Fig. 1: Sampling of anaerobic digesters (ADs) across the world.
From: MiDAS 5: Global diversity of bacteria and archaea in anaerobic digesters

a Geographical distribution of ADs included. b Distribution of digester technologies. CSTR Continuous stirred-tank reactor; TSAD Two-stage anaerobic digestion, UASB Upflow anaerobic sludge blanket. c Distribution of primary substrates. d Distribution of digester temperatures. The values next to the bars are the number of ADs in each group.