AWWA MTC64541

The effect of coagulation pH and coagulant type on ultrafiltration (UF) membrane fouling, total organic carbon (TOC) removal, and permeate metals residuals was examined on bench scale UF membranes. Results indicate an important relationship between fouling rate and pH. For ferric chloride and aluminum hydroxide higher pH values (~8) give much lower membrane fouling rates compared to pH values of 5.5 and 6.2. However, the opposite trend is observed for TOC removals, i.e. higher removals were seen at lower pH values. By adjusting pH to values that have been used in conventional processes to achieve optimal settling and TOC removal, high membrane fouling rates may occur. Results from this research can be used as preliminary data to help explore avenues for minimizing fouling rates at full-scale plants given a specific TOC removal target. Includes 9 references, tables, figures.