Technologies used in the wastewater treatment plants

The technology depends on the size of the territory and on the required output quality of the treated wastewater.     

The first part of the wastewater treatment plant is coarse pre-treatment which removes coarse impurities from the water inflow.

Then, mechanical treatment separates fine pollutants which did not dissolve in the wastewater.

Biological treatment removes the dissolved organic pollution by biological processes in the activation tank and separates sludge from the treated wastewater in a settling tank.
Before the wastewater is discharged, it is necessary to reduce nitrogen concentration. Biological processes are used to remove phosphorus during the treatment. In big wastewater treatment plants, chemical precipitation of phosphorus is used.  
The wastewater treatment plants include gas handling and sludge treatment systems.

For each wastewater treatment plant, the Water Authority issues the permit to discharge wastewater. The permit defines outflow limits and sampling frequency for the wastewater treatment plant. All wastewater treatment plants in SmVaK fulfill the required parameters. Each year a report is issued which assesses quality of the treated wastewater.