• 대한토목학회논문집
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• 제8권4호
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• pp.59-67
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• 1988

혐기성소화(嫌氣性消化)에 미치는 온도(溫度)의 영향(影響)을 가장 효과적으로 파악할 수 있는 체류시간(滯留時間) 5일(日)에서 인공(人工)슬러지를 대상으로 $35{\sim}55^{\circ}C$의 소화실험(消化實驗)을 행하였다. 소화온도증가(消化溫度增加)에 따라 메탄발효(醱酵)의 저해(沮害)가 감소하여, 중온(中溫) 및 중간영역(中間領域)의 온도(溫度)에서는 잔발효(酸醱酵)가 우세하였으나 $55^{\circ}C$에서는 활발한 메탄발효(醱酵)가 이루어졌다. 온도(溫度)의 변화(變化)는 미생물활성(微生物活性)뿐 아니라 슬러지의 물리(物理), 화학적(化學的) 특성(特性)에도 영향(影響)을 미친다고 추정된다. 또한 유입(流入) 슬러지의 희석(稀釋)에 의하여 소화저해(消化沮害)가 크게 감소하여 모든 온도(溫度)에서 활발한 메탄발효(醱酵)가 가능하였다. 소화효율(消化效率)은 수리학적(水理學的) 부하량외(負荷量外)에 유기물부하량(有機物負荷量)에도 지배받음을 알 수 있었다. 소화효율(消化效率)의 급격한 저해(沮害)가 발생된다고 보고된 $40{\sim}45^{\circ}C$에서도 뚜렷한 저해(沮害)는 없었다. 한편 소화온도증가(消化溫度增加)에 따라 소화(消化)슬러지의 침강특성(沈降特性)도 향상되었다.

• 환경위생공학
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• 제14권4호
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• pp.172-179
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• 1999

In this research, biological treatability test was conduced using seawater flocculated tannery wastewater by fixed biofilm reactor. During one cycle, the removal efficiency of organic corbon obtained with fixed biofilm process for treating tannery wastewater was considerably greater than that with activated sludge process. As the hydraulic retention time increased form 0.5day to 4day, removal efficiency of organic carbon was increased from 72% to 87.3%. Attached biomass in media increased with influent organic loading up to 29g MLSS/L, that could reduce the specific organic loading rate. The continual measurement of attached biomass was possible for the operation of the biofilm reactor. Equal and low nitrication rates were observed in both suspended growth activated sludge process and fixed biofilm process, despite commercial nitrifier was seeded. Through the process of treating the tannery wastewater, EC50 values which is measured by the use of Ceriopdaphnia dubia, were decreased to the extent of 50% after treatment of seawater flocculation and of 83% after biological treatment, respectively, compared to those of the untreated wastewater.

• 유기물자원화
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• 제15권2호
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• pp.136-146
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• 2007

상향류 혐기성 블랭킷 반응조를 이용한 매립지 침출수 처리시 입상슬러지 첨가 유무에 상관없이 성공적인 처리가 가능하였다. 입상슬러지의 첨가는 초기 운전기간를 현저히 단축할 수 있었다. 수리학적 체류시간 1일과 $4-8kgCOD/m^3.d$ 의 유기물 부하율에서 Control 반응조와 Granule 반응조의 COD 제거율은 90% 이상을 유지하였다. 실험기간 동안 입상슬러지 첨가 유무에 상관없이 슬러지 표면과 반응조 벽면에 무기 침전물이 축적되었다. 비메탄 활성도는 미생물의 기질에 대한 적응도와 유기물 부하량이 증가함에 따라 증가하였다. Granule 반응조의 최대 비메탄 활성도의 값은 $0.57gCOD/g{\cdot}VSS{\cdot}.d$로 나타났다. 비록 본 연구에서는 과도한 무기물 축적으로 인한 비메탄 활성도의 저감은 발생하지 않았으나 무기물의 제거를 위하여 유입수의 전처리 공정이 필요할 것으로 판단된다.

• 한국물환경학회지
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• 제23권3호
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• pp.397-402
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• 2007

Anammox reactor seeded with sewage sludge from RBC reactor and anaerobic granule from full-scale UASB reactor treating distillery wastewater was operated. Mixed granule and suspended sludge in the ammonium oxidizing process were taken and analyzed to investigate microbial community structure by molecular methods such as gene cloning and phylogenetic tree analysis after 250 days of continuous cultivation. The average nitrogen removal rate showed $0.9kg\;N/m^3-day$ after 250 days of continuous operation, then the maximum nitrogen removal rate showd $1.9kg\;N/m^3-day$ when $2.1kg\;N/m^3-day$ of nitrogen loading rate was applied. As results of gene cloning and phylogenetic tree analysis, Three kinds of phylum were found to be Proteobacteria, Acidobacteria and Planctomycetes (anammox bacteria) in mixed granule. Five kinds of phylum were found to be Proteobacteria, Chlorobi, Planctomycetes, Nitrospirae and Verrucomicrobia in suspended sludge. We found planctomycete KSU-1 and putative new anammox bacteria in the reactor. Microbial structure represented different consortia depending on the types of sludge in the anammox reactor.

• 한국환경과학회지
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• 제28권8호
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• pp.669-676
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• 2019

The purpose of this study was to evaluate the effects of different Hydraulic Retention Times (HRTs) on the contaminant removal efficiency using Aerobic Granular Sludge (AGS). A laboratory-scale experiment was performed using a sequencing batch reactor, and the Chemical Oxygen Demand (COD), nitrogen, orthophosphate removal efficiency, AGS/MLSS ratio, and precipitability in accordance with the HRT were evaluated. As a result, the COD removal efficiency was not significantly different with the reduction in HRT, and at a HRT of 6 h, the removal rate was slightly increased owing to the increase in organic loading rate. The nitrogen removal efficiency was improved by injection of influent division at a HRT of 6 h. As the HRT decreased, the MLSS and AGS tended to increase, and the sludge volume index finally decreased to 50 mL/g. In addition, the size of the AGS gradually increased to about 1.0 mm. Therefore, the control of HRT provides favorable conditions for the stable formation of AGS, and is expected to improve the contaminant removal efficiency with the selection of a proper operation strategy.

• 한국폐기물자원순환학회지
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• 제35권8호
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• pp.731-743
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• 2018

This study was performed to test the feasibility of thermophilic ($55^{\circ}$) co-digestion of municipal sewage sludge and food wastes. The management variables of co-digestion were the mixed ratios of municipal sewage sludge and food waste hydraulic retention times (HRTs). During the operation of thermophilic co-digestion, the reactor pH ranged from 7.0 to 7.5 and the reactor alkalinity remained above 3,200 to 4,000 mg/L as $CaCO_3$. The volatile fatty acids concentration increased as the HRT shortened from 20 days to 10 days and the mixture ratio increased to 1:4, but did not reach toxic levels for co-digestion of sewage sludge and food wastes. Methane productivity increased gradually as the organic loading rate increased. Maximum methane productivity reached 1.03v/v-d at an HRT of 10 days and at the mixture ratio of 1:4. The TVS removal efficiency decreased from 70.6% to 58.3% as the HRT shortened from 20 days to 10 days. TVS removal efficiency ranged from 57.0% to 77% during the entire operation. It is likely that thermophilic co-digestion of sewage sludge and food wastes is a very effective method both to environmentally treat food waste and to economically produce gas for energy.

• 환경위생공학
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• 제14권2호
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• pp.105-112
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• 1999

The removal characteristic of BOD, COD,T-N, and T-P was investigated in municipal wastewater treatment with anoxic and membrane submerged aerobic reactor. It was found that BOD and COD removal rate were obtained 90% and 92%, respectively, for 90 days operation. BOD and COD loading rate did not affect to the removal efficiency because MLSS concentration in aerobic tank was highly maintained.In the case of first reactor operated with anoxic and second reactor operated as aerobic, T-N, T-P removal rate were obtained 93% and 99% respectively.It was shown that removal efficiency could be maintained stable due to the complete removal of SS and sludge production decreased with increasing of sludge retention time.

• 환경위생공학
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• 제16권1호
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• pp.34-39
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• 2001

Submerged Membrane Bio-Reacter(SMBR) process was used to food wastewater treatment. From laboratory pilot-scale experiment data, it was confirmed that this process was very effective process for organics, suspended solid, and N, P treatment. It was found that BOD and COD removal rate were obtained 90% and 92%, respectively, for 150 days operation. Organics loading rate did not affect to the removal efficiency because MLSS concentration in aerobic tank was highly maintained. IN the case of first reactor operated with anoxic and second reactor operated as aerobic, T-N, T-P removal rate were obtained 93% and 95%, respectively. It was shown that removal efficiency could be maintained stable due to the complete removal of SS and sludge production decreased with increasing of sludge retention time.

• 대한환경공학회지
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• 제28권1호
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• pp.7-14
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• 2006

본 연구에서는 도시하수를 이용하여 two-sludge 시스템방식의 SBR3 공정의 질소제거 효율 향상능을 평가하기 위해 기존 재래식 SBR 공정(SBR1) 및 분할주입(step-feeding)을 통해 탈질효율 향상을 도모한 SBR2 공정과의 비교 연구를 수행하였다. 도시하수를 대상으로 한 연구결과 two-sludge 시스템 방식으로 질산화 반응이 별도의 반응조에서 진행되며(external nitrification), 질산화된 질산염은 생흡착된 유기물을 이용하여 효과적으로 탈질되는 SBR3 공정이 SBR1 및 SBR2 반응조에 비해 T-N 제거효율면에서 우수함이 관찰되었다. SBR3 공정과 SBR1 및 SBR2 공정의 T-N 제거효율 차이는 낮은 C/N 비에서 더 크게 관찰되었으며 이는 생흡착 기작을 이용하는 SBR3 공정이 SBR1 및 SBR2 공정에 비해 탈질시 유기물 이용을 효율적으로 함을 의미한다. SBR3 공정은 T-N 유입 부하율에 따른 T-N 제거효율 관계에서도 SBR1 및 SBR2 공정에 비해 성능이 우수함을 관찰할 수 있었다. SBR3 공정이 SBR1 및 SBR2 공정에 비해 높은 T-N 부하율에서도 질소제거효율이 높은 원인은 SBR3 공정이 two-sludge 시스템 방식으로 운영됨에 따라 질화박테리아가 독립된 반응조에서 질산화를 수행하므로(external nitrification) 질산화 반응시 소요되는 수리학적 체류시간을 단축시킬 수 있기 때문이다.

• 대한환경공학회지
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• 제31권12호
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• pp.1135-1142
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• 2009

본 연구는 고분자 응집제를 이용하여 짧은 시간에 입상형태의 슬러지를 제조한 다음, 입상슬러지를 호기성 입상화 장치에 주입하여 입상화를 시도하였다. 각 반응조에서 호기성 입자의 형성에 따른 입자의 크기, 밀도, 입자내 미생물 체외분비 고분자물질 등의 물리.화학적인 특성을 조사하였다. 입상형태의 슬러지를 호기성 입상화 장치에 주입하여 COD 부하량 3, 6, 9 $kg{\cdot}COD/m^3{\cdot}d$로 35일간 운전한 결과 최종 형성된 호기성 입장의 평균 크기는 각각 3.6 mm, 4.3 mm, 3.4 mm 이었고 호기성 입자의 침강속도는 각각 1.5 cm/s, 1.6 cm/s, 1.2 cm/s 이었다. COD 부하량에 따른 미생물 군집체의 비성장속도는 0.12 $d^{-1}$, 0.135 $d^{-1}$, 0.133 $d^{-1}$이었으며 전반적으로 호기성 입상화 장치에서는 COD 부하량이 $6kg{\cdot}COD/m^3{\cdot}d$로 운전된 반응조에서 호기성 입자의 물리 화학적인 특성이 우수하였다.