First results from a screening of filamentous organisms present in Buenos Aires's activated sludge plants

2002 ◽  
Vol 46 (1-2) ◽  
pp. 119-122 ◽  
Author(s):  
W.D. Di Marzio
Keyword(s):  
Activated Sludge ◽  
Dominant Species ◽  
Filamentous Bacteria ◽  
Low Oxygen ◽  
Morphologic Characteristics ◽  
Nocardia Sp ◽  
First Results ◽  
Aerobic Reactor ◽  
Dominant Bacteria ◽  
Low Oxygen Concentration

Activated sludge samples from municipal and industry plants were evaluated with the aim to recognise the mainly filamentous bacteria found. The routine tests recommended were performed: Gram, Neisser, PHB-Nilo blue epifluorescence reaction and S. The morphologic characteristics were determined. Correlation between environmental conditions and abundance of dominant bacteria were made. All plants were completely mixed configurations with anoxic reactor for denitrification ahead of main aerobic reactor. Also all systems were working at low F/M values or high sludge age (> ten days) and in some cases with low oxygen concentration. The dominant species were Type 021N, Thiothrix I, Sphaerotilus natans, Microthrix parvicella, Nocardia sp, Type 1701, Type 1863, Type 0041 and Type 0092.

Increase of nitrification efficiency at waste water treatment by implementation of bioaugmentation process

2014 ◽  
Vol 9 (4) ◽  
pp. 551-557
Author(s):  
Y. V. Mikhailova ◽  
M. V. Kevbrina ◽  
V. A. Grachev ◽  
Y. A. Nikolaev ◽  
V. G. Aseeva
Keyword(s):  
Activated Sludge ◽  
Specific Activity ◽  
Waste Water Treatment ◽  
Nitrifying Bacteria ◽  
Ammonium Concentration ◽  
Low Oxygen ◽  
The Stability ◽  
University Of Cape Town ◽  
The University ◽  
Low Oxygen Concentration

Low content of ammonia in the treated water is one of the most important indicators of the efficiency of biological wastewater treatment. Oxidation of ammonium to nitrate (nitrification) is carried out by nitrifying bacteria, which have low growth rates and are very sensible to certain unfavorable technological factors, such as low oxygen concentration and toxicants). To stabilize the number of nitrifying bacteria, increasing their activity in bioreactors with activated sludge and, therefore, to achieve stable and efficient removal of nitrogen compounds, various techniques are used, one of which is bioaugmentation technology. Bioaugmentation implies addition of the necessary microorganisms or creation of the conditions favoring their development in order to increase the specific activity of biological systems, such as activated sludge. In the Engineering and Technological Centre of JSC ‘Mosvodokanal’ for the first time in world practice, we studied the efficiency of nitrification in a plant operating under the scheme of the University of Cape Town process, in combination with an additional bioaugmentation reactor. Activated sludge in the reactor was enriched with nitrifying bacteria. At higher ammonium loads, which were modeled by adding the liquid phase of digested sludge, the main line did not remove ammonium to the maximum permissible concentration for fishery water bodies. The use of a bioaugmentation reactor resulted in ammonium concentration decrease from 40–50 to 0.4 mg N-NH4/l. This approach increased the stability of the activated sludge nitrifying bacteria to toxicants (thiourea).

Role of Glycogen as an Intracellular Carbon Reserve of Activated Sludge in the Competitive Growth of Filamentous and Non-Filamentous Bacteria

1991 ◽  
Vol 23 (4-6) ◽  
pp. 899-905 ◽  
Author(s):  
Y. Matsuzawa ◽  
T. Mino
Keyword(s):  
Activated Sludge ◽  
Feeding Pattern ◽  
Filamentous Bacteria ◽  
Competitive Growth ◽  
Maximum Capacity ◽  
Intermittent Feeding ◽  
Feeding Type ◽  
Continuous Feeding ◽  
The Relationship

Activated sludge mixed cultures were cultivated with a glucose containing substrate in order to investigate the relationship between the feeding pattern (continuous or intermittent feeding) and the glycogen reservation capacity of activated sludge. An experimental method to measure the maximum capacity of glycogen reservation in the sludge was developed. Sludge with higher glycogen reservation capacity has an ability to synthesize glycogen faster, which ensures the higher glucose uptake. Therefore, sludge which has high glycogen reservation capacity becomes predominant in intermittently fed reactors. When the feeding pattern was changed from continuous feeding to intermittent feeding, a filamentous bacterium, Type 1701, started to decrease and a gram positive tetrad coccus became predominant. When the feeding pattern was returned to continuous feeding, Type 1701 re-appeared. Type 1701 has lower glycogen reservation capacity than the tetrad coccus. Therefore, the former cannot dominate over the latter in intermittently fed reactors.

Effect of low oxygen concentration on activation of inflammation by Helicobacter pylori

2021 ◽  
Vol 560 ◽  
pp. 179-185
Author(s):  
Adiza Abass ◽  
Tokuju Okano ◽  
Kotchakorn Boonyaleka ◽  
Ryo Kinoshita-Daitoku ◽  
Shoji Yamaoka ◽  
...  
Keyword(s):  
Helicobacter Pylori ◽  
Oxygen Concentration ◽  
Low Oxygen ◽  
Low Oxygen Concentration

Effects of pH shock on microaerobic activated sludge system with a graphene oxide/nano-magnetic powder composite

2020 ◽  
Vol 35 (3) ◽  
pp. 457-463
Author(s):  
Huixia Lan ◽  
Xiangzhi Wang ◽  
Shixin Qi ◽  
Da Yang ◽  
Hao Zhang
Keyword(s):  
Graphene Oxide ◽  
Activated Sludge ◽  
High Throughput Sequencing ◽  
Impact Resistance ◽  
Magnetic Powder ◽  
Blank Group ◽  
Activated Sludge System ◽  
Ph Shock ◽  
Dominant Bacteria ◽  
The Impact

AbstractUsing the acclimated activated sludge from the pulping middle-stage effluent, the effect of pH shock on the micro-oxygen activated sludge system with a nano-magnetic powder/graphene oxide composite was studied. The results showed that the removal rates of chemical oxygen demand (CODCr) and ultraviolet adsorption at 254 nm (UV254) decreased. Also, the sludge settling performance was poor due to the impact of pH, but the impact resistance of nano-magnetic powder/graphene oxide group (MGO group) was higher and the recovery was faster. Results of high throughput sequencing indicated that the diversity of microbial community was reduced by the impact of pH, but it was significantly higher in MGO group than in the blank group. The dominant bacteria after pH shock or recovery in both of the system had a large difference. The percentage of the dominant bacteria in the MGO group was higher than that in the blank group. The MGO group had higher electron transfer system (ETS) activity which made the system having a strong pH impact resistance.

scholarly journals Deep learning-based morphology classification of activated sludge flocs in wastewater treatment plants

2021 ◽  
Author(s):  
Hisashi Satoh ◽  
Yukari Kashimoto ◽  
Naoki Takahashi ◽  
Takashi Tsujimura
Keyword(s):  
Wastewater Treatment ◽  
Deep Learning ◽  
Activated Sludge ◽  
Morphological Change ◽  
Wastewater Treatment Plants ◽  
Filamentous Bacteria ◽  
Sludge Flocs

A deep learning-based two-label classifier 1 recognized a 20% morphological change in the activated flocs. Classifier-2 quantitatively recognized an abundance of filamentous bacteria in activated flocs.

The Constant Low Oxygen Concentration in All the Target Cells for Mouse Tail Radionecrosis

1982 ◽  
Vol 92 (1) ◽  
pp. 172 ◽  
Author(s):  
J. H. Hendry ◽  
J. V. Moore ◽  
B. W. Hodgson ◽  
J. P. Keene
Keyword(s):  
Oxygen Concentration ◽  
Target Cells ◽  
Low Oxygen ◽  
Low Oxygen Concentration

scholarly journals Simultaneous Nitrification and Denitrification in an SBR with a Modified Cycle During Reject Water Treatment

2013 ◽  
Vol 39 (1) ◽  
pp. 83-91 ◽  
Author(s):  
Katarzyna Bernat
Keyword(s):  
Batch Reactor ◽  
Anaerobic Sludge ◽  
Simultaneous Nitrification And Denitrification ◽  
Low Oxygen ◽  
Total Removal ◽  
Operational Conditions ◽  
Reject Water ◽  
Do Concentration ◽  
Nitrification And Denitrification ◽  
Low Oxygen Concentration

Abstract In this study, the dependence between volumetric exchange rate (n) in an SBR (Sequencing Batch Reactor) with a modified cycle and simultaneous nitrification and denitrification (SND) efficiency during the treatment of anaerobic sludge digester supernatant was determined. In the SBR cycle alternating three aeration phases (with limited dissolved oxygen (DO) concentration up to 0.7 mg O2/L) and two mixing phases were applied. The lengths of each aeration and mixing phases were 4 and 5.5 h, respectively. Independently of n, a total removal of ammonium was achieved. However, at n = 0.1 d-1 and n = 0.3 d-1 nitrates were the main product of nitrification, while at n = 0.5 d-1, both nitrates and nitrites occurred in the effluent. Under these operational conditions, despite low COD/N (ca. 4) ratio in the influent, denitrification in activated sludge was observed. A higher denitrification efficiency at n = 0.5 d-1 (51.3%) than at n = 0.1 d-1 (7.8%) indicated that n was a crucial factor influencing SND via nitrite and nitrate in the SBR with a low oxygen concentration in aeration phases.

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