• KSBB Journal
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• v.22 no.3
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• pp.157-161
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• 2007

This study is to investigate the biological degradation and the characteristics of MEA, a pH regulator to be put in the cooling water circulation system for power plants, loading to elevate concentrations of COD and N when eluted into the water environment. MEA, $NH_4^+$ and CODcr were monitored in flask cultures and in a batch aerator. MEA was found to be biologically degradable, producing substantial amount of ammonia (max. 78.1%) in a form of $NH_4^+$ and other carboneous intermediates. The degradation reaction rates were similar one another over all MEA concentrations tested as the activated sludge (microbial consortium) was acclimated to MEA with the gradual and stepwise increase in MEA input into the batch aerator. Also, MLVSS kept increasing with increasing MEA input. The COD-based degradation reaction order was determined to be 1.

• 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 Korean Society of Water and Wastewater
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• v.20 no.1
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• pp.128-137
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• 2006

This study aims at developing the practical technology in the treatment of box-mill wastewater using the aerobic co-metabolism principle. The conventional activated sludge method exhibited the removal efficiency of $TBOD_5$ and $TCOD_{Mn}$ as 30~50% and 40~50%, respectively. Color was rather increased by 30~130% because the conventional treatment under the aerobic condition did not induce the conversion of molecular structure of dyeing agents. Meanwhile, when the aerobic co-metabolism principle was applied to the same wastewater, the removal efficiency of $TBOD_5$ and $TCOD_{Mn}$ were obtained as 92~97% and 90~94%, respectively. In particular, color was significantly reduced down to 65~85%. The enhancement of treatment efficiency was ascribed to occur not only that the non-degradables were converted to the second substrates, but also that the enzyme activity was increased as MLVSS was kept 3000mg/l or more with the first substrates injected.

• Journal of Environmental Science International
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• v.8 no.2
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• pp.221-225
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• 1999

This study was conducted to evaluate the treatment efficiency including reaction kinetics and hydraulic characteristics of food processing wastewater by using an ejector-type aeration system (ETAS) in activated sludge process. The oxygen transfer efficiency in ETAS can be changed in accordance with the depth of reactor. However, the optimum air velocity was found less than 1.82 m/hr at a superficial liquid velocity of 634 m/hr. The ETAS process showed higher organic material removal efficiency than that of the existing activated sludge process under hydraulic detention time 6 to 12 hours. This process, which can maintain MLVSS highly, is able to have high organic material removal efficiency at short HRT and deal with variable organic material loading.

• Journal of Korean Society of Water and Wastewater
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• v.11 no.1
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• pp.74-80
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• 1997

The objectives of this study were to compare the characteristics of water quality in alternative Aerobic-Anoxic(A/A) and Aerobic(Control) sludge digestion. The A/A process control parameter as the pH signal(dpH/dt) was used. Comparison of the result of A/A digestion with those of Aerobic digestion indicated a 54% saving in aeration compared to Aerobic digestion. TN removal efficiency rates of A/A and Aerobic digestion were 45% and 4%, respectively. The concentration of COD(64 mg/l and 268 mg/l for the A/A and Aerobic digestion, respectively) and Ortho-P in the supernatant were also less with A/A digestion. MLVSS and Coliform destructions were noticed similar for both digestion, but better dewatering charateristics were noted for the A/A digestion.

• Journal of Environmental Health Sciences
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• v.26 no.3
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• pp.76-80
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• 2000

The purpose of this study is to compare the performance of rubble support media coated perlite and non-coated media. As rubble was coated perlite, the porocity of reactor was increased 5.6%, whereas packing weight was decreased 17.6%. When rubble was coated perlite, microorganisms were attached on the surface of support media after 2 hours. TCOD removal efficiency of the reactor packed with rubble support media coated perlite was higher 4~9% than that of rubble. The end of experiment, MLVSS of rubble support media and rubble coated perlite was 1858.8mg/ι, 2785.9mg/ι, respectively.

• Journal of Environmental Health Sciences
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• v.26 no.3
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• pp.98-102
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• 2000

The aim of this study was to evaluate on the removal effect of total nitrogen in municipal wastewater by decreasing hydraulic retention time(HRT) from 6 hour to 4 hour on CNR process. CNR-A(Cilia Nutrient Removal) is the process combining A2/O process with cilium media of H2L corporation. The removal efficiencies for T-N were 63.1% in A-1 reactor, and 73.5% in A-2 reactor and 77.0% in A-3 reactor. The specific nitrification(g-NH3-N/g-MLVSS.d) of Oxic in CNR-A process was 0.07-0.32. The specific denitrification in Anoxic and the specific nitrification inOxic was higher in HRT 4 hour because of optimum F/M ratio.

• Journal of Environmental Health Sciences
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• v.35 no.2
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• pp.116-123
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• 2009

Laboratory scale experiments were conducted to investigate the removal characteristics of nitrogen and phosphorus by the variation of aeration time in four sequencing batch reactors (SBRs). In R1 which has the shortest aeration time as 1 h, MLVSS concentration in reactor decreased by the wash-out of biomass because of the poor sedimentation. The TOC removal efficiencies were almost similar in 3 reactors except R1. At the low aeration time as 1 h, the nitrification was severely inhibited by the deficiency of oxygen. ${NH_4}^+$-N removal efficiency was decreased by the decrease of aeration time. At the aeration time over 2 h, the phosphorus removal efficiency was not affected by the variation of aeration time. The nitrification was inhibited but the phosphorus release and uptake was not inhibited by the decrease of low aeration time. Therefore, we can see that the phosphorus removal microorganisms are superior to nitrification microorganisms in oxygen utilization.

• Journal of Korean Society of Water and Wastewater
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• v.7 no.1
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• pp.13-19
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• 1993

Anaerobic Digestion of thickened septage was investigated in this study. Thickening could reduce the volume of septage to be treated to about 40% with 12hr HRT. The VS and BOD removal efficiencies were respectively 28 to 45%, and 75% when digested the thickened septage with 30 day HRT Or $1.4kgVS/m^3/d$. The BOD removal efficiency could be increased to about 90% with subsequent settling tank with about 6 hours HRT. The gas production rate was 0.22 to $0.35m^3gas/kgVSadd$($0.75m^3gas/kgVSrm$), or $1.32m^3gas/kgBOD_{rm}$. In addition, the supernatant of thickener could be returned to the aeration tank treating domestic sewage. In this case, a BOD loading rate of 0.5 to $0.7kgBOD/m^3/d$ or 0.5kgBOD/kgMLVSS/d was proposed for 80% BOD reduction.

• Progress in Superconductivity and Cryogenics
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• v.23 no.3
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• pp.32-36
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• 2021

Milking parlor wastewater contains not only high concentrations of organic compounds, but often animal antibiotics. To discharge the antibiotics to public water area cause problem of antibiotics resistant bacteria. Magnetic separation was applied into improvement of milking parlor wastewater treatment process. A new process, composed of a magnetic activated sludge (MAS) process and a contact oxidation (CO) process, was proposed in this study. This process was evaluated by the simulated milking parlor wastewater (4500 mg/L COD_Cr and 10 mg/L tetracycline) using a bench scale experimental setup. As a result, the process was able to removed 97% COD_Cr as well as 94% tetracycline. The MLVSS (mixed liquor volatile suspended solids) concentration of MAS was maintained at 12000 mg/L without excess sludge drawing. This process was considered to be useful as treatment process for milking parlor wastewater in which waste-milk including antibiotics is often discharged.