AWWA ACE63031

This slide presentation outlines an arsenic treatment pilot study in El Paso, Texas, and includes full scale implementation of Mesilla Bolson (21 wells), the new Upper Valley Water Treatment Plant (UVWTP). Pilot Study at Well 303 technologies evaluated included: Granular Iron Media; Granular Ferric Hydroxide (GFH); Iron-Coated Activated Alumina (Alcan FS50); Bayoxide® E33 (SORB33TM); Coagulation/Microfiltration; Pall MF Unit; Coagulation/Filtration; and, AquaDisk Filter. Pilot study conclusions included: C/MF process flux rates > 90 gfd; chemical cleaning intervals > 100 days; the GIM technologies are effective for arsenic removal; media tested treated over 100,000 bed volumes (5-min EBCT); and, the addition of sodium hypochlorite had a significant effect on media life. Full scale implementation at Mesilla Bolson (21 wells), the new Upper Valley Water Treatment Plant (UVWTP) included: Conventional Treatment; IPS; Rapid Mix; Flocculation (horizontal paddle wheel); Sedimentation (parallel plate settlers); granular activated carbon filters; finished water blending; and, pH adjustment, disinfection, corrosion protection. Conclusions included: construction cost $27.5 million; change order percentage of less than 0.8% of total construction cost; El Paso is in compliance with the new Arsenic MCL as of December of 2005; UVWTP has been in operation since December of 2005; and, EPWU in compliance with Arsenic Rule by January 23, 2006.