|Better Farming Series 31. Biogas: What it is; How it is Made; How to Use it (FAO Better Farming Series, 1984)|
87. If the temperature where you are often falls below 15°C, you will have to keep the waste mixture in your biogas unit warm.
88. If you put your biogas unit under the ground or partly under the ground, this will help to keep the waste warm.
89. You can keep the waste mixture in your biogas unit warm by putting leaves, grass, straw or maize stalks around the large drum.
90. You can also keep it warm by adding a bucket or two of poultry drop, pigs mixed with other waste to the waste already in the large drum. Use one part of poultry droppings to three parts of other waste.