3.7 What is the biogas potential of various substrates?

The following table provides several examples of the biogas potential from various substrates:

Faeces0.02 – 0.03m3 biogas/person/day(UN, 1984)
Excreta undigested (incl. water from pour flush) *0.23m3 biogas/kgVSUPM 2019
Faecal sludge from pit latrines0.04m3 biogas/kgTS(Parker A., 2015)
Faecal sludge from unlined pit latrines0.063m3 biogas/kgTS(Tayler, 2018)
Faecal sludge from septic tank *0.03m3 biogas/kgVSUPM 2019
Septage after solid-liquid separation0.02m3 biogas/kgTS(Tayler, 2018)
Biowaste0.3 – 1.0m3 biogas/kgVS(Deublein D., 2011)
Kitchen waste0.6 – 1.2m3 biogas/kgVS(Vögeli Y., 2014)
Kitchen waste and human faeces0.8m3 biogas/kgVS(Vögeli Y., 2014)
Theoretical value0.35m3 CH4/kgCOD-removed(UN, 1984)
* Median
Biogas Potential of Various Substrates

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.