The Domžale-Kamnik Central Wastewater Treatment Plant in Slovenia’s Zahodna region has been upgraded to substantially reduce environmental pollution in the area. This has improved the ecological status of the Kamniška Bistrica River while protecting drinking water sources.
- 27 September 2019
The Domžale-Kamnik Central Wastewater Treatment Plant managed to reach the state-of-the-art and high environmental standards with added processes for the removal of nitrogen and phosphorus, and with increased wastewater inflow capacity.
The project provided a sustainable long-term wastewater collection and treatment system that meets quality standards and operates in accordance with the relevant environmental legislation to reduce environmental pollution.
This was achieved by improving wastewater treatment and waste treatment processes and by introducing constant monitoring and analysis. This ensures high-quality treated water. In addition, employees of the plant and the public were educated about topics including environmental protection and efficient usage of water and other resources.
Ecological impact
The plant is the fourth largest wastewater collection and treatment system in Slovenia. It treats municipal wastewater, rainwater and industrial wastewater from six municipal areas: Domžale, Kamnik, Mengeš, Cerklje na Gorenjskem, Komenda and Trzin.
It can receive up to 9 million cubic metres of wastewater per year, as well as septic tank sludge and liquid waste. The plant produces approximately 4 000 tons of waste sludge and 3 million kilowatt hours of electricity annually.
The project substantially lowered the levels of organic material in the Kamniška Bistrica River, including nitrogen and phosphorus content. This improved both the chemical and biological conditions of the river which is the final discharge point of the treated water. This in turn protects drinking water sources and conserves groundwater levels and quality.
All technological treatment processes were automated and are under constant control. Regular measurements and monitoring ensuring the treated water can be discharged into the river.
Three stages
The project achieved high environmental standards by adding processes which remove nitrogen and phosphorus from the water, and with increased wastewater inflow capacity.
Wastewater treatment is carried out in three stages. The first stage is mechanical wastewater treatment which removes course and fine solids, oil and grease.
The second stage is an aerobic, biological one that uses advanced sequencing batch reactor or SBR technology – a specialised sludge system which treats and removes undesirable components. During this stage, carbon, nitrogen and phosphorus compounds are removed.
Finally, biological digestion uses microorganisms to break down biodegradable material in the absence of oxygen. One of the end results of this is biogas, which is combusted to generate electricity and heat energy.
Total investment and EU funding
Total investment for the project “Upgrade of the Domžale-Kamnik Central Wastewater Treatment Plant” is EUR 15 500 000, with the EU’s European Regional Development Fund contributing EUR 13 200 000 through the “Implementation of European Cohesion Policy” Operational Programme for the 2014-2020 programming period. The investment falls under the priority “Environment and resource efficiency”.