Abstract: An apparatus for disinfecting surfaces and in particular human and animal wounds, includes a contractor for accumulating concentrated ozonated water and systems to deliver ozonated water from the reservoir to a nozzle having one or more jets for delivering a spray of ozonated water on to the surface to be treated. The nozzle has an encircling shroud and systems are provided for withdrawing ozonated gas liberated at the nozzle from around the nozzle. A collection tray is provided which is located under the surface/wound to be treated to receive ozonated water flowing from the treatment region and where any residual ozone is broken down.