DOI: 10.36347/sjet.2019.v07i11.005

Pages: 302-310

Biogas is a proven and widely used renewable energy technology which has been contributing to the environmental as well as social benefits. However, the limitation to the technology is that it has only been effective in mesophilic temperature range. This research has focused on study of biogas production potential in psychrophilic temperature range. Psychrophilic methanogens are found in permafrost sediments/ lake bottom of high-altitude lakes where the temperature is low. With overall research support from Cascade Research and Engineering Services (CaRES) Pvt. Ltd., who had samples collected from high altitude lakes of Gangapurna, and Gokyo, bench level digesters were prepared for this research purpose with various amount of organic feed. The digester was also tested adding only the organic wastes for comparative study. Three digesters were kept at room temperature (mesophilic temperature range). The so formed digesters were kept at 5 and 10 degree Celsius. The pressure reading and temperature of the samples were noted. After period of 55 days, the gas pressure and the gas composition were tested. The results showed increased biogas production while using the sample compared to the digester without the sample at same temperature. However, the biogas formed at the low temperature was still low compared to the biogas produced at mesophilic temperature range (room temperature). With the help of the biogas production potential as calculated, cylindrical biogas digester was designed of 2 m3 volume. The calculations showed 30 kg of organic wastes required per day for the designed biogas digester.