Information Sheet 67: Digestate as a Biofertiliser

The solid residue from anaerobic digestion of organic matter is referred to as either digestate or biosolids. Biosolids is the residue from anaerobic treatment of municipal sewage, while digestate is the residue from anaerobic digestion (AD) of other organic matter. Both materials can be beneficially used as a soil fertiliser and conditioner, although stricter regulatory limits apply to the application of biosolids to land to minimise potential health risk for humans, livestock and the environment. Digestate which meets specified quality limits is suitable for safe use as a fertiliser on land and is called biofertiliser.

Processing of residual organic matter in an anaerobic digester produces biogas as well as the digestate or biosolids.