Priyono, AgusAhmad AdriantoBahruddin2012-12-042012-12-042012-12-03nurasmihttp://repository.unri.ac.id:80/handle/123456789/789Kabupaten Kepulauan Meranti known as one of Indonesia's largest producer of sago. Kabupaten Kepulauan Meranti produce 202,181 tonnes of sago starch year. In producing sago will produce 40,000 liters of wastewater effluent sago/ton starch, so it can be expected to produce Kabupaten Kepulaun Meranti sago wastewater 22,156 kLiters/day. Sago effluent composition of organic matter (carbohydrates, proteins, fats and oils) are high, so that if discharged to water, it will cause water pollution and contaminate the surrounding environment. Efforts can be made to the anaerobic treatment. Anaerobic treatment is basically the help of bacteria. Bacteria need to do the breeding and acclimatization prior to anaerobic digestion. This study aims to determine the effect of acclimation time on biogas production, pH and biomass concentration (VSS), determine the optimal timing of the acclimatization process, and determine the kinetics of growth. The study was conducted using an anaerobic bioreactor with a volume of 20 L at room temperature operating conditions. The results showed that the acclimatization process lasts for 11 days, and the average pH of 6.8 to 7.2. Average biomass concentration during acclimatization of 0.212 g / L. Biogas produced an average of 1895 mL, while the specific growth rate (μ) of 0.0905. Thus, anaerobic bacteria used in wastewater treatment processes sago.otheracclimatizationbiogasbiomass concentration (VSS)pHsagoArticle