For the treatment scenario, a biological treatment procedure has
been chosen. In Bretagne there are about 400 treatment stations of
which 77% are of the biological type, accounting for 88% of the
slurry treated. Other treatment methods in the region include
physicochemical procedures and composting, the later accounting
for 7% of the total volume of slurry treated (Levasseur and Lemaire,
2006). Biogas production from pig slurry in Bretagne is still in an
experimental phase and, at present, there is not a single working
station. This is partly due to the fact that such type of slurry
treatment, although producing energy, does not solve the problem
of excess nutrients, as the digested sludge contains as many
nutrients as the input slurry.