Rocky water source

According to scientists based in the Netherlands, gypsum could become a novel source of fresh water in desert regions.¹ 

A rocky mineral abundant in desert regions where fresh water is usually in short supply, gypsum, calcium sulfate dihydrate (CaSO₄.2H₂ O), is 20 per cent water by weight. Peter van der Gaag of the Holland Innovation Team (HIT), in Rotterdam, suggests that a macro-engineering project designed to dehydrate deposits of the mineral could release trillions of litres of clean water suitable for drinking and irrigation purposes in desert regions.  

The dehydration process requires energy, but this is not in short supply in deserts, where sunlight is abundant, and in many cases fossil fuel deposits are mined and energy wasted as unwanted gas is flared on oil and gas fields. Van der Gaag explains that it takes only moderate heating to liberate water from gypsum, converting the mineral to its anhydrous form anhydrite. 'Such temperatures can be reached by small-scale solar power, or alternatively, the heat from flaring oil wells could be used', he says. 'And dehydration under certain circumstances starts at 60 Celsius, goes faster at 85 Celsius, and faster still at 100 degrees'.