In this work, the effects of the addition of a cationic polymer ADIFLOC KD 451 (ADIPAP, France) in the performance of a decentralized Anaerobic Membrane Bioreactor (AnMBR) pilot plant treating 1.5 m3 blackwater per day was studied. To this end, on-line sludge filterability characterizations were performed following the Delft Filtration Characterization (DFC) method. Likewise, a Supervisory Control and Data Acquisition (SCADA) system was used to measure and record the variations in transmembrane pressure (TMP). Polymer addition resulted in the modification of the biomass properties such as increased particle size measured as d50 from 19.49µm to 32.85µm and lower colloidal particles concentration. The combined effect of these changes influenced the fouling cake layer development rate. The preceding resulted in lower TMP in the pilot plant which indicates that higher operational fluxes can be achieved due to flux enhancer addition.