Biological aerated filters (BAFs) can combine ammonia, carbonaceous matter, and solids removal in a single-unit process. Biological nutrient removal (N and P) can also be accomplished. Removal rates based on reactor volume for carbonaceous BOD, ammonia, and nitrates of up to 4.1 kg BOD m−3 day−1, 1.27 kg NH3-N m−3 day−1 and 5 kg NO3-N m−3 day−1, respectively, are normally reported. The small footprint and adaptability of BAFs allows them to be used in upgrading established works, especially those in built up areas where space is at a premium. Although many configurations are available, including upflow and downflow, sunken, and floating media, the process still requires some optimization, especially with regard to media type, backwashing rates, and aeration control to decrease power consumption. Key words: biological aerated filter; wastewater treatment; submerged media bioreactor; carbonaceous matter removal; nitrification

A Review of Biological Aerated Filters (BAFs) for Wastewater Treatment

Definition du terme «biofilm». Exemples ou la formation de biofilms est nefaste (biocorrosion, pathologie); exemples ou la formation de biofilms est souhaitee (immobilisation de cellules). Mecanismes de formation (nature du support, transport des cellules, depot, adhesion a la surface, metabolisme de la cellule aux depens du support, production de polymere extracellulaire). Destruction du biofilm (action d'un predateur, effet de cisaillement, abrasion...)

Biologically active surfaces: Processes governing the formation and persistence of biofilms

Diffusion and reaction in biofilms

Modelling anaerobic biofilm reactors—A review

https://www.utm.mx/postgrado/MCPNyAl/Evaluacion2014/C1-Estructura%20y%20personal%20academico/1.4%20LGAC/1.4.2%20Participacion%20de%20estudianes%20y%20profesores/Articulos/Dr.%20Vania/jb-2012-524.pdf

Treatment of mezcal vinasses: A review

A simplified design method is developed for submerged filter and expanded bed biofilm reactors. The method incorporates limitations of both the electron donor and electron acceptor based upon Monod kinetics, and the stagnant liquid layer at the biofilm surface based upon the packing media and the waste flow rate. The model has been programmed so that calculations can be accomplished on a hand-held calculator, offering wide-scale availability to designers. The model consists of two basic processes: diffusion of substrate from the bulk liquid into the biofilm, and transformation of the substrate by bacteria within the biofilm. Conceptually, substrate must diffuse first from the bulk liquid through a stagnant liquid layer at the biofilm surface, and then into the biofilm until reaching a constant concentration, close to zero, at the effective depth.

Packed Bed Biofilm Reactors: Simplified Model

A simplified design method is applied to the design of submerged filter and expanded bed biofilm reactors. Typical design parameters as well as kinetic and mass transfer coefficients are listed for several bacterial reactions including fermentation, aerobic respiration, nitrification and denitrification. The Monod maximum utilization rate appears to be smaller for biofilm reactors than for suspended growth reactors. However, biofilm reactors have much larger substrate removal rates per unit volume than suspended growth reactors due to the larger organism concentration. The expanded bed reactor has greater substrate removal rates than the submerged filter due to larger surface areas, less trapping of influent suspended solids, and smaller stagnant liquid layer depths.

Alain D. Meunier

Papers

Packed Bed Biofilm Reactors: Simplified Model

Packed Bed Biofilm Reactors: Design