Bio fouling of membrane: Biofouling is the irreversible adhesion on a membrane of microorganisms and the extracellular polymers (ECPs, i.e., biofilm) that they produce. The process of adhesion involves three steps (2): bacterial adhesion, which can become irreversible in just hours, even without nutrients present.
Biofouling can have several adverse effects on membrane systems such as: Membrane flux decline due to the formation of a low permeability biofilm on the membrane surface. Increased differential pressure and feed pressure being needed to maintain the same production rate due to biofilm resistance. Membrane biodegradation caused by acidic by-products which are concentrated at the membrane surface. For example, cellulose acetate membrane has been found to be more susceptible to being biodegraded. Increased salt passage through membrane and reduced quality of the product water due to the accumulation of dissolved ions in the biofilm at the membrane surface thus increasing the degree of concentration polarization. Increased energy consumption due to higher pressure being required to overcome the biofilm resistance and the flux decline.