Science Forums 2

[Monomer]

More on desalination...

Australia is now paying more attention to desalination and the number of desalination plants in Australia is increasing. There are however a number of drawbacks, including:

• high costs
• high energy consumption
• the generation of large volumes of hyper-saline brine which is often discharged to the sea.

CSIRO is searching for alternative energy sources to run these plants and developing methods to avoid discharging the hyper-saline waters into the sea.

CSIRO’s research and development work focuses on:

• developing clever membrane technologies to improve the efficiency of desalination
• identifying major industrial waste heat sources and developing symbiotic technologies to recover heat and electricity needed for the desalination plants
• extracting mineral salts and extra water from the hyper-saline discharge waters.

Potentially salt may be extracted from the hyper-saline brine left after desalination. This could significantly reduce the area of land required for salt evaporation pans.

Hyper-saline waters can be converted into higher value products such as:

• caustic soda – for the alumina industry
• sodium cyanide – for the gold industry
• sodium hypochlorite – bleach
• polyvinyl chloride – PVC
• titanium tetrachloride – for titanium pigment and titanium metal production
• hydrochloric acid – a common minerals acid widely used by all industries.

Bitterns – the liquid remaining after the salt has been removed from the sea water – can also be converted into valuable products for use in:

• waste water and sewage treatment
• scrubbing sulfur dioxide and sulfur trioxide
• making light-weight flame retardant panels and boards
• Epsom salt production for horticulture
• refractory bricks for industrial furnaces
• magnesium metal production.

Bitterns also contain valuable potassium, bromine and lithium salts.

Desalination with zero sea discharge (Profile - Project)