Sequential Substrate Removal in Response to Qualitative Shock Loading of Activated Sludge Systems

Heterogeneous populations acclimated to sorbitol or mannitol were subjected to shock loading with glucose during growth on the sugar alcohol. Under these severe shock-loading conditions, glucose caused immediate cessation of sorbitol or mannitol removal. Metabolism of these compounds was renewed subsequent to glucose exhaustion. Under similar shock-loading conditions, with the use of cells operationally defined as “old,” the sugar alcohols were removed concurrently with glucose. In the absence of a nitrogen source with old cells, the added glucose was removed slowly in the presence of sorbitol and not at all in the mannitol-acclimated system. These results indicate the potential variability in purification efficiency attributable to substrate interaction.