The operation of an anaerobic digestion located on a farm and primarily fed by cattle slurry and manure, has been simulated using the Anaerobic Digestion Model 1. The effect of seasonally varying temperature on the biological reactions has been taken into account, as well as the non-availability of cattle slurry in summer. This can be compensated by co-digesting other substrates easily found in the vicinity of the farm such as glycerol (waste from biodiesel production) or roadside green weed silage.