IMPROVEMENT OF WASTE-WATER COAGULATION USING OZONE

A study to evaluate the effect of ozone on solids removal during the c oagulation-flocculation of wastewater from Mexico City drainage (inclu ding domestic and industrial) was conducted. Results of this study sho w significant improvements in the effluent quality with small ozone do ses. The optimum ozone dosage was found to be 3.32 mg L-1 +/- 0.20. Wi th this dosage it is possible to reduce the coagulant concentration fr om 50 mg L-1 to 40 mg L-1 without affecting the effluent quality. When coagulant dose is not reduced, an increase in the flocs' settling vel ocity due to a larger average size (with a decrease in TSS) is observe d before and after filtration. In all cases, reductions in turbidity a nd color levels are seen when polyelectrolytes are used. The best resu lts are achieved using a relation of approximate to 0.02 g O-3/g TOC.