Question

A new water treatment facility will be built to supply water to the town of Freemont. The town's population is currently 14,000 and the per capita water use is 100 gal per day. The new facility will be designed to account for increases in both per capita water use and population growth, and projections for water use will be determined for fifty years in the future. The population of the town of Freemont grows at an average rate of 2% per year. Based on historic trends for the town of Freemont, per capita water use increases at a rate of 0.1% each year Question 2: Coagulation-Flocculation An alternate water source for the town of Freemont is a lake 40 miles away. Since this is a surface water source with an acceptable hardness level, water softening is not required but a chemical coagulation step is needed instead Given the following water quality characteristics for the lake Ca2*, mg/L Mg2+, mg/lL Na, mg/L 130 15 21.5 3.8 5.8 HCO3, mg/L 82 SO4, mg/L 109 CI, mg/L CO3, mg/L 5.9 Mn2, mg/L 1.2 112 K', mg/L Fe2, mg/L Determine the alkalinity as mg/L as CaCO3. Assuming that the dose of alum is 60 mg/L, use the stoichiometric equation for coagulation using alum to determine how much alkalinity will be consumed in the coagulation reaction. Will a coagulation aid be required? If a lower dose of alum (11 mg/L) is used instead, determine (i) (ii) The coagulant consumption rate The mass of sludge produced each year due to coagulation-flocculation Assume that the volumetric flow rate of treated water will be the 50-yr-projection calculated previously

Answer 1

Alkanrty consumed 2t m Co-agulant Aid i Not beeqied ,Beccuse. Theve is alkalíni stil eent Cong u lant Consumption Yate:J1m9ILxo.1735 m3/s -- : Al (OHI is generaly libened as Sludye we Con See that in React alum be generntrd