BioCrack: Retrofitting the biogas plant: smooth running and efficiency with BioCrack

Case Study - Kotthoff biogas plant

Franz-Josef Kotthoff, farmer: We use 70 percent turkey and cattle dung, 20 percent maize silage and some grass silage as input for our 220 kWel biogas plant. In order to fully utilize the biogas plant's capacity, we used to add approx. three percent crushed rye, amounting to around a ton per day.

For a long time the impact of hurricane Kyrill was perceivable: wood and fibrous matter entered the biogas plant again and again via the input materials, which caused problems with the mixers and slide valves.

The Vogelsang RotaCut improved the situation quickly and the flowability of the substrate increased. Then we heard about the Vogelsang BioCrack system. The advantages were convincing. Installation is done only once, and the follow-up costs are minimal: the power consumption of each module is max. 35W and operation is maintenance-free.

We had two BioCrack modules installed. The daily carryover from the digester to the post digester is treated, an average of 70-80m³ per day. Furthermore, the re-circulated material which is pumped back from the post digester to the digester (50-60m³ per day) also flows through the BioCrack system.

Retrofitting the biogas plant in this way has considerably improved its efficiency: the viscosity of the digester contents became lower, the mixers have been using less power since then. Input quantities were reduced by more than ten percent. We can now dispense with the use of rye, which is now saving us 40,000 euros per year.

All in all the biogas plant is now running more smoothly and variations in the gas yield are lower. The entire biological process is more robust. Our conclusion: BioCrack increases the gas yield, operates automatically and causes no additional work. If anything, our work load has dropped due to the lower input quantities and no longer needing rye as an additional component.