The first full-scale plant for sludge disintegration through Cambi thermal hydrolysis was started up in Hamar, Norway at the end of 1995. It is the first plant with a new design where sludge is directly heated by live steam. During the last 3 years the plant worked with an availability of over 99 %. Prior to hydrolysis the sludge is dewatered and the digester is fed with 10-12 % DS, saving more than 50 % of digester volume compared with a conventional process. The degree of stabilization is around 60 % measured as rate CODconversion into biogas. The stabilised sludge, which is guaranteed free of pathogens, is an attractive product to agriculture and has a high fertilizing effect.