This Robot Harvester (design only) is designed to automatically collect rubbish, similar to the robot vacuum cleaners around the home. It sweeps up small rubbish and picks up large rubbish with its manipulators. The unit then takes itself to an unloading bay.
You could see this being extended one day so that the robot does some refining of the rubbish collected, even generating its own energy from the rubbish.
Via Adam Johnson