Bacteria biofilter reduces pig farm methane emissions

In the spring of 2024, Denmark housed almost 11.5 million pigs. Although many are exported, some are also consumed in Denmark.

But our meatballs and roast pork leave a climate footprint because of the pig manure, which during storage in slurry tanks produces methane – an extremely potent greenhouse gas. This has created an opportunity to test biofilters in pig production, as the technology has previously shown promising results in reducing methane emissions from landfills.

In 2020, a group of researchers from DTU Sustain therefore started designing and constructing a biofilter which they installed in 2022 at a Danish pig-producing farm in Gilleleje, north of Copenhagen.

A biofilter is established by excavating an area at a depth of about half a meter, which is filled with stones that act as gas distribution layers. An 80-cm thick layer of compost is placed on top of the stones.

The compost holds a naturally occurring group of bacteria that feed on methane, which means that the bacteria break down the unwanted greenhouse gas in their encounter with the methane. The filter works completely without the addition of chemicals, and the solution can therefore be applied in both organic and conventional production.

Image source: DTU.