Vol. 12, Special Issue 12 (2023)

Author(s):
Varun Vijayan A, Deepak Mathew DK, John Abraham, Roshin Anie Jose, Senthil Murugan S and Valavan P

Abstract:
The purpose of the current study was to compare the effectiveness of two innovative full-scale biogas digester designs, horizontal and up-flow anaerobic sludge blanket reactors in producing biogas from cow dung throughout the course of two seasons, particularly summer and monsoon. The horizontal flow digester (35 d) had the greatest hydraulic retention time (HRT), whereas the up-flow sludge blanket reactor had the shortest HRT (25 d). According to the results, the up-flow anaerobic sludge blanket reactor digester produced the most biogas when compared to another digester. The up-flow sludge blanket reactor produced the most biogas (61.05±0.45 m³) in the summer. The horizontal flow type reactor produced the least biogas (5.07±0.12 m³) during the monsoon, and there was a significant difference between the digesters. Summer was the season with the highest methane production (60.50 percent), which was substantially different from the other seasons, and the lowest concentration was generated by the horizontal flow type biogas digester (55.28 percent). The methane proportion was higher than during the monsoon and summer had the lowest carbon dioxide levels. The pH of the substrate varied considerably (p<0.01) during the summer and monsoon seasons, measuring 7.35±0.09 and 6.35±0.09 percent, respectively. In two seasons, sludge had a lower crude fibre value than the substrate, and the up-flow sludge blanket reactor had the lowest value (15.74±0.16). The amount of phosphorus in the substrate was determined to be 0.70±0.01 and 0.69±0.00 percent during the summer and monsoon seasons, respectively. For all two digesters in all two seasons, the phosphorus content of the sludge was greater than the substrate, with the up-flow sludge blanket reactor having the highest levels (1.96±0.01). In all seasons for the two digesters, the volatile solid content of the sludge was lower than that of the substrate. Biogas production is greatly influenced by temperature, and in high altitudes when temperatures are low, external heating can be used to increase output.