Interacción de Biopelículas Microbianas con Materiales para Redes de Agua Potable

S.E. RASTELLI; B.M. ROSALES,; C.I.ELSNER ; E.M. PUJOL

Quito

Simposio; 7mo Simposium Latinoamericano de Biocorrosión, Biorremediación y Biodeterioro (7LABS); 2009

Universidad Internacional SEK

Microbial interaction was found in all industrial installation in contact with aqueous media of different aggressiveness on substrata material. Results on drinking water network materials of the most diverse chemical composition are presented. The amount and adherence of extra cellular polymeric substance (EPS) deposited strongly depends on the colonized material. It also varied according to the type and amount of the chemical substances present in the used city of La Plata city drinking water. The influence of As(V) additioned in concentrations higher than the suggested guide value by the World Health Organization (WHO) was also assessed. Amongst the metal tubing materials commercial grey cast iron, galvanized steel and hydro-bronze as compared to polypropylene to differentiate electrochemical effects were tested. Different amount of growth and aspect of bacterial deposits were noticed in the presence and absence of As(V) contaminant ion. Microbial characterization was performed using biochemical and molecular techniques. All materials seemed to stimulate different amount and phenotype colonization. Techniques applied for morphology and chemical characterization of the colonized materials were environmental scanning electron microscopy (ESEM) and energy dispersive X-ray analysis (EDX). EDX analyses revealed different information about substrata susceptibility and microbial metabolic needs. Electrochemical polarisation of the test metals was also applied for better understanding the microbial colonization and biofilm effects on each metallic sample. Surprisingly, the more than 5,000 µg/l As(V) added to the "La Plata" drinking water, did not only fail to inhibit microbial growth but on the contrary it shortened the microbial lag phase observed and increased the amount of growth. The presence of As(V) ion showed uneven effect on each material tested with different attack nucleation.