Variation of parameters affecting the start-up of methanogenic fluidized bed reactors

The influence of the medium composition, the inoculum and the inoculation procedure on initial biofilm development in methanogenic fluidized bed reactors was studied on laboratory scale. Trace minerals but not vitamins were essential for biofilm development. Inoculation with heterogeneous bacterial cultures of potentially sand-colonizing microorganisms and/or with pure cultures of Methanothrix soehngenii did not accelerate biofilm development significantly as compared to inoculation with effluent from a fully operative fluidized bed reactor.