AWWA MTC57639

As membrane facilities increase in number and age, the need for upgrading the older facilities has continued to be required. Although many existing plants have implemented rehabilitation and replacement programs, little information has been published in the literature on this component of membrane plant operation and maintenance. Several key upgrade components include the following: well field and raw water feed lines; process pretreatment; membrane process; post-treatment; concentrate disposal; odor control and ancillary facilities (if required); storage; high-service pumping; and distribution system considerations. Specific items related to upgrading the membrane process can include the cartridge filters, high-pressure feed pumps, membrane elements, and operation monitoring systems. Other considerations can include PLCs and distributed control systems, SCADA and the use of VFDs in rehabilitation upgrade activities. Newer generation or modified membranes are thus placed into facilities that had been designed for an older model or version, which may require that newer operating conditions be employed to compensate for water transfer performance changes. Consequently membrane replacement requires careful planning, and should involve computer modeling, membrane probing, membrane profiling and hydraulic evaluations to document modifications in plant performance. Includes 17 references, table, figure.