The influence of variable organic loading on the start-up of an anaerobic fluidised bed reactor

Summary A stepped-loading start-up regime utilising variable organic influent concentrations in the range 1650–11600 mgCOD1^–1 was applied to an anaerobic fluidised bed bioreactor at 37°C. The reactor was sensitive to variable influent COD concentrations, but the stepped-loading aided rapid recovery from transient organic loading shocks. Variable effluent COD levels were produced but a COD removal efficiency of 76% was obtained at a final HRT of 0.5 d and an organic loading rate of 5.3 kg COD m^–3 d^–1.