Review of Bioreactor Designs Applicable to Oil Sands Process-Affected Water Treatment

Abstract

Tailings ponds contain significant amounts of organic contaminants that cannot be released to the environment without further treatment. The use of mature fine tailings (MFT) was proposed as a potential source of microorganisms for biological treatment to remove dissolved organic compounds from oil sands process-affected water (OSPW). To test the capacity of microorganisms indigenous to MFT for removal of organic compounds in OSPW, and to determine whether they could be extracted from MFT to form biofilm on biofilm carriers, two groups of batch bioreactors were established: one treating acetic-acid-supplemented OSPW, and one treating high pressure oxidation (HiPOx)-treated OSPW. In addition, several bioreactors that contained no MFT but MFT-originated biofilm were set up to test the feasibility of using MFT-originated biofilm to biodegrade organic compounds. The bioreactors supplemented with acetic acid yielded a rapid depletion of sulfate and nitrate with partial removal of chemical oxygen demand (COD). The COD was reduced from 600 mg/L to a minimum residual COD of 200 mg/L. This is lower than the COD in the original OSPW before acetic acid addition, indicating possible co-metabolic biodegradation of recalcitrant organic compounds.