3.7 What is the biogas potential of various substrates?
The following table provides several examples of the biogas potential from various substrates:
Substrate | Value | Unit | Source |
---|---|---|---|
Faeces | 0.02 – 0.03 | m3 biogas/person/day | (UN, 1984) |
Excreta undigested (incl. water from pour flush) * | 0.23 | m3 biogas/kgVS | UPM 2019 |
Faecal sludge from pit latrines | 0.04 | m3 biogas/kgTS | (Parker A., 2015) |
Faecal sludge from unlined pit latrines | 0.063 | m3 biogas/kgTS | (Tayler, 2018) |
Faecal sludge from septic tank * | 0.03 | m3 biogas/kgVS | UPM 2019 |
Septage after solid-liquid separation | 0.02 | m3 biogas/kgTS | (Tayler, 2018) |
Biowaste | 0.3 – 1.0 | m3 biogas/kgVS | (Deublein D., 2011) |
Kitchen waste | 0.6 – 1.2 | m3 biogas/kgVS | (Vögeli Y., 2014) |
Kitchen waste and human faeces | 0.8 | m3 biogas/kgVS | (Vögeli Y., 2014) |
Theoretical value | 0.35 | m3 CH4/kgCOD-removed | (UN, 1984) |
* Median |
It is essential to note that the amount of biogas produced can vary depending on various factors, such as the organic content of the feedstock, the retention time inside the containment, temperature, loading rate, and system efficiency. The subsequent chapters will cover these factors in detail.
Because human waste is heterogeneous, and the characteristics are highly variable, a BMP test is recommended before designing the anaerobic digester.