Solar Accelerator Anerobic Digester Design for Small-scale Bio-gas Production

The wide scale application of anaerobic digestion (AD) technology has been limited in colder climate regions as these systems can be adversely affected by low ambient temperatures, leading to a cumbersome digestion of the waste and longer hydraulic retention time resulting in reduced biogas yield. These issues can be addressed by developing small-scale locally applied systems/processes that can be improved by increasing the temperature of the biomass slurry to enhance the process rate. In this paper a new hybrid system is proposed. The proposed system is based upon a conceptual Solar Accelerator Anaerobic Digester (SAAD) design developed at the University of Ulster and TERI’s Enhanced Acidification and Methanation (TEAM) developed by The Energy and Resources Institute (TERI), India. An experimental programme determined the operational characteristics of the SAAD design covering the aspects of solar heating and its influence on batch AD process. The effect on the acidification process was also investigated by monitoring the batch pH, COD and volatile fatty acid concentration. The results showed that under a range of operating conditions the proposed system has a potential to degrade various feedstocks at a faster rate resulting in improvements in yield for different operating conditions.