Dewatering of sludges and digestates produced by the anaerobic digestion process is undertaken to minimise the transport of water when these materials are utilised off site.
Flocculating of digestates and subsequent solid / liquid separations can be a costly element of the overall process, and dewatering process requirements can vary in line with changes to feedstock characteristics, process operation and design (e.g. installation of a pre-treatment stage, changes in digestion retention time, etc).
In addition, changes to the digestion process itself, such as the introduction of a new feedstock, or installation of a pre-treatment stage, can have a significant impact on the characteristics of the digestate and hence dewatering requirement.
AD Centre researchers are working with industrial partners to better understand how process changes affect the physical, chemical and biological characteristics of digestate, and are investigating novel approaches to reducing the overall cost of the dewatering process whilst maintaining a consistent quality of recovered solids.