AWWA WQTC58982

The Metropolitan Water District of Salt Lake and Sandy (MWDSLS) is planning a new 70 mgd water treatment facility, called The Point of the Mountain Water Treatment Plant (POMWTP). That treatment plant is currently under design. Prior to initiating the design of the plant, MWDSLS conducted a pilot study to evaluate three candidate treatment trains. Those treatment trains were: Train #1, low pressure membrane filtration with conventional pretreatment; Train #2, low pressure membrane filtration with pre-sedimentation and post-granular activated carbon (GAC) adsorption; and, Train #3, conventional treatment with ozonation and ultraviolet (UV) disinfection. A major goal of the pilot study was to determine operating conditions under which each of the three trains could achieve the finished water goals established for this project. Those operating conditions were the basis for cost estimates. Pilot-scale testing was conducted for a period of ten months on the two source waters for the new plant. With respect to Trains #1 and #2 much of the piloting effort focused on developing design criteria (flux and recovery) for the low-pressure membrane process. In the pilot study a total of four commercially available membrane systems were evaluated in each train. Testing of treatment Train #3 was conducted using a new 7-gal/min conventional treatment train pilot, complete with pre- and intermediate-ozonation, and six granular media filter columns. Granular media filter designs included both anthracite and GAC designs, operated biologically, and a pre-chlorinated control filter. Key design criteria, necessary for cost estimation, included coagulant dosage, pre and intermediate ozone dosages, the hydraulic loading rate (HLR) of the filters, the depth of the media in the filters (i.e., L/d ratio), and a selection of either GAC or anthracite media. Includes tables, figures.