Monofermentation: more income, fewer disease bacteria

Energy-neutral farms are now a step closer to becoming a reality, thanks to the new monofermentor we will be building on our demo farm in Valkenswaard, the Netherlands, in early 2016. This new system will have two major advantages when compared to older fermentation systems. First of all, it will produce much larger volumes of methane gas, which farmers will be able to use to generate electricity and heat. Secondly, this system is significantly better for public health because disease bacteria are removed from the fertiliser using plug flow technology.

The development of the new monofermentor began some two and a half years ago, when we were working on a project with Wageningen University for the creation of antibiotic-free farms. At the time, we decided to switch to daily manure removal with a view to improving animal health. Nico Verdoes of Wageningen University and Research Centre (Wageningen UR) explains: ‘Having daily fresh manure will provide farmers with a range of new possibilities when it comes to on-site manure treatment.’ In this way, the start of one thing has created opportunities in a completely different domain.

System development

Nico Verdoes put us in contact with Encon Clean Energy, a company that provides manure treatment, manure processing, and energy solutions for the agricultural industry. Together with Encon, we started developing a standalone system that would be suitable for fermenting all of the manure from both the new pigsty and the existing pigsties on the demo farm.

The design process has now been completed, and the contracts with Encon are being signed this week. All of the drawings for the pipes and the positioning of the system are ready, so preparations can now be made on the farm for an early 2016 delivery of the fermentor. Approximately ten metres in height and six in width, the system will be transported to Valkenswaard crossways and fully assembled by water and land.

More energy

The major advantage of the new system is the plug flow technology. Whereas in the current systems, old and new manure are mixed, resulting in energy loss, plug flow fermentation prevents the two from coming into contact with one another. The manure goes through the system in ‘plugs’ and does not come out until twelve days later, preventing energy loss, and increasing methane output significantly.

Cleaner

But higher output was not the only reason for this methodology; the fact that the manure would be ‘cleaned up’ in the plug flow was also an important factor. In the twelve days in which the manure travels through the system in ‘plugs’, disease bacteria are killed, producing ‘clean’ manure.

In 2016, the system will be installed, put into commission and tested on the demo farm. We expect to have an initial, detailed set of results in April or May. Based on this information, we will submit applications for subsidies for a number of other farms in the summer. By the end of next year, we hope to be able to do the same for five additional farms.