The European Investment Bank ( EIB ) has approved a loan of 5 billion Swedish kronor ( US$520 million ) to the City of Stockholm to finance a new wastewater treatment plant.

The project involves closing the Bromma treatment plant and routing all the city’s wastewater to a significantly expanded and modernized treatment facility at Henriksdal. 

The new wastewater treatment system is expected to cost 19.5 kronor billion, or around US$2 billion. The EIB financing represents around 26% of the investment, and is being provided with a long maturity to match the project’s implementation date of 2031. 

The project will feature a new wastewater collection tunnel that will transport sewage from Bromma to Henriksdal. The plant will be expanded using advanced membrane technology, making it possible to treat more water without increasing the floor area and with significantly better results. 

Once the upgrade is complete, nitrogen discharge into the Baltic Sea is expected to fall by around 40% and phosphorus discharge by about 35%. The technology also removes microplastics and provides readiness for future treatment requirements, such as the removal of pharmaceutical residues. At the same time, the risk of overflows of untreated wastewater into Lake Mälaren, Stockholm’s source of drinking water, will be reduced. 

“This is an investment in a cleaner sea and a more secure water supply," says EIB vice-president Karl Nehammer. "By supporting Stockholm’s new treatment solution, we are helping to reduce discharge into the Baltic Sea and strengthen the city’s climate change adaptation measures. The project is fully in line with the EIB’s climate and environmental priorities." 

Stockholm city treasurer Sofie Nilvall adds: “We appreciate the EIB’s continued support for the City of Stockholm’s loan financing. This time it concerns one of our largest projects, the expansion and modernization of the Henriksdal wastewater treatment plant, which will strengthen the city in several areas, including the environment, public health, and preparedness." 

The project will help Sweden meet its commitments under the Baltic Sea Action Plan and the EU Water Framework Directive, and is classified as a climate and environmental investment.