Startup and stable operation of advanced continuous flow reactor and the changes of microbial communities in aerobic granular sludge

The impact of intermittent aeration on aerobic granular sludge in a continuous flow reactor was studied. Nine intermittent aeration modes were set up to investigate the change of DO, pH, COD removal efficiency and SOUR. The results showed DO and pH had different change tendencies. The 3-1 mode was the optimal mode under these experiment conditions. In aerating stage, the highest COD removal efficiency could achieve 96.32%. Stopping aeration for one hour, COD removal efficiency could still reach at 90.20%. This operation mode could save about 25% energy consumption theoretically. The comparison of SOUR between continuous aeration and 4-2 mode showed that the intermittent aeration had little effect on granular sludge activity. The theory of stress & damage and unbalanced growth could explain this appearance.

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Population Dynamics of Phenol Degrading Microorganisms in Activated Sludge Process under the Stress of Phenolic Wastewater

Water Science & Technology ◽

10.2166/wst.1991.0552 ◽

1991 ◽

Vol 23 (4-6) ◽

pp. 1001-1010 ◽

Cited By ~ 9

Author(s):

M. Okada ◽

T. Nakamura ◽

H. Ito ◽

A. Murakami

Keyword(s):

Activated Sludge ◽

Continuous Flow ◽

Shock Loading ◽

Flow Reactor ◽

Stable Operation ◽

Activated Sludge Process ◽

Flow Reactors ◽

Continuous Flow Reactor ◽

Phenolic Wastewater ◽

Continuous Flow Reactors

The process to gain and lose phenol degrading activity of activated sludge under different stress of phenol was studied by three types of operations, i.e. continuous flow reactor, aerobic SBR, and anaerobic/aerobic SBR under two types of loads, i.e. elevating and constant loads. The higher activity and tolerance under the higher concentration of phenol was gained in activated sludge of aerobic SBR under the constant high load. The higher phenolic stress, i.e. mixed liquor concentration of phenol, at the beginning of batch cycles seemed to increase the activity. Constant and low phenolic stress in continuous flow reactors and elevating load in SBR, however, could not build up tolerance and the higher degrading activity under the higher concentration of phenol. SBR operations which are able to give appropriate phenolic stress on activated sludge, even under the same daily loading of phenol as continuous flow reactor, would be preferable to build up and maintain the activity and to ensure stable operation of wastewater treatment even under shock loading. The degrading activity of activated sludge may be gained mainly by the increase in the ability of bacteria to degrade and tolerate phenol and not by the increase in population.

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Continuous flow aerobic granular sludge reactor for dairy wastewater treatment

Water Science & Technology ◽

10.2166/wst.2015.007 ◽

2015 ◽

Vol 71 (3) ◽

pp. 440-445 ◽

Cited By ~ 10

Author(s):

C. Bumbac ◽

I. A. Ionescu ◽

O. Tiron ◽

V. R. Badescu

Keyword(s):

Continuous Flow ◽

Flow Reactor ◽

Batch Reactor ◽

Oxygen Demand ◽

Granular Sludge ◽

Experimental Period ◽

Phosphate Removal ◽

Dairy Wastewater ◽

Aerobic Granular Sludge ◽

Removal Efficiencies

The focus of this study was to assess the treatment performance and granule progression over time within a continuous flow reactor. A continuous flow airlift reactor was seeded with aerobic granules from a laboratory scale sequencing batch reactor (SBR) and fed with dairy wastewater. Stereomicroscopic investigations showed that the granules maintained their integrity during the experimental period. Laser diffraction investigation showed proof of new granules formation with 100–500 μm diameter after only 2 weeks of operation. The treatment performances were satisfactory and more or less similar to the ones obtained from the SBR. Thus, removal efficiencies of 81–93% and 85–94% were observed for chemical oxygen demand and biological oxygen demand, respectively. The N-NH+4 was nitrified with removal efficiencies of 83–99% while the nitrate produced was simultaneously denitrified – highest nitrate concentration determined in the effluent was 4.2 mg/L. The removal efficiency of total nitrogen was between 52 and 80% depending on influent nitrogen load (39.3–76.2 mg/L). Phosphate removal efficiencies ranged between 65 and above 99% depending on the influent phosphate concentration, which varied between 11.2 and 28.3 mg/L.

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