Waste management has become of major concern around the world during the recent 30 years. Sustainable waste treatment concepts that favour waste recycling and the recirculation of nutrients back to soil will have the highest benefit for the environment (Lema and Omil, 2001; Sakai et al, 1996; Braber, 1995). Anaerobic digestion (AD) of the organic fraction of municipal solid waste (OFMSW) offers the advantage of both a net energy gain by producing methane as well as the production of a fertilizer from the residuals (Edelmann et al, 2000; Sonesson et al, 2000; Hamzawi et al, 1999).