Reclaimed wastewater from constructed wetland as an alternative water source for agriculture: effect on agronomic traits on tomato (Solanum lycopersicum L.) and lettuce (Lactuca sativa L.) crops

Due to global warming, a reduction in the availability of water is expected everywhere around the world. To face this challenge, it is necessary to develop strategies for saving and reusing treated wastewater. This is a priority, especially in agriculture, and in particular for vegetable crops that require a higher amount of water compared to other crops. During 2022, reclaimed wastewater of a hybrid constructed wetland (horizontal subsurface unit followed by free water surface unit), used for tertiary treatment of effluents from a farmhouse located in Eastern Sicily, was reused by micro-irrigation techniques to irrigate vegetable crops. The effects of domestic wastewater treated with a hybrid constructed wetland (CW) were evaluated on tomato (Solanum lycopersicum L.) and lettuce (Lactuca sativa L.). The seedlings of both crops were transplanted adopting the split-plot experimental design: the main plot was split in reclaimed water, reclaimed water treated with UV and groundwater; each of them was split into three sub-plots represented by the type of dripline utilized: the driplines “blue” and “yellow” are treated with two different antimicrobial compounds otherwise the “green” driplines are untreated as control (provided by Irritech®). Finally, the subsub-plot was represented by the genotype: 'Big Rio' and 'SV8840MT' for tomato, and 'Gretta Erre' and 'Gardenia' for lettuce. All combinations of the experimental factors were replicated three times for both crops. Significant differences were observed for both cops due to the water used for the irrigation and the typology of the dripline adopted.