Methane production during laboratory-scale co-digestion of cattle slurry with 10 wt. % of various biowastes

The paper summarizes the results from twenty model tests of continuous one-stage mesophilic anaerobic co-digestion of cattle slurry (90 wt. %) and various biowastes (10 wt. %). Digestion was conducted in 0.06 m³ reactors with hydraulic retention times ranging from 60 to 98 days during the research period 2007-2010. Methane production intensity and specific methane production are discussed. The highest methane production intensity (0.85 m_N³.m^-3.d^-1) was from a mixture of 63 wt. % of total solids from biscuit meal EKPO - EB and from 37 wt. % of total solids from cattle slurry. The highest specific methane production from 1 kg of added organic compounds (0.67 m_N³.kg_VSp^-1) was given by a mixture containing 61 wt. % of total solids using spring barley Aksamit (milled grain) and 39 wt. % of total solids from cattle slurry. The highest substrate-specific methane production (0.92 m_N³.kg_VSp^-1) was from milled grains of winter rye Aventino.