Optimizing process of biogas production from wastewater treatment plants

The necessary transition of energy supply to renewable sources and the current shortage of natural gas, make biogas production increasingly important. Sewage treatment plants throughout South Tyrol have considerable potential for generating renewable energy in the form of biogas and can therefore make a decisive contribution to the Climate Change Adaptation Plan.

The anaerobic process for producing biogas from sewage sludge is well known and technically established, but can and must still be optimised in certain respects. One of these is the formation of foam in digesters. A phenomenon that is known in literature and causes problems for process engineering and plant maintenance. As part of the industrial research project "OptDigest", we are collaborating with several companies to study this phenomenon and propose effective strategies to reduce foam in the digestive process.

We provide our technical know-how for the construction of a pilot plant for the pre-treatment of sewage sludge, which minimises foam formation. After initial laboratory tests, the pilot plant was installed in the Mühlbach/Rio Pusteria wastewater treatment plant by ARA Pustertal AG/SpA. Stuga KG developed the technical control of the process and Inewa Consulting is responsible for project management.

At the end of September 2022, leading industry experts, wastewater treatment plant operators and representatives of the provincial authorities met for an event. In addition to the results of the ongoing research project, other current issues concerning the operation of wastewater treatment plants were also discussed. The project OptDigest, which is co-financed by research and development funds from the Department for Innovation and technology of the Autonomous Province of Bolzano, will be completed at the end of 2022.