Pilot study on the treatment of lake water with algae by ultrafiltration–ozone–biologically activated carbon

Abstract For the treatment of lake water with algae, the coagulation–ultrafiltration–ozone–biologically activated carbon (CUF–O3–BAC) integrated process was first used to treat East Taihu Lake water in China, aiming at evaluating the removal efficiencies of algae, permanganate index (CODMn), UV254, NH3-N and disinfection by-products (DBPs) precursors. In addition, the long-term performance of the membrane operation under the fluxes of 60, 70, 80 and 90 L/(m2·h) was also investigated, and kinetic models were established. The experimental results showed that the integrated process had positive impaction of algae, CODMn, UV254 and NH3-N removal, and the removal rates were 95.89 ± 1.52, 76.18 ± 4.38, 72.06 ± 4.72 and 81.31 ± 6.71%, respectively. The CUF process was prone to increase the formation potentials of DBPs. Although ozone could reduce the formation risks of chlorinated trihalomethanes (THMs) to a certain extent, it is ineffective to reduce those of brominated THMs and haloacetic acids (HAA5). However, the CUF–O3–BAC process was an effective technology for the removal of THMs and HAA5 precursors in drinking water treatment. Finally, it was found that the relationship between transmembrane pressure (TMP) and time conformed to the first-order and second-order kinetic models, and the linear fitting coefficients were all above 90%.