Forum: Eye on new desalination process to meet water demand

According to the website of national water agency PUB, Singapore's total water demand by 2060 could almost double from the 430 million gallons (1.63 million cubic m) a day now.

Newater and desalinated water will meet up to 85 per cent of Singapore's future water demand (A watertight pact with Malaysia, March 10).

Countries such as Algeria, Saudi Arabia and Israel produce their own desalinated water.

We may not produce the quantity that a country such as Saudi Arabia does with the conventional, high-energy- consumption reverse osmosis process using polymer membrane filters, because polymers cannot handle a diverse mix of contaminants. The cost would be prohibitive.

Fortunately, there is an opportunity for us to adopt a new graphene-based desalination process to meet water demand.

Graphene could change the seawater desalination process drastically. The material comprises a honeycomb sheet of carbon just one atom thick. It has a unique microscopic structure where the channels allow only pure water molecules to pass through while rejecting bigger particles of contaminants.

The unique feature of a graphene-based filter is its physicochemical properties, tolerant of chlorine, acid, oil and high temperature, to name a few.

It is relatively cheap to produce and an ideal candidate for purification.

Moreover, the new desalination process consumes at least 50 per cent less energy.

Graphene-based membranes have the potential to become next-generation membranes with high permeability to high selectivity. However, they are not commercially available yet.

The industry has been working to meet other criteria to deliver improved cost-to-benefit ratios in the modern desalination process. Before 2060, I hope the process will be widely commercialised.

Paul Chan Poh Hoi

Join ST's Telegram channel and get the latest breaking news delivered to you.