To my knowledge, technologies for biogas or bio-methane production from various bio-substrates through anaerobic digestion or their co-digestion are available in the literature. But very little literature is available on the optimum conditions for anaerobic digestion and/or their co-digestion. Therefore, a total of six studies are mentioned in this document to address this issue. Among of these a baseline survey and 5 lab based experiments were carried out (i) to investigate the potentials, status, problems, barriers and future needs for implementation and dissemination of biogas plants in...