In situ versus pre-quorum quenching of microbial signaling for enhanced biofouling control in membrane bioreactors

The impact of the signal molecules present in the wastewater itself on membrane fouling in the membrane bioreactor (MBR) has been unexplored. This study investigates the contribution of these molecules to the degree of membrane fouling and the anti-fouling efficacy using two quorum quenching (QQ) strategies, namely in situ and pre-QQ. The results showed that wastewater generated a significant amount of signal molecules during its transport through the sewer system, exacerbating membrane fouling. In situ QQ implemented by the direct addition of QQ media (e.g., QQ beads) to the MBR reduced membrane fouling. Pre-QQ carried out by placing a QQ tank before the MBR mitigated fouling as much as in situ QQ. Splitting the QQ media into pre-QQ and in situ QQ was found to be more effective than dosing all of the QQ media into the MBR (i.e., in situ QQ alone). Model predictions successfully estimated the steady-state concentration of the signal molecules in the MBR.