A two year experiment, to study the feasibility of wastewater reuse for a safe irrigation in the Sicilian context, has been initiated. Eight plots in two fields, totalling 629 m2, were planted with cowpeas (Vigna unguiculata L. Walp.), the irrigation water being supplied by a pilot plant treating 22 m3/day of municipal wastewater. The plant consists of an extended aeration biological system followed by rapid sand filtration and a choice of disinfection systems.
Analyses performed on all waters used in the experiment indicate that safe irrigation water, virtually pathogen-free, can be produced if careful operational techniques are adopted. Despite all possible care, however, soil samples taken throughout the growing season revealed cross-contamination problems, even in the plots irrigated with city water. Analyses were also performed on plants and beans collected over 17 successive harvests.