Low-energy greywater treatment and urban greening using green walls

In the water-scarce Middle East, particularly in Qatar, urbanization heavily relies on energy-intensive desalination. This research explores an innovative solution: integrating greywater treatment within vegetated green walls for sustainable urban greening. By combining the biofiltration power of plants with the adsorption properties of green wall media, this approach aims to purify lightly polluted greywater from buildings for reuse in landscaping, cleaning, or even non-potable applications. The research delves into several key areas: (i) identifying hardy, attractive plants that thrive in the Qatari climate and greywater (ii) testing lightweight media that excel in drainage and plant support, with the possibility of using local waste for added sustainability and (iii) evaluating the treatment effectiveness of various plant-media combinations under various experimental conditions. This study also assesses the real-world feasibility of the system through a pilot-scale outdoor green wall, demonstrating its potential to reduce desalination dependence, enhance water security, and contribute to a greener, more sustainable urban landscape in the Middle East.