Role of storage phenomena on removal of different substrates during pre-denitrification.

Removal mechanisms of different substrates during the pre-denitrification step of an anoxic/aerobic sequencing process are studied. Biomass was cultivated in an anoxic/aerobic SBR and fed with a mixture of low and high molecular weight compounds. Substrate removal mechanisms are studied by means of batch tests, performed under anoxic conditions. The dynamic response to a spike of four different substrates (acetate, glucose, glutamic acid and ethanol) is described by simultaneously considering substrate and electron acceptor removal, and PHB and carbohydrates storage. PHB storage is a relevant mechanism during the removal of acetate and ethanol, while glucose is removed mainly by carbohydrate storage.