Fouling in pleated microfiltration cartridges caused by Pseudomonas putida

Characteristics and mechanisms of the fouling of microfiltration pleated cartridges (10-inch, PES, pore size of 0.2 µm) in biotechnical applications were analyzed, in order to obtain information about strategies that allow increasing their lifespan. Specifically, fouling experiments were carried out using the biodegradation of salicylic acid by means of Pseudomona putida as model of cellular media. A complete blocking mechanism with non-uniform distribution of the fouling along the pleated structure was proposed. Main accumulation of solids was located into the space between pleats near to the external perimeter of the filter, whereas the base of the pleats remained relatively clean, only fouled by small particles that can cause a small standard blocking of the pores. Concerning fouling cures, air scouring only provoked moderate recoveries of permeability after relaxation periods of days when spaces between pleats are completely filled and the biomass began to accumulate over the pleated structure. Backflushing (30 s) effectiveness tended to decrease with operation time and consecutive applications, but improved the effect of a subsequent relaxation on the permeability recovery. After chemical cleaning, permeability recovery (R) of 87.8% was observed, which implies a considerable increase of the lifespan of the cartridge.