Abstract: An improved method for treating liquids by disinfection and clarification which includes a means to mix and maintain consistency of the flow in a generally uniform composition prior to and during treatment. The mixture being connected to a section of conduit arranged in a pattern in a target area of a microwave generator so that all matter in the flow is exposed and excited by the electro-magnetic energy for a predetermined period of time and a control means to regulate flow of the mixture so as to allow flow only when mixture is treated, to a prescribed level. The method includes an automatic means to sense degree of treatment and to increase or decrease flow, as required, to maintain uniformity of treatment. Disposable filter means is provided when removal of undesirable contaminents is required.