Anaerobic biological treatment of high strength cassava starch wastewater in a new type up-flow multistage anaerobic reactor

► A new type up-flow multistage anaerobic reactor (UMAR) was designed. ► UMAR can effectively treat high COD concentration cassava starch effluent. ► UMAR system is able to withstand fluctuate of the organic loading rate and pH. ► Second order kinetic model and modified Stover-Kincannon model can be used to UMAR. ► Methanothrix bacteria with high activity were dominant in the anaerobic sludge.