New Kinetic Modeling for Water Disinfection Using Commercial Peracetic Acid (PAA)

FLORES, M. J.; BRANDI, R. J.; CASSANO, A. E.; LABAS, M. D.

San Diego

Congreso; The 20th International Conference on Advanced Oxidation Technologies for Treatment of Water, Air and Soil (AOTs-20).; 2014

To study the synergism between de HP and PAA present in the commercial mixture, experiments were carried out using dilutions of the unmodified mixture, and the same composite but HP inhibited. Also, experimental tests were performed using only HP as disinfectant agent. In all experiments, a well-stirred batch annular reactor having a total reaction volume of 2000 cm3 was employed. For the experimental runs PAA commercial mixture (PAA 15% v/v; Hydrogen Peroxide 20%; acetic acid 25% and water 40%) was used. It is important to study separately the effect of the two oxidizing components of the mixture. Inhibition of hydrogen peroxide was achieved using catalase (from Aspergillus niger), allowing in this way the study of the efficiency of PAA alone. Escherichia coli strain ATCC 8739 was used throughout this work. In this study, a model is proposed which explains all these different behaviors. In the first place, it represents in detail the performance of HP and PAA acting alone. When the behavior of both disinfectants was evaluated separately, it was found that the mixture is much more efficient than HP and PAA acting alone. Furthermore, it was found that PAA without hydrogen peroxide is much more efficient than HP alone. It is shown that disinfection requires an initial chemical change that can be named ?chemical sensitization action?, to disrupt the first resistance of the bacterium cell. A kinetic scheme inactivation process for E. coli was developed. With the experimental results was possible to model each stage to explain the synergistic effect between APA and HP in the commercial mixture.We are currently exploring the addition of extra HP to the commercial mixture to analyze an even greater synergistic effect.