Abstract: A robotic tank cleaning system is provided, comprising a light-weight, collapsible, and robotically controllable frame having an articulatable washing nozzle for spraying a petroleum-based solvent on a surface to be cleaned. Hydraulic power and control units are also provided which allow an operator to control the motion of the frame and washing nozzle from outside the tank, as well as a solvent supply system for delivering solvent to the washing nozzle. A hoisting mechanism is included to allow placement and retrieval of a waste removal pump, and a clearing blade is attached to the frame to assist movement of waste material to the waste removal pump. Waste material comprising dislodged oil sludge and expended solvent is collected in waste fractioning tanks where the collected oil sludge is allowed to settle below the expended solvent. The separated solvent in the waste fractioning tanks is redirected through the solvent supply system and is reused for further spraying of the tank interior.