Abstract: A method and apparatus of washing laundry using a reduce amount of, or without the use of, hot water and detergents using a closed-loop or open-loop ozonated wash water system wherein wash water maintained in a contact tank is ozonated by an ozone generator prior to use in the washing machine. The oxygen and/or dried air used in the ozone generator to generate the ozone is concentrated by an oxygen concentrator before being fed into the generator. The system includes a venturi injector for entraining ozone into the water in the storage and contact tanks. The system also includes the use of contact extenders, static mixers and flow restriction fittings. The spent wash water may be collected, filtered and reused, thereby eliminating waste water disposal problems, resulting in considerable water and energy savings.