The aim of the study was to conduct an initial analytical survey of a small number of samples analyze the proportion of fossil carbon in sewage sludge and digester gas and to correlate it with other data collected in a sewage treatment plant.

A conservative but representative standard value of 80% biogenic carbon could be derived for sewage treatment plants if they receive less than half of the load from commercial sources – despite continued significant fluctuations. This value, which corresponds to a value derived from Article 31 (1 c) MRR can be used as a standard value for sewage sludge and digester gas from sewage treatment plants with predominantly municipal wastewater.