AWWA INF53957

AWWA INF53957 Decisions, Decisions, Decisions--Lead the Way to Constructing the Largest Membrane Softening Plant in the USA (at Boca Raton, Florida)
Conference Proceeding by American Water Works Association, 06/01/2001

Andrews, Douglas R.^Richards, S. April^Pujals, Victor J.^Brinson, Frank

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In recent years, the City of Boca Raton, Florida, has experienced a gradual, butsteady increase in the levels of color in the raw and finished water at itsGlades Road Water Treatment Plant. In addition, increasing levels of dissolvedorganics in the raw water have made compliance with more stringent regulationsfor disinfection byproducts (DBPs) more and more difficult with the existingconventional lime softening process. While the existing lime process does removesome color, DBP precursors, and associated constituents, it is not capable ofmeeting upcoming DBP standards while at the same time meeting color standards. Inaddition, the utility is receiving increasing customer complaints about highcolor levels in the finished water. With the passage of increasingly stringentregulations for DBPs under the United States Environmental Protection Agency(USEPA) and State of Florida Safe Drinking Water Acts (SDWAs), the City hasrecognized the need to pursue other treatment process alternatives to providecontinued compliance with drinking water quality regulations. In order to complywith new drinking water standards and meet the utility's treatment goals, theCity has evaluated several alternatives for process modifications, includingenhanced lime softening, ozonation, and membrane softening. Due to the efficiencyof the membrane process in removing color and DBP precursors, the City haselected to pursue membrane softening process modifications to meet theirtreatment objectives. This process is being used increasingly in Florida as analternative (or a complement) to conventional lime softening to treat relativelyhighly colored groundwater supplies such as the City's. The City's service areais currently close to buildout, with a projected maximum day buildout demand of60 million gallons per day (mgd). In order to meet this demand, comply with waterquality standards, and meet other water quality goals, the proposed plan ofaction is to implement a 40-mgd membrane softening process for blending with theexisting lime softening process product water. This plant will be the largestmembrane softening process in the United States when it comes on line in late2002. This paper describes the design of the plant. Includes figure, tables.