Anaerobic Digestion of organic waste in Province of Bolzano
About this good practice
Before the installation of the anaerobic digestion plant, in the province of Bolzano, Italy, many municipalities had small composting facilities. As for the largest municipality, namely the city of Bolzano, organic waste was not collected and went to incineration along with other urban solid waste. Therefore, with the establishment of European directives that obliged the municipality of Bolzano to implement separate collection of organic waste, a treatment plant had to be built (exporting waste to other regions was not an option). Not only Bolzano but also other municipalities could deliver their waste to the anaerobic digestion plant from then on.
From a technical point of view, the objective was achieved by implementing a wet anaerobic digestion plant for organic waste with energy recovery , which has a treatment capacity of 32 thousand tons per year. Anaerobic digestion is a process in which microorganisms break down biodegradable material in the absence of oxygen. The process produces a biogas, which is used directly as fuel, in combined heat and power gas engines. The produced electricity is self consumed and sold to the grid. The process still generates a quantity of digested sludge that must be sent to a composting plant.
Both the province and municipalities benefit directly from this process, as well as the citizens who see a low tariff thanks to its efficiency. In addition, clean energy is produced which further lowers the operating costs of the plant.
Resources needed
The plant is financed with public money. Financing takes place through the province with waste tariffs and directly with the disposal costs paid by the municipalities per ton of waste. The total investment cost was €25 million and the yearly operating cost of 2023 was around €2.7 million.
Evidence of success
The results achieved in the collection of organic waste in the main towns have been highly successful. The percentage of sand and residues in the organic waste is low and the specific production of biogas is very high reaching 170 Nm3 per ton. Considering the amount of biogas produced, the plant is energetically self-sufficient and sold about two-thirds of the produced electricity in 2022. The price for waste disposal is also low at €79 per ton. The revenue of 2023 was €2.6 million.
Potential for learning or transfer
The practice is easily transferable to other regions. The information of the population is of particular importance. It is highly recommended to start an intensive information campaign before the construction and planning of plants. Early awareness will be very useful in fighting fears and concerns before they can settle. Most concerns are related to the production of unpleasant odors, safety, environmental impact. However, modern biogas plants are designed to reduce odor emissions and are subjected to strict safety regulations.
It is important that local communities understand and appreciate the benefits of this process, such as the production of renewable energy and the protection of the environment. It’s crucial to provide technical explanations that are both accessible and comprehensive, in order to foster transparency in plant management. This can be achieved by listing the benefits, potential issues, and risks of the process, as well as how they are addressed.
Further information
Extension of anaerobic digestion plant, Lana
Website
Good practice owner
You can contact the good practice owner below for more detailed information.
eco center s.p.a.