Research Partnership with Developing Countries
A Programme funded by Swiss National Science Foundation (SNSF) and Swiss Agency for Development and Cooperation (SDC)

Development of iron-catalyzed low-cost solar process for drinking water disinfection in rural areas from Colombia

Contextual justification of the project In Colombia, over half of the population does not have access to safe drinking water and depend on superficial water sources of high natural organic matter (NOM) content. A significant part of rural population has not access to treated drinking water and where a basic disinfection is provided, this consists in chlorination. Chlorine is effective for most microorganisms and can also oxidize some chemical pollutants, but when it attacks NOM, carcinogenic by-products, mainly trihalomethanes are generated. Key innovative proposition of this project In this project we propose to enhance the solar disinfection (SODIS) performances by adding, before solar illumination, low quantities of cheap, easy to purchase and non-toxic hydrogen peroxide. Under solar light, latter substance will react with iron salts naturally present in Colombian water sources, to produce a photo-Fenton reaction which generates a highly reactive lOH very efficient in bacteria inactivation. Scientific objective The scientific objective is to systematically study the influence of main process parameters for the system NOM/bacteria/Fe2+ or 3+/H2O2/solar light and define its potential to inactivate pathogenic microorganisms (i.e. E. coli) and oxidize natural organic matter. In particular the interactions of Fe2+ and Fe3+ with NOM (i.e. humic acids) and with bacterial cell membranes will be studied. The optimized system will be tested for simultaneous disinfection and degradation of xenobiotics such as pesticides. Engineering ecological and social durability of the helio-photo-Fenton system Based on scientific results, three different types of pilot scale reactors will be investigated under solar light. The optimized process will finally be assessed under its ecological and economical sustainability and, in close collaboration with a community based organization in a rural Colombian region; one (or several) demonstration treatment units will be constructed and tested. Expected benefit of this project The results of this study will contribute to the comprehension of iron-catalyzed drinking water treatment and its possible large application to solar water treatment. The developed technology could be adapted to other regions of Latino-America, Africa and Asia having similar issues in sunny regions. The photo-Fenton system in SODIS would be low-cost, with free solar energy and iron naturally present in drinking water. This innovative disinfection method not only kill pathogenic microorganism but also simultaneously eliminates chemical pollutants such as pesticides and limits the generation of toxic disinfection by products (DBPs).

Contacts

Dr. César Pulgarin
Groupe de génie électrochimique
EPFL - SB - ISIC - GGEC
Bâtiment CH
Station 6
CH-1015 Lausanne
cesar.pulgarin(at)epfl.ch

Luis Norberto Benítez Vásquez
Departamento de Química
Facultad de Ciencias Naturales y Exactas
Universidad del Valle
Ciudad universitaria Melendez
Cl 13 No. 100-00
25360
CO- Cali-Valle del Cauca
lubebite(at)univalle.edu.co