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In this work we evaluated the combination of nitrification and anammox bacteria in a single tank to remove ammonia by deammonification process. The deammonification process is a completely autotrophic nitrogen removal approach that eliminates the carbon needs for denitrification. Thus, it can be a promising approach for the biological removal of ammonia (NH4+) from anaerobic digester effluents that are low in carbon and high in ammonia concentration. A high performance nitrifying sludge, HPNS (NRRL B-50298), was mixed with anammox bacterial sludge, Brocadia caroliniensis (NRRL B-50286), in a single reactor. The reactor was an aerated vessel operated under continuous flow. It contained biofilm plastic carriers that were fluidized by the aeration. The process water temperature was 22oC and DO <0.5 mg/L. It was tested using inorganic synthetic wastewater and anaerobically digested swine wastewater. Ammonia removal rates of 1.2 kg N/m3-reactor/day were obtained with influent wastewater concentration of 440 mg/L NH4-N and a removal efficiency of 87%. The stoichiometry of the reaction obtained was consistent with deammonification process combining partial nitritation and anammox. Analyses of the 16S rRNA of the single tank bacterial community detected Brocadia caroliniensis and Nitrosomonas europaea, and a large number (54 to 63%) of Bacteroidetes. Results obtained with the deammonification process showed several advantages over nitrification/denitrification: 1) it reduced 56% of the oxygen requirements to remove the ammonia; 2) it did not require carbon; and 3) it removed nitrogen at higher rates in a single-tank, further reducing equipment costs. Therefore, deammonification can be a key technology for development of more economical and energy efficient biological ammonia removal systems in the near future.