The Dobrna Wastewater Treatment Plant (WWTP) ensures preliminary mechanical and secondary biological treatment of sewage from 4000 Population Equivalents (P.E.). The raw sewage is collected from the area of DOBRNA and conveyed to the WWTP by a combined sewerage system.
WWTP consists of mechanical pre-treatment section, two sections for biological treatment – older one with capacity of 1 800 P.E. and one new designed and executed by Hydrotech with capacity of 2 200 P.E.. For separation of treated water and activation sludge new sedimentation tank was constructed with hydraulic capacity of 4 000 P.E.. Existing sludge holding tank is used for surplus sludge. The treated final effluent is conducted to the river.
For nutrients removal pre-denitrification and phosphorus precipitation processes are included in the biological treatment process.