Quantifying the percentage of methane formation via acetoclastic and syntrophic acetate oxidation pathways in anaerobic digesters

This technique was performed on a selection of mesophilic digesters representing samples of low to high TAN concentrations (0.2-11.1 g kg−1 wet weight). In high TAN digesters, the ratio between 14CO2 and 14CH4 was in the range 2.1-3.0; indicating 68-75% of methane was produced via the hydrogenotrophic route; whereas in low ammonia samples the ratio was 0.1-0.3, indicating 9-23% of methane was produced by the hydrogenotrophic route. These findings have been confirmed further by phylogenetic studies.