The capacity of the existing wastewater treatment plant in Ljubljana is no longer sufficient and the plant must be upgraded with new energy-efficient technology. Therefore, the Water Utility of Ljubljana has decided to invest in Krüger's thermal hydrolysis technology, Exelys. This technology will be integrated by Krüger's parent company Veolia who will install it in a new building at the existing wastewater treatment plant.

The plant will make it possible to produce far higher amounts of biogas from the plant's sludge and in this way, the plant becomes much more self-sufficient in energy.

The wastewater treatment plant of the future

People from Ljubljana's Water Utility Company have visited Billund BioRefinery. Often referred to as the Wastewater Treatment Plant of the Future, its technology combines treatment of household waste and wastewater sludge while  producing biogas for electricity and heating at the same time. It is ground-breaking as it builds on innovation and a combination of a series of technologies with Krüger's thermal hydrolysis as pivotal point.

"Now, we install Exelys at the wastewater treatment plant in Ljubljana to enable them to produce significantly more biogas in the digesters, and the gas will thus operate the existing sludge dryers", says Lars Henrik Andersen, Project Manager with Krüger A/S.

Hydrolysed and digested sludge is much easier to dewater and together with the higher gas production the new wastewater treatment plant will use far less energy than the existing plant.

"Apart from the installation of Exelys, new clarifiers will also be installed so the general capacity will be extended. In this way, the wastewater treatment plant will be able to comply with the strict national and EU standards on effluent discharge into the Ljubljanica River that runs through the old part of the town", says Lars Henrik Andersen.

Krüger designs the Exelys specifically for the wastewater treatment plant and prepares control descriptions for all components applied. After the modular plant has been manufactured locally in a workshop, it will be supplied as a prefabricated "package plant" in Ljubljana, i.e. as a complete plant.

The Exelys technology is flexible and can be adjusted to fit all plants and requirements. Read more about the advantages in the sidebar to the right.  

Exelys technology

Innovative and compact solution for continuous sludge hydrolysis.

'Plug & play' solution

Value

Optimised sludge treatment that:

-     Reduces the amount of dry solids by 25-35%

-     Produces 30-35% more biogas

-     Is free from odour nuisances

•       Possibility of reducing the investment costs for a new digester - or, alternatively increase the capacity of the existing digester
•       Reduce the amount of sludge for disposal
•       Flexible operation – can be adjusted to fit all plants and requirements

Exelys at Billund BioRefinery

A Lighthouse project supported by MUDP and VTUF with a DKK 15 mill. grant

PE: 70,000

The energy production has increased by 60% from approx. 8.6 mill. kWh to approx. 14 mill. kWh annually.

The sludge amount has been reduced by 30%.

The discharge of nutrients from the plant has been reduced by almost 60%

The content of nitrogen and phosphorus in the organic fertiliser has increased by approx. 18%.