• 한국환경과학회지
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• 제8권5호
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• pp.617-623
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• 1999

This study was carried out to obtain the optimal operating parameter on organic matters and nutrient removal of mixed wastewater which was composed of sewage and stable wastewater using SBR. A laboratory scale SBR was operated with An/Ae(Anaerobic/Aerobic) ratio of 3/3, 2/4 and 4/2(3.5/2.5) at organic loading rate of 0.14 to 0.27 kgBOD/$m^3$/d. TCOD/SCOD ratio of mixed wastewater was 3, so the important operating factor depended upon the resolving the particulate parts of wastewater. Conclusions of this study were as follows: 1) For mixed wastewater, BOD and COD removal efficiencies were 93-96% and 85-89%, respectively. It was not related to each organic loading rate, whereas depended on An/Ae ratio. During Anarobic period, the amount of SCOD consumption was very little, because ICOD in influent was converted to SCOD by hydrolysis of insoluble matter. 2) T-N removal efficiencies of mixed wastewater were 55-62% for Exp. 1, 66-76% for Exp. 2, and 67-81% for Exp. 3, respectively. It was found that nitrification rate was increased according to organic concentration in influent increased. Therefore, the nitrification rate seemed to be achieved by heterotrophs. During anoxic period, denitrification rate depended on SCOD concentration in aerobic period and thus, was not resulted by endogenous denitrification. However, the amount of denitrification during anaerobic period were 3.5-14.1 mg/cycle, and that of BOD consumed were 10-40 mg/cycle. 3) For P removal of mixed wastewater, EBPR appeared only Mode 3($3^＊$). It was found that the time in which ICOD was converted to VFA should be sufficient. For mode 3 in each Exp., P removal efficiencies were 74, 87, and 81%, respectively. But for 45-48 of COD/TP ratio in influent, P concentration in effluent was over 1 mg/L. It was caused to a large amount of ICOD in influent. However, as P concnetration in influent was increased, the amounts of P release and uptake were increased linearly.

• KSBB Journal
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• 제28권2호
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• pp.80-85
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• 2013

The bacterial community structure in a biological reactor fed influent from a wastewater treatment system was investigated by denaturing gradient gel electrophoresis (DGGE) and in situ hybridization. Sludges were collected from three biological reactors (aerobic, oxic, and anoxic tanks) at the M wastewater treatment facility (WTF). The influent of the MWTF consisted of mixed tannery wastewater (40~65%) and seafood wastewater (35~60%). The treatment processes resulted in a removal efficiency for BOD (biochemical oxygen demand) and COD (chemical oxygen demand) of 83.6~98.2% and 72.8~84.6%, respectively for tannery wastewater than for seafood wastewater resulted in greater survival of biomass in the biological reactors and a higher removal of BOD, COD, and T-N of about 8~18%. In contrast, addition of greater amounts of seafood wastewater decreased the amount of biomass in the bioreactors due to the increasing concentration of chromium from that wastewater and it also. The dominant bacterial species during the high seafood wastewater input period were Burkholderia cepacia (JX901049) and an uncultured bacterium (JF247555), while Pseudomonas geniculata (HQ256559) was dominant during the high tannery wastewater input period. Flavobacteriumsp. BF.107 (FM173271) and Hyphomicrobium zavarzinii (Y14306) were dominant under anoxic conditions.

• 상하수도학회지
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• 제11권2호
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• pp.112-127
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• 1997

The purpose of this study is to get optimum operating factors of Upflow Anaerobic Sludge Blanket (UASB) reactor by introducing methods that make it to reduce inhibition possible in each process wastewater treatment. The used substrates, concentrated corn starch liquid (CSL) wastewater, modified starch, filtering and decoloring wastewater, ion refining wastewater, and mixed wastewater including modified starch and not including modified starch, are generated from molasses process. The seeding sludge is the digested sludge that had been applied to molasses wastewater. Batch test to reduce the inhibition factors that might be existed in each wastewater was examined. Based on the this test, the optimum operating factors according to alkalinity and pH variation was studied through the continuous test using three 5.5 L UASB reactor. The first reactor added $NaHCO_3$ to control alkalinity. The hydraulic retention time (HRT) reduced to 8 hours and the organic loading rate increased gradually. The second reactor changed the pH of influent from 7.0 to 6.0 using NaOH. The third reactor was operated without changes to compare the above two reactors. As the result, the inhibition in concentrated CSL wastewater was removed by adding iron (II). When trace metals were added to mixed wastewater not including modified starch, the digestability by gas production rate increased to more fifty percentage than mixed wastewater that was not adding the trace metals. The reason that the inhibition did not decreased in spite of adding trace metals and nutrients was influenced by high concentration generated during the acid fermentation. The UASB reactors using the mixed wastewater with the most effective performance were operated as 500 mg/L as $CaCO_3$ alkalinity and 6.0 pH at steady state, and at this time, the gas production rates were 283 and 311mL gas/g $COD_{added}$. The COD removal rates were 84.7 and 86.3%, respectively.

• KSBB Journal
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• 제28권3호
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• pp.157-164
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• 2013

Depending on season, mixed wastewater can show great deviations in terms of the influent ratios of tannery and seafood-wastewater. Increases in the ratio of tannery wastewater in influent water also result in increases in the concentration of chromium, which decreases the ratio of BOD/T-N so that the removal efficiency of organic and nitrogen pollutants in biological wastewater treatment deteriorates. No substantial differences occur in the ratios of Eubacteria/total bacteria as the ratio between tannery wastewater and seafood wastewater changes in the influent water. In contrast, the cell numbers and activities of Eubacteria and total bacteria significantly decline with increasing ratios of tannery wastewater in the influent water. Stable removal of organic and nitrogen pollutants by biological wastewater treatments leads to dominance of Proteobacteria groups in all biological treatment basins. In aeration and oxic basins, ${\gamma}$-Proteobacteria account for approximately 21% of the Eubacteria groups, at $1.9{\times}10^9{\sim}2.0{\times}10^9$ cells/mL, while in an anoxic basin, ${\beta}$-Proteobacteria account for approximately 19% of the Eubacteria groups, at $1.3{\times}10^9$ cells/mL. However, a substantial decline in dominance of approximately 11% occurs for ${\gamma}$-Proteobacteria in aeration and oxic basins and about 1% for ${\beta}$-Proteobacteria in an anoxic basin. Mixed wastewater that undergoes extensive property changes of the influent water shows an efficiency of biological treatment that is greatly influenced by the ratio of dominant Proteobacteria groups.

• KSBB Journal
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• 제22권3호
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• pp.129-133
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• 2007

This study represents that a removal efficiency of organic matters in wastewater is activated by a sludge process using new mixed microbial population. In case of mixed microorganisms, removal rates of suspended solid (SS), biochemical oxygen demand (BOD) and chemical oxygen demand (COD) were over 90 percent under experimental condition, and removal efficiency of organic matters, sludge density index (SDI) and capillary suction time (CST) in mixed population were higher than that in not-mixed microorganism, while total kjeldahl nitrogen (TKN) and total phosphorus (T-P) which indicate a degree of eutrophication were removed easily in both case. From these results, we may propose that an application of the mixed microbial population is useful to treat domestic wastewater including a great deal of organic matters.

• 한국환경보건학회지
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• 제19권4호
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• pp.38-43
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• 1993

The characteristics of food wastewater treatment in an anaerobic packed bed reactor (APBR) with polyurethane as a packing material and sludge bed reactor (ASBR) was studied. The reactor of 9cm-ID, 150cm-height was fed in a continuous mode from bottom of reactor. For the purpose of constant temperature of reactor, water jacket was installed. The used packing materials was polyurethane sponge foam. Methane which was produced by decomposed organics collected at the top of the reactor for using as a fuel. The substrates used were synthetic, mixed and food wastewater. For the acclimatization of microorganisms, mixed wastewater was used. The major analyses were gas production, COD, pH and volatile acids. Based upon the completed works, the results are as follows: When food wastewater was fed the quantity of produced gas was less than that of synthetic wastewater, but food process saw higher methane content than synthetic process. As well as COD removal efficiency of food process reached at about 85%. In aspect of effluent volatile acid, food process showed low concentration of below 500 mg/l, therefore anaerobic reaction stabled. Conclusively food wastewater used can be digested by anaerobic treatment, especially anaerobic packed bed reactor showed 82% of COD removal, 75% of methane content, 10 l of gas production, and anaerobic sludge bed reactor did 79% of COD removal, 75% of methane content, 81 of gas production at 4 kgCOD/m$^3$day, 36$\circ$C.

• 공업화학
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• 제20권3호
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• pp.301-306
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• 2009

본 연구에서는 냉연도금공장의 각 단위공정에서 발생되는 폐수를 미생물을 이용하여 안정하게 처리하기 위하여 각 폐수의 특성파악과 처리조건을 도출하고자 하였다. 발생되는 폐수 중 알칼리성폐수가 전체폐수의 64%를 차지하였으며, 산중금속함유폐수는 30%를 차지했다. 탈류폐액의 COD는 53890 mg/L로 전체 폐수발생량의 0.03%에 불과함에도 불구하고 COD의 53%를 유발하고 있었으며, COD의 94%는 SCN에 의해 기인하였다. 혼합폐수를 미생물로 처리할 때 혼합폐수 중 SCN농도가 200 mg/L 이하일 때 제거가 용이하였다. 반면 COD 유발물질은 400 mg/L 이하가 되더라도 처리효율이 미흡하였다. 이는 탈류폐액 중에는 난분해성 유기물질이 다량 함유되어 있기 때문이라 판단된다. 혼합폐수를 처리할 때 초기에 pH가 7.33이었지만 8 h 후에는 7.99로 상승하였다. 이는 탈류폐액에 함유된 SCN이 박테리아에 의해 분해될 때 발생되는 암모니아에 의해 기인한 것으로 사료된다.

• 상하수도학회지
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• 제19권5호
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• pp.625-631
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• 2005

Disinfection characteristics of mixed oxidants produced by mean of electro-chemical method were evaluated. Inactivation rate of B. subtilis spore on the mixed oxidants were similar with that of chlorine. Based on the experimental results, activation energy of mixed oxidants and chlorine with B. subtilis spore at pH 8.3 were calculated as 30.8, $34.7kJ{\cdot}mol^{-1}$ respectively. UV absorption spectrum of both chlorine and mixed oxidants present similar. Molar extinction coefficients of chlorine and mixed oxidants at 292nm, which is maximum absorption wavelength of $OCl^-$ were 357, $377M^{-1}cm^{-1}$, respectively. Disinfectant decay rate and formation rate of THM in the S WTP filtrate also shows insignificant difference for both mixed oxidants and chlorine. In consequent, it was confirmed that high portion of chlorine presents in the mixed oxidants.

• Journal of Advanced Marine Engineering and Technology
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• 제33권8호
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• pp.1187-1195
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• 2009

본 논문은 완전 혼화조를 이용한 폐수처리 공정의 응집특성에 대한 연구를 목적으로 한다. 완전 혼화조 시스템은 유체 저장조, 임펠러가 장착된 3단의 혼화 및 응집부, 응집보조제 및 응집제 주입부, 응집 침전조 그리고 제어부로 구성된다. 실험용 폐수는 터널 공사현장에서 폐수 슬러지를 수거하여 약 1,000NTU의 탁도를 갖도록 만들었다. 응집보조제의 주입량이 증가함에 따라 약 99% 정도까지 탁도 제거율이 증가하였으며, 응집제의 주입량이 일정한 범위 이상으로 증가하면 탁도 제거율이 감소하는 것을 알 수 있다.

• Journal of Microbiology and Biotechnology
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• 제6권2호
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• pp.116-119
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• 1996

The biological treatment by a mixed culture GE2 immobilized on activated carbon was investigated with a phenolic resin industrial wastewater containing 41,000 mg/l of phenol and 2,800 mg/l of formaldehyde. At a dilution of 20 times with aerated tap water, influent and effluent $COD_{Mn}$ were 4,587 mg/l and 46 mg/l, that is, $COD_{Mn}$ removal efficiency was 99.0%. At this time, phenol and formaldehyde con-centration of the effluent were 1.24 and 6.80 mg/l, indicating removal efficiencies of 99.9 and 94.1%, respectively.