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Projects aim to eliminate waste from wastewater

a glass is filled with water from a faucet
Water treatment used to be primarily about protecting the environment from contaminants. Nowadays, sea- and wastewater are purified into drinking water and all parts of wastewater are to be reused. At the new pilot and demo facility in Loudden, Stockholm, new solutions for circular water treatment are being tested and developed. (Photo: Mostphotos)
Published Mar 21, 2023

The demand for water treatment is increasing throughout the world – and so is the risk of waste. Today, water treatment processes aim to protect the environment from contaminants, while recycling all parts of the wastewater.
“Requirements are constantly being tightened due to water shortages”, says KTH alumnus Östen Ekengren, who is senior advisor at IVL Swedish Environmental Research Institute.

Ekengren is currently involved in relocating the Hammarby Sjöstadverk water research facility, which is run by IVL and KTH, to new premises in Loudden, Stockholm. 

“Our water research is leading in Europe. Over the years research groups, presidents, government ministers, students and all kinds of other people have come here for study visits,” he says.

Östen Ekengren in front of a red screen in the water research facility in Loudden
Östen Ekengren is currently working on the new water research facility in Loudden ahead of its opening this spring. After doing his MSc in Chemical Engineering at KTH in 1978, Östen Ekengren began his career at IVL Swedish Environmental Research Institute, currently cooperating with KTH in water research.

At the new pilot and demo facility in Loudden, efforts will continue to develop new methods for effective water treatment and recycling.

The methods make it possible to return the treated wastewater and all nutrients to the natural cycle of nature, while energy is produced and harnessed via heat recovery, for example.

“The challenge in water supply worldwide is to establish circular water solutions. We need to go from treatment processes that simply protect the environment to creating circular solutions. Treated water in areas with water shortages needs to be of high enough quality to be reusable in agriculture, industry and people’s homes.”

Can you give some examples of circular water solutions?
“We’re running tests on the island of Gotland , where because of the shortage of water there, water has to be reused in new ways. Seawater is desalinated, and wastewater and rainwater are treated.”

Ekengren says that a housing project in Chile reuses all wastewater from housing blocks in different ways.

Water from showers, baths, kitchens and washing machines from the 240 apartments in the area is treated separately, and used to water the green spaces between the buildings. 

“When water is reused, its quality obviously has to be assured. The researchers take measurements using sensor technology so that we can guarantee safe water in the future,” Ekengren says.

Östen Ekengren portrait

Ozone and activated carbon removes toxic chemicals

He says that a lot of research today focuses on removing all drug residues and per- and polyfluoroalkyl substances (PFAS) from water as effectively as possible.

“Between 95 and 99 per cent of all drug residues in water can be removed by treating it with ozone, a process known as ozonation. An activated carbon and sand filter then captures the remaining solids.

Ekengren also emphasises that water consumption in industry needs to be more efficient.
In order to create circular processes for industrial water, a raft of collaborative projects between KTH researchers and Swedish companies in the IVL network within Sjöstadverket Water Innovation Center  are underway.

“Thanks to our new treatment processes, companies have been able to recover acids that can then be used in making stainless steel. Airports are recovering glycol from the water used to de-ice planes. Car manufacturers have found methods for pre-treating surfaces prior to lacquering and have managed to reduce water consumption by as much as 80 per cent,” Ekengren says.

“Generally speaking, all water in society has to be reused far more.”

Katarina Ahlfort
Photo: Theresia Köhlin

Sjöstadverket Water Innovation Centre, SWIC

• SWIC is a development and testing centre for sustainable, climate-efficient new solutions for municipal and industrial water.
• The centre is run by IVL Swedish Environmental Research Institute and KTH.
• The focus of the water research is to reduce levels of nitrogen, phosphorus, drug residues, PFAS and other substances using biological, chemical and physical methods.
• At the same time nutrients, metals and cleaned water are returned to the ecosystem.
• Energy is also harnessed in the form of heat recovery, for instance.

Belongs to: About KTH
Last changed: Mar 21, 2023