Excess sludge is an inevitable drawback of the waste-activated sludge process. Both the reduction of the amount of sludge produced and improving its dewaterability are of paramount importance. With more stringent environmental and legislative constraints, increasing sludge production and limited disposal options, new reduction alternatives have to be found. This paper presents different advanced sludge treatment (AST) processes, i.e. thermal hydrolysis (neutral, acid, alkaline) and chemical oxidation using H2O2. Semi-pilot and pilot-scale experiments are conducted in order to achieve optimum t