Utilization of treated wastewater derived from microalgae production for the irrigation of horticultural crops

Access to quality water is essential for agricultural production, but in many parts of the world freshwater resources are scarce and demand is high. Therefore, the use of treated wastewater for agricultural irrigation has become an increasingly relevant and promising practice. The main objective of this research was to analyse the effects of wastewater following microalgae production for use in irrigation on the growth and development of Pelargonium hortorum plants. The treatments used were: 100%NS 100% nutrient solution; 100%Wb wastewater before microalgae production; 100%Wa wastewater after microalgae production; 75%NS-25%Wa 75% nutrient solution and 25% of the wastewater after microalgae production; 50%NS-50%Wa 50% nutrient solution and 50% of the wastewater after microalgae production; 25%NS-75%Wa 25% of the nutrient solution and 75% of wastewater after microalgae production; 100%TW 100% tap water, and 2 5%TW-75%Wa 25% tap water and 75% wastewater. Pelargonium hortorum var silvia was used and transplanted into pots with a coconut fibre substrate. It was concluded that wastewater, after the production of microalgae, can be used as fertigation water, but should be supplemented with 50% nutrient solution to achieve results similar to 100% fertilization. This wastewater is rich in essential nutrients such as N, P, and K, which can stimulate plant growth compared to tap water. However, it also exhibits a high concentration of salts such as Cl and Na. These findings may have important implications for sustainable agriculture, providing an alternative for wastewater management and reuse in agricultural practices.