Digestate mechanical separation: Efficiency profiles based on anaerobic digestion feedstock and equipment choice.

Graphical abstract Highlights • Database gathering performance data on more than 60 full-scale digestate separators. • Classification of separators into low and high-performance equipment. • Very distinct profiles of digestate components separation. • Dependency of separator choice and AD feedstock. • Simple approach to predict digestate separation based on equipment and AD feedstock. Abstract Digestate mechanical separation is present in numerous anaerobic digestion plants. In this study, data from literature and from unpublished analysis were gathered to evaluate digestate separation efficiency for different mechanical separators. For the first time, efficiency indicators allowed the definition of two mass distribution profiles. The low-performance profile was characterized by each component being mainly destined to the liquid fraction, excluding P, Mg and Ca in a few cases. Screw presses represented 68% of these separators and 78% of digestates came from mainly fibrous inputs such as cow manure and silage. In the high-performance profile, digestate compounds were effectively concentrated in the solid fraction, except nitrogen. The great majority of separators were decanting centrifuges, and the anaerobic digestion inputs were principally non-fibrous such as pig slurry, sludge and agro-industrial waste. This study represents a source for benchmarking digestate separation and opens a possibility to forecast more realistically digestate separation performance. [ABSTRACT FROM AUTHOR]