Membrane Processes Treatment and Possibility of Agriculture Reuse of Textile Effluents: Study Case in Tunisia

Several processes have been developed to treat the textile effluents. Membrane technologies are among the most reliable processes for purifying these effluents. However, due to high costs, only reduced quantities are being treated. The recycling practices of treated textile effluents (TTE) in agriculture have not been appropriately explored. This work evaluates the quality of waters treated by membrane processes and puts forward a scenario for optimizing TTEs in agriculture. Four types of TTE have been tested to irrigate <i>Sesbania bispinosa</i> plants: water from biological treatment (BT) and water from three membrane processes after BT (Ultrafiltration (UF), Nanofiltration (NF), and Reverse Osmosis (RO)). The results indicate that the NF and RO membranes have a high affinity to remove monovalent and multivalent ions. Indeed, the removal of SO₄²⁻, Na⁺, and Cl⁻ by NF was 83, 61, and 55%, respectively. Thus, the RO reduces approximately 96% of these elements. Irrigation with NF and RO waters has no negative effect on the soil and <i>Sesbania</i> plants, contrary to BT and UF waters. It appears that the reuse of TTE resulting from BT is not a good alternative; however, by carrying out additional treatments by NF and RO, their reuses have been made possible. The achieved results are a proposal to simultaneously solve three major problems affecting most of the world’s population: (1) environmental pollution by reducing the discharge of untreated textile effluents and improving the quality of this discharged water; (2) the pressure on water resources in the agricultural sector by replacing a conventional resource with a non-conventional resource (TTE); and (3) the lack of fodder, especially in the summer, by opting for crops that adapt to the quality of these TTE.