AWWA WQTC71420

Algal blooms cause membrane fouling in seawater desalination. High-pressure reverse osmosis (RO) membranes are affected by algogenic organic matter (AOM) that passes through pretreatment. When the pretreatment technology is low-pressure microfiltration (MF) or ultrafiltration (UF), it is severely fouled by AOM and algal cells. AOM is heterogeneous in size because algae are broken apart during natural cell lysis or by shear in pumps and valves. The main hypothesis of this work is that a certain size class of AOM is the most highly fouling. Bench-scale experiments revealed that in both high-pressure and low-pressure filtration, particulate AOM between 0.22 and 2 µm in size tends to be the highly fouling fraction on the membranes currently employed in most applications. Adsorption of biopolymers had little fouling potential when particulate material was not present. Includes 15 references, figures.