Comparison between disintegrated and fermented sewage sludge for production of a carbon source suitable for biological nutrient removal

There is a need to investigate processes that enable sludge re-Use while enhancing sewage treatment efficiency. Mechanically disintegrated thickened surplus activated sludge (SAS) and fermented primary sludge were Compared for their capacity to produce a carbon Source suitable for BNR by completing nutrient removal predictive tests. Mechanically disintegration of SAS using a deflaker enhanced volatile fatty acids (VFAs) content from 92 to 374 mg l(-1) (4.1-fold increase). In comparison, primary Sludge fermentation increased the VFAs content from 3.5gl(-1) to a final concentration of 8.7gl(-1) (2.5-fold increase). The carbon source obtained from disintegration and fermentation treatments improved phosphate (PO4-P) release and denitrification by up to 0.04 mg NO3-N g(-1) VSS min(-1) and 0.031 mg PO4-Pg(-1) VSS min(-1), respectively, in comparison to acetate (0.023 mg NO3-N g(-1) VSS min(-1) and 0,010 mg PO4-Pg(-1) VSS min(-1)). Overall, both types of sludge were suitable for BNR but disintegrated SAS displayed lower Carbon to nutrient ratios of 8 for SCOD:PO4-P and 9 for SCOD:NO3-N. On the other hand, SAS increased the concentration of PO4-P in the settled sewage by a further 0.97 g PO4-P kg(-1) SCOD indicating its potential negative impact towards nutrient recycling in the BNR process. (C) 2009 Elsevier B.V. All rights reserved.