Granulation of digested sewage sludge in mesophilic UASB reactors treating distillery waste waters from sugar cane molasses

Ramos, José Gustavo Venâncio da Silva; Obaya, M.C; Valdés, E; Villa, P.; Eng, Felipe

doi:10.1002/abio.370140312

“…This phenomenon has been experimentally verified in aerobic biofilms: fast growing heterotrophic organisms are located at the outside, whereas slower growing nitrifying organisms can be found at the inside (Okabe et al, 1995;Okabe et al, 1996;Tijhuis et al, 1996;Watanabe et al, 1990). A similar structural organization has been observed in anaerobic, methanogenic granules and sulfate reducing granules as well (MacLeod et al, 1990;Ramos et al, 1994;van Houten et al, 1995).…”

Section: Introductionsupporting

confidence: 55%

Control of heterotrophic layer formation on nitrifying biofilms in a biofilm airlift suspension reactor

Benthum¹,

Loosdrecht²,

Heijnen³

1997

Biotechnol. Bioeng.

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A Biofilm Airlift Suspension (BAS) reactor was operated with nitrifying biofilm growth and heterotrophic suspended growth, simultaneously converting ammonium and acetate. Growth of heterotrophs in suspension decreases the diffusion limitation for the nitrifiers, and enlarges the nitrifying capacity of a biofilm reactor. Neither nitrifiers nor heterotrophs suffer from additional oxygen diffusion limitation when the heterotrophs grow in suspension. Control of the location of heterotrophic growth, either in suspension or in biofilms over the nitrifying biofilms, was possible by manipulation of the hydraulic retention time. A time delay for formation and disappearance of the heterotrophic biofilms of 10 to 15 days was observed. Surprisingly, it was found that in the presence of the heterotrophic layers the maximum specific activity on ammonia of the nitrifying biofilms increased. The reason for the increase in activity is unknown. The effect of heterotrophic biofilm formation on oxygen diffusion limitation for the nitrifiers is discussed. Some phenomena compensating the increased mass transfer resistance due to the growth of a heterotrophic layer are also presented.

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“…During the treatment of effluents composed mainly of carbohydrates in the mesophilic range of temperatures (35ºC), the granulation process appears to develop slowly as the influent COD concentration decreases to below 500 mg COD/l (Ramos et al, 1994). Other researchers reported that granulation did not occur during the startup of UASB digesters treating a synthetic wastewater composed mainly of glucose (Brito et al, 1997), or during the treatment of a glucose-supplemented domestic sewage (Gnanadiphathy and Polprasert, 1993).…”

Section: Discussionmentioning

confidence: 99%

Sludge granulation during anaerobic treatment of pre-hydrolysed domestic wastewater

Ligero¹,

Soto

²

2002

WSA

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The aim of this study was to examine sludge granulation during the anaerobic treatment of pre-hydrolysed municipal wastewater. The pretreated wastewater had a total chemical oxygen demand (CODt) of 432 ± 20 mg/l, a soluble COD (CODs) of 259 ± 8 mg/l, volatile fatty acids (VFA) of 101 ± 9 mg/l and suspended solids (SS) of 94 ± 12 mg/l. Prior to entering the digester, the influent was supplemented with sucrose, which increased the total and soluble COD by 300 mg/l. An upflow anaerobic sludge bed (UASB) digester was operated at different hydraulic retention times (HRT) ranging from 26.7 h to 2.2 h, while the organic load rate (OLR) ranged from 0.9 to 7.3 kgCOD/m 3 ·d. Sludge granulation was observed after day 150 of operation, at an HRT of 3.4 h, when small granules of less than 2 mm in size appeared. The granules had a weak structure and low density, with the specific methanogenic activity of the sludge being about 0.24 g CH 4 -COD/gVSS·d. After granulation, the digester performance was 57% CODt removal and 76% CODs removal for steady state operation at an HRT of 3.4 h and an OLR of 5.6 kgCOD/m 3 ·d.

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Control of heterotrophic layer formation on nitrifying biofilms in a biofilm airlift suspension reactor

Benthum

¹

,

Loosdrecht

²

,

Heijnen

³

1997

Biotechnol. Bioeng.

View full text Add to dashboard Cite

A Biofilm Airlift Suspension (BAS) reactor was operated with nitrifying biofilm growth and heterotrophic suspended growth, simultaneously converting ammonium and acetate. Growth of heterotrophs in suspension decreases the diffusion limitation for the nitrifiers, and enlarges the nitrifying capacity of a biofilm reactor. Neither nitrifiers nor heterotrophs suffer from additional oxygen diffusion limitation when the heterotrophs grow in suspension. Control of the location of heterotrophic growth, either in suspension or in biofilms over the nitrifying biofilms, was possible by manipulation of the hydraulic retention time. A time delay for formation and disappearance of the heterotrophic biofilms of 10 to 15 days was observed. Surprisingly, it was found that in the presence of the heterotrophic layers the maximum specific activity on ammonia of the nitrifying biofilms increased. The reason for the increase in activity is unknown. The effect of heterotrophic biofilm formation on oxygen diffusion limitation for the nitrifiers is discussed. Some phenomena compensating the increased mass transfer resistance due to the growth of a heterotrophic layer are also presented. © 1997 John Wiley & Sons, Inc. Biotechnol Bioeng 53: 397–405, 1997.

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Granulation of digested sewage sludge in mesophilic UASB reactors treating distillery waste waters from sugar cane molasses

Cited by 3 publications

References 11 publications

Control of heterotrophic layer formation on nitrifying biofilms in a biofilm airlift suspension reactor

Control of heterotrophic layer formation on nitrifying biofilms in a biofilm airlift suspension reactor

Sludge granulation during anaerobic treatment of pre-hydrolysed domestic wastewater

Control of heterotrophic layer formation on nitrifying biofilms in a biofilm airlift suspension reactor

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