Design a rapid mix basin for 1 million gallons per day flow. The rapid mix should be S feet deep and square in surface area. T

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The minimum temperature of the water is 5 °C, the free chlorine residual in the effluent from the basin is to be 2 mg/L, the first-order decay coefficient for chlorine is assumed to be 0.2 h-¹, and the flow rate is 1.5 x 104 m³/d. The pH of the water varies between 7.2 and 8.0. Make the calculations for a plug-flow basin. Cta values for achieving 99.9% reduction of Giardia lamblia Temperature (°C) Disinfectant pH ≤1 5 10 15 20 25 Free chlorineb 6 165 116 87 58 44 29 (2 mg/L) 7 236 165 124 83 62 41 8 346 243 182 122 91 61 9 500 353 265 177 132 88 Ozone 6-9 2.9 1.9 1.4 0.95 0.72 0.48 Chlorine 6-9 63 26 23 19 15 11 dioxide Chloramine 6-9 3800 2200 1850 1500 1100 750 (preformed) aC is in mg/L and t is in minutes Ct values depend on the concentration of free chlorine Calculate the dosage of chlorine kg/day) and the detention time minutes) required for 99.9% reduction of G. lamblia. 121.5 486 118 91 40 45 151.5

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