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Membrane biofilm development improves COD removal in anaerobic membrane bioreactor wastewater treatment.

Smith AL, Skerlos SJ, Raskin L - Microb Biotechnol (2015)

Bottom Line: High membrane fouling significantly improved permeate quality, but resulted in dissolved methane in the permeate at a concentration two to three times the equilibrium concentration predicted by Henry's law.Restoring fouled membranes to a transmembrane pressure (TMP) near zero by increasing biogas sparging did not disrupt the biofilm's treatment performance, suggesting that microbes in the foulant layer were tightly adhered and did not significantly contribute to TMP.The results describe an attractive operational strategy to improve treatment performance in low-temperature AnMBR by supporting syntrophy and methanogenesis in the membrane biofilm through controlled membrane fouling.

View Article: PubMed Central - PubMed

Affiliation: Department of Civil and Environmental Engineering, University of Michigan, 2350 Hayward Road, Ann Arbor, MI, 48109, USA.

No MeSH data available.


Effect of different degrees of biofilm development (low fouling, medium fouling and high fouling) on permeate quality during Phase 2 of AnMBR operation.A. Bioreactor (soluble) and permeate COD concentrations. Influent COD was 410 ± 46 mg l−1.B. Bioreactor and permeate acetate concentrations. Error bars represent the standard deviation of triplicate IC injections.C. Bioreactor and permeate propionate concentrations. Error bars represent the standard deviation of triplicate IC injections.D. Dissolved methane oversaturation in the permeate calculated assuming a Henry’s law constant of 34 300 atm at 15°C (Tchobanoglous et al., 2003), and measured methane partial pressure in the biogas and dissolved methane concentration in the permeate. The methane content of the biogas was approximately 90%, with the balance being carbon dioxide. A high methane content is expected given the low organic loading rate and differences in methane and carbon dioxide solubility at this temperature. Error bars represent the standard deviation of duplicate dissolved methane extractions and triplicate GC injections of each dissolved methane extract.
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fig02: Effect of different degrees of biofilm development (low fouling, medium fouling and high fouling) on permeate quality during Phase 2 of AnMBR operation.A. Bioreactor (soluble) and permeate COD concentrations. Influent COD was 410 ± 46 mg l−1.B. Bioreactor and permeate acetate concentrations. Error bars represent the standard deviation of triplicate IC injections.C. Bioreactor and permeate propionate concentrations. Error bars represent the standard deviation of triplicate IC injections.D. Dissolved methane oversaturation in the permeate calculated assuming a Henry’s law constant of 34 300 atm at 15°C (Tchobanoglous et al., 2003), and measured methane partial pressure in the biogas and dissolved methane concentration in the permeate. The methane content of the biogas was approximately 90%, with the balance being carbon dioxide. A high methane content is expected given the low organic loading rate and differences in methane and carbon dioxide solubility at this temperature. Error bars represent the standard deviation of duplicate dissolved methane extractions and triplicate GC injections of each dissolved methane extract.

Mentions: Differences in permeate COD concentrations were observed throughout Phase 2 and corresponded to the level of membrane fouling (Fig. 2A). The HF permeate consistently had the lowest COD with a concentration of 22 mg l−1 at the end of Phase 2. Permeate volatile fatty acid (VFA) levels showed a similar trend (Fig. 2B and C). The VFA concentrations in the bioreactor and LF permeate were similar throughout Phase 2, indicating minimal biological activity across the LF membrane. These observations indicate that controlled membrane fouling can substantially improve effluent quality in AnMBR, and further suggest that the activity of syntrophic propionate oxidizing populations and their methanogenic partners can be promoted through membrane biofilm development (see below).


Membrane biofilm development improves COD removal in anaerobic membrane bioreactor wastewater treatment.

Smith AL, Skerlos SJ, Raskin L - Microb Biotechnol (2015)

Effect of different degrees of biofilm development (low fouling, medium fouling and high fouling) on permeate quality during Phase 2 of AnMBR operation.A. Bioreactor (soluble) and permeate COD concentrations. Influent COD was 410 ± 46 mg l−1.B. Bioreactor and permeate acetate concentrations. Error bars represent the standard deviation of triplicate IC injections.C. Bioreactor and permeate propionate concentrations. Error bars represent the standard deviation of triplicate IC injections.D. Dissolved methane oversaturation in the permeate calculated assuming a Henry’s law constant of 34 300 atm at 15°C (Tchobanoglous et al., 2003), and measured methane partial pressure in the biogas and dissolved methane concentration in the permeate. The methane content of the biogas was approximately 90%, with the balance being carbon dioxide. A high methane content is expected given the low organic loading rate and differences in methane and carbon dioxide solubility at this temperature. Error bars represent the standard deviation of duplicate dissolved methane extractions and triplicate GC injections of each dissolved methane extract.
© Copyright Policy - open-access
Related In: Results  -  Collection

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fig02: Effect of different degrees of biofilm development (low fouling, medium fouling and high fouling) on permeate quality during Phase 2 of AnMBR operation.A. Bioreactor (soluble) and permeate COD concentrations. Influent COD was 410 ± 46 mg l−1.B. Bioreactor and permeate acetate concentrations. Error bars represent the standard deviation of triplicate IC injections.C. Bioreactor and permeate propionate concentrations. Error bars represent the standard deviation of triplicate IC injections.D. Dissolved methane oversaturation in the permeate calculated assuming a Henry’s law constant of 34 300 atm at 15°C (Tchobanoglous et al., 2003), and measured methane partial pressure in the biogas and dissolved methane concentration in the permeate. The methane content of the biogas was approximately 90%, with the balance being carbon dioxide. A high methane content is expected given the low organic loading rate and differences in methane and carbon dioxide solubility at this temperature. Error bars represent the standard deviation of duplicate dissolved methane extractions and triplicate GC injections of each dissolved methane extract.
Mentions: Differences in permeate COD concentrations were observed throughout Phase 2 and corresponded to the level of membrane fouling (Fig. 2A). The HF permeate consistently had the lowest COD with a concentration of 22 mg l−1 at the end of Phase 2. Permeate volatile fatty acid (VFA) levels showed a similar trend (Fig. 2B and C). The VFA concentrations in the bioreactor and LF permeate were similar throughout Phase 2, indicating minimal biological activity across the LF membrane. These observations indicate that controlled membrane fouling can substantially improve effluent quality in AnMBR, and further suggest that the activity of syntrophic propionate oxidizing populations and their methanogenic partners can be promoted through membrane biofilm development (see below).

Bottom Line: High membrane fouling significantly improved permeate quality, but resulted in dissolved methane in the permeate at a concentration two to three times the equilibrium concentration predicted by Henry's law.Restoring fouled membranes to a transmembrane pressure (TMP) near zero by increasing biogas sparging did not disrupt the biofilm's treatment performance, suggesting that microbes in the foulant layer were tightly adhered and did not significantly contribute to TMP.The results describe an attractive operational strategy to improve treatment performance in low-temperature AnMBR by supporting syntrophy and methanogenesis in the membrane biofilm through controlled membrane fouling.

View Article: PubMed Central - PubMed

Affiliation: Department of Civil and Environmental Engineering, University of Michigan, 2350 Hayward Road, Ann Arbor, MI, 48109, USA.

No MeSH data available.