Weltec Biopower in Vechta, Germany, is developing a fast method for identifying inhibitors in biogas substrates.
Traces of such substances in the input mass are detrimental to the digester’s bacteria and counterproductive to the digestion process. Even a small amount of mould is sufficient to cause such an adverse effect in silage, while ammonium, copper, zinc, drugs and disinfectants are often identified as inhibitors in slurry and manure.
Since December 2016, Weltec has been involved in a research project to establish a new procedure that will solve this problem. The project is subsidised by the German federal ministry of food and agriculture and in collaboration with the Göttingen University of Applied Sciences and Art (Hawk).
For the test, feedstocks are first examined in Weltec’s lab and at Hawk, with the help of Ankom’s system which delivers information on gas production. A change of the acid spectrum is monitored while deliberately adding inhibitors. The resulting target curves will be compared with the gas production curves of substrates to reveal whether the substrate contains any inhibitors.
“Plant operators will be able to decide whether to buy offered silage or liquid manure or whether to use a certain batch of their own slurry,” explains project superviser Sabine Lampe. She added that substrate providers could use the test to provide evidence of product quality.