Slide 1Water TreatmentGroundwater Treatment Plant Treatment of Groundwater for Hardness RemovalSurface Water Treatment Plant Surface Water Treatment for Turbidity and Color RemovalWater TreatmentWater TreatmentCE 326 Principles of Environmental EngineeringCE 326 Principles of Environmental EngineeringDepartment of Civil, Construction and Environmental Department of Civil, Construction and Environmental EngineeringEngineeringIowa State UniversityIowa State UniversityFebruary 29, 2008February 29, 2008Tim Ellis, Ph.D., P.E.Tim Ellis, Ph.D., P.E.Water Treatment •Groundwater–hardness (aesthetic consideration)–disinfection (required by SDWA)•Surface Water–turbidity and color removal–filtration (required by SDWA)–disinfection (required by SDWA)CE 326 Principles of Environmental Engineering, Copyright © 2008 Tim Ellis, Iowa State UniversityGroundwater Treatment PlantTreatment of Groundwater for Hardness RemovalBore Hole WellAerationHard WaterCa+2 + Mg+2to remove CO2and H 2S Fe2+ → Fe3+RapidMixSlowMixSedimentationweir overflow rate: 268-322 m3/m. d surface overflow rate:57-70 m3/m2 . d105-130 m3/m2 . d for upflow solids contactRecarbonationaddCO2 to decrease pHadd lime (for CH)and soda ash (for NCH)raise pH to 10 - 11.5 to precip. hardnessadd D. O.FiltrationClear-wellto distri-butionadd Cl2 , polyphosphateand F-G values for Rapid Mix: 700-1000 s-1In-Line blender: 3000-5000 s-1Gto values for Flocculation Type G(s-1) Gto Softening (10%) 130-200 200,000-250,000Softening (39%) 150-300 390,000-400,000E.S. = 0.35 - 0.55 mmU.C. = 1.3 - 1.7depth = 0.3 - 0.75loading rate = 120 - 240 m3/m2dCE 326 Principles of Environmental Engineering, Copyright © 2008 Tim Ellis, Iowa State UniversitySurface Water Treatment Plant Surface Water Treatment for Turbidity and Color RemovalStreamBacteria, Color,TurbidityRapidMixSlowMixSedimentationweir overflow rate: surface O. R.: 143-179 m3/m. d light floc 20 - 40 m3/m2 . d179-268 m3/m. d heavy flocalum or iron salts for coagulationFiltrationClear-wellto distri-butionadd Cl2 , polyphosphate,and F-lime for pHIntake and Pump Stationadd Cl2 or O3 for taste and odorG values for Rapid Mix: 700-1000 s-1In-Line blender: 3000-5000 s-1Gto values for Flocculation Type G(s-1) Gto Low turbidity 20-70 60,000-200,000High turbidity 30-80 36,000-96,000G: 700-1000 s-1t: 30-60sflocculationbasinsedimentationbasinE.S. = 0.35 - 0.55 mmU.C. = 1.3 - 1.7depth = 0.3 - 0.75loading rate = 120 - 240 m3/m2dCE 326 Principles of Environmental Engineering, Copyright © 2008 Tim Ellis, Iowa State