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Analysis of nitrification efficiency and microbial community in a membrane bioreactor fed with low COD/N-ratio wastewater.

Ma J, Wang Z, Zhu C, Liu S, Wang Q, Wu Z - PLoS ONE (2013)

Bottom Line: In this study, an approach using influent COD/N ratio reduction was employed to improve process performance and nitrification efficiency in a membrane bioreactor (MBR).Besides sludge reduction, membrane fouling alleviation was observed during 330 d operation, which was attributed to the decreased production of soluble microbial products (SMP) and efficient carbon metabolism in the autotrophic nitrifying community. 454 high-throughput 16S rRNA gene pyrosequencing revealed that the diversity of microbial sequences was mainly determined by the feed characteristics, and that microbes could derive energy by switching to a more autotrophic metabolism to resist the environmental stress.Further, ammonia oxidation was the rate-limiting step during the full nitrification.

View Article: PubMed Central - PubMed

Affiliation: State Key Laboratory of Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Tongji University, Shanghai, PR China.

ABSTRACT
In this study, an approach using influent COD/N ratio reduction was employed to improve process performance and nitrification efficiency in a membrane bioreactor (MBR). Besides sludge reduction, membrane fouling alleviation was observed during 330 d operation, which was attributed to the decreased production of soluble microbial products (SMP) and efficient carbon metabolism in the autotrophic nitrifying community. 454 high-throughput 16S rRNA gene pyrosequencing revealed that the diversity of microbial sequences was mainly determined by the feed characteristics, and that microbes could derive energy by switching to a more autotrophic metabolism to resist the environmental stress. The enrichment of nitrifiers in an MBR with a low COD/N-ratio demonstrated that this condition stimulated nitrification, and that the community distribution of ammonia oxidizing bacteria (AOB) and nitrite oxidizing bacteria (NOB) resulted in faster nitrite uptake rates. Further, ammonia oxidation was the rate-limiting step during the full nitrification.

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Schematic diagram of R0 fed with low COD/N-ratio wastewater and control reactors (R1∼R5).OLR, J, HRT, SRT and SAD represent organic loading rate, permeate flux, hydraulic retention time, and sludge retention time and specific aeration demand per unit projected area of riser zone, respectively.
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pone-0063059-g001: Schematic diagram of R0 fed with low COD/N-ratio wastewater and control reactors (R1∼R5).OLR, J, HRT, SRT and SAD represent organic loading rate, permeate flux, hydraulic retention time, and sludge retention time and specific aeration demand per unit projected area of riser zone, respectively.

Mentions: The lab-scale MBR (R0) consisted of a tank with an effective volume of 26 L (Figure S1 in Supporting Information). The influent came from a dynamic membrane separation (DMS) reactor (Figure 1). In our previous work, we have successfully decreased the COD/N ratio of raw wastewater through organic carbon recovery by the DMS reactor [14]. The characteristics of the wastewater are listed in Table 1. Two 40 cm×30 cm flat sheet membrane modules (PVDF, 0.40 µm, Kubota Corporation, Japan) were mounted vertically between two baffle plates located in the tank; the permeate flux (J) was set at 18–24 L/(m2·h).


Analysis of nitrification efficiency and microbial community in a membrane bioreactor fed with low COD/N-ratio wastewater.

Ma J, Wang Z, Zhu C, Liu S, Wang Q, Wu Z - PLoS ONE (2013)

Schematic diagram of R0 fed with low COD/N-ratio wastewater and control reactors (R1∼R5).OLR, J, HRT, SRT and SAD represent organic loading rate, permeate flux, hydraulic retention time, and sludge retention time and specific aeration demand per unit projected area of riser zone, respectively.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3646889&req=5

pone-0063059-g001: Schematic diagram of R0 fed with low COD/N-ratio wastewater and control reactors (R1∼R5).OLR, J, HRT, SRT and SAD represent organic loading rate, permeate flux, hydraulic retention time, and sludge retention time and specific aeration demand per unit projected area of riser zone, respectively.
Mentions: The lab-scale MBR (R0) consisted of a tank with an effective volume of 26 L (Figure S1 in Supporting Information). The influent came from a dynamic membrane separation (DMS) reactor (Figure 1). In our previous work, we have successfully decreased the COD/N ratio of raw wastewater through organic carbon recovery by the DMS reactor [14]. The characteristics of the wastewater are listed in Table 1. Two 40 cm×30 cm flat sheet membrane modules (PVDF, 0.40 µm, Kubota Corporation, Japan) were mounted vertically between two baffle plates located in the tank; the permeate flux (J) was set at 18–24 L/(m2·h).

Bottom Line: In this study, an approach using influent COD/N ratio reduction was employed to improve process performance and nitrification efficiency in a membrane bioreactor (MBR).Besides sludge reduction, membrane fouling alleviation was observed during 330 d operation, which was attributed to the decreased production of soluble microbial products (SMP) and efficient carbon metabolism in the autotrophic nitrifying community. 454 high-throughput 16S rRNA gene pyrosequencing revealed that the diversity of microbial sequences was mainly determined by the feed characteristics, and that microbes could derive energy by switching to a more autotrophic metabolism to resist the environmental stress.Further, ammonia oxidation was the rate-limiting step during the full nitrification.

View Article: PubMed Central - PubMed

Affiliation: State Key Laboratory of Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Tongji University, Shanghai, PR China.

ABSTRACT
In this study, an approach using influent COD/N ratio reduction was employed to improve process performance and nitrification efficiency in a membrane bioreactor (MBR). Besides sludge reduction, membrane fouling alleviation was observed during 330 d operation, which was attributed to the decreased production of soluble microbial products (SMP) and efficient carbon metabolism in the autotrophic nitrifying community. 454 high-throughput 16S rRNA gene pyrosequencing revealed that the diversity of microbial sequences was mainly determined by the feed characteristics, and that microbes could derive energy by switching to a more autotrophic metabolism to resist the environmental stress. The enrichment of nitrifiers in an MBR with a low COD/N-ratio demonstrated that this condition stimulated nitrification, and that the community distribution of ammonia oxidizing bacteria (AOB) and nitrite oxidizing bacteria (NOB) resulted in faster nitrite uptake rates. Further, ammonia oxidation was the rate-limiting step during the full nitrification.

Show MeSH
Related in: MedlinePlus