Peracetic Acid as alternative oxidant treatment

FLORES, MARINA J.; NIERES, PABLO D.; CASSANO, ALBERTO E.; LABAS, MARISOL D.

San Diego, California

Conferencia; The 17th International Conference on Advanced Oxidation Technologies for Treatment of Water, Air and Soil (AOTs-17); 2011

Redox Technologies

According to World Health Organization (WHO) more than 1100 million people have not access to improved water supply and sanitation. The problem is especially concentrated in underdevelopments countries. The first aspect is related not only to the removal of potentially pathogenic agents, but also to the control of potentially dangerous disinfection byproducts (DBPs). Commonly, several oxidants with disinfection power such as ozone, chorine and chlorine dioxide have been applied in water disinfection techniques but it is known that neither of them are free from some of the important drawbacks such as lack of residual disinfection, toxicity, poor germicidal activity, damaging aquatic life, formation or undesirable by-products, high cost or operational limitations. In this work the use of peracetic acid (PAA) as an alternative oxidant treatment was studied. Peracetic acid finds increasing use in the recent years because of its ecologically positive properties and it relative low cost. Additionally, it is characterized by its easy technical preparation and its environmental benefits (the reaction products are oxygen, water, and acetic acid). However, the most remarkable attributes of PAA are the broad spectrum of activity even in the presence of heterogeneous organic matter, absence of persistent toxic or mutagenic residual byproducts, no quenching requisites, small dependence of pH, short contact time requirements and effectiveness for primary and secondary effluents. This high efficiency is due to its ability to generate strongly oxidant chemical species such as , the superoxide radical or its conjugated base  and the hydroxyl radical . It is suggested that PAA disrupts the chemiosmotic function transport of the lipoprotein cytoplasmic membrane through dislocation or rupture of cell walls. Furthermore, intracellular PAA may also oxidize essential enzymes; thus vital biochemical pathways, active transport across membranes, and intracellular solute levels are impaired. It was also demonstrated that PAA acts on the bases of the DNA molecule. This study was aimed at evaluating the disinfection efficiency of the PAA commercial solution (15%) with the usual indicator of fecal contamination, Escherichia coli. The disinfection aptitude of PAA was studied at different concentrations (1,1.5, 2, 3 4, 5, 6 mg / liter) as well as various inactivation times. The reacting system used in all experiments was an annular, well-mixed batch reactor having a total volume is 2000 cm3. The reactor had a cooling jacket connected to a water bath to maintain the system at a constant temperature of  20 ° C. Strong mixing conditions were achieved with a specially designed device.    The feasibility of PAA for water efficient water disinfection has been verified in this work: a 99.99% reduction of  E. coli  C.F.U. was achieved, with doses ranging from 1 to 6 mg/L and 5 minutes of contact time. A kinetic disinfection mechanism is proposed to explain the obtained results.