Inactivation efficiency of total coliforms and Escherichia coli in doped natural water by heterogeneous Fenton: Effect of process factors

The microbiological contamination of water is responsible for millions of deaths in the world annually, until now the disinfection of water has been based on the chlorination; however there is a growing concern for the formation of trihalomethanes, for this reason it was evaluated the inactivation of total coliforms and Escherichia coli (E. coli) by using the advanced oxidation process known as heterogeneous Fenton, catalysed with pillared clay, prepared by ultrasound and microwave in a semibatch reactor using as process factors the concentration of the oxidizing agent, catalyst load, pH, and the reaction time. The test of inactivation was made in natural water from “Pasto river”, this water was doped with the microorganism until a concentration of 10 6 CFU/mL, the samples were analysed by the microbiological method of membrane filtration. The results showed that the factors evaluated, have a statistically significant effect (p<0.05) in the percentage of inactivation of total coliforms and E. coli, with 95% confidence, regardless of the treatment used in the preparation of the catalyst (ultrasound and microwave). The best conditions for the inactivation of microorganisms were pH of 3.7, catalyst load of 0.5 g/L, time among 180 240 min and H2O2 concentration between 0.12 and 0.18 mg/L, allowing inactivation efficiency of coliforms and E. colibetween 42% to 75%. Received 17 Oct 2014, Revised 29 Aug 2016 , Accepted 03 Sept 2016