Adequação das condições operacionais de uma ETA “Convencional” que trata água com cor e turbidez baixas

Abstract

Water with turbidity and color apparent low to moderate are sometimes challenging to treat, especially in Water Treatment Plants (WTP) of full cycle with clarification by decantation (WTPs "conventional") because should be coagulated preferably in adsorption-neutralization mechanism loads. Such water can be coagulated in the sweep mechanism, generally with a high dose of coagulant, to produce settleable flocs which are removed in the decanter. However, it is also possible, in an advantageous overall, making the water coagulation at adsorption and charge neutralization mechanism with usually lower dose, and in this case there will be only a destabilization of the particles and formation of tiny floc (not settleable) to be removed on the filters. In some cases WTP enables the bypass of water directly to the filter (with or without pre-flocculation), since the decantion units practically lost its function and ETA, although it is physically configured as a complete cycle, it operates as a direct filtration system. Despite the advantages of this configuration, it is generally more difficult for the operator to find the dose and pH suitables for the adsorption and charge neutralization mechanism. The objective was to adapt a WTP with such characteristics. We did jartest tests simulating the complete cycle and downstream direct filtration, and treatments as pre-oxidation, coagulation, preoxidation with coagulation and adsorption coagulation, varying dosages of the respective products in each treatment and at different pH. All treatments performed attended Ordinance 2.914/11 for apparent color, but only the treatments in which there was coagulation attended for turbidity and apparent color simultaneously, and the best results of treatment of pre-oxidation with coagulation.