Patent ID: 8864993

Claim:
A method of biologically treating wastewater in a wastewater treatment system to remove carbon and ammonium from the wastewater, the method comprising: A. treating the wastewater in a mainstream including: 1. separating primary sludge from the wastewater and producing a primary effluent having a relatively low ammonium concentration and a relatively low temperature; 2. directing the primary effluent to at least one mainstream reactor; 3. biologically treating the wastewater in the mainstream reactor to remove carbon from the wastewater and producing a secondary effluent and secondary sludge; B treating the primary sludge and secondary sludge in a sidestream including: 1. directing the sludge to a sidestream anaerobic digester and treating the sludge in the anaerobic digester to produce digested sludge; 2. directing the digested sludge to a sidestream dewatering system and dewatering the digested sludge to produce reject water having a relatively high ammonium concentration and relatively high temperature; 3. directing the reject water to a sidestream deammonification biofilm reactor having biofilm carriers therein and growing a biomass on the biofilm carriers for simultaneously nitrifying and denitrifying ammonium; 4. utilizing the biomass on the biofilm carriers in the sidestream biofilm reactor to simultaneously nitrify and denitrify ammonium; C. after the biomass has been subjected to the reject water and the relatively high ammonium concentration therein, contacting the secondary effluent in the mainstream with the biomass and utilizing the biomass to reduce the ammonium concentration in the secondary effluent; D. after contacting the secondary effluent in the mainstream with the biomass and removing ammonium from the secondary effluent, rejuvenating the biomass by contacting the biomass with the reject water having the relatively high ammonium concentration and relatively high temperature in the sidestream; and E. continuing to alternate contact of the biomass with the secondary effluent and the reject water to: 1. remove ammonium from the secondary effluent in the mainstream; and 2. remove ammonium from the reject water and rejuvenate the biomass in the reject water in the sidestream.