Desinfecção eletroquímica de águas de abastecimento: investigação do desempenho de um sistema integrado com filtro de polipropileno e reator com eletrodos de esponja de níquel e titânio/platina.

Abstract

With the growing concern about global water scarcity, literature has focused on the development of innovative technologies for water treatment, highlighting challenges in the availability of drinking water. Traditional water treatment methods, despite their efficiency, face some setbacks, such as resistance of certain microorganisms to treatment, formation of toxic by-products, inefficiency in removing emerging pollutants, chemical reagent expenses, complex infrastructure, and inefficiency in contaminant removal depending on the water source. This necessitates more efficient approaches. Electrochemical disinfection emerges as a promising alternative, allowing in situ generation of biocides and avoiding the handling of concentrated oxidizing agents. In an effort to contribute to the progress of this technology, a tubular electrochemical reactor was developed, with a porous nickel cathode and a platinum coated titanium anode positioned in an electrolytic system along with a polypropylene filter. The main objective of this work was to evaluate the reactor's performance in generating oxidizing species and eliminating Escherichia coli. The development of this work was divided into two phases. The first involved the fabrication and operation of the system under a potential difference of 12V and a flow rate of 1L/min with different concentrations of E. coli, without pre-treatment. In the second phase, the reactor's performance in the electrochemical treatment of synthetic freshwaters was studied with a potential difference of (12-14) V and flow rates of (1.0-1.5) L/min, evaluating performance in terms of turbidity, color removal, and disinfection. Under the best conditions of Phase I, approximately 86% inactivation of Escherichia coli was achieved. In Phase II, efficient removal of turbidity and color from wastewater was observed, reducing up to 55.0% of turbidity and 57.0% of color. Despite the good efficiency, the parameters did not meet the potability standards required by legislation. Due to the low chloride ion concentrations present, it was not possible to study their influence on the inactivation of Escherichia coli in both phases. In the same phase, an inactivation of about 99.99% of Escherichia coli was achieved under the action of the electric field with a potential difference of 14V, operating with recirculation and simulating a series operation.