Scottsdale, Arizona's Water Campus Project is a water resources managementfacility applying leading edge technology to help ensure future water supplies inthis desert community. As part of the project, an integrated membrane system(IMS), (consisting of microfiltration (MF) and reverse osmosis (RO)), is beingused to treat both surface water and tertiary effluent prior to sub-surfacerecharge. The water that is recharged will percolate through the soil andeventually mix with local groundwater. The city receives credit, based on thevolume recharged, from the Arizona Department of Water Resources (ADWR) towardsgroundwater withdrawals within its service area. The microfiltration systemtreats both surface water and effluent. At times, both are treated simultaneouslyin adjacent units, affording a unique opportunity to compare membrane performanceon different feed sources. The RO system was designed to treat tertiary effluentand, as a result, the original operating plan required the system be shut downwhen all available effluent was used for irrigation. However, water quality andoperational concerns resulted in a modification to this plan. Currently, when alleffluent is being used for irrigation, some Colorado River water (delivered viathe Central Arizona Project (CAP) canal) is now treated through the RO. Themembrane portion of the project began operation in the fall of 1999. In May of2000, additional microfilters were purchased to increase production. Pipingmodifications are planned to increase system flexibility and maximize microfilteruse. This paper will discuss process operations, membrane performance, productioncosts, and water quality relevant to the use of an IMS for the recharge, andsubsequent indirect potable reuse of tertiary effluent. Includes 8 references, tables, figures.
