Abstract: A fluid treatment system utilizes a circulating pump and an ozone generator arranged to receive atmospheric air and emit ozone-rich air into a delivery pipe which is connected to the upstream, suction side of the circulating pump, for introducing ozone-rich air to the fluid to be treated prior to the fluid entering the pump, whereupon complete mixing and dispersement of the ozone through the fluid is achieved. The ozone generator comprises at least one pair and preferably a plurality of pairs of spaced flat plate electrodes, one of each pair being of smaller longitudinal and lateral dimensions than the other and one of the electrodes of each pair also being provided with a plurality of dimpled projections on its surface facing the other electrode of its pair. Air passageways are arranged to extend between each electrode pair so as to expose the entire surface area of the electrodes to the air moving therebetween.