Engineering new ways to treat dirty water

University of Canterbury engineers plan to 3D print the next generation of wastewater treatment filters.

Researchers have $3 million and three years to come up with some new ways to clean up wastewater.

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The project - Clean Water Technology for restoring Te Mana o te Wai - is led by ecological engineer Aisling O'Sullivan, who also leads CELTS, the Centre for EcoLogical Technical Solutions, at the University of Canterbury.

The team includes 3D printing and product design expert Tim Huber, from the university's School of Product Design, Ricardo Bello-Mendoza, works with wastewater in the area of humanitarian engineering and researchers from six other institutions.

Current technology

In September 2020, new rules and regulations were introduced as part of the Government's Essential Freshwater package of reforms. Water treatment plants are now required to bring their facilities up to standard to meet the more stringent water discharge guidelines.

"Currently around 60 percent of municipal water treatment facilities that discharge to inland waterways would not meet the new regulations," says Aisling.

"Our aim is to better enable them and other industries to tackle water pollution issues in a more reliable and sustainable way."

At the moment, wastewater treatment plants use filters made from activated carbon or plastic biofilm carriers to treat wastewater. These plastic filters end up in landfill.

Developing new technology

"Our goal," says Aisling, "is to create the next generation of water treatment media, that are sustainable, that are not made from plastic, and that are going to be able to circumvent the limitations associated with filters currently."

The project is focusing on nutrients, especially nitrogen and phosphorous, along with heavy metals and pathogens, and the new filters will accumulate and immobilise these from the wastewater.

Aisling and the team plan to biofabricate the new filters using 3D printing and additive manufacturing.

"We can use a precise recipe of the materials we use - and some of those materials will be waste resources that we'll reuse," says Aisling. "We'll also be able to manipulate the shape of , the porosity of them and the chemical recipe on the outside."

Tim has experience in printing very complex 3D structures that create interesting flow patterns. He says that the key will be making structures that are very porous, as this will offer a very large surface area and increase the amount of nutrients that can be absorbed…

Go to this episode on rnz.co.nz for more details