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To help meet future water needs, a treatability study is being conducted by the St. JohnsRiver Water Management District in central Florida and CH2M HILL to quantify the treatment requirements andcosts for a potential surface water treatment facility to be located along the reach of the St. JohnsRiver between the southern end of Lake Monroe in Sanford and De Land. This pilot study willidentify the feasibility, appropriate use, treatment technologies and costs to use surface water tooffset groundwater demands.Selecting treatment technologies for any water treatment system is driven primarily by drinkingwater regulations and the meeting of consumer expectations. For surface water treatment, theprimary regulations are the Enhanced Surface Water Treatment Rules (ESWTR) and theDisinfectant/Disinfection Byproduct (D/DBP) Rules. The planning process for any treatmentfacility on the St. Johns River has a 5- to 10-year window. Therefore, upon construction of thisfacility, compliance would likely be required for the Long Term 2 (LT2) ESWTR and Stage 2D/DBP rules.The approach to meeting these regulations is multibarrier treatment involving the following unitprocesses:coagulation and flocculation;clarification;filtration; and,disinfection.This approach requires each process to remove waterborne pathogens, with each processoperating at a high rate of efficiency. The effectiveness is cumulative, in that each unit processhelps the subsequent unit process work more effectively than if operated alone. The St. Johns River water has typical surface water characteristics for Florida. The characteristicdark brown color of the water is due to the organics in the water. These organics are mostlydissolved humic and fulvic matter. Total organic carbon concentrations are often in excess of 30mg/L with colors exceeding 400 Pt-Co. Additionally, the St. Johns River has uniquecharacteristics due to the brackish content of the water. This brackish surface water has totaldissolved solids (TDS) concentrations ranging from 400 milligrams per liter (mg/L) to 1,060mg/L and chloride concentrations ranging from 139 mg/L to 455 mg/L. Because of these uniquecharacteristics, partial desalting must be used along with conventional treatment. Includes tables.

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Edition: Vol. - No. Published: 03/05/2003 Number of Pages: 7 File Size: 1 file , 220 KB