High- and low-solids anaerobic digestion in laboratory model fermenter made from silage bags

Abstract

A laboratory physical model of a new type of anaerobic fermenter for “dry” and “wet” anaerobic digestion consisting of silage bags was designed. In the model, the experiment based on high-solids discontinuous anaerobic co-fermentation of agricultural substrates was carried out. It was verified that a horizontal fermenter constructed from silage bags is a suitable type of equipment for the production of biogas. The biogas production peaked at 4th day and was completed by 18th day. Within 18 days of discontinuous high-solids process (18.5-20.0 wt. %TS) the intensity of biogas production reached 1.18 mN3. m-3 . d-1, or 0.0012 mN3. kg-1 . d-1, and the specific methane production 0.01 mN3. kg-1, or 0.07 mN3. kgVS-1. After conversion of the modeling process to a semi-continuous low-solids mode (3.5-5. 5 wt. %TS) during the daily dosage of 87 wt % mixture of biscuit meal EKPO-EB with 13 wt % CaO, the intensity of biogas production reached the value 2.42 mN3 . m-3 . d-1, or 0.0105 mN3 . kg-1 . d-1. The fermentation bag appears to be a more efficient device in the semi-continuous “low-solids” Laboratory model: “(2 inches)”.