Salt-Based Cooling and Wastewater/Brine Reuse by Photo-Electrodialysis for Hydroponic Greenhouses

The application of farming in greenhouses with low energy consumption is of utmost importance in Qatar, as it allows for the cultivation of a wide variety of crops and reduces reliance on imports, contributing to food security and self-sustainability. Significant amounts of energy are required to lower the air temperature to levels suitable for optimal plant growth within the greenhouse. In arid climates such as Qatar's desert region, the process of cooling greenhouse environments is particularly energy intensive. Conventional cooling methods often require substantial energy inputs, which can strain the available resources. Finding sustainable and efficient cooling solutions is crucial for the long-term viability of greenhouse farming in such environments. Simultaneously, water scarcity is a pressing concern in arid regions, including Qatar, making efficient water management essential for agricultural practices. Access to clean water sources can be limited, and utilizing available water resources effectively becomes a mandatory aspect of sustainable farming. To address these challenges, a salt-based cooling process that leverages endothermic reactions is proposed. Endothermic salts, when dissolved in water, absorb heat from the surrounding environment, leading to a cooling effect. By utilizing these salts in greenhouse cooling systems, the energy required for lowering the temperature can be significantly reduced, making the process more sustainable and cost-effective. Additionally, the project aims to tackle the water demand issue by incorporating wastewater recovery through the innovative photo-electrodialysis (PED) process. PED is a technique that harnesses the power of solar energy to facilitate an electrochemical procedure. This process effectively eliminates contaminants from wastewater while also reclaiming valuable nutrients like nitrate, phosphate, and potassium. By this way, the treated water becomes suitable for reuse in agricultural activities and decreases fertilizer demand. This process not only provides a sustainable water source for greenhouse irrigation but also generates hydrogen gas as a by-product, which can be utilized for other energy applications. The ultimate objective of this project is to achieve self-sufficiency in meeting food requirements without relying heavily on external sources. By implementing salt-based endothermic cooling and wastewater recovery through PED, the greenhouse farming industry in Qatar can significantly reduce its energy consumption, effectively manage water resources, and move towards a more sustainable and self-sustaining agricultural model. This not only contributes to Qatar's food security goals but also serves as an example of sustainable farming practices for other arid regions facing similar challenges.

Hamad Bin Khalifa University (HBKU)