top of page

Start of operations for first full-scale denitrifying bioreactor for mine drainage treatment  

19 September 2018: the first liters of nitrate-laden drainage water started to flow through a denitrifying bioreactor at LKAB’s Kiruna iron ore mine. The bioreactor, which is the first full-scale bioreactor system for the passive removal of nitrate from mine drainage, promotes the conversion of nitrate to harmless nitrogen gas. Nitrate is derived from the use of explosives in the underground mine, and environmental regulations require the LKAB reduce nitrogen discharges to the surface water environment.


The NITREM bioreactor was developed in a previous pilot-scale study conducted in the Vinnova-financed project miNing.

“My doctoral student Albin Nordström and I have worked in Kiruna for two years with a pilot-scale plant to remove nitrogen from process water,” says Roger Herbert. “This bioreactor worked so well both for us and for LKAB that we decided to seek funding to develop a full-scale plant for the treatment of waste rock leachate.” 

The NITREM project has had an intense start-up period since April 2018 when a water collection system and a group of three bioreactors were designed at LKAB in Kiruna, Sweden. At present, the water collection system and one bioreactor is in operation; the remaining two bioreactors will be completed during the fall of 2018. The performance of the bioreactor will be monitored until the end of the project period in 2021.

The bioreactor construction is part of the upscaling project NITREM that is primarily funded by the European Institute of Innovation and Technology (EIT) Raw Materials program and LKAB. The objective with the NITREM (NITrogen REMoval from waste rock) project is to establish a service for the passive removal of nitrogen from waste rock leachate with a bioreactor technology, in conjunction with long‐term waste rock management and sustainable landscape design. The technology development is driven by EUs Water Framework Directive and will enable the industry to meet current and future discharge requirements. An outcome from the project will be a low cost and low maintenance technology that is ready for market introduction and customer testing.

The NITREM project is led by Roger Herbert from the Department of Earth Sciences at Uppsala University. Other project partners are researchers from SLU and the Spanish state’s highest scientific council, CSIC, mining companies LKAB and Boliden, and consulting firms WSP and Cedervall Arkitekter.

The NITREM project has been awarded funding for the period of 2018–2021. The budget for the project is EUR 4.8 million, of which EUR 2.5 million will be financed by participating mining company LKAB.

Roger Herbert, Project coordinator NITREM


bottom of page