AWWA ACE68642

This powerpoint presentation begins by providing background information on the project including: excessive groundwater withdrawals throughout Florida; project located in Southwest Florida Water Management District Southern Water Use Caution Area; Peace River Facility (PRF) 24 mgd; Aquifer Storage Recovery (ASR) System 22 wells with 17 mgd capacity; and, recovered ASR water retreated at PRF WTP. Topics presented include: previous research and findings; proposed bench scale tests -- conventional lime softening, conventional soda ash softening, and conventional softening with ferric and alum addition; proposed pilot study (synthetic Goethite Absorber with and w/o pre-chlorination); desktop evaluation on other potential alternatives (reverse osmosis (RO), electrodialysis reversal (EDR), ion exchange (IX), and Vibratory Shear Enhanced Membrane Process (VSEP)); and, cost evaluation and next steps. Pilot study results include: raw water As ranged from 43 µg/L to 61 µg/L (treated water As concentrations consistently below 2 µg/L detection limit - As removal efficiency of >98%); total treated water bed volume was 5377 and no As breakthrough was observed, backwash not needed during 3 weeks pilot study; measured feed water turbidity was consistently low -- media differential pressure was increased slowly from 0.2 psi to 5 psi, and a monthly backwash is anticipated based on linear prediction. Includes figures.