• Journal of Korean Society of Environmental Engineers
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• v.29 no.9
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• pp.997-1002
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• 2007

The objectives of this research are to remove dissolved organic matter and nitrogen compounds by using aerated submerged bio-film(ASBF) reactors in batch systems and improve understanding of dissolved organic matter and nitrogen compounds removal rates with dynamic relationships between heterotrophic and autotrophic bacteria in the fixed-film reactor. This research explores the possibility of enhancing the performance of shallow wastewater treatment lagoons through the addition of specially designed structures. These structures are designed to encourage the growth of a nitrifying bacterial bio-film on a submerged surface. Specially, the effects of cold temperatures on the dissolved organic matter and ammonia nitrogen performance of the ASBF pilot plant was investigated for the batch system. It is anticipated thai the ASBF would be used for a design of biological treatment for removing of dissolved organic matter and nitrogen compounds in new wastewater treatment plants as well as existing wastewater treatment plants.

• Journal of the Korea Organic Resources Recycling Association
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• v.31 no.2
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• pp.19-38
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• 2023

Nitrous oxide, one of the six greenhouse gases from Kyoto protocol, is known to be emitted in biological nitrification and denitrification reactions at wastewater treatment plant. In this study, EQPS which is a computer program that can simulate nitrous oxide gas emission amount at wastewater treatment plants is used. The MLE process which treats wastewater from combined sewer is studied. Operational variables which are MLR, water temperature at reactor and primary clarifier by-pass percentage are changed to define the condition which produces the least amount of nitrous oxide gas. 200 % of MLR, 20 ℃ of water temperature at bioreactor and 15 % of primary clarifier by-pass percentage are shown the least nitrous oxide emission factor. Also, it is found that the deep aeration tank produces less amount of nitrous oxide gas since less air is required to meet oxygen demand in this type of aeration tank.

• Journal of Korea Soil Environment Society
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• v.4 no.1
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• pp.97-108
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• 1999

Reduction 2, 4, 6-trinitrotoluene by zero valent iron was studied in a batch reactor under anoxic conditions. Results showed that the removal of trinitrotoluene (TNT)followed a pseudo-first order reaction and the rate was linearly dependent on the available reactive surfau area of the zero valent iron surface area, resulting a rate constant of 0.0981min$^{1}m$$^{-2}m$. High concentrations of the final product, presumably triaminotoluene which needs to be treated by other means, accumulated in the solution. However , little amount of TAT was extracted from the metal surface by using acetonitrile or phosphate buffered water (pH 7.0). Other common major intermediate in biological TNT degradation, a group of aminodinitrotoluenes, was not detected in the solution. Therefore, it is postulated that the reduction of nitro group by $Fe^0$ occurs simultaneously in all three positions and a TNT reduction model by zero valent iron was suggested.

• KSBB Journal
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• v.18 no.2
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• pp.111-116
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• 2003

Hydrogen producing acidogenic microorganisms were self-immobilized using organic-inorganic hybrid polymer within 5 minutes. During the continuous tratment of synthetic wastewater at a hydraulic retention time of 20 hours, at 37$^{\circ}C$, pH 5.0, the self-immobillized granules were maintained in a stirred tank reactor. The black colored granules gradually became milky. Image analysis showed that the mean diameter of the milky colored granules ranged from 1.5 to 20. mm. The maximum bio-gas procuction rate was 380 ml/L/hy and the concentration of H$_2$was around 50%, while no methane was detected. Granular ECP was extracted and its content was measured to elucidate the role of the organic-inorganic hybrid polymer. Further increases of granule concentration are expected to increase the hydrogen production rate.

• KSBB Journal
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• v.4 no.2
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• pp.87-93
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• 1989

To develop high dfficiency-low energy consumption attrition coupled bioreactor for enhanced enzymatic hyerolysis of insoluble biomass, a tumbling drum type bioreactor was installed, and its efficiency was evaluated. The effects of drum structure and poerational conditions were investigated. The optimal saccharification at 3L drum was obtained at 8 baffled drum, drum diameter to baffle height ratio of 1:0.05, 100rpm, and addition of 600g of 3mm glass bead per liter. The consumed power for rolling of drum and energy consumption for half digestion of cellulose were measured, and compared with enhanced rate and yield to predict the economic prospect of the process. The tumbling drum type bioreactor seems to have appropriated structure for industrial scale operation, and further investigation for scale-up need to be conducted.

• Microbiology and Biotechnology Letters
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• v.42 no.3
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• pp.307-311
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• 2014

This study investigated the effects of polyurethane foam on continuous hydrogen production from mixed wastes. Molasses was co-fermented with non-pretreated sewage sludge in a sequencing batch reactor. The results indicated that the addition of polyurethane foams as a microbial carrier in the reactor mitigated biomass loss at HRT 12 h, while most of the biomass was washed out during the operation period with no carrier. There was a stable hydrogen production rate of $0.4L-H_2/l/d$ in the carrier-sequencing batch reactor. Suspended biomass in the carrier-reactor indicated it possessed the highest specific hydrogen production rate ($241{\pm}4ml-H_2/g\;VSS/d$) when compared to that of biomass on the surface ($133{\pm}10ml-H_2/g\;VSS/d$) or inner carrier ($95{\pm}14ml-H_2/g\;VSS/d$).

• Journal of Korean Society of Water and Wastewater
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• v.18 no.5
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• pp.619-627
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• 2004

Purposes of this study were to examine closely the extracellular polymeric substances (EPS) which was a membrane fouling contaminant, to control detected EPS by powdered activated carbon (PAC) dosage etc. and to evaluate the possibility of practical reuse facility. With high removal efficiency of general pollutants, when the PAC is added to MBR, improvement of removal efficiency of $COD_{cr}$, and color was expected and treated wastewater can be reused. It was judged that the correlation between EPS and membrane fouling was very high. Carbohydrate and DNA in the EPS were judged to be cause of membrane fouling. If EPS could be controled, not only membrane fouling would be decreased but also operation time would be extended. In experiment of powdered activated carbon (PAC), characteristics of the best PAC for membrane fouling control were the particle size of $7{\mu}m$, lodine Number of 1,050, surface area of peat of $1,150m^2/g$. In lab test, operation time of MBR by PAC dosage of 200mg/gVSS was longer than one of MBR by without PAC dosage. Because EPS, especially carbohydrate and DNA, was controled successfully by PAC, membrane fouling in MBR could be decreased.

• Journal of Korean Society of Water and Wastewater
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• v.17 no.4
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• pp.559-566
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• 2003

From this research, the performances of a sludge reduction in the sewage sludge aerobic digestion was experimented by using a sludge pretreatment and membrane bioreactor. The submerged plate membrane was used as the solid-liquid separation membrane. After drawing small amounts of sludge in a bioreactor and then doing the alkaline treatment and ozone treatment, the sludge was sent to back to the reactor. The HRT in the reactor was set as 5 days and the operation in the reactor was carried out at the DO of 1mg/L on average. After 100 days of operation in the reactor, it was shown that the reduction efficiency of total solids was more than 83%. Most of volatile solids were removed through mineralization, and the considerable portion of the non-volatile solids was dissolved and then flowed out with the effluent. Only about 16.3% of total solids in the sludge was accmulated in the reactor even without the loss of volatile fraction. Also, by deriving nitrification and denitrification in one reactor simultaneously, more than 90% of nitrogen removal effect was realized and the experiment was run smoothly without fouling of membrane, even in the high concentration of MLSS. Based on this experiment, sludge can be reduced considerably at a low HRT by these two newly suggested approach.

• Journal of Environmental Science International
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• v.5 no.1
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• pp.61-69
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• 1996

The combined wastewater of municipal landfill leachate and municipal sewage was treated using several sets of bench-scale aerated circulating system including porous media. Investigated items in this experiment were the dominant protozoa and metazoa in this system, the variation of microfauna relationship between operating condition and dominant genera. Also considered the factors determining dominant genera and their role. The outcome of this research is as follows; 1. Aspidisca, Vorticella, Truhellophyllum, Lecane, Philodina, Cyclops were mainly appeared prior to combinding leachate, while Trachelocerca, Bodo, Glaucoma were the dominant genera after combinding leachate. 2. As to metazoa, Nematode and Philodina were not influenced by 5oA leachate mixing ratio, meanwhile Crustacea has high sensitivity for increased leachate mixing ratio and it was not appeared in 5% leachate mixing ratio. 3. The appropriate treatability could'nt be expected at the above 10% leachate mixing ratio. Especially, in the condition of 20% leachate mixing ratio, all of the microfauna were affected damage seriously on their existence. Meanwhile hydraulic retention time, substrate loading rate and slut자e production rate didn't give notable influence on increasing the number of microfauna. 4. As to protozoa, saprozoic and holozoic species were appeared commonly and polysaprobic species were dominent. 5. Filamentous organsms were nearly not affected by leachate mixing. It seems that they could live without any trouble at the 10% leachate mixing ratio, if the substrate is sufficient. 6. Diversity of microfauna had a reducing trernd as the sewage was mixed with leachate.

• Microbiology and Biotechnology Letters
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• v.35 no.1
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• pp.73-80
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• 2007

Biofilm media was equipped in two-compartmented wastewater treatment bioreactor which was separated by porcelain septum. DC 2.0 volt of electric potential was charged to anodic (oxidative) biofilm media (ABM) to induce oxidation potential but not to that of carbon (neutral) biofilm media (CBM) that was used for control test. Biofilm structure, biomass variation, Off variation and wastewater treatment efficiency in the bioreactor equipped with ABM (ABM-bioreactor) and CBM (CBM-bioreactor). Time-coursed variation of biofilm structure forming on surface of ABM and CBM was observed by scanning electron microscopy. The biofilm growing on ABM was dispersed on surface and was not completely covered the media but the biofilm growing on CBM was continuously increased and finally covered the media. The ORP of CBM was decreased to 100 mV, which was reciprocally proportional to the biomass growth. However, the ORP of ABM was about 800 mV, which was maintained during operation for about 60 days. The treatment efficiency of COD in the ABM bioreactor was 2 times higher than those in the CBM bioreactor. From these results, we proposed that electrochemical oxidation potential charged to biofilm media may inhibit formation of biofilm extremely condensed and activate bacterial cell metabolism.