Foaming in activated sludge plants treating dairy waste

Wheatley, Andrew D.; Johnson, K.A.; Winstanley, C.I.

doi:10.1080/09593338809384556

Cited by 7 publications

(3 citation statements)

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“…This is the opposite to the results reported for bentonite and N. amarae (4): Proteins are well established as foam forming/stabilising agents (14,15). Bovine serum albumen (BSA) was, therefore, added to a nonfoaming sludge and the foaming capacity of the resultant suspensions was examined.…”

Section: Figurementioning

confidence: 47%

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Activated sludge foams: An examination into their stability and their control

Khan

Forster

1990

Environmental Technology

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This paper examines the stability of foams produced by Rhodococcus rubra and by activated sludge. The half life of the foams was used as the criterion for judging stability. With R. rubra, it was found that the foam stability could be increased from 650 minutes to 3100 minutes over a seven day period by a daily sequence of foaming, foam-breaking, resting and re-foaming. This ageing process also changed the surface properties of the cells. Foam formation and foam destruction were also examined using antifoams and chemicals which had the potential for surface modification.

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Section: Figurementioning

confidence: 47%

“…The formation of stable foams by sludges has been associated with surface-bound proteins (15) and certainly proteins are known to have good foamability. However, this property does not necessarily confer stability to foams (21).…”

Section: Biomass Concentration (Fl I )mentioning

confidence: 99%

Activated sludge foams: An examination into their stability and their control

Khan

Forster

1990

Environmental Technology

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“…Here, anti‐foaming agents are either continuously added to the product to inhibit foam formation or discontinuously added when foam formation is detected. The use of anti‐foam may cause an undesirable contamination of the processes, which can lead to performance losses, lower product quality, and are therefore not allowed in numerous food processes 5, 8.…”

Section: Introductionmentioning

confidence: 99%

Resonant Ultrasonic Defoaming in Aqueous Evaporation/Boiling Processes at Different Size Scales

et al. 2022

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Unwanted foam bears the risk of affecting different thermal industrial processes negatively, by reduced process efficiency, contamination, and total shutdown. Mechanical defoaming methods are difficult to implement, while chemical antifoaming agents are challenging in correct dosing. Ultrasonic defoaming actuators destroy foams purely mechanically from air-borne, but their energy consumption per area is still excessive at 10 W cm -2 . Results show that a frequency sweep between 40-168 kHz and a water-borne sonication needs power densities of around 0.1 W cm -2 for a lab-scale experiment to a copper column still. At this power level, ultrasound enforces the foam drainage, thus reducing the foam height and the process time of the column still by 20 %. The chosen frequency range indicates a resonant behavior of small liquid-loaded lamella and plateau channels.

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