Water

Sofia wastewater plant expands biogas production unit

Sofia wastewater plant expands biogas production unit

Photo: Sofiyska voda

Published

November 7, 2021

Country

Comments

comments icon

0

Share

Published:

November 7, 2021

Country:

Comments:

comments icon

0

Share

Sofiyska voda presented its new digester at the wastewater treatment plant in Sofia. The tank, which cost EUR 3.1 million, increased the biogas production capacity by 25%.

The wastewater treatment facility near Kubratovo in Bulgaria’s capital city added a digester of 7,000 cubic meters for sludge fermentation. It is operated by Veolia’s subsidiary Sofiyska voda, which produces drinking water and manages wastewater for 1.4 million people in Sofia.

The French company said the plant is the second in terms of energy efficiency among its 2,500 units. The construction of the digester, a tank for the extraction of biogas from waste sludge, cost EUR 3.1 million and it will increase the capacity of green energy production by 25%, according to the announcement.

Contribution to circular economy

The firm already has four digesters, built in 1984, OFFNews.bg reported, adding the new tank would enable the company to upgrade the old ones. The methane from the sludge fuels a cogeneration system, which produces 24 GW of electricity per year.

Sofiyska voda operates four drinking water and two wastewater treatment plants as well as three combined heat and power units. It said it plans to build another cogeneration unit.

After the sludge is stabilized in the digester, it is dewatered and donated to farms for fertilizing certain types of crops, the firm said and added the material is rich in phosphorus and nitrogen. It sends the purified water to the Iskar river, completing the circular economy cycle.

Sofia wastewater plant biogas production
Photo: Veolia

More than self-sufficient

Sofiyska voda stressed its biogas and cogeneration system protected it from the recent spike in electricity prices as the output is 10% higher than the consumption of the wastewater treatment plant. The firm added it aims to become fully energy independent. The Kubratovo facility processes more than 350,000 cubic meters of wastewater a day.

The Sofia Municipality owns 22.9% of the Sofiyska voda. The utility asked the citizens not to throw wet wipes into the sewer, explaining that the material causes congestion in wastewater treatment plants.

A similar wastewater treatment plant with a biogas cogeneration system was recently built in Kruševac in neighboring Serbia.

Comments (0)

Be the first one to comment on this article.

Enter Your Comment
Please wait... Please fill in the required fields. There seems to be an error, please refresh the page and try again. Your comment has been sent.

Related Articles

Western Balkan coal plants cut harmful emissions 2024 breaches extreme

Western Balkan coal plants cut harmful emissions in 2024 but breaches remain extreme

19 June 2025 - SO2 emissions from NERP-bound coal plants in BiH, Kosovo*, North Macedonia and Serbia were six times above legal limits last year

serbia air quality ebrd loan sinisa mali sara pavkov Matteo Colangeli

Serbia secures EUR 50 million loan for air quality projects

12 June 2025 - The Government of Serbia has secured a EUR 50 million loan to be invested in a series of air quality protection projects

EU strategic status Rio Tinto lithium project fueling tensions Serbia

EU’s strategic status for Rio Tinto’s lithium project risks fueling tensions in Serbia

06 June 2025 - The addition of the planned lithium mine in Serbia to the EU's strategic projects for raw materials has again stirred up public controversy

European Commission Jadar project Serbia strategic projects critical raw materials

European Commission declares Jadar project in Serbia one of its strategic projects for critical raw materials

04 June 2025 - Rio Tinto's project Jadar in Serbia is now one of the EU's 13 strategic raw materials projects outside of its borders