20 MLD of water is flowing through a 3.0 km long pipe of diameter 50 cm. The quantity of chlorine used to treat the water is 4.5 mg/l is applied at the entry of this pipe so that disinfected water is obtained at the exit of the pipe. The flow-through pipe is supposed to be increased by 6 MLD. The minimum amount of chlorine (in kg per day) required to be applied to achieve the same degree of disinfection assuming the dilution coefficient 1 is ___________.