Foaming in activated sludge plants: A survey in Queensland, Australia and an evaluation of some control strategies

Blackall, Linda L.; Harbers, Anne E.; Greenfield, P. F.; Hayward, A. C.

doi:10.1016/0043-1354(91)90011-e

Cited by 36 publications

(22 citation statements)

References 12 publications

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“…Increases of the MCRT or SRT have been frequently reported to be associated with foaming events (33) but cannot be used to predict them (9). Furthermore, a lagged SRT showed a much stronger relationship with G. amarae-like cell concentrations in the mixed liquor, because its growth rate was much lower than those of other bacterial groups in aeration tanks, as was reported previously (8,60).…”

Section: Discussionmentioning

confidence: 49%

“…2 and 3b and e). This combination of factors could easily explain why single-variable analyses of produced foaming events provide contradictory results across plants (9).…”

Section: Discussionmentioning

confidence: 99%

“…For example, 88% of 47 plants in North Carolina and 97% of 31 plants in Illinois experienced foaming (16,35). Only 8% of 46 plants studied in Queensland, Australia, never reported occurrences of foaming (9). This illustrates the lack of an understanding of the physical, chemical, and biological factors that initiate and promote foaming events across treatment processes as well as the difficulty in eliminating foaming on a permanent basis.…”

mentioning

confidence: 91%

“…However, no common operational parameters, design criteria, and sewage compositions were found to be predictive of foaming events in full-scale Australian wastewater treatment plants (9). Conflicting reports make it difficult to forecast the occurrence of this group of organisms.…”

mentioning

confidence: 99%

“…A number of operational and physicochemical parameters, such as extended mean cell residence times (MCRTs), high concentrations of long-chain hydrocarbons, certain pH ranges, and temperatures, were found to be factors that promoted foaming events (9,10,43,51). However, no common operational parameters, design criteria, and sewage compositions were found to be predictive of foaming events in full-scale Australian wastewater treatment plants (9).…”

mentioning

confidence: 99%

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Interaction of Operational and Physicochemical Factors Leading to Gordonia amarae-Like Foaming in an Incompletely Nitrifying Activated Sludge Plant

Asvapathanagul

Huang

Gedalanga

et al. 2012

Appl Environ Microbiol

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eThe overgrowth of Gordonia amarae-like bacteria in the mixed liquor of an incompletely nitrifying water reclamation plant was inversely correlated with temperature (r ‫؍‬ ؊0.78; P < 0.005) and positively correlated with the solids retention time (SRT) obtained a week prior to sampling (r ‫؍‬ 0.67; P < 0.005). Drops followed by spikes in the food-to-mass ratio (0.18 to 0.52) and biochemical oxygen demand concentrations in primary effluent (94 to 298 mg liter ؊1 ) occurred at the initiation of G. amarae-like bacterial growth. The total bacterial concentration did not increase as concentrations of G. amarae-like cells increased, but total bacterial cell concentrations fluctuated in a manner similar to that of G. amarae-like bacteria in the pseudo-steady state. The ammonium ion removal rate (percent) was inversely related to G. amarae-like cell concentrations during accelerated growth and washout phases. The dissolved oxygen concentration decreased as the G. amarae-like cell concentration decreased. The concentrations of G. amarae-like cells peaked (2.47 ؋ 10 9 cells liter ؊1 ) approximately 1.5 months prior to foaming. Foaming occurred during the late pseudo-steady-state phase, when temperature declines reversed. These findings suggested that temperature changes triggered operational and physicochemical changes favorable to the growth of G. amarae-like bacteria. Fine-scale quantitative PCR (qPCR) monitoring at weekly intervals allowed a better understanding of the factors affecting this organism and indicated that frequent sampling was required to obtain statistical significance with factors changing as the concentrations of this organism increased. Furthermore, the early identification of G. amarae-like cells when they are confined to mixed liquor (10 7 cells liter ؊1 ) allows management strategies to prevent foaming.

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Section: Discussionmentioning

confidence: 49%

“…2 and 3b and e). This combination of factors could easily explain why single-variable analyses of produced foaming events provide contradictory results across plants (9).…”

Section: Discussionmentioning

confidence: 99%

mentioning

confidence: 91%

mentioning

confidence: 99%

mentioning

confidence: 99%

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Interaction of Operational and Physicochemical Factors Leading to Gordonia amarae-Like Foaming in an Incompletely Nitrifying Activated Sludge Plant

Asvapathanagul

Huang

Gedalanga

et al. 2012

Appl Environ Microbiol

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Scum in Activated Sludge Plants: Impact of Non-filamentous and Filamentous Bacteria

Lemmer¹,

Lind

Müller

et al. 2000

Acta hydrochim. hydrobiol.

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Excessive scum production is a widespread phenomenon in present activated sludge wastewater treatment. The question how foaming is initiated and stabilized is still unanswered. Hydrophobic wastewater ingredients and surface active material such as synthetic surfactants are discussed among others as major causative agents for scum production. Focusing on biological impacts non‐filamentous bacteria isolated from scum turned out to contribute to flotation by both cell surface hydrophobicity and emulsification activity, depending on the prevailing substrate and milieu conditions. The biological characterization of scum based on microscopic sludge investigation of conspicuous microorganisms resulted in a significant shift of filamentous and non‐filamentous organism populations with Gram‐positive bacteria prevailing in present nutrient removal plants as compared to the situation ten years ago. Their hydrophobic cell surface is supposed to support adherence and stabilization of interfaces and thus promote sludge flotation. In scum six types of filamentous bacteria turned out to be numerous: Microthrix parvicella and nocardioform actinomycetes, both of them being enriched in the scum fraction, moreover Nostocoida limicola and Eikelboom types 0041/0675, 1851, and 0092. Possible interactive mechanisms between non‐filamentous and filamentous scum bacteria and their selection factors are discussed in order to contribute to a better understanding of scum formation and to provide efficient troubleshooting measures.

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Microbial Foaming and Bulking in Activated Sludge Plants

Stainsby¹,

Philp²,

Dunbar³

et al. 2004

Water Encyclopedia

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Microbial foaming and bulking are among the most frequent and widespread problems in activated sludge (AS) wastewater treatment plants (WWTPs). Bulking has plagued AS plants almost since their inception nearly a century ago, whereas microbial foaming was not documented until around 30 years ago. Both problems are associated with the excessive growth of various filamentous bacteria, although the mechanisms by which they form are not fully understood. Initial attempts to identify these bacteria shifted attention from engineering aspects to the microbiological activities fundamental to the activated sludge process. Subsequently, filament identification keys and abundance scales became routine tools for monitoring filamentous populations in activated sludge. More recently, molecular biological techniques have enabled more detailed and precise study of the diversity and ecology of bacterial communities associated with foaming and bulking.

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Foaming in activated sludge plants: A survey in Queensland, Australia and an evaluation of some control strategies

Cited by 36 publications

References 12 publications

Interaction of Operational and Physicochemical Factors Leading to Gordonia amarae-Like Foaming in an Incompletely Nitrifying Activated Sludge Plant

Interaction of Operational and Physicochemical Factors Leading to Gordonia amarae-Like Foaming in an Incompletely Nitrifying Activated Sludge Plant

Scum in Activated Sludge Plants: Impact of Non-filamentous and Filamentous Bacteria

Microbial Foaming and Bulking in Activated Sludge Plants

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