Turin makes waves with low-cost desalination tech
Engineers in Turin have discovered a low-cost technology to turn seawater into drinking water using solar energy.
The team from the Department of Energy of Politecnico di Torino has devised a new prototype inspired by plants which desalinates seawater in a sustainable and low-cost way, using just solar energy.
Turin is home to a growing water management research centre, including Politecnico di Torino’s Clean Water Center, which aims to design and advance innovative water and wastewater treatment systems using alternative energy sources. The Italian city is also home to Hydroaid, a non profit association focussed on the field of water resources management. Established in 2001 in Turin, it was granted special consultative status with the United Nations Economic and Social Council (UN ECOSOC) in 2011, an important recognition of its contribution in water management issues.
The proposed technology does not use expensive pumps and mechanical components, and does not require specialised technicians for installation and maintenance. It is therefore being touted as an attractive option for isolated coastal areas in developing countries with limited infrastructure and investment, and a shortage of drinking water.
“Inspired by plants, which transport water from roots to leaves by capillarity and transpiration, our floating device is able to collect seawater using a low-cost porous material, thus avoiding the use of expensive and cumbersome pumps. The collected seawater is then heated up by solar energy, which sustains the separation of salt from the evaporating water. This process can be facilitated by membranes inserted between contaminated and drinking water to avoid their mixing, similarly to some plants able to survive in marine environments, for example mangroves,” explains Matteo Fasano and Matteo Morciano.
‘Passive’ technologies for desalination such as this have formerly been limited by low energy efficiency. However, researchers at Politecnico di Torino have looked at more efficient management of the absorbed solar thermal energy, through the ‘recycling’ of solar heat in several cascade evaporation processes.
The prototype has been tested directly in the Ligurian sea (Varazze, Italy), reaching record values of productivity up to 20 litres per day of drinking water per square meter exposed to the sun.
The researchers are continuing work within the Clean Water Center and are now looking for possible industrial partners to make the prototype more durable, scalable and versatile. Other applications could include: providing safe and low-cost drinking water in emergency conditions, for example in areas hit by floods or tsunamis and left without electricity or running water; use in floating gardens for food production; or treating the intrusion of saline water into freshwater aquifers, a particularly serious problem in some areas of Southern Italy.
Published Date: 07/01/2019