Initial Steps of Microbial Colonization and MIC of Drinking Water Network

INICIAL STEPS ON MICROBIAL COLONIZATION AND CORROSION ON DRINKING WATER NETWORKS

Blanca Rosales, Manuela Pujol and Elena Rastelli

CIDEPINT / CIC-CONICETAv. 52 entre 121 y 122, (1900) La Plata, Argentina
ABSTRACT

Different materials are being used as substratum in an experimental loop to study the microbial population deposited from the La Plata city drinking water. The colonisation and corrosion of pure and commercial metals forming these systems is used to analyse the microbial effect on network pipes of iron, zinc and copper. High purity samples are simultaneously tested as reference metals and polyethylene is used as non metallic base for microbial deposition. In a second identical loop As⁺⁵ will be added to the flowing water in concentrations higher than suggested by the Health Word Organisation as sanitary safe limits. This ion effect on the microbial population as on the other parameters controlling the operation in the water treatment plant during the distribution service will be established. Bacterial extracellular polymeric material (EPM) will also be analysed in connection with any selective As ion fixation mechanism on biofilms grown on the different substrata. The electrochemical effect on this mechanism will be focused in the light of the metallic as compared to the polyethylene substratum. Results will help to select the best As elimination process from the tubing inner deposit preventing this dangerous contaminant to re-enter the water circulating in untreated networks.