Effect of Temperature and PH on Biogas Production from Cow Dung and Dog Faeces
Ralph F. Muvhiiwa
Phillip M. Chafa
Tonderayi S. Matambo
The effect of feed, temperature and pH on biogas production was investigated using 500 ml small scale laboratory flasks. Feed containing cow dung and dog faeces produced the most biogas for small scale experiments. The combinations were scaled up to assess the feasibility of producing biogas from two 150 L bio-digester containers in natural conditions, with the containers being placed above and below ground. Variation of temperature in the mesophilic range did not have much effect on the concentration of methane produced. High temperatures favoured more methane production compared to low temperatures. The maximum concentration of methane was 45 per cent in the laboratory experiment at 30oC and 34 per cent in the digester above the ground. The low pH values may have inhibited the action of the methanogenic bacteria, resulting in low methane production in samples with food waste. A total biogas volume of 31.8 L was produced per 50 kg mass of feed in the above-ground bio-digester after 66 days.