Biogas Generation Digester

Generally farmers with animal manure in slurry form will already have an anaerobic digester working on the farm. We propose to use this existing pond/dam where possible in order to reduce the overall cost of implementing a biogas recovery system. This type of digester is commonly referred to as a plug flow digester.

A typical plug flow digester consists of a pond/dam lined with either concrete or an impermeable membrane (HDPE). In areas where earthen dams are constructed and the structure of the soil does not allow permeability, a lining may not be required (clay soils). To ensure true plug flow conditions, the length has to be considerably greater than the width and depth. The digester is covered with a flexible cover gas holder, anchored to the ground. The inlet and outlet to the digester are at opposite ends, and feeding is carried out semi-continuously, with the inflow displacing an equal amount of digester effluent at the opposite end.