Inside a hollow drum which is filled with 250kg organic waste of density 350kg/m3, 1000mm long shaft diameter is 75 mm , has attached 5 blades at equal distance of length 300mm, is rotating inside a drum. Then how much power will be needed to rotate a shaft within loaded drum?

You will need to tell us the rotational velocity of the machine. I suggest that you model this as if trying to lift a 250 Kg mass at the end of a 338 mm long arm. The power required to do this is:

P = mgrw

where m = 250 Kg, g = 9.8 m/s^2, R = 0.338 m, and w = rotational speed of the machine, in radians/second. This will give you the power required in watts.