Sustainable Decentralized Urban Water and Wastewater Treatment in Off-grid Areas of Developing Countries Using NbS and Integrated Green Technologies

The harsh impacts of climate change, once considered a myth by the masses, have become a reality. Each year we are observing the problems of extreme weather and natural disasters, and among the most vulnerable countries lie the developing countries, like in the sub-continent region (including Bangladesh, India, Pakistan, and Yemen) or the African region (Angola, Benin, Burkina Faso, Burundi, and the Central African Republic). Despite the rapid growth of these regions economically and in terms of population, the shortage of affordable and effective urban water and wastewater treatment remains a critical problem. It is mostly due to a lack of resources for proper treatment facilities, which leads to the spread of oral-fecal diseases. The nature-based systems have the market potential for water utilization and implementation in permitted water environments (irrigation systems), for the generation of bioenergy in closed loops (circular economy), resource recovery and ornamentation, and other beneficial ecosystem services, e.g., pollinators attraction from plants. Further, they can be used for stormwater management, flood protection and risk management, implementation of blue-green infrastructures, urban water in food, water, and energy ecosystem, and urban water pollution control.