Utrecht University uses biomeiler to extract heat and compost at educational farm the Tolakker

It is hard to miss the biomeiler at the Tolakker: the tank has a 6-metre diameter and is 3 metres high. What makes a biomeiler special is that the composting process generates usable heat. Within the biomeiler there are several tubes. The water in these tubes captures the heat released during the composting process. That heat is then used by the Tolakker. About 100 megawatts of heat are expected to be released every year. That is equivalent to the annual consumption of four households.

The biomeiler is filled with wood chips and two hundred cubic metres of organic waste. After two years, this produces high-quality compost. Lasse: ‘The composting process in the biomeiler is given plenty of time. Because we can regulate the conditions, this compost will soon contain twice as much organic matter as normal compost. Organic matter nourishes life in the soil and retains water better.’

Puzzle

To realise the project, a lot had to be arranged. Think financing, permits and, of course, a location. Lasse: ‘We looked at ten locations, but each time there was a reason why it couldn’t be done there after all. Zoning plans, cables and pipes: it was like a puzzle, new problems popped up every time.’

To speed up the process, Lasse enlisted the help of the Centre for Living Labs. Together, they invited all stakeholders to a meeting. Then the project gained momentum. Eventually, the installation could be built at the Veterinary Medicine faculty’s teaching farm, the Tolakker. Education coordinator and lecturer IJmert de Vries: ‘Within the Tolakker, we are always looking for opportunities to further improve our business processes and make them more sustainable. Think of the solar panels on the roof of the stables, how we produce organic milk and how we try to increase biodiversity together with other faculties and students. This is how education and research at the Tolakker come together in a beautiful way. Lasse’s project fits seamlessly with our ambition, as an educational farm, to look even more closely at innovation opportunities for a better future.’

Biomeiler 2.0

In cooperation with the Biomeiler Foundation, two improvements have been made to the biomeiler. The first improvement is the addition of a lid. The lid allows additional heat to be captured. The second improvement is active aeration. Lasse: ‘Bacteria cause organic material to compost. They need oxygen, but the amount of oxygen listens closely. With active aeration, the composting process runs optimally and the heat yield is as high as possible.’ Over the next two years, the effectiveness of the improvements will be measured by students.