Remoção de oocistos de Cryptosporidium parvum em água contaminada através da utilização da Cavitação Hidrodinâmica

Abstract

The biological contamination of surface water used in public supply poses risks to human health. Among the pathogenic protozoa, Cryptosporidium spp. assumes an important role, being related to several outbreaks of waterborne diseases. Like the technologies used in water treatment and in the physical adjustment of water potability, however, some situations are ineffective in removing pathogenic microorganisms such as Cryptosporidium spp. Advanced Oxidative Processes (POAs) are an alternative to new technologies that have been studied and have shown important results in the removal of contaminating agents and microorganisms from water resources. The aim of the present study was to evaluate the process of hydrodynamic cavitation in the removal of Cryptosporidium parvum oocysts in ultrapure water samples experimentally contaminated at different inlet pressures.The water samples were contaminated with oocysts of C. parvum at a concentration of 1 x 105 oocysts / liter. Initially, a pilot test was performed using the inlet pressure of 7,0 bar in the cavitation system and 10 mL samples were collected at zero time and every 10 minutes for 60 minutes, totaling 7 samples for analysis and counting of oocysts through flow cytometry and microscopy. optics. Subsequently, the tests were carried out using the inlet pressures of 1,0, 3,0 and 5,0 bar and the oocyst concentrations were counted in the flow cytometer, since this was shown to be effective in quantification. The results obtained demonstrated a reduction in the amount of oocysts in all the pressures used when compared to the control reaching 73% removal of oocysts of C. parvum. The inlet pressures of 3,0 and 5,0 bar presented a first-order kinetics model relating the reduction in the concentration of oocysts and time of exposure of the samples to hydrodynamic cavitation. The inlet pressure 3,0 bar showed a higher coefficient k (0.01677). These results demonstrate that the hydrodynamic cavitation system is a promising alternative in the removal of oocysts of C. parvum with possibilities for the treatment of water on a small or large scale.