This study compared microbial characteristics and oil sands process-affected water (OSPW) treatment performance of five types of microbial biomass (MBBR-biofilm, IFAS-biofilm, IFAS-floc, MBR-aerobic-floc, and MBR-anoxic-floc) cultivated from three types of bioreactors (MBBR, IFAS, and MBR) in batch experiments. Chemical oxygen demand (COD), ammonium, acid extractable fraction (AEF), and naphthenic acids (NAs) removals efficiencies were distinctly different between suspended and attached bacterial aggregates and between aerobic and anoxic suspended flocs. MBR-aerobic-floc and MBR-anoxic-floc demonstrated COD removal efficiencies higher than microbial aggregates obtained from MBBR and IFAS, MBBR and IFAS biofilm had higher AEF removal efficiencies than those obtained using flocs. MBBR-biofilm demonstrated the most efficient NAs removal from OSPW. NAs degradation efficiency was highly dependent on the carbon number and NA cyclization number according to UPLC/HRMS analysis. Mono- and di-oxidized NAs were the dominant oxy-NA species in OSPW samples. Microbial analysis with quantitative polymerase chain reaction (q-PCR) indicated that the bacterial 16S rRNA gene abundance was significantly higher in the batch bioreactors with suspended flocs than in those with biofilm, the NSR gene abundance in the MBR-anoxic bioreactor was significantly lower than that in aerobic batch bioreactors, and denitrifiers were more abundant in the suspended phase of the activated sludge flocs.
Bibliographical noteFunding Information:
Dr. Liu acknowledges the financial support from the Natural Sciences and Engineering Research Council of Canada (NSERC), the Napier-Reid Ltd., Shell Canada, and the Helmholtz Alberta Initiative (HAI). Dr. Gamal El-Din acknowledges the financial support from the Helmholtz Alberta Initiative (HAI) and the NSERC Senior Industrial Research Chair (IRC) Program in Oil Sands Tailings Water Treatment through the support by Syncrude Canada Ltd., Suncor Energy Inc., Shell Canada, Canadian Natural Resources Ltd., Total E&P Canada Ltd., EPCOR Water Services, IOWC Technologies Inc., Alberta Innovates – Energy and Environment Solutions, and Alberta Environment and Sustainable Resource Development.
© 2016 Elsevier B.V.
- Integrated fixed-film activated sludge (IFAS)
- Membrane bioreactor (MBR)
- Moving bed biofilm reactor (MBBR)
- Naphthenic acids (NAs)
- Oil sands process-affected water (OSPW)