Abstract: A tertiary waste water treatment system wherein the waste water is subjected to physical chemical processes. The waste water is treated with a coagulating agent, a polyelectrolyte and then is clarified in a lamina preferably of unique design. The clarified waste water is then filtered and passed through an ozonation-sonication chamber wherein the liquid flows counter to the ozone. Within the tower, the liquid is subjected to substantial levels of sonication, enough to cause cavitation, either simultaneously with or prior to encountering large concentrations of ozone. After the ozonation-sonication treatment, the effluent may be discharged or it may be passed through an ozone contact chamber.

Abstract: A clarifier including a lamina comprising a plurality of substantially parallel spaced apart plates extending at an angle to the vertical. The parameters of the lamina are optimized in accordance with disclosed mathematical relationships depending on whether the tank is circular or rectangular. Means for equalizing the flow of the tank are described, as well as means for supplementary removal of additional particulates after the liquid has passed through the lamina.