Abstract

Reuse of treated wastewater (TWW) for irrigation can be an effective strategy in Mediterranean countries to overcome the pressure on freshwater resources if its economic viability is demonstrated. In this work, the assessment of the economic feasibility of irrigation and nutrient management with TWW reuse was carried out in the citrus sector in the Souss Massa region, in Morocco. Considering the effects of TWW reuse on yields, water and fertilizer requirements, a mathematical non-linear optimization model was used to identify the optimal allocation of land and of non-uniform quality irrigation water and to assess the impacts on the economic performance of the citrus sector. Different water price and irrigation technology scenarios have been simulated. Overall results indicated that the re-use of TWW - with a current price higher than the conventional resource - must be subsidized to be proposed as a convenient alternative for irrigation. A reduction in the TWW price from its current level (0.23 Euro / m3) to a level equal to that of fresh water (0.15 Euro / m3) would encourage farmers to use TWW on 59% of the total cultivated area, leading to a 350 mm reduction in quantity of used fresh water per hectare.