Fortilife ^™ Director ^™ biofouling diagnostic tool developed for biofilm visualisation on reverse osmosis membranes

Imaging techniques are important for biofilm studies. Biofilm samples should ideally be visualised with minimal sample preparation so as not to alter their original structure. However, this can be challenging and resource-intensive in most cases. This study details the development of a novel tool (Fortilife^™ Director^™) to visualise biofouling. The method utilises a microparticle suspension that effectively highlights biofilm boundaries without altering its structure, allowing for high-contrast, in-situ visualisation. Experimental applications across various membrane types, including reverse osmosis and nanofiltration, demonstrate the capability of the tool to quantify biofilm surface coverage accurately. Results from studies on different feed waters underline the effectiveness in evaluating biofouling severity and distribution patterns, correlating surface coverage with operational performance metrics such as pressure drop increase. The Fortilife^™ Director^™ represents a promising advancement in the management of biofouling in membrane filtration systems, offering a more reliable means of monitoring and optimising operational efficiency.