Abstract:Membrane aerated biofilm reactors (MABRs) are a promising biological wastewater treatment technology, whose industrial applications have dramatically accelerated in the recent five years. Increasing popularity and fast industrial adaptation are coupled with increased needs to monitor, optimize and control MABRs with available online sensors. Observations of commercial scale MABR installations have shown a distinctive and repetitive pattern relating oxygen purity in MABR exhaust gas to reactor ammonia concentra… Show more
“…There is little change in the slope for biofilm thickness greater than 200 μm, averaging 0.21 with variation less than 10% of the mean. Both ammonia and oxygen are limited (dual‐substrate limitation) when the biofilm is thicker than 200 μm as higher mass transfer resistance builds, which has negative impacts on diffusion of ammonia from the bulk liquid and the resulting bulk ammonia concentration (Casey et al, 2000; Pérez‐Calleja et al, 2022; Yang et al, 2022).…”
Section: Resultsmentioning
confidence: 99%
“…The MABR unit volume was set at 16 m 3 with tank depth of 3.5 m and membrane area of 1,920 m 2 to reflect the size of a typical commercial cassette (Zeelung 2.0). The MABR media wall thickness was 160 μm, the median of the tested range in the previous study from our group (Yang et al, 2022). The biofilm thickness was varied from 20 to 1,000 μm (50 thicknesses), and the biofilm specific mass was varied from 2 to 100 g TSS/m 2 correspondingly.…”
Section: Mabr Process Model Setupmentioning
confidence: 97%
“…The fingerprint plot for biofilm thicknesses of 60, 80, 100, or 200 μm is essentially a flat line with slopes close to zero. The flat lines represent the oxygen limitation condition where increasing the bulk ammonia concentration will not lower the exhaust oxygen purity (Yang et al, 2022). In such high ammonia loading condition, the MABR system is overloaded, and oxygen demand is higher than the fixed oxygen supply typically used in practice.…”
Section: Effects Of Ammonia Loading Fluxmentioning
confidence: 99%
“…A previous study from our group illustrated a method to monitor nitrification performance and biofilm development in MABRs using a soft sensor called the MABR fingerprint, which is a plot of exhaust oxygen purity in the gas phase versus the bulk liquid ammonia concentration (Yang et al, 2022). The results presented there indicated that biofilm thickness can be evaluated indirectly by analyzing the slope of the inclined linear segment of this plot, referred to as representing ammonia-limited conditions in the MABR biofilm.…”
The ongoing commercialization and installation of full‐scale membrane aerated biofilm reactors (MABRs) stimulate the increasing need to monitor biofilm development. Biofilm thickness in MABRs can be assessed indirectly by plotting the exhaust oxygen purity versus bulk ammonia concentration, defined here as the MABR fingerprint soft sensor. Dynamic simulations with diurnal flow variations of an MABR unit model were implemented over a broad range of biofilm thicknesses and influent conditions consisting of variable C/N ratios and applied ammonia fluxes to assess the utility of the MABR fingerprint. Results show that the continuously decreasing trend of the MABR fingerprint plot slopes can be employed as a useful signal for biofilm thickness control in nitrogen removal processes. This technique is useful in a wide range of influent conditions and is helpful for MABR operators and designers to arrange biofilm thickness control events efficiently and determine where in an overall treatment process the technique can be applied to control biofilm thickness and optimize process performance.Practitioner points
The linear relationship between exhaust oxygen purity and bulk ammonia concentration is defined as the MABR fingerprint plot.
MABR fingerprint plots are generated for a given biofilm thickness with diurnal flow or short‐term loading variations implemented.
Continuously decreasing trends of the MABR fingerprint plot slopes are useful signals for biofilm control in nitrogen removal.
The MABR fingerprint is useful over a wide range of influent conditions regarding C/N ratios and applied ammonia fluxes.
MABR practitioners can use the fingerprint plots to determine when biofilm control measures should be taken.
“…There is little change in the slope for biofilm thickness greater than 200 μm, averaging 0.21 with variation less than 10% of the mean. Both ammonia and oxygen are limited (dual‐substrate limitation) when the biofilm is thicker than 200 μm as higher mass transfer resistance builds, which has negative impacts on diffusion of ammonia from the bulk liquid and the resulting bulk ammonia concentration (Casey et al, 2000; Pérez‐Calleja et al, 2022; Yang et al, 2022).…”
Section: Resultsmentioning
confidence: 99%
“…The MABR unit volume was set at 16 m 3 with tank depth of 3.5 m and membrane area of 1,920 m 2 to reflect the size of a typical commercial cassette (Zeelung 2.0). The MABR media wall thickness was 160 μm, the median of the tested range in the previous study from our group (Yang et al, 2022). The biofilm thickness was varied from 20 to 1,000 μm (50 thicknesses), and the biofilm specific mass was varied from 2 to 100 g TSS/m 2 correspondingly.…”
Section: Mabr Process Model Setupmentioning
confidence: 97%
“…The fingerprint plot for biofilm thicknesses of 60, 80, 100, or 200 μm is essentially a flat line with slopes close to zero. The flat lines represent the oxygen limitation condition where increasing the bulk ammonia concentration will not lower the exhaust oxygen purity (Yang et al, 2022). In such high ammonia loading condition, the MABR system is overloaded, and oxygen demand is higher than the fixed oxygen supply typically used in practice.…”
Section: Effects Of Ammonia Loading Fluxmentioning
confidence: 99%
“…A previous study from our group illustrated a method to monitor nitrification performance and biofilm development in MABRs using a soft sensor called the MABR fingerprint, which is a plot of exhaust oxygen purity in the gas phase versus the bulk liquid ammonia concentration (Yang et al, 2022). The results presented there indicated that biofilm thickness can be evaluated indirectly by analyzing the slope of the inclined linear segment of this plot, referred to as representing ammonia-limited conditions in the MABR biofilm.…”
The ongoing commercialization and installation of full‐scale membrane aerated biofilm reactors (MABRs) stimulate the increasing need to monitor biofilm development. Biofilm thickness in MABRs can be assessed indirectly by plotting the exhaust oxygen purity versus bulk ammonia concentration, defined here as the MABR fingerprint soft sensor. Dynamic simulations with diurnal flow variations of an MABR unit model were implemented over a broad range of biofilm thicknesses and influent conditions consisting of variable C/N ratios and applied ammonia fluxes to assess the utility of the MABR fingerprint. Results show that the continuously decreasing trend of the MABR fingerprint plot slopes can be employed as a useful signal for biofilm thickness control in nitrogen removal processes. This technique is useful in a wide range of influent conditions and is helpful for MABR operators and designers to arrange biofilm thickness control events efficiently and determine where in an overall treatment process the technique can be applied to control biofilm thickness and optimize process performance.Practitioner points
The linear relationship between exhaust oxygen purity and bulk ammonia concentration is defined as the MABR fingerprint plot.
MABR fingerprint plots are generated for a given biofilm thickness with diurnal flow or short‐term loading variations implemented.
Continuously decreasing trends of the MABR fingerprint plot slopes are useful signals for biofilm control in nitrogen removal.
The MABR fingerprint is useful over a wide range of influent conditions regarding C/N ratios and applied ammonia fluxes.
MABR practitioners can use the fingerprint plots to determine when biofilm control measures should be taken.
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