Microalgae Cultivated in Industrial Wastewater as Agricultural Bioinputs: Technical and Life Cycle Assessment to Support Sustainable Production

This study evaluated the technical and environmental feasibility of using wastewater-cultivated microalgae biomass as a nutrient source for tomato plants. A field experiment tested different foliar application doses of microalgae biomass (control, 0.5%, 2.5%, 5%, and 10%) on tomato plants. Postharvest analysis of eight plant and fruit parameters showed no significant differences among treatments. Environmental feasibility was assessed through life cycle assessment, comparing a baseline scenario (mineral fertilizer) with an alternative scenario in which microalgae biomass was used as both a nutrient and water source. The Ecoinvent database and ReCiPe 2016 methodology were applied at both midpoint and end point levels. The alternative scenario demonstrated reduced environmental impacts across all 18 midpoint categories, including substantial reductions in water consumption (107.43%) and ionizing radiation (53.54%). At the end point level, the baseline scenario had 23.05% higher impact in the human health category than the alternative.