Lab-scale autothermal thermophilic aerobic digestion can maintain and remove nitrogen by controlling shear stress and oxygen supply system

Autothermal thermophilic aerobic digestion (ATAD) is used to treat human excreta hygienically. We previously reported a unique full-scale ATAD, showing distinctive bacterial community transitions and producing high-nitrogen-content liquid fertilizer; nevertheless, the mechanism remains unclear. One hypothesis involves using gas-inducing (GI) agitator. designed lab-scale GI system compared it with disk-turbine (DT) agitator by mimicking temperature shift of ATAD. The agitation its speed greatly affected physicochemical properties structure. at 1000 rpm (GI1000; high total carbon removal efficiency, 88.3%), few nitrifying denitrifying bacteria, maintained ammoniacal nitrogen concentration had more shared operational taxonomic units related Acinetobacter sp., Arcobacter Longimicrobium sp. ATAD 490 DT (DT1000). Furthermore, DT1000, abundance bacteria such as Alcaligenes aquatilis Pseudomonas caeni, removed 94.7% 71.9% efficiency. These results suggested that shear stress oxygen supply would change structure, thus performances. Consequently, possible can be applied for not only production highly nitrogen-containing fertilizer but also extremely wastewater.