Digestate is the secondary useful product produced by the anaerobic digestion (AD) process.

It is a useful waste by-product of AD, and can be used as a fertilizer due to its nitrogen-rich nature.

If the digestate is used to fertilize energy crops or animal feed (feedstocks), then the AD process can be considered somewhat self-sustaining, as the diagram below shows:

Anaerobic digestion (AD) process showing how digestate can be re-used

Likely future developments involving digestate include improved post-processing to increase its usefulness even further.


The quality of digestate can be assured by following the standard PAS 110, whose full title is: Specification for whole digestate, separated liquor and separated fibre derived from the anaerobic digestion of source-segregated biodegradable materials.

Page Last Updated: 23 June 2020