Análise da eficiência da solução alternativa coletiva de tratamento de água (SALTA-z) para a potabilidade aplicada ao semiárido brasileiro.

Abstract

Access to water and sanitation services is a universal right that results in health promotion and improvement in the population's quality of life. However, when it comes to rural communities, traditional territories or population clusters far from urban centers, this right is often neglected, being worsened in areas with low water availability which suffer an intense degradation of water quality, like the Brazilian semi-arid region. Water direct consumption or such consumption without adequate treatment can generate health risks for these populations, requiring the development and implementation of technologies that can minimize the risks of water ingestion. Aiming at the universalization of sanitation, the National Health Foundation of Brazil (FUNASA) has SALTA-z, a collective alternative water treatment solution using zeolite, developed by the State Superintendence of Pará (SUEST/PA), which was initially conceived to guarantee drinking water for the riverside population of the state of Pará. Due to its acceptance and effectiveness in the riverside communities, this social technology was replicated to other areas of Brazil, including the semi-arid region. The implementation of such technology requires its validation regarding the potabilization of the waters of the region, understanding its particularities. In view of this, the thesis aimed to evaluate the performance of SALTA-z treatment for water from eutrophicated reservoirs in the Brazilian semi-arid region, addressing the supply of safe and potable water for human consumption in rural and traditional communities in this area, through the evaluation of operational factors (dosage of coagulating and disinfecting agents and settling time) and of water quality parameters that are directly related to the use of chemical products and characteristics inherent to the waters of surface reservoirs in the semi-arid region. For this purpose, studies were carried out in real scale and in bench scale, through the reproduction of the system in jar test equipment and laboratory filters, since SALTA-z is a technology that presents the same steps of the conventional treatment (coagulation, flocculation, sedimentation, disinfection and filtration, in that order). The results revealed the importance of optimizing the operational factors and choosing the right coagulating agent in the treatment process, aimed at reducing color and turbidity, removing cyanobacteria and cyanotoxins, and also promoting a lower residual aluminum in the water, when using aluminum sulfate. It can be inferred that this technology does not present potential for salt removal. Regarding the treatment concept that includes the disinfection step prior to filtration, there was no significant influence on the efficiency of the system, but the importance of verifying the possible formation of by-products from the oxidation of organic matter remaining in the decanted water is highlighted. However, during the operations, compliance with the Brazilian potability ordinance (Portaria GM/MS no 888/2021) was observed in relation to the physical-chemical and biological parameters evaluated. From the analyzes carried out in this thesis, it can be concluded that SALTA-z is a technology capable of performing the treatment of surface waters in the semi-arid region, highlighting the need of evaluation for reservoirs that present different degrees of trophism. Also noteworthy is the importance of training SALTA-z operators, and the involvement of the community, in order to have a good control of the process and the maintenance of the quality of the water produced.