The physicochemical and biological sludge (PCS and BS) from a Moroccan dairy industry, constitute a source of organic matter that is ranging between 50 to 90%. The composition of this sludge is very specific because they were derived from an effluent mixture (milk, orange ...). Assessment of anaerobic digestion for treating these wastes showed the promising results in terms of methane production and organic pollution removal. Indeed, the methane yields were 5.601 and 20.79 mlSTP.gVS-1 gave respectively by BS and PCS for the maximal load (100% of substrate). The total solid and volatile solid reduction reached to 79.63 and 83.60% for BS while it reached 87.064% and 89.161% for PCS for the same load (100% of sludge)
