Sofia Wastewater Treatment Plant – Kubratovo

Contracting Authority
Sofia Municipality

Kubratovo, Bulgaria

Period of implementation
September 2022 - January 2025
Glavbolgarstroy’s role in the project
Prime contractor "GBS - Plovdiv"
Nature of works

Reconstruction, Modernization, and Completion of the Sofia Wastewater Treatment Plant - Kubratovo.

The activities within the scope of the project envisage the construction of the first Anamox installation in Bulgaria to reduce nitrogen concentrations in sediment waters. This includes building a bypass from the aerated sand-oil impoundment to biobasins, as well as thermal hydrolysis reactors for additional sludge treatment, in addition to the existing anaerobic stabilization process.

The aim of the project is to enhance the efficiency of wastewater treatment by reducing the final ammonia content in treated water, mitigating eutrophication, and implementing a new sludge treatment facility to decrease its quantity.

The established design indicators aim to achieve ammonia removal rates of 80-90% and total nitrogen removal rates of 75-85%.