AWWA WQTC58893

In the last decade the number of large-scale, greater than 1 mgd (4 Ml/d), water treatment plants applying microfiltration or ultrafiltration (MF/UF) membranes has increased rapidly, from one to almost 100 worldwide. Projects implemented in the first half of the 1990s decade generally applied MF/UF with minimal pretreatment, typically just a 200 to 500 micron prescreen. More recently, MF/UF membranes have been integrated with additional operations. It is beneficial for utilities and engineers considering implementation of membrane filtration to understand the increased range of treatment objectives and, in some cases, lower life cycle costs, offered by integrating MF/UF with more conventional processes. This paper discusses methods for integrating MF/UF membranes into water treatment plants that include: simple membrane filtration (with minimal pretreatment); direct membrane filtration (coagulated-flocculated water to MF/UF); coagulation-sedimentation (settled water to MF/UF); lime softening; and, integration with post-treatment, such as granular activated carbon (GAC), reverse osmosis (RO) membranes, or ultraviolet (UV) light disinfection. Specific projects are presented in the paper as examples to give a better understanding of how membrane processes are being applied today. Includes 5 references, tables, figures.