Enhanced coagulation, flocculation and immersed ultrafiltration for treatment of low alkalinity and highly coloured upland water

The use of pre-coagulation micro- and ultrafiltration (PC-MF/UF) technology to treat highly coloured upland waters is a relatively new application of a rapidly developing technology. The results presented indicate that there is scope for enhancement of the process by further developing and understanding the pre-treatment conditions. The major challenge faced in this work was that there are no specific references or criteria for treatment of highly coloured upland waters in terms of defining optimum pre-treatment and membrane operating conditions for process engineering purposes. It was found that the cyclical operation of the aeration system and control of pH had a significant impact in reducing the rate of TMP (trans membrane pressure development). Also, significant levels of organics were removed but limited by the relatively high organic content of the raw water. Finally, there appeared to be a limit to the flux at which the membrane could sustain long intervals between chemical cleaning.