Mas Agua Para Todos
Adapting to CC and Mitigating Water Scarcity by Innovative UWM in Cuba

Result 1

Integrated use of saline water as secondary quality water in the Cuban urban water cycle

Saline (sea and brackish) water is the biggest world water reserve (making up to 96% of total world water reserves whereas fresh water reserves comprise 4%, from which only 0.08% can be reachable and usable). Since only a minor fraction of drinking water is used for human consumption (2-3 L out of a water consumption of 600 to 1000 L per person per day in Cuban urban environments) and a lavish part is used for the conveyance of human wastes (e.g. excreta), the direct use of seawater or brackish water for toilet flushing, and other non-potable uses, can lead to a more efficient water usage by reducing fresh water demand.

The pioneer in innovative demonstration of large-scale use of seawater in urban sanitation is Hong Kong, revealing the enormous potential of seawater as a source for toilet flushing and other non-potable uses in water-poor urban coastal areas as a means towards sustainable water cycle management. The success of this innovative management approach is further enhanced by the development of the SANI wastewater treatment process (which stands for Sulfate and Autotrophic Nitrogen removal Integrated). The SANI system is able to treat saline wastewater achieving (i) high organic matter and nutrient removal efficiencies, (ii) lower energy requirements, (iii) minimized green house emissions, (iv) lower sludge production and (v) relatively higher fecal coliform removal.

Through the pilot-scale demonstration of the SANI system developed by Hong Kong University of Science and Technology (HKUST) and Delft University of Technology (TUDelft) and building up on a worldwide consortium on the use of saline water as secondary quality water in urban environments led by UNESCO-IHE (SALINE project ), this result contributes to protect the environment in a cost-effective manner, allowing to implement and support fresh water saving practices through the replacement of fresh water by saline seawater or brackish water for sanitation purposes (toilet flushing), but also providing an efficient treatment to municipal wastewater streams with higher salt contents due to seawater intrusion into the sewerage network, a common problem in Coastal regions.

Seawater Intake System in Hong Kong for household use