Nitrogen removal potential and biofilm characteristics in the anaerobic ammonium oxidation ('ANAMMOX') biofilter reactor

The effects of influent substrate concentration load, hydraulic load and total nitrogen load on total nitrogen removal rate were compared in an up-flow ANAMMOX bio-filter reactor. The deep region division and bacterial distribution in the ANAMMOX bio-film were deduced based on the theory of microenvironment and the existence of substrate transfer gradient. In addition, the composition and distribution model was obtained for the bio-film. The results showed that the maximum nitrogen removal rate in the ANAMMOX reactor increased linearly as the increasing of influent substrate concentration load, hydraulic load and total nitrogen load, respectively. The results indicated that the maximum of nitrogen removal rate, influent hydraulic load and substrate concentration of c(NH4+-N+ NO2--N) were 12 kg/(m(3).d), 4.79 m(3)/(m(2).h) and 240 mg.L-1, respectively. The microenvironment of the biofilm, portrait grads distribution of the nitrite concentration along the depth of biofilm and the high ground amount of the biomass made the nitrite resistibility increase up to 130 mg.L-1. The biomembrane system include biofacies and microenvironment were extraordinary complicated since it affected by some factors such as the inoculum of biofilm, influent organic matters concentration, dissolved oxygen concentration, mass transfer capability of biofilm and micro-environment in the bioreactor.