• KSCE Journal of Civil and Environmental Engineering Research
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• v.10 no.3
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• pp.127-136
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• 1990

In this paper, the experimental study was carried out for the removal of olive oil in wastewater by the use of Biological Fluidized Bed(BFB) with the reticulated polypropylene sheets as media. The nonbiodegradable olive oil, one of the animal and vegitable oil, was used bacause of the relative simplicity of constitution. Biological degraciability and removal characteristics of emulsified olive oil were studied by batch and continuous experiments respectively. From the results of batch experiments, it was observed that the emulsified olive oli used in BFB reactor was absorbed by media and sludge in about 12 hours, and degradation of the absorbed olive oli was mostly completed for 24 hours. The functional relationship of Michaelis-Menten's Enzyme reaction equation exists between oil concentration and maximum specific rate of olive oil. From the continuous experiments for the removal of olive oil using BFB reactor, it was proved that the substrate removal rate coefficient $k=0.004d^{-1}$, which is the first order kinetics. It was apperared that oxygen utlization coefficients for synthesis(a') and endogeneous respiration(b') of microorganisms in the reactor are respectively 0.85mg $O_2/mg$ $COD_{cr}$ and 0.011mg $O_2/mg$ BVS. day.

• Environmental Engineering Research
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• v.10 no.5
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• pp.247-256
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• 2005

A combination of the submerged membrane activated-sludge bioreactor(SMABR) equipped with non-woven fabric filter and oyster-zeolite (OZ) packed-bed adsorption column was studied to evaluate the advanced tertiary treatment of nitrogen and phosphorous. The non-woven filter module was submerged in the MBR and aeration was operated intermittently for an optimal wastewater treatment performance. Artificial wastewater with $COD_{Cr}$ of 220 mg/L, total nitrogen (T-N) of 45 mg/L, and total phosphorous (T-P) of 6 mg/L was used in this study. MLSS was maintained about $4,000\;{\sim}\;5,000\;mg/L$ throughout the experiments. The experiments were performed for 100-day with periodic non-woven filter washing. The results showed that $COD_{Cr}$ could be effectively removed in SMABR alone with over 94% removal efficiency. However, T-N and T-P removal efficiency was slightly lower than expected with SMABR alone. The permeate from SMABR was then passed through the OZ column for tertiary nutrients removal. The final effluent analysis confirmed that nutrients could be additionally removed resulting in over 87% and 46% removal efficiencies for T-N and T-P, respectively. The results of this study suggest that the waste oyster-shell can be effectively reclaimed as an adsorbent in advanced tertiary wastewater treatment processes in combination with SMABR equipped with non-woven fabric filter.

• Membrane and Water Treatment
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• v.9 no.3
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• pp.181-188
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• 2018

A sidestream contains the filtrate or concentrate from the belt filter press, filter backwash and supernatant from sludge digesters. The sidestream flow, which heads back into the sewage treatment train, is about 1-3% less than the influent flow. However, the sidestream can increase the nutrient load since it contains high concentrations of phosphorus and nitrogen. In this study, the removal of PO4-P with organic matter characteristics and bacteriological changes during the sidestream treatment via ladle furnace (LF) slag was investigated. The sidestream used in this study consisted of 11-14% PO4-P and 3.2-3.6% soluble chemical oxygen demand in influent loading rates. LF slag, which had a relatively high $Ca^{2+}$ release compared to other slags, was used to remove $PO_4-P$ from the sidestream. The phosphate removal rates increased as the slag particle size decreased 19.1% (2.0-4.0 mm, 25.2% (1.0-2.0 mm) and 79.9% (0.5-1.0 mm). The removal rates of dissolved organic carbon, soluble chemical oxygen demand, color and aromatic organic matter ($UV_{254}$) were 17.6, 41.7, 90.2 and 77.3%, respectively. Fluorescence excitation-emission matrices and liquid chromatography-organic carbon detection demonstrated that the sidestream treatment via LF slag was effective in the removal of biopolymers. However, the removal of dissolved organic matter was not significant during the treatment. The intact bacterial biomass decreased from $1.64{\times}10^8cells/mL$ to $1.05{\times}10^8cells/mL$. The use of LF slag was effective for the removal of phosphate and the removal efficiency of phosphate was greater than 80% for up to 100 bed volumes.

• Journal of Korean Society of Water and Wastewater
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• v.27 no.2
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• pp.261-272
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• 2013

Algae boom (Red tide) in south coastal area of Korea has been appeared several times during a decade. If algae boom appears in the desalination plant, media filter and UF filter are clogged quickly, and the plant should be shutdown. In general, Algae can be removed from water by flotation better than by sedimentation, because of the low density of algal cell. The purpose of this study conducts the CFD simulation of DAF flotation basin to apply the design of the dissolved air flotation with ball filter in the Test Bed for SWRO desalination plant. In this study, Eulerian-Eulerian multiphase model was applied to simulate the behavior of air bubbles and seawater. Density difference model and gravity were used. But de-sludge process and mass transfer between air bubbles and seawater were ignored. Main parameter is hydraulic loading rate which is varied from 20 m/hr to 27.5 m/hr. Geometry of flotation basin were changed to improve the DAF performance. According to the result of this study, the increase of hydraulic loading rate causes that the flow in the separation basin is widely affected and the concentration of air is increased. The flow pattern in the contact zone of flotation basin is greatly affected by the location of nozzle header. When the nozzle header was installed not the bottom of the contact zone but the above, the opportunity of contact between influent and recycle flow was increased.

• 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.

• Journal of Environmental Health Sciences
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• v.35 no.3
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• pp.214-219
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• 2009

This study examined the removal efficiency of the nitrogen and phosphorus in order to compensate for the combined process of ATAD(Autothermal Thermophilic Aaerobic Digestion) and EGSB(Expended Granular Sludge Bed), which are treatment methods for livestock wastewater, by introducing SBR(Sequencing Batch Reactor) as post-treatment process. The analysis on the treatment efficiency of each operation mode showed that, in the case of T-N, the treatment efficiency were 67.1% and 74.2% for Run-1 and Run-2, respectively, and in the case of T-P, the values were 71.2 and 74.1, respectively, which are indicating that the treatment efficacy is higher in the condition of Run-1, in which the time period of Anoxic and Aerobic segments were increased. In addition, the result of analyzing removal characteristics of nitrogen and phosphorus by Influx load showed that removal efficiency of nitrogen was better in the case of high influx load than in the case of low influx load. Regardless of Influx load, phosphorus showed constant influx concentration, so that removal efficiency of phosphorus was influenced littler by Influx load than that of nitrogen. This study also fed methanol as an external carbon source and performed experiment to induce denitrification under anoxic condition by using nitrate among nitrogen compounds of SBR reactor, and the results showed that intermittent feeding was more effective in Nitrogen Removal than composite feeding.

• Korean Journal of Environmental Agriculture
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• v.31 no.4
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• pp.351-358
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• 2012

BACKGROUND: Constructed wetlands for wastewater treatment are vegetated by wetland plants. Wetland plants are an important component of wetlands, and the plants have several roles in relation to the livestock wastewater treatment processes. The objectives of this study were to investigate the growth characteristics and nutrient absorption of water plants in constructed wetlands for treating livestock wastewater. METHODS AND RESULTS: In this study, livestock wastewater treatment plant by constructed wetlands consisted of $1^{st}$ water plant filtration bed, $2^{nd}$ activated sludge bed, $3^{rd}$ vertical flow(VF), $4^{th}$ horizontal flow(HF) and $5^{th}$ HF beds. Phragmites communis TRINIUS(PHRCO) was transplanted in $3^{rd}$ VF bed, Iris pseudoacorus L(IRIPS) was transplanted in $4^{th}$ HF bed and PHRCO, IRIPS and Typha orientalis PRESEL(THYOR) were transplanted in $5^{th}$ HF. Growth of water plants in constructed wetlands were the highest in October. The IRIPS growth was higher than other plant as 264 g/plant in October. The absorption of nitrogen and phosphorus by IRIS were 3.38 g/plant and 0.634 g/plant, respectively. The absorption of K, Ca, Mg, Na, Fe, Mn, Cu and Zn by water plants were higher in the order of IRIPS > THYOR > PHRCO. CONCLUSION(S): The absorption of nutrients by water plants were higher on the order of IRIPS > THYOR > PHRCO in constructed wetlands for treating livestock wastewater.

• Journal of Korean Society of Environmental Engineers
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• v.22 no.4
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• pp.797-806
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• 2000

The objectives were to compare the biodegradable threshold concentrations of phenol with the different composition of the influent carbon source and examine the SMA (Specific Methanogenic Activity)and the possibility of simultaneous removal of high-strength organics and nitrogen compounds in UASB(Upflow Anaerobic Sludge Blanket) - PBR(Packed Bed Reactor) process. The results showed that UASB reactors were efficient to remove phenol and phenol + glucose from synthetic wastewater. At phenol conc, of 600 mg/L and SCOD conc. of 2100 mg/L in UASB reactor(with only phenol as substrate), the removal efficiencies of phenol and SCOD were over 99% and 93% respectively, under MLVSS of 20 g. The activity of microorganism was $0.112g\;phenol/g\;VSS{\cdot}d$, $0.351g\;SCOD/g\;VSS{\cdot}d$. The gas production rate was $0.115L/g\;VSS{\cdot}d$ and $CH_4$ content in gas was about 70%. At phenol conc. of 760 mg/L and SCOD conc. of 4300 mg/L in UASB reactor( with phenol + glucose as substrates), the removal efficiencies of phenol and of SCOD were over 99% and 90% respectively, under MLVSS of 20 g. The activity of microoganism was $0.135g\;phenol/g\;VSS{\cdot}d$, $0.696g\;SCOD/g\;VSS{\cdot}d$. The gas production rate was $0.257L/g\;VSS{\cdot}d$ and $CH_4$ content in gas was about 70%. Serum bottle test showed that the activity of granule was inhibited over 1600 mg/L phenol conc, and denitrification and methanogenesis simultaneously took place in UASB granules under co-substrates conditions. PBR reactor packed with cilium type media, was efficient in nitrification. In condition of $0.038kg\;NH_4-N/m^3-media{\cdot}d$. 10~12 mg/L phenol conc. and 200~500 mg/L SCOD conc., nitrification efficiency was over 90% and phenol removal efficiency was over 98%.

• Journal of Korean Society of Environmental Engineers
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• v.22 no.11
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• pp.2047-2058
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• 2000

The effects of operating parameters on performance of upflow anaerobic sludge blanket(UASB). anaerobic filter(AF), and two-stage anaerobic sludge bed filter (ASBF) bioreactors in treating swine wastewater were evaluated by operating the lab-scale bioreactors upto hydraulic retention time(HRT) of 1 day and organic loading rate (OLR) of $5.1kg-COD/m^3{\cdot}d$ for 200 days. Swine wastewaters of which characteristics were affected by types of hog raising and seasons contained high concentrations of COD, SS, and ammonia. Inoculation of the bioreactors with waste sludge from anaerobic treatment facility of local municipal wastewater treatment plant was effective in developing biomass in the bioreactors. Acclimation period of the bioreactors with swine wastewaters required approximately 40 days, but that for AF and two-stage ASBF, which were filled with media, was faster than VASB. The bioreactors showed high and stable COD removal efficiency of 77~91% at influent T-N concentrations of 370~800mg/L but low and unstable COD removal efficiency of 24~94% at influent T-N concentrations of 760~1,310mg/L. It is essential to remove ammonia prior to anaerobic treatment since the concentrations of ammonia in swine wastewaters showed toxic effects to methanogenic bacteria. The bioreactors were effective in treating swine wastewaters with COD removal efficiency of 78.9~81.5% and biogas generation rate of $0.39{\sim}0.59m^3/kg-COD_r$ at OLR of $1.1{\sim}2.2kg-COD/m^3{\cdot}d$: however, an increase of OLR by reducing HRT and increasing influent COD caused decrease of COD removal efficiency. The extent of decrease in COD removal efficiency was higher in UASB than AF and two-stage ASBF. AF and two-stage ASBF anaerobic bioreactors were effective in treating varing characteristics of swine wastewaters since they showed high and stable COD removal efficiency at high OLR due to effective retention of biomass by media and staging.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.13 no.2
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• pp.121-128
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• 2008

As an aquatic ecotoxicity test method, a bioassay using the inhibition of sporualtion of the green macroalga, Ulva pertusa, has been developed. Optimal test conditions determined for photon irradiance, pH, salinity and temperature were $100\;{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$, $7{\sim}9$, $25{\sim}35\;psu$ and $15{\sim}20^{\circ}C$, respectively. The validity of the test endpoint was evaluated by assessing the toxicity of four metals (Cd, Cu, Pb, Zn) and elutriates of sewage or waste sludge collected from 9 different locations. When the metals were assayed, the $EC_{50}$ values indicated the following toxicity rankings: Cu ($0.062\;mg{\cdot}L^{-1}$) > Cd ($0.208\;mg{\cdot}L^{-1}$) > Pb ($0.718\;mg{\cdot}L^{-1}$) > Zn ($0.776\;mg{\cdot}L^{-1}$). When compared with other commonly used bioassays of metal pollution listed on US ECOTOX database, the sporualtion test proved to be the most sensitive. Ulva sporulation was significantly inhibited in all elutriates with the greatest and least effects observed in elutriates of sludge from industrial waste ($EC_{50}=6.78%$) and filtration bed ($EC_{50}=15.0%$), respectively. The results of the Spearman rank correlation analysis for $EC_{50}$ data versus the concentrations of toxicants in the sludge presented a significant correlation between toxicity and four heavy metals(Cd, Cu, Pb, Zn). The method described here is sensitive to toxicants, simple to use, easy to interpret and economical. It is also easy to procure samples and maintain cultures. The present method would therefore probably make a useful assessment of aquatic toxicity of a wide range of toxicants. In addition, the genus Ulva has a wide geographical distribution and species have similar reproductive processes, so the test method would have a potential application worldwide.