A printing system for forming three-dimensional objects, layer by layer is provided. The system includes inkjet printing heads, each printing head adapted to dispense one of a modeling material, a support material or a reusable waste material that comprises one or more materials that were previously discharged from at least one of the inkjet printing heads; a modeling material container; a support material container; a reusable waste material container and a leveling unit that removes surplus material from previously deposited layers, the surplus material being provided to the reusable waste container via a tube.