NOVELTY - The method comprises treating wastewater in an anaerobic zone (18) to remove organic matter from the wastewater and to form granules of a biomass, transferring wastewater effluent from the anaerobic zone to an aeration zone, treating the wastewater effluent with a source of oxygen and an activated sludge in the aeration zone to further remove organic matter from the wastewater effluent and to form additional activated sludge, transferring a portion of the activated sludge from the aeration zone to the anaerobic zone, and removing a portion of the granules of biomass from the anaerobic zone.    USE - The method is useful for treating wastewater such as industrial wastewater including effluent from a process for manufacturing of terephthalic acid and a biofuel (all claimed).    ADVANTAGE - The method is capable of economically and environmental friendly treating the wastewater thus providing highly purified water.    DETAILED DESCRIPTION - The method comprises treating wastewater in an anaerobic zone (18) to remove organic matter from the wastewater and to form granules of a biomass, transferring wastewater effluent from the anaerobic zone to an aeration zone, treating the wastewater effluent with a source of oxygen and an activated sludge in the aeration zone to further remove organic matter from the wastewater effluent and to form additional activated sludge, transferring a portion of the activated sludge from the aeration zone to the anaerobic zone, and removing a portion of the granules of biomass from the anaerobic zone. The growth yield of the granules of biomass is greater than 6% or the growth yield of biomass in the anaerobic zone is 12%. The anaerobic zone comprises an upflow anaerobic sludge blanket reactor. The removed portion of the granules of biomass comprises an excess of granules formed in the anaerobic zone. The portion of the activated sludge transferred from the aeration zone to the anaerobic zone is transferred directly and without any treatment steps. An INDEPENDENT CLAIM is included for a system for treating wastewater.    DESCRIPTION OF DRAWING(S) - The diagram shows a schematic view of a system for treating wastewater.    Inlet line (12)    Equalization tank (14)    Fed through line (16)    Anaerobic zone (18)    Aerobic zone. (24)