The objective of this study was to determine if there was any difference in the bioremediation of oil sands process-affected water (OSPW) and to quantify and identify bacteria present in different scenarios. Two reactors were compared in this study: an acetic acid amended OSPW bioreactor, (AAAO bioreactor) and a HiPOx treated OSPW bioreactor (HTO bioreactor). The AAAO bioreactor contained 1750 mL OSPW and 250 mL of mature fine tailings (MFT). The second bioreactor contained the exact amount of OSPW and MFT with the only difference that OSPW was treated with an advanced oxidation process (HiPOx). The AAAO bioreactor was able to remove 70% of COD and 15% of naphthenic acids (NA). The HTO bioreactor removed 48% of COD and 19% of NA removal under nitrate reducing conditions. Bacterial quantification showed that sulfate reducing bacteria (SRB) was the dominant specie at the end of the AAAO bioreactor operation with a final 4.2x106 copy number per gram. In contrast, the HTO bioreactor showed that total bacteria was the dominant specie with 7.0x107 copy number per gram. A community analysis was performed on both bioreactors. In the AAAO bioreactor bacteria identified were Acidovorax sp., Acidovorax ebreus, Acidovorax defluvii, Cryobacterium psychrotoleans, Brachymonas petroleovorans, and uncultured members of the Desulfocapsa and Syntrophacea genus. In the HTO bioreactor, identified bacteria were Acidovorax sp., Hydrogenophaga defluvii, Rhodoferax sp., Desulfotomaculum sp., Pseudomonas stutzeri and uncultured members of the Desulfocapsa genus.