was observed that the removal rate of TCOD was 80 to 95 percentage. Ammonia nitrogen was removed over 90 percentage in the less volumetric loading rate than $0.1{\;}kgN/m^{3}/d$. But because of non-limitation of organic materials, it was reduced to 70 percentage in the more volumetric loading rate than $0.6{\;}kgN/m^{3}/d$. But denitrification rate was observed 100 percentage in the all of loading rate. This is caused by the maintenance of optimum temperature, sufficient carbon source, and competition of electron acceptors. The results of COD mass balance at the $1.21{\;}kgCOD/m^{3}/d$ was observed with the 71.7% percentage of influent COD. It was revealed that the most part of organic materials was removed in the aerobic and the anaerobic reactor because 38.4 percentage was conversed into $CH_{4}$ gas and 11 percentage was removed in the aerobic reactor with cell synthesis and metabolism. Besides, 5.7% organics was used to denitrification reaction and 3.7% organics related to sulfate reduction.

• Journal of Korean Society of Environmental Engineers
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• v.22 no.4
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• pp.629-637
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• 2000

A two-phase anaerobic reactor with a submerged microfiltration system was tested for its ability to produce methane energy from organic wastewater. A membrane separation system with periodic backwashing with compressed air was submerged in the acidogenic reactor. The cartridge type of microfiltration (MF) membrane with pore size of $0.5{\mu}m$ (mixed esters of cellulose) was tested. An AUBF (Anaerobic Upflow Sludge Bed Filter: 1/2 packed with plastic media) was used for the methanogenic reactor. Soluble starch was used as a substrate. The COD removal was investigated for various organic loading with synthetic wastewater of 5,000 mg starch/L. When the hydraulic retention time (HRT) of the acidogenic reactor was changed from 10 to 4.5 days, the organic loading rate (OLR) varied from 0.5 to $1.0kg\;COD/m^3-day$. When the HRT of the methanogenic reactor was changed from 2.8 to 0.5 days, the OLR varied from 0.8 to $5.8kg\;COD/m^3-day$. The acid conversion rate of the acidogenic reactor was over 80% in the 4~5 days of HRT. The overall COD removal efficiency of the methanogenic reactor showed over 95% (effluent COD was below 300 mg/L) under the highly fluctuating organic loading condition. A two-phase anaerobic reactor showed an excellent acid conversion rate from organic wastewater due to the higher biomass concentration than the conventional system. A methanogenic reactor combined with sludge bed and filter, showed an efficient COD and SS removal.

• Journal of Environmental Science International
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• v.16 no.12
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• pp.1369-1382
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• 2007

To find proper water quality management strategy for oxygen consumption organic matters in Jinhae bay, the physical process and net supply/decomposition in terms of COD was estimated by three-dimensional eco-hydrodynamic modeling. The estimation results of physical process in terms of COD showed that transportation of COD was dominant in loading area from land to sea, while accumulation of COD was dominant in $middle{\sim}bottom$ level. In case of surface level, the net supply rate of COD was $0{\sim}60\;mg/m^2/day$. The net decomposition rate of COD was $0{\sim}-0.05\;mg/m^2/day$($-5{\sim}-10$ m, in depth) to 2 level, and $-0.05{\sim}-0.20\;mg/m^2/day(10m{\sim})$ to bottom level. These results indicate that the biological decomposition and physical accumulation of COD are occurred for the most part of Jinhae Bay bottom. The variation of net supply or net decomposition rate of COD as reducing land based input loading is also remarkable. Therefore, it is important to consider both allochthonous and autochthonous oxygen demanding organic matters to improve the water quality of Jinhae Bay.

• Journal of the Korea Organic Resources Recycling Association
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• v.3 no.2
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• pp.37-45
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• 1995

The performance and the operational problems of UASB(Upflow Anaerobic Sludge Blanket) reactor for treatment of dairy wastewaters were investigated. Synthetic milk wastewater was successfully treated up to the loading rate of 3.9kg $COD/m^3.day$, with a specific gas production rate of 1. 23 I/I. day and a COD removal efficiency of over 90%. However, the sludge rising was observed at the loading rate of 2.1kg $COD/m^3.day$, due probably to the formation of scum layer at the surface of settling compartment. The BMP(biochemical methane potential) of raw milk wastewater and ice cream wastewater, measured by using SBT(serum bottle test), were 0.135 and 0.66ml $CH_4/mg\;COD_{added}$, respectively. The sludge activity increased more than 8 times from 0.159g $COD-CH_4/g$ VSS. d during 90 days of operation.

• Journal of environmental and Sanitary engineering
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• v.8 no.1
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• pp.107-116
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• 1993

This study is conducted to investigate treatability by activated sludge process for wastewater from acetaldehyde manufacturing plant. The optimum hydraulic retention time in aeration tank for removal of high strength substrate were measured. The removal efficiency were checked out by hydraulic retention time : 35hr., 40hr. and 45hr., respectively. $COD_{Cr}$, like substances were removed in all hydraulic retention time zone directed for efficiency, but non-biodegradable substances were remained. $COD_{Cr}$ biomass loading was 0.81kg $COD_{Cr}/kgMLVSS$ . day at 35hr. of retention time, 0.34 kg$COD_{Cr}$/kg MLVSS . day at 40hr., and O.l9kg$COD_Cr$/kgMLVSS . day at 45hr. And the mean $COD_{Cr}$, removal efficiency was 65.5%, 81.6% and 83.0%, respectively. And also $COD_{Cr}$, volume loading was 1.01kg$COD_{Cr}/m^3$ day, 0.87kg$COD_{Cr}/m^3$ - day, and 0.79kg$COD_{Cr}/m^3{\cdot }$day, respectively. The basic design parameter obtained is as fallows. The value of Specific substrate removal rate coefficient (k), Yield coefficient(Y) and Decay coefficient($k_d$) was $0.0013day^{-1}$, $0.505kgMLVSS/kgCOD_{Cr}$ and $0.040day^{-1}$, respectively.

• Journal of Environmental Health Sciences
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• v.24 no.1
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• pp.132-140
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• 1998

Laboratory-scale experiments were conducted using a three-stage rotating biological contactor unit followed by lime precipitation and sedimentation with effluent recycle to the first stage. The purpose of this study was to evaluate the effects of hydraulic loadings of 0.031-0.076 $m^3/m^2/d and recycle ratio of 1 to 3 on the simultaneous removal of organics and nutrients from domestic wastewater. Lime was added to maintain pH of 10.4-11.0 in the coagulation-flocculation reactor. Results showed that the highest nitrogen removal rate of 70.5% occurred at the lower hydraulic loading of 0.031 $m^3/m^2/d at a recirculation rate of 300%, and similarly, highest nitrification occurred at the same hydraulic loading and recycle ratio. Concentration of ammonia nitrogen in the effluent was less than 1 mg/l at the same operating conditions for higher nitrogen removal. Whereas, high BOD and COD removal was observed at hydraulic loading rate of 0.054 $m^3/m^2/d, and high removal of organic matter was evident from the consistent low COD and BOD value. Results obtained from the operating condition of higher loading rate, 300% of recycle rate showed the highest removals. Increasing in recycle rate and hydraulic loading rate increased the volatile solids fraction of the sludges generated to the extent of 47% at 0.076 $m^3/m^2/d hydraulic loading and 300% recirculation rate. Since pH in the flocculator was maintained at the pH of 10.4-11.0, above 90% removal of phosphorus was obtained. Average concentration of suspended solids was always maintained over 40 mg/l in the effluent. Therefore an RBC unit operating at a hydraulic loading near 0.031 $m^3/m^2/d with a recycle rate of 300% is a viable and feasible alternate conditions to produce an effluent with relative low organic matter and phosphorus, provided that there is a neutralization unit to control the pH and SS of the effluent.

• Journal of Korean Society of Environmental Engineers
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• v.31 no.12
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• pp.1135-1142
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• 2009

This study was carried out to investigate of aerobic granulation by using aerobic granular reactor. To make aerobic granular sludge in short period of time, we used polymer. In reactor, we have studied on physicochemical characteristics of particle size, density, and microbial secreting polymer depending on aerobic particle's formation. The results of running aerobic granular reactor with 3, 6, 9 $kg{\cdot}COD/m^3{\cdot}d$ of COD loading rate and 35 days reaction time showed that particle size were 3.6 mm, 4.3 mm, and 3.4 mm respectively. The settling velocities were 1.5 cm/s, 1.6 cm/s, and 1.2 cm/s respectively. The microbic growth rates were 0.12 $d^{-1}$, 0.135 $d^{-1}$, and 0.133 $d^{-1}$ respectively. The overall result of aerobic granular reactor showed that $6kg{\cdot}COD/m^3{\cdot}d$ of COD loading rate had optimal physicochemical characteristics.

• Journal of Korean Society on Water Environment
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• v.20 no.6
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• pp.583-588
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• 2004

This research examined the treatment efficiency and methane production rate in treating slurry-type swine waste using UASB (upflow anaerobic sludge blanket) reactor. The UASB reactor was operated at an organics volumetric loading rate (VLR) of $2.6-15.7kgCOD/m^3/day$. A stepwise increase of the VLR resulted in a temporary deterioration in the COD removal rate in UASB reactor but recovered quickly. The COD removal rate were 65-70% for VLR up to $5 kgCOD/m^3/day$. When organics VLR was $10kgCOD/m^3/day$, the COD removal rate decreased sharply and there was loss of 17.537g of the seeding biomass due to sludge washout. This result indicated that the UASB system cannot be adapted to more than $10kgCOD/m^3/day$ of VLR. As the organic load increased from 2.6 to $15.7kgCOD/m^3/d$, the biogas production rate varied from 3.2 to 10.8 L/d and the methane conversion rate of the organic matter varied from 0.30 to $0.23m^3CH_4/kg\;COD_{removed}$. The methane content showed the range of 70.1-81.5% during the experimental period. The volatile solids (VS) removal efficiency was similar at the low VLR (< $5 kgCOD/m^3/day$), but it decreased sharply at the high VLR (> $5 kgCOD/m^3/day$). The VS reduction rate was, moreover, large those of COD. The result shows that hydraulic retention time above 2 days is essential in case of treating wastewater containing 1% of solids.