How to reduce water consumption in dialysis machine design

Water treatment systems using forward osmosis are already drastically reducing water consumption in a range of applications. Doing the same in hemodialysis could significantly increase the sustainability of this essential treatment.

It’s no secret that hemodialysis consumes a huge amount of water. At the Dialysis Department at the University Hospital of Copenhagen, Denmark, which has around 250 patients, water consumption is 10 million liters (around 2.6 million gallons) a year – 5-10% of the hospital’s entire water budget. It’s no wonder, therefore, that the hospital’s Board of Directors are pushing the center to reduce water use.

“Water is a scarce resource. In order to preserve resources, dialysis systems with the ability to re-use water would be a great improvement,” says Marianne Rix, Head of Hemodialysis at the University Hospital of Copenhagen.

Using forward osmosis to reduce water use in hemodialysis

Luckily, there’s a solution. Current, hemodialysis machine designs rely on reverse osmosis to purify the water prior to treatment. However, despite its widespread use, reverse osmosis is surprisingly inefficient. In some hemodialysis centers, only half of water entering the unit is purified. The rest is discarded down the drain. In most hospitals, the spent dialysate effluent also goes directly into the sewer.

According to Esben Gad, Vice President of Business Development at Aquaporin, the solution is forward osmosis – a water treatment method that is gaining traction in a number of industries and applications. Applied to current hemodialysis solutions, Esben believes forward osmosis could reduce water consumption by at least 75%.

“Put simply, reverse osmosis applies pressure to drive water across a filtration membrane, while forward osmosis uses the natural force of osmotic pressure to pull the water across the membrane,” says Esben Gad. “Forward osmosis is gaining traction because it can provide a tighter barrier to purify water without the need for high pressure pumping. It can also improve recovery rates when cleaning dialysate effluent after treatment,”

Harnessing the natural power of aquaporins

At Aquaporin, researchers and engineers have spent more than a decade perfecting a unique membrane module that uses aquaporin proteins to filter water. Called Aquaporin Inside®, the modules are now being used effectively in a number of commercial applications.

Aquaporin proteins are present in the cells of all living organisms, from bacteria and plants to man. They facilitate rapid and highly selective water transport across the cell membrane and, due to their special architecture, they allow only water molecules to pass. All other compounds are rejected. As part of an Aquaporin Inside® membrane, they enable extremely fast and energy-efficiently water filtration.

“If integrated into existing dialysis machines, a forward osmosis water purification system using our membranes could reduce water consumption by 75%,” explains Esben. “For a buyer like the University Hospital of Copenhagen, that’s a saving of 7.5 million liters of water a year, which would be enough to turn the heads of many major decision-makers.”


If you’d like to know more about Aquaporin’s membranes and how they can help futureproof dialysis machines – including home hemodialysis applications – download our whitepaper here.


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