While Algeria wants to increase the proportion of its drinking water supplied by desalination to 50% by 2030, it also wants to reduce the environmental impact of this practice, which is reputed to be extremely energy-intensive. This is why Energy Recovery recently placed an order for PX® pressure exchangers. The energy efficiency technology supplier, based in California in the United States of America, has won a contract worth 28 million dollars.
Under the contract signed with the Algerian government, the PX® pressure exchangers are to be delivered by the end of 2023. The equipment will be installed in all the North African country’s seawater desalination plants, which are expected to have a capacity of 3.6 million m3 per day, for 19 installations by 2024.
PX® technology will “reduce energy consumption in desalination by up to 60% and offer the lowest life cycle cost of any energy recovery device on the market”, says Energy Recovery. This will enable Algeria to move towards less energy-intensive and more sustainable desalination.
Energy Recovery’s PX® pressure exchangers installed in a wastewater treatment plant©Energy Recovery
Theoretically, the energy bill for desalination depends on the process used. Distillation is a thermal process in which salt water is heated in a boiler to recover fresh water. This technique requires up to 15 kWh per m3. The reverse osmosis process, on the other hand, requires between 2.5 and 3 kWh per m3. This other method involves applying pressure to a volume of salt water through a semi-permeable membrane that retains the salt and other impurities.
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Energy Recovery estimates that these PX units will also prevent more than 560,000 tonnes of carbon dioxide equivalent (CO2) from entering the atmosphere each year, the equivalent of taking around 120,000 passenger cars off the road.
Inès Magoum