Novel anammox reactor start-up method using immobilized particles as biocatalyst and its kinetic characteristics

Anaerobic ammonium oxidation (anammox) immobilized particles were added to a reactor as biocatalyst to start an up-flow anammox reactor. The kinetic characteristics of the immobilized particles were studied using batch tests. The results demonstrated that using immobilized particles as the biocatalyst succeeded in starting the anammox reactor in 49 d. The removal rates of NH4+-N and NO2--N were 80.7 and 83.1%, respectively. The total nitrogen removal load was 0.505 kg m(-3) d(-1). The results of the kinetic characteristics study demonstrated that the half-saturation constants of the immobilized particles for ammonium and nitrite were 1.57 and 1.505 mmol L-1, respectively. These constants were lower than those of flocculent anammox sludge (FAS), which indicated that the immobilized particles utilize the substrate better in adverse environments. The half-suppression constants of the immobilized particles for ammonia and nitrite were 724.2 and 66.65 mmol L-1, respectively, and higher than those of FAS. Thus, the immobilized particles could survive longer in high-concentration substrates. As a biocatalyst in a reactor, the anammox immobilized particles exhibited robust kinetic characteristics and effectiveness, which are important to the development of new biocatalyst techniques for anammox.