Biogas Productivity and Quality as influenced by Fermentation Temperature and Agitation Process

Document Type : Original Article

Author

Agricultural engineering, agriculture, benha, cairo

Abstract

The main aim of this work is to study the influence of fermentation temperature and agitation speed on the biogas quality and productivity. To achieve that, the effect of fermentation temperatures (control, 35 and 45 °C) and three agitation speeds (50, 100 and 150 rpm) on the pH, total solids, volatile solids of slurry, biogas yield, methane yield, CO2 and H2S was studied. The results show that the pH of slurry was ranged from 5.83 to 7.47 for all treatment. The TSS and VSS of slurry decreases with increasing fermentation temperature, agitation speed and retention time. The best fermentation temperature for biogas production was 35°C, the highest value of accumulated biogas yield was 87.82 m3 per ton TS was found at a fermentation temperature of 35°C. The biogas yield increases with increasing agitation speed. The methane yield increased gradually until it reached the peak after 30 day for control and 20 day for 35 and 45 ºC fermentation temperature and then decreased until it reached day 60. The highest value of CO2 yield was 5.2 m3 per ton TS was obtained at 45°C fermentation temperature, while the lowest value of CO2 yield was 4.8 m3 per ton TS was obtained at a fermentation temperature of 35°C. The highest value of H2S yield was 1.8 m3 per ton TS was obtained at 45°C fermentation temperature.

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