Bert-slurry only AD (Anaerobic Digestion) plants apply a unique and patented PON technology. The Power Of Nature is used to mix the substrates in the digester. These natural forces help saving on operational cost and investment. It allows to build small plants e.g. 30 kW. No other biogas system is using the power of nature as consequently as does Bert. Hence Bert offers a unique technology which is optimized for liquid fermentation and small plants.