• 한국물환경학회지
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• 제23권6호
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• pp.993-997
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• 2007

The upflow anaerobic sludge blanket (UASB) reactor can be effective for treating simple organic compounds containing high concentration of ammonia nitrogen. The chemical oxygen demand (COD) removal efficiency was about 80% at ammonia nitrogen concentration up to 6,000 mg-N/L. This result also showed that it would be possible to treat propionate effectively at free ammonia nitrogen concentration up to 724 mg-N/L if sufficient time was allowed for adaptation. However the specific methanogenic activity (SMA) of granule was lower than that of granule in the reactor with lower ammonia nitrogen concentration. At 8,000 mg-N/L, the inhibition of high ammonia concentration was observed with evidence of increase of the volatile suspended solids (VSS) concentration in the effluent. It might be ascribed to the decrease in the content of extracellular polymer (ECP), which resulted to the sloughing off of obligated proton-reducing acetogens and heterogenotrophic methanogens from the exterior of granular sludge. This caused a great portion of the finely sludge to be easily washed out. Therefore, failure to maintain the balance between these two groups of microorganism cause accumulation of the hydrogen partial pressure in the reactor, which could have inhibited the growth of acetate utilizing methanogens.

• 한국환경과학회지
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• 제5권4호
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• pp.513-524
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• 1996

Laboratory investigation was conducted to evaluat the mixing effects on organic removal efficiency to treat low-strength synthetic wastewater using modified anaerobic - filter reactor combining anaerobic filter and upflow anaerobic sludge blanket. Using the modified process the low-strength wastewater like municipal sewage could be treated with 85% T-COD removal efficiency at hydraulic retention time of 6 hours. At the constant organic loading of 0.5 kg COD/m 3-day, the organic removal efficiency and effluent COD concentration are increased as influent COD concentration increased from 125 mg/l to 500 mg/l. Mixing effects on organic removal efficiency are evident and optimum mixing speed is found as 50RPM. Placing the granular sludge and media on which slime layer was pre-formed into the reactor seemed to be very effective In achieving short start-up period. Therefore, the steady state was achived after 4 weeks and 1 week based on T-COD and S-COD, respectively.

• 한국환경보건학회지
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• 제32권2호
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• pp.179-185
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• 2006

Effect of organic loading rate on UASB performance was evaluated under the renditions of some surface area/reactor volume ratio and different reactor diameter. At the low leading rate of 0.4 kg $COD/m^3{\cdot}d$, reactor performance was not affected by reactor diameter. At the organic loading rate of 6 kg $COD/m^3{\cdot}d$, however, volatile acid accumulation and low COD removal efficiency is observed in reactor having 6.4 cm diameter, while volatile acid is not accumulated at all and high COD removal efficiency is observed in reactor having 3 cm diameter. Such a difference of reactor performance depending on reactor diameter can be explained that sludge bed can be fluidized by evolved gas bubble in narrow reactor, while sludge bed ran not be fluidized by evolved gas bubble only in wide reactor. At a high organic loading rate of 20 kg $COD/m^3{\cdot}d$, it can be judged that there is no relation between reactor configuration and reactor performance because all reactors showed very low COD removal efficiencies regardless of reactor diameter. Narrow and tall type reactor is favorable condition for making sludge bed fluidization at a constant surface area/reactor volume ratio. Thus, it can be judged that reactor configuration and sludge bed fluidization have great influence to reactor performance.

• 유기물자원화
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• 제14권4호
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• pp.151-160
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• 2006

침출수의 혐기성 처리시 오염물질 거동과 미생물 특성을 평가하기 위하여 10개월간 실험을 수행하였다. 상향류 혐기성 슬러지 블랭킷 (UASB) 반응조의 경우 최대 유기물 부하 $20kgCOD/m^3.d$까지 약 90%의 COD 제거율을 나타내었다. 높은 유기물 부하 ($18-20kgCOD/m^3.d$)에서는 프로피온산의 농도가 상대적으로 증가하여 프로피온산의 초산으로의 전환이 율속단계로 나타났다. UASB 반응조를 이용한 침출수 처리는 높은 유기물 제거능에도 불구하고 입상슬러지와 반응조 내부 등의 무기물 축적으로 인한 운전상의 문제가 발생하였다. 입상슬러지 내 주된 무기물의 성분은 칼슘화합물로 나타났다. 본 연구에서는 비메탄 활성도의 급격한 감소는 발생되지 않았으나 무기물 축적으로 인한 운전상의 문제를 저감하기 위해서는 무기물 제거를 위한 전처리 공정의 도입이 필요할 것으로 판단된다.

• Biotechnology and Bioprocess Engineering:BBE
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• 제9권5호
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• pp.345-351
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• 2004

We investigated the anaerobic ammonium oxidation (anammox) reaction in a lab-stale upflow anaerobic sludge blanket (UASB) reactor. Our aim was to detect and enrich the organisms responsible for the anammox reaction using a synthetic medium that contained low concentrations of substrates (ammonium and nitrite). The reactor was inoculated with granular sludge collected from a full-scale anaerobic digestor used for treating brewery wastewater The experiment was performed during 260 days under conditions of constant ammonium concentration ($50\;mg\;NH_4^+-N/L$) and different nitrite concentrations ($50{\~}150\;mg\;NO_2-N/L$). After 200 days, anammox activity was observed in the system. The microorganisms involved in this anammox reaction were identified as Candidatus B. Anammoxidans and K. Stuttgartiensis using fluorescence in situ hybridization (FISH ) method.

• Biotechnology and Bioprocess Engineering:BBE
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• 제11권3호
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• pp.199-204
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• 2006

The purpose of this work was to evaluate the development of the anammox process by the use of granular sludge selected from a digestion reactor as a potential seed source in a lab-scale UASB (upflow anaerobic sludge blanket) reactor system. The reactor was operated for approximately 11 months and was fed by synthetic wastewater. After 200 days of feeding with $NH_4^+\;and\;NO_2^-$ as the main substrates, the biomass showed steady signs of ammonium consumption, resulting in over 60% of ammonium nitrogen removal. This report aims to present the results and to more closely examine what occurs after the onset of anammox activity, while the previous work described the start-up experiment and the presence of anammox bacteria in the enriched community using the fluorescence in situ hybridization (FISH) technique. By the last month of operation, the consumed $NO_2^--N/NH_4^+-N$ ratio in the UASB reactor was close to 1.32, the stoichiometric ratio of the anammox reaction. The obtained results from the influent-shutdown test suggested that nitrite concentration would be one key parameter that promotes the anammox reaction during the start-up enrichment of anammox bacteria from granular sludge. During the study period, the sludge color gradually changed from black to red-brownish.

• 유기물자원화
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• 제16권3호
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• pp.75-82
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• 2008

상향류 혐기성 슬러지 블랭킷 반응조을 이용한 프로피온산의 처리시 고농도 황산염의 영향을 조사하였다. 반응조의 평균 유기물 부하와 수리학적 체류시간은 $1.2kg \;COD/m^3{\cdot}d$와 1.6일로 유지하였다. 황산염이 없는 조건에서 UASB 반응조의 경우 95%의 COD 제거율을 보였으며 황산염이 $2,000mgSO_4^{2-}/L$로 존재하는 경우 용존 황화물의 영향으로 COD 제거율이 83%로 감소하였다. 메탄 생성균과 황산염 환원균의 경쟁관계를 평가하기 위하여 미생물의 상호작용에 관해 조사하였다. $COD/SO_4^{2-}$ 비가 1인 경우 이용 가능한 전자 수용체의 평균 58%가 메탄 생성균에 의해 이용되며 나머지가 황산염 환원균에 의해 사용되었다. 초산과 프로피온산을 기질로 이용한 비메탄 활성도의 경우 미생물이 기질에 적응함에 따라 증가하였다.

• 유기물자원화
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• 제16권4호
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• pp.91-97
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• 2008

본 연구에서는 상향류 혐기성 블랭킷 반응조를 이용한 침출수 처리시 입상활성탄과 입상슬러지의 첨가가 반응조의 성능에 미치는 영향을 평가하였다. Control 반응조의 경우 식종물질로 혐기성 소화슬러지를 이용하였으며 GAC 반응조와 Granule 반응조의 경우 Control 반응조와 동일 방식으로 식종하였으며 단지 GAC와 입상슬러지를 소량 첨가하였다. Granule 반응조가 초기 운전기간 동안 가장 짧은 순응기간을 보였으며 GAC 반응조의 경우에도 운전초기에 만족할 만한 성능을 보였다. 그러나 활성탄의 흡착능이 소모됨에 따라 유출수 COD 농도가 점차 증가하는 경향을 보였다. 반응조가 안정화된 후 GAC 반응조가 다른 반응조에 비해 약간 우수한 결과를 보였으며 모든 반응조의 COD 제거율은 수리학적 체류시간 1일에서 90% 이상을 나타내었다. 특히 GAC 반응조의 경우 COD 제거율의 변화 없이 유기물 부하 $4.0{\sim}8.2kg\;COD/m^3.d$에서 95%를 유지하였다. 소량의 입상슬러지 첨가에 의해 초기 운전기간을 단축시킬 수 있었으며 처리효율은 GAC 첨가에 의해 향상되는 것으로 나타났다.

• 환경위생공학
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• 제13권2호
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• pp.47-56
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• 1998

Effects of sulfate on the anaerobic substrate utilization were evaluated using UASB (Upflow Anaerobic Sludge Blanket) reactor. Effect of sulfate on the organic removal rate was dependent on the relative amount of microorganisms in the reactor, the operational condition, and the characteristics of sludge. When the sulfate shock was applied to 0.0 - 3.0g SO$_{4}$$^{2-}$/d, more than 95% of COD removal efficiency was achieved. Therefore, if F/M ratio was kept to low sufficiently with recirculation, it is shown that operation of the reactor was not affected significantly, though sulfate shock load was doubled compared to the normal operation. Provided that it is shocked by high strength of sulfate or temporary shock load is applied frequently the efficiency of reactor may be disadvantageous as well as the wash-out of sludge will be increased by decreasing the size to the accumulated frequency of granular sludge and the size with maximum frequency.

• 한국환경과학회지
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• 제4권2호
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• pp.201-214
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• 1995

Design approach of upflow Anaerobic Sludge Blanket(UASB) process based on the biological kinetic parameters are known to be very difficult since the characteristics of the granular slut비e depends on the type of wastewater and size distribution of the granular sludge also depends on the upflow velocity in the UASB reactors. Furthermore, industrial wastewater containing toxic substances has been treated by UASB process without the clear knowledge of toxic effects on the granular slut형e. Hence, the present research was aimed on the intensive evaluation of biological kinetic parameters of the granular sludge in UASB reactor with and without toxic substance of 2, 4-dichlorophenol in order to present the basic design measures for UASB process design. The results could be summarized as follows. The biological kinetic parameters(k and Ks) considerably varied with the granular size of the sludge. Generally, 연e k and ks values of the granular sludge increased with the particle size of the granule. The biological kinetic parameters(k and Ks) of the granular sludge obtained from batch test were not applicable to design purpose of UASB process due to substrate diffusional limitation into the granular sludge in the completely mixed UASB reactors. The toxic effects on k and Ks greatly varied with the granular sixte. And as the toxicant concentration increased, the k value decreased while the Ks value increased. Inhibition constant(hi) for k with the toxicant of 2, 4-dichlorophenol varied from 0.5 to 2.3 depending on the granular sizes while the inhibition constant(Ki) for Ks varied from 20.7 to 80.1, showing the mixed inhibition.