Impact of temperature, microwave radiation and organic loading rate on methanogenic community and biogas production during fermentation of dairy wastewater

► Dairy sewage treatment in a new reactor joining suspended sludge and trickling bed. ► Fermentation at 1 or 2 kg COD/(m3 d) at 35 or 55 °C kept by microwaves or convection. ► Temperature and microwaves as main factors affecting species succession of Archaea. ► Microwaves promoted methanogens' diversity and supported biogas production. ► Methanosarcinaceae determined Archaea diversity and methane-rich biogas production.