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 374mgl −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 (PO 4 -P) release and denitrification by up to 0.04mgNO 3 -Ng −1 VSSmin −1 and 0.031mgPO 4 -Pg −1 VSSmin −1 , respectively, in comparison to acetate (0.023mgNO 3 -Ng −1 VSSmin −1 and 0.010mgPO 4 -Pg −1 VSSmin −1 ). Overall, both types of sludge were suitable for BNR but disintegrated SAS displayed lower carbon to nutrient ratios of 8 for SCOD:PO 4 -P and 9 for SCOD:NO 3 -N. On the other hand, SAS increased the concentration of PO 4 -P in the settled sewage by a further 0.97gPO 4 -Pkg −1 SCOD indicating its potential negative impact towards nutrient recycling in the BNR process.