Effects of reclaimed wastewater irrigation on soil and tomato fruits: A case study in Sicily (Italy)

The study aims to investigate the effects of reclaimed urban wastewater for irrigation on tomato fruit quality and hydrological soil behaviour. Tomato plants were drip and sub-drip irrigated under field conditions during the 2004 growing season in Eastern Sicily (Italy). Different drip and sub-drip laterals and filtering technologies were tested during the trial; the most suitable irrigation technology was identified by data processing including emission uniformity, flow reduction and filter performance computations. The hydraulic properties and microbial soil contamination were determined before and after wastewater application. Tomato crop production quality and microbial plant contamination were investigated during the trial. Wastewater application resulted in increased microbial contamination (Escherichia coli 3 × 103 MPN/100 mL; Faecal Streptococci 1.2 × 103 MPN/100 mL) on the soil surface. A disturbed layer of soil was observed characterized by reduced soil porosity and a consequent decrease in water retention and hydraulic conductivity. The negligible microbial contamination of fruit and washing solution (up to 40 MPN/100 mL) suggested that the treated wastewater can be used as a valid alternative for irrigation of tomatoes.