Methane emission reduction from storage of manure and digestate-slurry

Abstract

Manure storage is a source of methane. An option to mitigate methane emissions from manure storage is to collect the methane produced in the storage and feed it into a dispersion layer underground. In the soil above, the methane is subsequently oxidized by methanotrophic bacteria. A previous study indicated that the method seems technically and economically feasible with costs for emission reduction of methane of €1–4 per ton CO2‐eq. mitigated. The concept was demonstrated at a pilot facility next to a storage for manure digestate and proof of concept was achieved at field scale. It was technically simple to capture methane and feed it into a dispersion system at about 1 m below the surface. Indications exist, that part of the methane was oxidised in the soil. However actual methane oxidation could not be determined, because there are serious doubts whether all methane did enter the oxidation field. For actual applications, quantification of gas generation in manure and oxidation rate of the soil need to be improved, to design an oxidation field.