How can municipalities around the Oslofjord meet stricter environmental requirements, connect new housing to an overstretched wastewater system, and at the same time limit rising costs for residents? This was discussed on 25 August, when KRED-NMBU and Ås Municipality brought together around 60 participants for a co-creation meeting at Ås Cultural Centre.
The Oslofjord faces major environmental challenges, while municipalities are preparing billion-kroner investments in water and wastewater infrastructure. The dominant approach has been to collect wastewater in larger, centralised treatment plants. The meeting explored whether decentralised and source-separated solutions could also contribute to lower energy use, better resource utilisation and reduced costs.
The Oslofjord as a testing ground
The Mayor of Ås, Bengt Nøst-Klemmetsen, opened the meeting by emphasising the need to develop and test new wastewater solutions. Ås is planning a five-year pilot project starting in 2027, in collaboration with NMBU and the business sector, with the aim of treating wastewater as a resource while contributing to climate, food and supply security.
NMBU’s Pro-Rector for Research and Innovation, Erik Trømborg, described the Oslofjord as “a world in miniature”, where population growth, land-use development, climate change, agriculture and wastewater are closely interconnected. He also highlighted the importance of bringing researchers, municipalities, residents and businesses together to develop solutions.
Can wastewater become a resource?
NMBU Professor Arve Heistad highlighted challenges in today’s wastewater systems, including leakage, overflows and infiltration of rainwater. He presented source separation as one possible way to reduce pressure on treatment plants while recovering valuable nutrients.
Urine makes up only a small proportion of wastewater but contains a large share of its nitrogen and phosphorus. If these nutrients can be recovered locally, they could potentially be reused, including as fertiliser. Heistad also called for more knowledge about which measures actually produce the greatest environmental benefits for the Oslofjord.
New technologies are already being tested at Søndre Follo Wastewater Treatment Plant. General Manager Geir Ove Simensen presented, among other things, membrane technology aimed at reducing energy and land requirements. Georg Finsrud, Chief Technology Officer at Scanwater, also presented source-separation and mobile treatment solutions developed in collaboration with NMBU.
“Someone has to be first”
A key discussion concerned the risks of testing new solutions. Municipalities need action now, but are also reluctant to make major investments in technologies that may not deliver the expected results.
Several participants argued that this risk should be managed through pilot projects, documentation and evaluation rather than by waiting for others to take the first step.
“We have to dare to try and make room for those who have good solutions that are affordable for all residents,” was a central message from Søndre Follo Wastewater Treatment Plant.
Municipalities need real choice
The political discussion also focused on how much freedom municipalities actually have to choose alternative solutions. Bengt Nøst-Klemmetsen and Gunvor Eldegard from Akershus County Council emphasised that municipalities should be able to choose their solutions as long as environmental requirements are met.
At the same time, a lack of expertise and capacity was highlighted as a challenge. Many municipalities depend on external consultants, who may favour established solutions when deadlines and sanctions create a high level of risk.
Participants therefore called for better support for pilot facilities and stronger public-sector expertise in wastewater technology.
From waste to resource
The meeting also explored how wastewater can become part of more circular systems. Recovering nutrients from wastewater could allow them to be reused, including in local food production.
Several participants suggested that a source-separation pilot facility in Follo could become an important showcase for new wastewater solutions and fit well with the region’s ambitions to develop an innovation district around NMBU.
The need for collaboration and action
Towards the end of the meeting, participants were asked what should happen first. Suggestions included reducing infiltration of rainwater into wastewater systems, establishing cross-disciplinary working groups, and strengthening cooperation between municipalities, research institutions and businesses.
The Oslofjord needs action, while municipalities are facing major investments in wastewater infrastructure. The question is therefore how these investments can deliver the greatest possible environmental benefits, resource efficiency and value for residents.
The meeting showed that the answer may not lie in a single solution, but in being willing to test several alternatives before billions are committed to existing technologies.