An industrial scale UASB reactor treating a brewery wastewater was monitored during several
months, in order to assess the usefulness of a morphological parameter relating the filaments length to the
projected area of aggregates, LfA, to anticipate washout problems. It was observed that a selective washout
of filamentous bacterial forms could explain the decrease of the acetoclastic and hydrogenophilic activity
observed in the trial period. This selective washout was predicted by a peak in LfA that occurred just before
a steady increase in the effluent VSS values.Grant SFRH/BD/3187/2000.Fundação para a Ciência e a Tecnologia (FCT) – PRAXIS XXI/BD/20325/99
