Temperature Effect on Biogas Production from Co-digestion of Food Waste, Potash and Cow Dung

Abstract

Temperature influence on biogas production from co-digestion of substrate (food waste, potash and cow dung) was investigated. Different concentrations of the substrate (4% to 12%) were mixed and loaded into the anaerobic digesters to produce biogas. Results of temperature effects on the biogas volume indicated that as the days of production increased, the temperature in the digesters increases and the volume of the biogas produced also increased. For digester B1 to B5, the temperature increase ranged from 10.1 to 44.5oC while the volume of the biogas produced increased from 11.3 to 25.9; 15.3 to 30.9; 10.1 to 34.5; 18.5 to 36.0 and 18.8 to 36m3/day for digesters B1, B2, B3, B4 and B5 respectively. For digesters B6 to B9, the temperature increase ranged from 20.6 to 48.4oC while the volume of the biogas produced increased from 22.1 to 40.2; 20.6 to 41.5; 24.9 to 42.0 and 24.2 to 42.5m3/day for digesters B6, B7, B8 and B9 respectively. A total 17859.6m3 of biogas was generated for a period of 90 days. Average temperature ranges from 29.30 ± 3.00oC for digester B1 (4% concentration of sample) to 41.46 ± 4.33oC of digester B8 (11% concentration of sample). This result was further clarified from the Analysis of variance and multiple comparisons of the temperature which revealed that digesters B5, B8 and B9 had no significant difference among them. The correlation of temperature and volume of biogas generated by each digester revealed that temperature significantly influenced the quantity of biogas generated at P= 0.01 and r = 0.760 (B2G), r = 0.740(B3G), r = 0.721(B6G) and r = 0.650(B8G) showing relationship were significant and had a high relationship between temperature and the substrates.