Abstract: A wastewater purification system that uses mechanical and chemical processes to separate contaminants from municipal and other sanitary wastewater, concentrates the resulting sludge for disposal, and purifies the resulting product water for reuse as irrigation water, potable water or for disposal. The wastewater purification system can be scaled from a mobile system mounted on a skid or a tracker trailer to a large municipal wastewater treatment system. The wastewater purification system can include a hydrocyclone feeding a flotation tank. Flocculant is added upstream from the hydrocyclone after air injection by a Venturi air injector or similar device. Coagulant is added before the air injection. A dose of flocculant is added after the hydrocyclone within the vortex of the hydrocyclone and before the wastewater exits near the top of the flotation tank.