Fluidized Bed Reactors for Anaerobic Wastewater Treatment

Iza, J.

doi:10.2166/wst.1991.0221

Cited by 94 publications

(41 citation statements)

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“…Examples of natural methanogenic habitats are freshwater environments such as wetlands, sediments, and rice paddy fields, as well as intestinal tracts of higher animals and insects (4,6,8,21,28). Methanogenic processes can be applied to treat industrial wastewaters in high-rate anoxic bioreactors (16,19,33). The microorganisms involved in methanogenic decomposition are usually immobilized in granular aggregates or biofilms, which is essential for a high conversion rate (23) and prevents biomass from being washed out of the reactor.…”

mentioning

confidence: 99%

Biochemical Evidence for Formate Transfer in Syntrophic Propionate-Oxidizing Cocultures of Syntrophobacter fumaroxidans and Methanospirillum hungatei

Bok

Luijten

Stams

2002

Appl Environ Microbiol

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The hydrogenase and formate dehydrogenase levels in Syntrophobacter fumaroxidans and Methanospirillum hungatei were studied in syntrophic propionate-oxidizing cultures and compared to the levels in axenic cultures of both organisms. Cells grown syntrophically were separated from each other by Percoll gradient centrifugation. In S. fumaroxidans both formate dehydrogenase and hydrogenase levels were highest in cells which were grown syntrophically, while the formate-H 2 lyase activities were comparable under the conditions tested. In M. hungatei the formate dehydrogenase and formate-H 2 lyase levels were highest in cells grown syntrophically, while the hydrogenase levels in syntrophically grown cells were comparable to those in cells grown on formate. Reconstituted syntrophic cultures from axenic cultures immediately resumed syntrophic growth, and the calculated growth rates of these cultures were highest for cells which were inoculated from the axenic S. fumaroxidans cultures that exhibited the highest formate dehydrogenase activities. The results suggest that formate is the preferred electron carrier in syntrophic propionate-oxidizing cocultures of S. fumaroxidans and M. hungatei.Methanogenic decomposition of complex organic matter is a widespread process, which accounts for a large fraction of the global methane emission (15). Examples of natural methanogenic habitats are freshwater environments such as wetlands, sediments, and rice paddy fields, as well as intestinal tracts of higher animals and insects (4,6,8,21,28). Methanogenic processes can be applied to treat industrial wastewaters in high-rate anoxic bioreactors (16,19,33). The microorganisms involved in methanogenic decomposition are usually immobilized in granular aggregates or biofilms, which is essential for a high conversion rate (23) and prevents biomass from being washed out of the reactor.The amount of energy available in methanogenic conversions is small, and therefore the microorganisms involved are forced to cooperate syntrophically (24, 28). In particular, oxidation of intermediary reduced organic compounds, such as ethanol, butyrate, and propionate, is energetically unfavorable. Nevertheless, the methanogens involved keep the concentrations of the oxidation products, acetate and H 2 (or formate), low enough to create a situation in which all partners involved gain energy. To dispose of reducing equivalents, acetogens reduce protons or bicarbonate. Both H 2 and formate have been proposed as electron carriers in syntrophic degradation. Several studies have provided evidence for H 2 transfer by demonstrating syntrophic growth with methanogens that oxidize only H 2 . Schmidt and Ahring (25) studied interspecies electron transfer in granules from a mesophilic anaerobic sludge bed reactor, and concluded that formate transfer was not important during propionate and butyrate oxidation in this system.On the other hand, Thiele and Zeikus (29) provided evidence that interspecies formate transfer was the dominant mechanism in a whey-processing digester,...

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mentioning

confidence: 99%

Biochemical Evidence for Formate Transfer in Syntrophic Propionate-Oxidizing Cocultures of Syntrophobacter fumaroxidans and Methanospirillum hungatei

Bok

Luijten

Stams

2002

Appl Environ Microbiol

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“…In spite of both adverse incidents, removals of chlorophenols remained extraordinarily high. Also, this is a strong recommendation to FBBR as reactor configuration for its robustness and resistance to adverse episodes (Iza, 1991;Switzenbaum, 1983;Zárate-Segura et al, 2004).…”

Section: S-4: 15 Vvd Aeration Rate 120 Mg/l Of Tcp and 30 Mg/l Of Phementioning

confidence: 99%

Impact of long-term partial aeration on the removal of 2,4,6-trichlorophenol in an initially methanogenic fluidized bed bioreactor

Garibay-Orijel

Hoyo‐Vadillo

Ponce-Noyola

et al. 2006

Biotechnol. Bioeng.

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A fluidized bed bioreactor (FBBR) was operated for more than 1000 days under two regimes, Methanogenic (M) and Methanogenic-Aerobic (M-A), to remove 2,4,6-trichlorophenol (TCP) and phenol (Phe) from a synthetic wastewater, containing different amounts of TCP and Phe, using different aeration flow-rates (0, 2.13, and 1.06 NL O(2)/L.day). M conditions (80:20 mg/L of TCP:Phe, 0 NL O(2)/L.day) showed similar TCP and Phe removal (>95%). Nevertheless accumulation of 4-chlorophenol (4CP) up to 16 mg/L and Phe up to 4 mg/L was observed, while in M-A conditions (80:20 mg/L of TCP:Phe, 2.13 NL O(2)/L.day) TCP and Phe removal achieved 99.9(+)% and after 70 days no accumulation of intermediates were detected. The increase of TCP and Phe in the influent under M-A conditions from 80:20 to 120:30 mg/L of TCP:Phe did not negatively affect the removal of TCP, intermediates and Phe; in fact, they were similar to those in previous M-A conditions. The decrease in the oxygen flow rate from 2.13 to 1.06 NL O(2)/L.day had no negative effect on pollutant removals, which were as high as in previous two M-A conditions. The specific methanogenic activity of bioparticles of the fluidized bed decreased with long-term partial aeration, starting from 1.097 mmol CH(4)/h.g(TKN) in the M regime (day 60) to <0.02 mmolCH(4)/h.g(TKN) at day 1050, suggesting aerobic regime in the bioreactor rather than an M-A regime. In conclusion, complete removal of TCP and less chlorinated intermediates could be achieved in an initially methanogenic FBBR under conditions of partial aeration, although long-term operation seemed to negatively affect the methanogenic activity of biomass. It is also likely that after extended aeration the microbial community was finally enriched with strains with the ability to attack 2,4,6-TCP under aerobic conditions. This report represents the first evidence of a long exposure to oxygen of an anaerobic microbial consortium that efficiently remove TCP.

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“…The AFBR had a recirculation rate that provided an initial dilution of the effluent and increased the mass transfer. Furthermore, the process, which included an attached biofilm, improved the contact between the substrate and the biomass, was more stable, and was better able to tolerate recalcitrant and toxic pollutants [7,8].…”

Section: Introductionmentioning

confidence: 99%

The comparative advantages of ethanol and sucrose as co-substrates in the degradation of an anionic surfactant: microbial community selection

Macedo

Okada

Delforno

et al. 2015

Bioprocess Biosyst Eng

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The efficiency of linear alkylbenzene sulfonate (LAS) removal from laundry wastewater and the related microbial community was investigated in an anaerobic fluidized bed reactor (AFBR). The AFBR was operated in three stages, in addition to the biomass adaptation stage without LAS (stage I). The stages were differentiated by their supplementary co-substrates: stage II had sucrose plus ethanol, stage III had only ethanol, and stage IV had no co-substrate. The replacement of sucrose plus ethanol with ethanol only for the substrate composition favored the efficiency of LAS removal, which remained high after the co-substrate was removed (stage II: 52 %; stage III: 73 %; stage IV: 77 %). A transition in the microbial community from Comamonadaceae to Rhodocyclaceae in conjunction with the co-substrate variation was observed using ion sequencing analysis. The microbial community that developed in response to an ethanol-only co-substrate improved LAS degradation more than the community that developed in response to a mixture of sucrose and ethanol, suggesting that ethanol is a better option for enriching an LAS-degrading microbial community.

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Fluidized Bed Reactors for Anaerobic Wastewater Treatment

Cited by 94 publications

References 0 publications

Biochemical Evidence for Formate Transfer in Syntrophic Propionate-Oxidizing Cocultures of Syntrophobacter fumaroxidans and Methanospirillum hungatei

Biochemical Evidence for Formate Transfer in Syntrophic Propionate-Oxidizing Cocultures of Syntrophobacter fumaroxidans and Methanospirillum hungatei

Impact of long-term partial aeration on the removal of 2,4,6-trichlorophenol in an initially methanogenic fluidized bed bioreactor

The comparative advantages of ethanol and sucrose as co-substrates in the degradation of an anionic surfactant: microbial community selection

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