Introduction to West Basin
West Basin is a public agency that provides imported drinking water and recycled water to 17 cities and nearly one million people in the coastal Los Angeles area. West Basin is member agency of the Metropolitan Water District of Southern California. West Basin is an internationally recognized expert in water recycling, conservation, water education and water resource management, and currently treats over 40 million gallons a day (mgd) of secondary municipal effluent to produce five different recycled water qualities.
Historically, the majority of major microfiltration (MF) and ultrafiltration (UF) membrane systems have been provided by suppliers that incorporate proprietary features into their modules and system designs. These proprietary features are not easily adaptable to alternative concepts when equipment repair or membrane replacement is required. As a result, membrane replacement is usually sole-sourced to the proprietary system supplier and subject to the commercial practices and potential limitations of the equipment and membranes provided by that supplier.
Recently, a number of membrane module suppliers have entered the market and offer an alternative method of delivery for MF/UF products. The module supplier works with an Original Equipment Manufacturer (OEM), who is responsible for designing the system to satisfy the requirements of the membrane module supplier. Although the relationship between the module supplier and OEM can be exclusive, some OEM’s can offer multiple membrane products, and have recently begun to offer system designs which may be able to use more than one type of membrane module.
There can be variability within proprietary or non-proprietary membrane modules that may impact operation of a facility. Issues such as fiber breakage, potting failures, and variability of membrane product performance have led some suppliers to alter designs and introduce new products to replace existing products when performance is unacceptable.
When proprietary hardware such as manifold and module frame assemblies are considered, there have been instances of failure or product obsolescence resulting in unanticipated and expensive retrofit replacement necessary to maintain system operation.
West Basin found that retrofit/replacement of the 25 older proprietary microfiltration units used at various locations was more expensive than simply replacing the system itself.
As part of the on-going effort to improve operation at its facilities, West Basin began to review specifications for some the latest generation of pressurized MF/UF modules and found that there is a substantial level of consistency among PVDF current product offerings…..
West Basin’s Universal Pilot Approach
Given its historical use of MF/UF membrane process for the treatment of recycled water, and the recent success with the installation of a PVDF membrane filtration system at the Edward C. Little Facility Water Recycling Facility (ECLWRF), West Basin developed an alternative approach for the evaluation of membrane modules for future or replacement needs. This approach involves the evaluation of membrane modules products on a West Basin designed and provided pilot unit, using a common or “Universal” approach in lieu of a supplier or OEM provided unit….