Unique about the plant in Kastellin (Châteaulin) is that the digestate is being treated afterwards with a cost-effective technology, which cleanses digestate to disposable waste water. The cleaned water is also being used again for the digesters. This way the amount of nitrogen in the digester is lowered to acceptable levels to prevent inhibition of nitrogen fixation activity which is required given the large input of chicken manure. The biogas plant is fed with chicken manure, pig manure, cattle manure and organic waste streams and produces enough biogas equivalent to the annual natural gas consumption of 2,250 households.


Location Kastellin (Châteaulin), France
Start-up February, 2018
Capacity 28,000 tons / year (12,500 tons liquid, 15,500 tons solid)
Input Chicken manure, pig manure, cattle manure and organic waste streams.
Digester(s) 1 x 2,700 m³ (Ø 15 m x 16 m )
After-digester(s) 1 x 3,300 m³ (Ø 24 m x 8 m)
Solid feeding input 1 x 80 m³ solid feeding / mixing bin
After-storage 2 x Ø 30 m x 8 m
Digestate treatment • Screw press separator
• Decanter centrifuge for fine particle separation


  • Unique digestate treatment technology cleanses the thin fraction to disposable waste water and removes 100,000 kg of nitrogen annually;
  • Maximal heat recovery with heat pump;
  • Regenerative system