A wastewater is to be disinfected with 35mg/L of chlorine to obtain 99% kill of microorganisms. The number of micro-organisms remaining alive (N_t) at time t, is modelled by N_t = N₀ e^–kt, where N0 is number of microorganisms at t = 0, and k is the rate of kill. The wastewater flow rate is 36m³/h, and k = 0.23 min-If the depth and width of the chlorination tank are 1.5 m and 1.0m, respectively, the length of the tank (in m, round off to 2 decimal places) is _________