Phylogenetic analysis of the bacterial community in a full scale autothermal thermophilic aerobic digester (ATAD) treating mixed domestic wastewater sludge for land spread

► Phylogeny presented based on optimised niche specific molecular tools. ► ATAD contains large numbers symbionts, capnophiles and anaerobes. ► Alkalophilic cellulolytic phylotypes are keys to stability of elevated temperature. ► Dataset may have utility in bioaugmentation for improvement of ATAD sludge settling. ► Great dissimilarity in microorganisms between worldwide ATAD systems.