Fundamentally, in enzymatic treatment about 0.3 to 0.5% weight/volume of the suitable enzymes (mainly cellulase) are added to the sludge during the mixing stage at a suitable pH, temperature, and mixer speed. The optimal conditions for oil recovery from sludge according to Ho et al. (1992), at laboratory scale are digestion at a pH 4.6, temperature 30°C, time 5 h, and the enzyme concentration of 0.5% weight per volume followed by washing with 0.03 mol per dm cubed SDS solution. The economic viability of this technique at the commercial scale is not well established but has very high potential of application in other related areas other than mere oil recovery. The commercial viability of the process is affected by the lengthy processing chain and additional equipment that is needed. For example, the sludge will be cooled from 90°C to ambient temperature, thereby increasing the retention time of sludge in the holding tanks for a day or two. This is one of the drawbacks of this recovery technique at the moment.