Water scarcity in the water supply in Tangará da Serra - MT: analysis of the treatability efficiency of different raw waters

Intense and prolonged droughts can cause several economic and social impacts, such as the interruption of water supply to the population.With the significant impact on the levels of water sources, municipal managers are looking for other alternatives to capture water from a new water source. Therefore, the research, combined with the laboratory tests preceding the treatment, guides the definition of the proper operating conditions of the Water Treatment Plant; in other words, they technically improve and reduce costs. The test in static reactors stands out, what allows the evaluation of the coagulation and flocculation processes and their effects in the following phases of treatment. Thus, the aim of this research was to evaluate the efficiency of the coagulation and flocculation process in the treatment of different raw water for public supply in a medium-sized city in the state of Mato Grosso. Water samples were collected from the Queima-Pé stream and the Sepotuba river during different seasonal periods. The methodology was based on the following steps: preparation of a third sample with a mixture of 50% of the waters; raw water characterization and tests in static reactors. The results emphasize that rainfall influenced mainly in the water colors. Regarding the Sepotuba River, during the drought period, mainly in the months of July, August and September, the turbidity of the raw water proved to be inferior and close to the potability standard established by Brazilian legislation. However, the formation of very fine and small flakes was observed, with moderate color removal efficiency and turbidity reaching a maximum value of 37%, which can be justified by the reduced alkalinity of the raw water. That way, it is recommended to add an alkalizing agent in order to make the treatment more efficient. Keywords: Water Treatment. Jar Test. Water Mixtures. Potability.