• Journal of Microbiology and Biotechnology
• /
• 제20권11호
• /
• pp.1592-1596
• /
• 2010

To verify the dominance of microorganisms in wastewater biological treatment, PCR-DGGE (denaturing gradient gel electrophoresis) was performed as a supplementary support method for screening of the dominant microorganisms from activated sludge. Results suggest that the dominant microorganisms in activated sludge are primarily responsible for strengthening its effectiveness as a biological treatment system, followed by the non-main dominant microorganisms, whereas the non-dominant microorganisms showed no effects. The degree of microbial abundance present on the profile of PCR-DGGE was in line with the treatment efficiency of augmented activated sludge with isolated cultures, suggesting that PCR-DGGE can be used as an effective supplementary method for verifying culturable dominant microorganisms in activated sludge of coking wastewater.

• Biotechnology and Bioprocess Engineering:BBE
• /
• 제9권3호
• /
• pp.151-155
• /
• 2004

The bioremediation of water system contaminated with phenolic compounds having endocrine-disrupting activity, i.e. 2,4-dichlorophenol, 2,4-dichlorophenoxy acetic acid (2,4-D), and 2,4,5-trichlorophenoxy acetic acid (2,4,5-T), was investigated by using ozone oxidation and activated sludge treatment. Ozone oxidation (ozonation time: 30 min) followed by activated sludge treatment (incubation time: 5 days) was an efficient treatment method for the conversion of phenolic compounds in water into carbon dioxide and decreased the value of total organic carbon (TOC) up to about 10% of initial value. Furthermore, 2,4-D was dissolved in water containing salt, i.e. artificial seawater (ASW), and this water was used as model coastal water contaminated with phenolic compounds. The activated sludge treatment (incubation time: 5 days) could consume significantly organic acids produced from 2,4-D in the model costal water by the ozone oxidation (ozonation time: 30min) and decrease the value of TOC up to about 35% of initial value.

• 한국환경보건학회지
• /
• 제31권2호
• /
• pp.172-178
• /
• 2005

A laboratory experiment was performed to investigate simultaneous removal of phosphorus and nitrogen from raw sewage by intermittently aerated activated sludge process packed with aluminum and silver plate. Two continuous experimental process, i.e. an intermittently aerated activated sludge process, and an intermittently aerated activated sludge process with an aluminum and silver plate packed into the reactor were compared. The pitting corrosion of aluminum does not affect the performance of the biological treatment. The amounts of Al eluted from aluminum plate 17 mg to 60.6 mg in this experimental conditions, and Al/P mole ratio were from 3.31 to 11.25. The total nitrogen removal efficiency in Run E were $60.6\%$ at the HRT of 12 hours. The effluent $PO_4-P$ concentration as low as $1.0\;mg/\iota$ could have been obtained during the continuous experiment in Run E at HRT of 12 hours.

• Applied Biological Chemistry
• /
• 제45권1호
• /
• pp.25-29
• /
• 2002

활성슬러지에 의한 생물학적 폐수처리에 있어 주된 관리인자는 유기물의 효율적인 제거와 슬러지의 침강성을 일정치 이하로 유지하는 것이다. 식품폐수의 하나인 고농도의 대두가공폐수를 일반적인 활성슬러지법을 적용한 결과 최적 F/M비(food-to-microorganism ratio)는 0.24(kg-BOD/kg-MLVSS day)였으며 그 이상의 농도인 0.48(kg-BOD/kg-MLVSS day)에서는 슬러지 팽화현상이 발생하여 고농도의 식품폐수처리에는 효율적이지 못하였다. 이를 개선하기 위하여 응집보조제(NaOH)를 활용하여 유입폐수의 pH를 9.0으로 조절한 결과, 2.88(kg-BOD/kg-MLVSS day)의 고농도 폐수를 유입하여도 슬러지의 팽화현상없이 SVI(sludge volume index)를 150 이하로 유지하였다. 이것은 최대 허용부하를 일반적인 활성슬러지법에 비하여 7.2배 높일 수 있는 효율적인 방법으로 평가되었다.

• 한국환경과학회지
• /
• 제8권4호
• /
• pp.533-538
• /
• 1999

Fuzzy algorithm of automatic control for dissolved oxygen(DO) concentration in the aeration tank of an activated sludge process is proposed. Among variables repirometry and air flowrate are selected as significant input factors and the relationship with DO is estimated using a multiple regression model. The DO concentration and the amount of repirometry are fuzzified and the fuzzy rule base are determined. Using the fuzzy algorithm, the change of amount of air flowrate are determined and the change of amount of DO is derived.

• 상하수도학회지
• /
• 제20권5호
• /
• pp.747-753
• /
• 2006

Air flotation is a solid-liquid separation process that utilizes up-flow microbubbles to thicken activated sludge and enhance clarification efficiency. Continuous air flotation experiments were performed to investigate the effect of operation parameters such as initial MLSS (mixed liquor suspended solid) concentration, air pressure, surface loading rate, air to solid (A/S) ratio, and flotation time on thickening efficiency. An initial activated sludge concentration ranged from 3,000 to 12,000mgSS/L and thickened sludge concentration varied from 6,400 to 28,100mgSS/L. The result showed that the thickening efficiency was mainly dependent on surface loading rate, A/S ratio, and flotation time. The pressure did not affect the thickening efficiency when it kept in the range of 1.6 to 1.8 bar. Experimental results showed that the thickening efficiency of activated sludge was increased only when the feed sludge concentration exceeded 5,000mgSS/L and the thickened concentration was over 20,000mgSS/L. At this time, SS concentration in the clarified liquid was ranged from 5 to 10mg/L.

• 상하수도학회지
• /
• 제13권4호
• /
• pp.27-34
• /
• 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.

• 상하수도학회지
• /
• 제21권3호
• /
• pp.279-285
• /
• 2007

Toxicity evaluations using oxygen uptake rate (OUR) on activated sludge process were investigated. On toxicity evaluations of heavy metals, all toxicants in experiments decreased OUR with respect to the concentrations of the toxicants, while high toxicities with cyanide and mercury were observed respectively. On toxicity evaluations of composite heavy metals, composite toxicities had similar results as to the total sum of each toxicants that presents accurate toxicity evaluation using OUR. From these results, it is concluded that activated sludge is effective indicator for toxicity evaluation on wastewater of biological treatment plants.

• 한국환경보건학회지
• /
• 제33권6호
• /
• pp.493-496
• /
• 2007

The influences of contact time and ratio of food to microorganism (F/M) on uptake of wastewater organic matter in a short contact process were investigated using three activated sludge batch reactors fed with synthetic wastewater, sewage and livestock wastewater. About 64% of influent soluble chemical oxygen demand (SCOD) in the synthetic wastewater and 61% of SCOD in the sewage and 43% of SCOD in the diluted livestock wastewater were adsorbed into the activated sludge within 30 min. The specific mass of organic matter uptaken in the synthetic wastewater was 55 mg SCOD/g mixed liquor suspended solids (MLSS). In the same manner, 20 and 14 mg SCOD/g MLSS were calculated as the values in the sewage and livestock wastewater, respectively.

• 한국생물공학회:학술대회논문집
• /
• 한국생물공학회 2002년도 생물공학의 동향 (X)
• /
• pp.431-434
• /
• 2002

단일균이나 활성슬러지를 이용하여 폐수를 처리하고자 할 때 폐수의 pH 가 단일균이나 활성 슬러지의 최적 pH 에 적합하지 아니한 경우에는 미생물을 고정화하여 희망하는 pH에서 최대의 분해활성을 나타내도록 최적 pH를 어느정도 변화시킬 수 있으며, 기존의 활성슬러지법 보다는 활성 슬러지를 고정화하여 처리하는 것이 높은 부하에서도 제거 효율이 높기 때문에 반응조의 콤펙트화가 가능할 것으로 사료된다.