A wastewater is to be disinfected with 35 mg/L of chlorine to obtain 99% kill of micro- organisms. The number of micro-organisms remaining alive (Nt) at time t

Q. A wastewater is to be disinfected with 35 mg/L of chlorine to obtain 99% kill of micro- organisms. The number of micro-organisms remaining alive (Nt) at time t, is modelled by Nt = No e–kt , where No is number of micro-organisms at t = 0, and k is the rate of kill. The wastewater flow rate is 36 m³/h, and k = 0.23 min^‒1. If the depth and width of the chlorination tank are 1.5 m and 1.0 m, respectively, the length of the tank (in m, round off to 2 decimal places) is______________                   

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