A waste bin comprises a receptacle with a mouth, a lid 8 attached to the receptacle by a hinge and an actuator to open and close the lid. The lid includes an outer casing 8 and an inner casing 5 with a cavity 11 in between, the inner casing including one or more apertures 9 leading from the cavity to inside the receptacle when the lid is closed. An ozone generator, preferably an ultraviolet source 15, sits within the cavity to discharge ozone into the receptacle. A switch generates a control signal when the lid is opened or closed and a control unit 6 causes the ozone to be discharged into the receptacle for a period when the lid is closed and to stop when the lid is opened. The bin may include a ventilation circuit comprising an inlet in the inner casing for air from the receptacle, a fan arranged to draw air from the inlet across the ozone generator and an outlet for discharging ozone-enriched air to the receptacle. The ultraviolet source may comprise an elongate lamp in a channel-shaped reflector that is open at both ends, and the inner casing may have two inlets adjacent the ends of the reflector.
