Upgrade of the Domžale-Kamnik central wastewater treatment plant

Domžale-Kamnik central wastewater treatment plant is the fourth largest wastewater collection and treatment system in Slovenia run jointly by six municipalities (Domžale, Kamnik, Mengeš, Cerklje na Gorenjskem, Komenda and Trzin). This major ecological project seeks to provide a sustainable long-term wastewater collection and treatment system serving 149,000 PE for a period of several decades that meets respective quality standards and operates in accordance with the relevant environmental legislation in order to reduce environmental pollution. With the new process approach the upgraded system significantly improves the ecological status of the Kamniška Bistrica River, and in turn helps protect drinking water sources and protect and conserve groundwater.

The project covered the upgrade of the existing wastewater treatment plant to provide tertiary treatment which includes removal of nutrients such as phosphorus and nitrogen from wastewater. The new system uses the Sequence Batch Reactor (SBR) technology. The project covers the construction of an entry facility for septic sludge. The upgrade improved the quality of treatment, increased operational safety and the intake of waste water as well as reduced emissions of harmful substances into the air. The upgraded WWTP system covers three main stages:

- a new entry facility which upgrades the existing mechanical stage,

- a new aerobic biological stage with advanced sequential reactor technology, which includes anaerobic selector for partial biological phosphorus removal and simultaneous nitrification and denitrification, and a very new modern process of demonification for nitrogen purification of highly loaded internal return lines,

- existing anaerobic biological stage with the production of biogas and cogeneration.

The central WWTP acquired the single environmental permit which, in addition to limiting emissions into water, also includes reducing emissions into the air and other emissions, while enabling controlled reception of certain liquid waste for the increased production of biogas and electricity. The upgrade results in better treatment and in making sure all parameters on the outlet in the Kamniška Bistrica River are below the permissible limit. The upgrading of the central WWTP system will in the long-term improve the ecological status of the Kamniška Bistrica River under the outflow of the central WWTP as the load has been significantly reduced due to the improved effluent quality.

Upgrade of the central wastewater treatment plant infrastructure was part of a joint project Wastewater collection and treatment in the area Domžale-Kamnik.

More about the project

Video by Eva Jagodič made under the contest EU project, my story 2018

Photo: Blaž Oman