Coupled bio-solar photocatalytic treatment for reclamation of water polluted with pharmaceutical and pesticide residues: Impact on tomato irrigation

Abstract

Reusing reclaimed water for crop irrigation can mitigate water scarcity in agriculture; however, contaminants such as pharmaceuticals and pesticides in wastewater pose risks. This study investigated the impact of a coupled bio-solar photocatalytic treatment on the reclamation of water polluted with seven pharmaceuticals and seven pesticides for irrigation of two tomato crop cycles. Pollutant residues were removed using natural sunlight and TiO₂/Na₂S₂O₈ in a pilot plant located in Murcia, Spain. Efficient removal (> 96 %) of all target pollutants was achieved in the effluent after coupled treatment. Reclaimed water was then used to irrigate the tomato crops, and several yield and quality parameters were analysed to evaluate the effects on the harvested tomatoes. No significant differences were observed in the total yield, number and mean fruit weight, size, pericarp firmness, external colour, and nutritional data between the crops irrigated with reclaimed, control, and polluted water. However, differences in the degree of ripeness were observed. None of the investigated pollutants was detected above the limit of quantification in tomato samples irrigated with reclaimed water, except for venlafaxine (0.028 µg kg⁻¹) in the second crop cycle. When the crop was irrigated with polluted water, different pollutant residues were detected in soil (10) and tomato (4) samples. The results suggest that coupled bio-solar photocatalytic treatment is an effective method for reclaiming water polluted with pharmaceutical and pesticide residues, and the reclaimed water can be safely used for tomato irrigation without compromising crop yield and quality.