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PROPOSAL FOR <br />On -Call Engineering Design Services <br />Maximum Production Rate <br />2,454 gpm <br />Pump Rating <br />2050 gpm / 220 ft TDH <br />Pump Motor Size <br />125 HP <br />Well Pump Depth <br />310 ft bgs <br />Well Casing Diameter <br />18 in. ID <br />Total Well Depth <br />1152 ft bgs <br />Maximum Pumping Water Level <br />240 ft bgs <br />Minimum Pumping Water Level <br />214 ft bgs <br />PFAS Treatment Systems <br />The standard train (2 vessels) IX treatment systems are widely commercially available in 2 sizes for treatment <br />plants of similar size to Santa Ana Well 26: 10-ft diameter with or 12-ft diameter. Ion exchange resin has a <br />high headloss per ft of bed depth, and for this reason many facilities cap their treatment capacity based on a <br />maximum resin depth of 3.7-ft per vessel. The recommended treatment capacity for PFAS removal is 500 to <br />1,100 gpm per 10-ft vessel train and 700 gpm to 1,600 gpm per 12-ft vessel train. <br />Santa Ana Well 26 could be configured with two (2) 12-ft trains and treat the maximum production currently <br />reported, or two (2) 10-ft trains to treat the well pump design flow rate of 2,050 gpm. Either IX system should <br />also consider the installation of 5-micron pre-treatment cartridge or bag filters ahead of the IX vessels. <br />Design Flow Rate (gpm) <br />2,050 <br />2,454 <br />PFAS Treatment Concept: <br />Number of IX Trains <br />2 Trains <br />2 Trains <br />Flow per Train (gpm) <br />1,025 gpm <br />1,227 gpm <br />EBCT (min) <br />2.15 min <br />2.56 min <br />Superficial Flow (gpm/sf) <br />13.1 gpm/SF <br />10.8 gpm/SF <br />IX Resin per Vessel (W) <br />294 <br />550 <br />Vessel Diameter (ft) <br />10 <br />12 <br />System Height (ft) <br />20' - 4" <br />15 - 9" <br />Vessel Surface Area (sf) <br />78.5 <br />113 <br />Allowable Superficial Flow (gpm/sf) <br />6 -18 <br />Design Minimum EBCT (min) <br />2 <br />Well 26 Hydraulic Evaluation <br />Hydraulic calculations for the expected pressure losses through the PFAS treatment plant using the IX vessels <br />and pretreatment bag filters were estimated based on the information provided for Santa Ana Well 26 based <br />on Alternative B, as presented above. The headloss for the IX vessels is calculated as a function of the resin <br />depth as it relates to the flow through the IX train. The system losses were calculated for both clean <br />pre-treatment filters and pre-treatment filters with maximum dP prior to replacement. Table 3 summarizes the <br />design points at the maximum and minimum lifts for the pretreatment conditions as well as the proposed <br />IX treatment condition. <br />TETRA TECH Page 110 <br />