THE ESTABLISHMENT AND CHARACTERIZATION OF A NITRIFIER POPULATION IN ACONTINUOUS-FLOW MULTISTAGE MODEL USED TO STUDY MICROBIAL-GROWTH AND INTERACTIONS INHERENT IN AQUATIC ECOSYSTEMS

The enrichment, isolation and establishment of a population of nitrifi ers within a continuous-flow multi-stage model is described. The estab lishment and, subsequent, spatial separation of the components of a ni trifier population within the model appeared to be dependent on: speci fic growth rate/overall dilution rate, as dictated by the cumulative c hamber volume, at various points a long the model; and the interaction s between the micro-organisms and the prevailing environmental conditi ons. With time, nitrifying activity appeared to be grown-rate independ ent and true steady-state conditions were not achieved due to the pres ence of mixed microbial populations and the gradual accumulation of fl occulant biomass and biofilms which facilitated increased nitrifying a ctivity. These factors have important implications for subsequent pert urbation studies which must be made before the various processes of ni trification become consolidated in the same space.