A revolution rooted in the circular economy: thanks to separate waste collection, organic waste is fed into an anaerobic digestion process to produce biogas.
Biomethane: a clean resource of biological origin
So, what makes this source of methane “bio”? Quite simply, it’s how it is produced: not by drilling into deep underground deposits, but by fermenting organic waste in dedicated facilities. Biomethane can be produced continuously, it is inexhaustible, and production can be increased simply by building more plants. This makes it one of the clearest examples of a circular economy.
In Spilamberto, a biodigester converted into a biomethane plant
An innovative plant for the production of biomethane is in operation in Spilamberto, in the province of Modena. It was developed by the NewCo Biorg, a joint venture between the Hera Group and Inalca (Cremonini Group), through a total investment of around €28 million and the use of the best available technologies.
Starting from separately collected organic waste and agri-food effluents, the plant – the result of converting an old biodigester – produces, at full capacity, 3.7 million cubic metres of biomethane per year, a 100% renewable fuel intended for transport, and around 18,000 tonnes of compost.
A cutting-edge plant for the energy transition and the circular economy
The 100% renewable natural gas is produced through anaerobic digestion of organic waste from separate collection carried out mainly in Modena and the province, along with waste from local agri-food processing and meat production by Inalca. Once refined, it becomes biomethane and can be fed into the gas network.
Significant environmental benefits: around 7,000 tonnes of CO₂ avoided
Thanks to the injection of biomethane into the network and its use in transport, significant environmental benefits are expected. Every year, around 3,000 tonnes of oil equivalent (TOE) in fossil fuels are saved, and approximately 7,000 tonnes of CO₂ emissions are avoided. Absorbing such an amount of CO₂ would require, on average, 280,000 trees.
What happens in our plant in Sant'Agata
Organic waste, collected through separate waste collection, undergoes anaerobic digestion to produce biogas. This is how the process works: the waste is shredded and screened, then remains for about 21 days in four horizontal digesters, where suitable microorganisms carry out the digestion process and produce biogas (composed of methane and carbon dioxide). After this, the biogas undergoes an upgrading, or purification, phase using pressurised water: the carbon dioxide dissolves and separates from the methane. The result is biomethane, a gas with a methane content above 95%, and a completely renewable source of energy. Not only that: at the end of the digestion process, lignocellulosic material is added to the outgoing solid fraction, producing a compact mass that then undergoes composting to create high-quality compost, which can be used as potting soil or agricultural fertiliser.
Biomethane is therefore another revolution rooted in the circular economy, one that we at Hera Group are committed to advancing. We do all this with the goal of creating shared value, as Andrea Ramonda, CEO of Herambiente, emphasises: “The direction we have taken looks towards the industrial sector with an increasing focus to creating shared value and partnerships. We are aware that sustainable waste management, focused on recovery and in full compliance with regulations, is essential in today’s world and generates benefits for the entire community.”
Working together for a circular city
At Hera Group, we have joined forces with Bologna Airport and Tper to launch a circular economy project that contributes to decarbonising urban mobility and improving air quality.
What does this partnership involve? The Airport delivers its organic waste to Hera, which collects it at the Sant'Agata Bolognese plant together with similar waste produced by citizens and transforms it into biomethane that Tper purchases to feed the fuel tanks of a significant part of its bus fleet.
This is an important step forward for our Group and for two major organisations in our area, which, like us, serve hundreds of thousands of people. We share a commitment to improvement and sustainability, in line with the UN 2030 Agenda.
Wastewater "gets beautiful" with ultrasound treatment
The ultrasound hydrolysis system, installed in the Forlì treatment plant, makes the life cycle of wastewater sludge circular. The result: less sludge to dispose of, and more biogas produced.
Wastewater is all the water that, after having been used in domestic, agricultural, and industrial activities, must be treated before being returned to the environment.
This water contains a solid part – sludge – which is removed during treatment. But, in addition to giving a new life to wastewater, can we also make the sludge life cycle circular, by reducing the amount to be disposed of?
Back in 2017, we started research to answer these questions, and, once again, we decided to invest in new technologies to lighten the impact on the environment and be more virtuous. In November 2019, our efforts became a reality, thanks to the ultrasound sludge hydrolysis system, installed at the Forlì treatment plant.
In this system, part of the sludge from the wastewater treatment process is subjected to sound waves. The waves, in contact with the liquid matrix to be treated, biodegrade more volatile solids, increasing biogas production, and reducing the final dry matter in the sludge. All this makes it possible to significantly reduce the volume of sludge to be disposed of and opens up new scenarios for the use of the biogas obtained thanks to the ultrasound system.
During 2020 the initial results will be reported and we look forward to sharing the successes of this new adventure with you.