Abstract

The irrigation water used by Chilean producers must fulfill both national and international quality standards. However, producers are constantly facing microbiological quality problems in the irrigation water, mainly fecal bacteria in the irrigation channel network. Photocatalysis using titanium dioxide (TiO 2) activated by solar radiation is an alternative to conventional water detoxification and disinfection technologies. Many publications show that this technique is effective, harmless, and has a low cost, but there are no reported applications for agricultural waters. The main focus of this research is the application of heterogeneous solar photocatalysis to decrease the microbiological load in irrigation water using a photocatalyst (TiO 2) activated by sunlight UV radiation and supported in concrete mortar that could be used as a channel's lining. Laboratory tests were made in static reactors of low volume, in addition to tests done in controlled conditions of operation in a prototype channel of 104 m in length. Low volume tests showed up to 100% removal for Escherichia Coli ATTCC 25922, with cumulative radiation energy of 1500 J/L, which allow the fulfillment of irrigation water quality standards. For the prototype channel, removal was 85% at 50 m and 90% at the end of the channel. These preliminary results indicate that the use of this technology in the irrigation water disinfection is feasible and low cost. Nevertheless, it is necessary to advance in the development of a design methodology for real-scale applications in a Good Agricultural Practices framework. © 2009 American Society of Agricultural and Biological Engineers.