Small but powerful: mini desalination plants

Small but powerful: mini desalination plants

Across the world, mini desalination plants are becoming increasingly popular and helping to redefine how communities access clean drinking water – even in the most remote and surprising of places.

Desalination is the process of creating fresh, drinkable water using reverse osmosis membrane technology. The reverse osmosis process applies intense pressure to force untreated water, most commonly seawater, through semi-permeable membranes which reject salts and minerals to allow only fresh water to pass through it.

This revolutionary process is used by large-scale desalination plants like ours, the Sydney Desalination Plant (SDP), where seawater from the Tasman Sea is sourced and treated to meet Australian Drinking Water Guidelines and provide high quality drinkable water.

According to the BBC, more than 300 million people across the globe rely on drinking desalinated water.  As the demanding effects of climate change add pressure to the supply of vital resources such as drinking water, it is no surprise that the number of desalination plants globally has doubled in the past decade.

Traditionally, desalination plants are large in size, like our Plant in Kurnell which produces about 91 gigalitres of fresh water a year for residents in Sydney, about 15 per cent of supply.  Saudi Arabia is the world’s biggest producer of desalinated water, with its al-Jubail plant making more than 1000 million litres of drinking water daily, closely followed by Israel’s Sorek plant which generates more than 624 million litres of drinking water a day.

As only 0.5 per cent of the Earth’s water is fresh drinking water, larger desalination plants are increasingly being relied on to provide drinking water to large populations and cities.

But in recent years “mini desal” plants have emerged as handy sources of drinking water on farms, ships and small remote communities.

Mini desals

Mini desals are effectively scaled-down version of larger desalination plants like SDP’s. They are engineered to produce high-quality drinking water in smaller quantities – which is what makes them so perfect for remote or underserved areas.

Unlike their large-scale counterparts, mini desals are flexible, portable and durable for a range of environments, especially in regions prone to floods and droughts. They typically have capacity to generate up to 500 litres of fresh drinking water per day, can be as small as a suitcase, weigh less than 10 kilograms, and are also easy to transport, making them ideal for disaster-prone areas.

Mini desals work similarly to larger desalination plants and use reverse osmosis technology to run salty water through filters and membranes to remove unwanted substances to produce fresh water, just on a smaller scale.

On farms, mini desals can mean an inexhaustible water supply that is not dependent on the weather. The ABC examined this farm in Western Australia which uses its portable desalination system for watering stock and for spraying gardens and crops.

On most cruise ships, desalinated water is the primary water source and according to Chunke Environmental Technology, is used to cool engines, boil feed water, and for washing and drinking.  Ships in the Royal Caribbean Group, for example, produce 90 per cent of their freshwater using the reverse osmosis method.

An island in Vanuatu, which experiences increased drought and cyclone activity in the Pacific, is an example of a disaster-zone area which successfully uses desalinated water. Moerk Water create sustainable and reliable water treatment solutions and installed a solar powered system here in 2018, which meant that when Cyclone Harold struck in 2020, water production was not adversely affected.

The future looks bright with these mini powerhouses in motion.

As technology progresses and gets more advanced, we can expect mini desals to be more energy efficient, more affordable, and have the capacity to bring fresh drinking water to areas which need it most.