Proceedings

Anaerobic digestion is a biological process in which organic matter is broken down to form a gas mixture
known as biogas. The resulting gas mixture consists mainly of methane (50-70% vol) and carbon dioxide
(25-50% vol), with small volumes of other gases such as hydrogen, hydrogen sulphide, ammonia, etc.
Measuring the ratio of Volatile Fatty Acids (VFA) and Alkalinity (ALK) in the Anaerobic Digestion process is vital, to prevent process upsets and maximize biogas production. Maintaining a healthy ratio of these 2 parameters can help increase biogas production and prevent the risks of running a sour digester.

In an anaerobic digester, complex organic compounds are converted to biogas (methane) in a 2-step
process.
1) Acidogenesis – Complex organic molecules are hydrolysed to soluble organic molecules like
sugars, amino acids, and fatty acids.
2) Methanogenesis – The soluble organic molecules are further broken down to volatile fatty acids
and then converted to biogas.