Como melhorar o desempenho das ações de dessalinização de água para o consumo humano no semiárido da Bahia

Abstract

The desalination process using reverse osmosis membranes has provided drinking water for families in the semiarid region of Brazil since the 1990s. Currently, this process is being used by a federal program called “Água Doce”. Its predecessor, the “Água Boa” Program, resulted in the abandonment of part of the systems by the population and and responsible agency. Having in mind to collaborate towards avoiding the same outcomes on the current program, this research proposes to present possible ways to improve the performance of the actions of desalination of saline water from tubular wells drilled on crystalline rock formations. Therefore, in view of the complexity of approaching the reality of this scenario, several methodological instruments were applied, namely: documentary and bibliographic reviews, field research in a community benefited by the Program, risk / failure assessment and technical and economic feasibility analysis. The results obtained allowed to characterize the scenario of this study, to explore the Program management model and technical data of the systems design. This, consequently, allowed us to understand the complexity involved in the implementation and continuity of the Program. It was possible to identify the problems experienced to keep the systems in operation, such as: system outages due to lack of maintenance, lack of spare parts and equipment, lack of chemical products, absence of operators, and suspension of payment of the operators by the City Hall. The application of Risk Management contributed to the development of a) A proposal for a risk methodology regarding the scenario of the Água Doce Program in the state of Bahia; b) The development of an Analytical Risk Structure for the Program; c) A survey of a list of 36 risks, categorized and ranked according to the urgency of their treatments. The analysis of the first monitoring of the program in Bahia evidenced the occurrence of risks raised during the application of the Risk Management methodology, which had the effect of suspending the operation of 31% of the systems of the installed systems. The technical analysis made it possible to verify that, being the systems designed to supply 10L / day / person, the wells’ flow rates are not being used according to their full production capacity. Total dissolved solids in the purified water of most systems is below 200 mg / L, superior quality than specified for drinking water (1000 mg / L). Regarding the consumption of electricity of six systems in the municipality of Ipirá, in Bahia, there was an average trend of increase of 3.92kWh / m3 between the projected and the measured. A study of alternative centralization of individual systems in centralized systems was carried out, which was not shown to be advantageous. Therefore, this work allowed the development of a list of opportunities for reliability in the water supply by the Program, presented along the body of the chapters.