Start-up regimes for anaerobic fluidised systems treating diary wastewater

Four anaerobic fluidised-beds were started-up on a dairy-type effluent of 5000 mg COD litre⁻¹ using different regimes: (a) two-phase; (b) Ca²⁺ addition; (c) polymer addition; and (d) control. Substrate removal efficiencies reached 76–92% at 9·4 kg COD⁻³ day⁻¹ in the two-phase, calcium- and biopolymer-amended reactors. The data suggest that removal efficiency and biomass concentration peaks were variable but mature biofilms, which were dependent on the protocol applied, were developed in the above-mentioned three reactors. Volatile fatty acids concentrations were reflected by intermediary/partial alkalinity variations.