COMPARATIVE STUDY OF THE PRE-OXIDATION STAGE IN WATER TREATMENT USING DIFFERENT OXIDANTS

Abstract

In this study, the pre-oxidants tested (sodium hypochlorite, sodium dichloroisocyanurate, hydrogen peroxide, and potassium permanganate) were analyzed regarding their behavior at different concentrations and contact times. The objective was to optimize the pre-oxidant dosage and observe how contact time affected the efficiency of the process. The concentration of 1.5 mg/L was effective for the first three oxidants (sodium hypochlorite, sodium dichloroisocyanurate, and hydrogen peroxide), resulting in good removal of color and turbidity, with residual values close to the recommended levels. For potassium permanganate, the concentration of 0.2 mg/L proved to be the most efficient. Regarding the contact time in the pre-oxidation stage, the increase in oxidation time resulted in a greater amount of oxidized sample, indicating an increase in oxidant demand. In conclusion, the application of all tested oxidants in the pre-oxidation stage significantly contributed to improving the efficiency of water treatment. Subsequently, the different stages of water treatment were evaluated through physicochemical parameters using different oxidants in the pre-oxidation stage. Jar tests were conducted to evaluate the behavior of each stage (pre-oxidation, coagulation, flocculation, sedimentation, and filtration), and water quality was monitored. Water treatment with pre-oxidants showed greater treatment efficiency than samples without the use of oxidants. Pre-oxidation, combined with coagulation and flocculation, contributed to better performance in solid removal. When comparing the treatments, sodium hypochlorite showed the best results.