Application of water disinfection technologies for agricultural waters

Irrigation water is a potential source of contamination of leafy vegetables that are grown in the field. There is an urgent need to support technologies that are designed to ensure food safety, including those technologies that can disinfect irrigation water used to cultivate crops. Previous research has yet to evaluate the microbial and economic efficacies of water disinfection technologies to be applied during primary production to combat foodborne pathogens. The literature describes potential water disinfection technologies that could be applied, but studies often focus on plant pathogens and mainly focus on laboratory-scale research. In this study, ozone, UV, and membrane filtration were evaluated at the lab-scale, and UV with and without pre-filtration were examined in a field trial to determine the reduction of E. coli in surface water that is used to irrigate leafy vegetables. The cost-effectiveness and applications at the field-scale were also considered. We determined that UV treatment (300–600 J/m2) reduced E. coli up to 3 log in irrigation water. In the lab, we found that ozone, UF, and combined disinfection technologies reduced E. coli up to 4 log. The cost calculation for UV disinfection (0.09 €/m3) showed to be less than that of ozone (0.36 €/m3) and UF (0.43 €/m3). Overall, UV was found to be the most feasible disinfection technology in terms of microbial and cost efficacies to treat surface water used for the agricultural irrigation of crops. The outcomes of this research can provide input into the minimum requirements needed for water disinfection technologies considering the use and reuse of agricultural waters.