The AGRISOL project will test the scientific hypothesis that solar-powered desalination of brackish water by means of newly developed nanofiltration (NF) membranes is a technologically and economically sustainable solution to the irrigation challenges typical in rural areas that lack freshwater but that have access to brackish water sources.
The project entails several innovative solutions in terms of the state-of-the-art in the field:
NF membranes for brackish water desalination operate at pressures around 4 bars. This pressure is much lower than that typically used (15 bar) in reverse osmosis (RO). We expect a reduction in energy consumption of about half and improved economic viability compared to state-of-the-art RO desalination systems;
The desalination unit is designed bearing in mind the requirements of the crops. NF membranes are characterized by lower salt retention with respect to RO, but the range of concentration of Na and Cl in NF permeate is suitable for high crop yields. The proposed design will maximize the concentration of crop micro-nutrients such as calcium and magnesium in the permeate, eliminating the need for further addition of such nutrients;
The study is the first to investigate the potential of combining the state of the art in membrane desalination with solar energy technology for use in agriculture;
An innovative solution for brine disposal is tested, consisting in growing commercially valuable halophytes with the desalination brine. A serious concern in inland desalination is thus transformed into a potential economic advantage;
The wider diffusion of solar desalination systems has thus far been limited by a lack of long-term monitoring. In this project, we will continuously operate and monitor two solar desalination systems for two years.