Performance evaluation of anaerobic baffled biodigester for treatment of black water

In this study, the performance of anaerobic baffled biodigester installed in different regions of South India was evaluated for black water treatment. The evaluation was based on the vendors, establishment, impact of different sampling methods (grab and composite sampling) and the application of post-treatment unit. The treatment efficiency of the digester was assessed in terms of removal of organics (biological oxygen demand (BOD), chemical oxygen demand (COD)), total suspended solids (TSS) and pathogens (faecal coliform). The maximum removal rate of COD, BOD and TSS was found to be in the range of 70-75%, 68-80% and 55-75% respectively. Variations were observed between the grab and composite samplings with respect to the removal efficiency of organics, solids and pathogens. There was no significant difference in the performances of anaerobic biodigesters installed by different vendors in South India. The application of post-treatment unit such as gravel bed/reed bed after biodigester facilitated the removal of residual organic pollutants and provided better quality outlet water. The results indicated that the performance of anaerobic baffled biodigesters varies based on the number of users, location, usage pattern and the post-treatment unit installed.