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  1. Article ; Online: Nitrite reduction using a membrane biofilm reactor (MBfR) in a hypoxic environment with dilute methane under low pressures.

    Alrashed, Wael / Chandra, Rashmi / Abbott, Timothy / Lee, Hyung-Sool

    The Science of the total environment

    2022  Volume 841, Page(s) 156757

    Abstract: Methane-based membrane biofilm reactors (MBfRs) can be an effective solution for nitrogen control in wastewater, but there is limited information on nitrite reduction for dilute wastewater (e.g., municipal wastewater) in hypoxic MBfRs. This study ... ...

    Abstract Methane-based membrane biofilm reactors (MBfRs) can be an effective solution for nitrogen control in wastewater, but there is limited information on nitrite reduction for dilute wastewater (e.g., municipal wastewater) in hypoxic MBfRs. This study assessed the impacts of dilute (20 %), low-pressure methane (0.35-2.41 kPa) applied to MBfRs at hydraulic retention times (HRTs) of 2-12 h on nitrite removals, dissolved methane concentrations, and the resulting changes in the microbial community. High nitrite flux along with rapid and virtually complete (>99 %) nitrite removals were observed at methane pressures of 1.03-2.41 kPa at HRTs above 4 h, despite the use of diluted methane gas for the MBfR. The lowest methane pressure (0.35 kPa) was also able to achieve up to 98 % nitrite removals but required HRTs of up to 12 h. All scenarios had low dissolved methane concentrations (<10 mg/L), indicating that dilute methane at low supply pressures can effectively remove nitrite while meeting dissolved methane guidelines in treated effluent. Methylococcus genus was the key bacterium in MBfR biofilm grown at different HRTs and methane pressures, along with Methylocystis and other heterotrophic denitrifiers (Terrimonas and Hyphomicrobium). This study indicates that methane-based denitrification MBfRs can be a valuable tool to meet nitrogen limits for dilute wastewater coupled to partial nitrification, while limiting the release of methane to the environment.
    MeSH term(s) Anaerobiosis ; Biofilms ; Bioreactors/microbiology ; Denitrification ; Methane ; Nitrites ; Nitrogen ; Oxidation-Reduction ; Waste Water/microbiology
    Chemical Substances Nitrites ; Waste Water ; Nitrogen (N762921K75) ; Methane (OP0UW79H66)
    Language English
    Publishing date 2022-06-16
    Publishing country Netherlands
    Document type Journal Article
    ZDB-ID 121506-1
    ISSN 1879-1026 ; 0048-9697
    ISSN (online) 1879-1026
    ISSN 0048-9697
    DOI 10.1016/j.scitotenv.2022.156757
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  2. Article: Nitrite reduction using a membrane biofilm reactor (MBfR) in a hypoxic environment with dilute methane under low pressures

    Alrashed, Wael / Chandra, Rashmi / Abbott, Timothy / Lee, Hyung-Sool

    Science of the total environment. 2022 Oct. 01, v. 841

    2022  

    Abstract: Methane-based membrane biofilm reactors (MBfRs) can be an effective solution for nitrogen control in wastewater, but there is limited information on nitrite reduction for dilute wastewater (e.g., municipal wastewater) in hypoxic MBfRs. This study ... ...

    Abstract Methane-based membrane biofilm reactors (MBfRs) can be an effective solution for nitrogen control in wastewater, but there is limited information on nitrite reduction for dilute wastewater (e.g., municipal wastewater) in hypoxic MBfRs. This study assessed the impacts of dilute (20 %), low-pressure methane (0.35–2.41 kPa) applied to MBfRs at hydraulic retention times (HRTs) of 2–12 h on nitrite removals, dissolved methane concentrations, and the resulting changes in the microbial community. High nitrite flux along with rapid and virtually complete (>99 %) nitrite removals were observed at methane pressures of 1.03–2.41 kPa at HRTs above 4 h, despite the use of diluted methane gas for the MBfR. The lowest methane pressure (0.35 kPa) was also able to achieve up to 98 % nitrite removals but required HRTs of up to 12 h. All scenarios had low dissolved methane concentrations (<10 mg/L), indicating that dilute methane at low supply pressures can effectively remove nitrite while meeting dissolved methane guidelines in treated effluent. Methylococcus genus was the key bacterium in MBfR biofilm grown at different HRTs and methane pressures, along with Methylocystis and other heterotrophic denitrifiers (Terrimonas and Hyphomicrobium). This study indicates that methane-based denitrification MBfRs can be a valuable tool to meet nitrogen limits for dilute wastewater coupled to partial nitrification, while limiting the release of methane to the environment.
    Keywords Hyphomicrobium ; Methylococcus ; Methylocystis ; bacteria ; biofilm ; denitrification ; denitrifying microorganisms ; environment ; methane ; microbial communities ; municipal wastewater ; nitrification ; nitrites ; nitrogen
    Language English
    Dates of publication 2022-1001
    Publishing place Elsevier B.V.
    Document type Article
    ZDB-ID 121506-1
    ISSN 1879-1026 ; 0048-9697
    ISSN (online) 1879-1026
    ISSN 0048-9697
    DOI 10.1016/j.scitotenv.2022.156757
    Database NAL-Catalogue (AGRICOLA)

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  3. Article: Methane-based denitrification kinetics and syntrophy in a membrane biofilm reactor at low methane pressure

    Lee, Jangho / Alrashed, Wael / Engel, Katja / Lee, Hyung-Sool / Neufeld, Josh D / Yoo, Keunje

    Science of the total environment. 2019 Dec. 10, v. 695

    2019  

    Abstract: A methane-based membrane biofilm reactor (MBfR) was assessed for a tertiary nitrogen removal process in domestic wastewater treatment. To mitigate effluent dissolved methane concentrations, the MBfR was operated with a 20% methane mixing ratio and a low ... ...

    Abstract A methane-based membrane biofilm reactor (MBfR) was assessed for a tertiary nitrogen removal process in domestic wastewater treatment. To mitigate effluent dissolved methane concentrations, the MBfR was operated with a 20% methane mixing ratio and a low pressure of 0.003 atm. The nitrate concentration was reduced from 20 to 4 mg/L with a low methane concentration of 3.3 mg/L in the effluent at 4 h hydraulic retention time (HRT). An in situ dissolved oxygen sensor showed a concentration of 0.045 mg/L in the MBfR, demonstrating methane oxidation under hypoxic conditions. Both 16S rRNA gene sequencing and metagenomic analysis identified bacteria capable of oxidation of methane coupled to denitrification (Methylocystis), whereas other bacteria were implicated in either methane oxidation (Methylococcus) or nitrate reduction (Escherichia). Reduced genetic potential for nitrate reduction to nitrite at a shorter HRT coincided with a decreased efficiency of denitrification, suggesting rate limitation by this initial step of denitrification. Genes encoding nitrite reduction to dinitrogen were at similar relative abundance under both HRT conditions. Our results provide mechanistic evidence for microbial syntrophy between aerobic methanotrophs and denitrifiers in methane-fed MBfRs operated under varying HRTs, with important implications for novel biological nitrogen removal to dilute wastewater.
    Keywords anaerobic conditions ; bacteria ; biofilm ; denitrification ; denitrifying microorganisms ; dissolved oxygen ; Escherichia ; genes ; genetic traits ; metagenomics ; methane ; methanotrophs ; Methylococcus ; Methylocystis ; mixing ; mixing ratio ; nitrate reduction ; nitrates ; nitrites ; nitrogen ; oxidation ; ribosomal RNA ; sequence analysis ; sewage treatment ; wastewater
    Language English
    Dates of publication 2019-1210
    Publishing place Elsevier B.V.
    Document type Article
    ZDB-ID 121506-1
    ISSN 1879-1026 ; 0048-9697
    ISSN (online) 1879-1026
    ISSN 0048-9697
    DOI 10.1016/j.scitotenv.2019.133818
    Database NAL-Catalogue (AGRICOLA)

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  4. Article ; Online: Methane-based denitrification kinetics and syntrophy in a membrane biofilm reactor at low methane pressure.

    Lee, Jangho / Alrashed, Wael / Engel, Katja / Yoo, Keunje / Neufeld, Josh D / Lee, Hyung-Sool

    The Science of the total environment

    2019  Volume 695, Page(s) 133818

    Abstract: A methane-based membrane biofilm reactor (MBfR) was assessed for a tertiary nitrogen removal process in domestic wastewater treatment. To mitigate effluent dissolved methane concentrations, the MBfR was operated with a 20% methane mixing ratio and a low ... ...

    Abstract A methane-based membrane biofilm reactor (MBfR) was assessed for a tertiary nitrogen removal process in domestic wastewater treatment. To mitigate effluent dissolved methane concentrations, the MBfR was operated with a 20% methane mixing ratio and a low pressure of 0.003 atm. The nitrate concentration was reduced from 20 to 4 mg/L with a low methane concentration of 3.3 mg/L in the effluent at 4 h hydraulic retention time (HRT). An in situ dissolved oxygen sensor showed a concentration of 0.045 mg/L in the MBfR, demonstrating methane oxidation under hypoxic conditions. Both 16S rRNA gene sequencing and metagenomic analysis identified bacteria capable of oxidation of methane coupled to denitrification (Methylocystis), whereas other bacteria were implicated in either methane oxidation (Methylococcus) or nitrate reduction (Escherichia). Reduced genetic potential for nitrate reduction to nitrite at a shorter HRT coincided with a decreased efficiency of denitrification, suggesting rate limitation by this initial step of denitrification. Genes encoding nitrite reduction to dinitrogen were at similar relative abundance under both HRT conditions. Our results provide mechanistic evidence for microbial syntrophy between aerobic methanotrophs and denitrifiers in methane-fed MBfRs operated under varying HRTs, with important implications for novel biological nitrogen removal to dilute wastewater.
    MeSH term(s) Biofilms ; Bioreactors/microbiology ; Denitrification ; Methane/metabolism ; Waste Disposal, Fluid/methods ; Waste Water/microbiology
    Chemical Substances Waste Water ; Methane (OP0UW79H66)
    Language English
    Publishing date 2019-08-06
    Publishing country Netherlands
    Document type Journal Article
    ZDB-ID 121506-1
    ISSN 1879-1026 ; 0048-9697
    ISSN (online) 1879-1026
    ISSN 0048-9697
    DOI 10.1016/j.scitotenv.2019.133818
    Database MEDical Literature Analysis and Retrieval System OnLINE

    More links

    Kategorien

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