The chlorine demand curve on the graph was obtained for a drinking water for a 1.5 hour contact time (total residual chlorine and chlorine dose are expressed in mg/L as Cl2). The hypochlorite solution contains 12% by weight solution of NaOCl (? = 1160kg/m3, MW (NaOCl) = 74.5g/mol, MW (Cl2)=71g/mol).
1. Determine the dose of chlorine required to obtain a free residual of 0.6 mg/L (5 points)
2. Calculate the daily mass of NaOCl that must be added each day (10 points)
3. Determine the daily volume of NaOCl to be applied to this water to produce a free residual of 0.6 mg/L after a travel time of 1.5 hour in a flow of 320m3/d. (15 points)