Case study 9:

 Kalundborg, Denmark

Strengthening water, energy and material reuse at the Kalundborg industrial symbiosis

Strengthening water, energy and material reuse at the Kalundborg industrial symbiosis

The Kalundborg Industrial Symbiosis Association exists since 1972 and interlinks thirteen private and public companies. The local industrial sector includes petrochemical, light building construction material, food, pharma, biotech, energy and bioenergy as well as waste processing. Even though, the Kalundborg Industrial Symbiosis already recovers and reuses certain materials, water and energy, there are still options to intensify and extend the circular economy related strategies. One aspect is the treatment of wastewaters which is done by two companies Novozymes and Kalundborg Utility.

ULTIMATE focuses on the optimisation of two wastewater treatment plants aiming at developing and implementing a joint control system for both plants. Through digitalization, the joint operation of the two wastewater treatment plants shall increase the energy efficiency of their treatment processes as well as the environmental efficiency. In addition, fit-for-purpose water is recovered in a pilot plant containing a novel ultra-tight ultrafiltration membrane that suggests to protect the downstream reverse osmosis unit more efficiently from fouling than a conventional ultrafiltration membrane. The tests will yield important insights to fully exploit the water reuse potential at the Kalundborg Industrial Symbiosis.

Additionally, new purposes are identified for the heat recovered from the effluent of the municipal wastewater treatment plant. The recovered thermal energy used to serve the district heating system in Kalundborg. However now, the Kalundborg district heating system is mainly supplied with heat from a wood-chip burning combined heat and power plant newly constructed.

A concept study is conducted for the recovery of materials. This will look into promising technologies for the recovery process, estimate the economic value of the recovered product, assess the potential for usage and evaluate the impact on the wastewater treatment plants of Novozymes and Kalundborg Utility.

ULTIMATE CS9 Kalundborg Symbiosis, DK

Key innovations & actions

Exploitation of water reuse potential

Identification of new purposes for recovered heat

Concept study for the recovery of sulphur & acetic acid


Pilot A (conventional UF membrane) :

Reverse osmosis membranes :

Pilot B (novel UF membrane) :


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