Anaerobic digestion of sewage concentrates represents a very suitable means of generating bioenergy while reducing a huge amount of waste to disposal. Effective biogas production from sewage sludge can be achieved by optimizing operational conditions. In this study, the research was designed to compare the biogas production efficiency from sewage sludge recovered from coagulation and absorption process with sludge recovered from bioflocculation, centrifuged and chemical coagulation (Al2(SO4)3+CMC) processes through biomethane potential experiment (BMP). From the results obtained, the maximum methane production rate of 56.85 mLCH4/gCOD was achieved from concentrates collected during coagulation and absorption treatment process without solid retention time (SRT), concentrates collected during 0.5 d SRT had maximum methane production rate of 110.88 mLCH4/gCOD, methane production rate of 154.28 mLCH4/gCOD was achieved from 2 d SRT concentrate. The Al2(SO4)3+CMC treated concentrate had methane yield of 143 mLCH4/gCOD while bioflocculation concentrate had methane yield of 139 mL/gCOD and centrifuged concentrate had the yield of 124 mL/gCOD within the period of 22 to 29 days. The overall result showed that concentrates recovered from coagulation, adsorption and Al2(SO4)3+CMC processes produced the highest methane with better efficiency and recorded the most stable performance throughout the period of the experiment and this encouraged the future use in anaerobic digestion for large scale methane production.