Monitoring biofilm thickness using the membrane aerated biofilm reactor (MABR) fingerprint soft sensor to optimize nitrogen removal

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 pointsThe 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. The MABR fingerprint plots can be used to indicate the biofilm development in nitrogen removal using the change of the plot slopes. This technique is useful in a broad range of influent conditions regarding variable C/N ratios and applied ammonia fluxes.image

Automated summary

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 indirectly assessed by plotting the exhaust oxygen purity versus bulk ammonia concentration, defined as the MABR fingerprint soft sensor. 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.