In a method and apparatus for treating fluids, a pump delivers a fluid flow from a fluid source to a manifold. The manifold divides the fluid flow into first and second fluid flows, which are delivered from the manifold to a housing. The housing includes therein a first vortex nozzle positioned in opposed relationship to a second vortex nozzle. The first fluid flow enters the first vortex nozzle to create a first rotating fluid flow, and the second fluid flow enters the second vortex nozzle to create a second rotating fluid flow. The first and second vortex nozzles impinge the first and second rotating fluid flows in a collision chamber, thereby treating the fluid.