Treatment of oil sands process-affected water (OSPW) using ozonation combined with integrated fixed-film activated sludge (IFAS)

• Published in: Water research (Oxford) 2015-11, Vol.85, p.167-176
• Main Authors: Huang, Chunkai, Shi, Yijing, Gamal El-Din, Mohamed, Liu, Yang
• Format: Article
• Language: English
• Subjects: Activated sludge; Bacteria; Bacteria - genetics; Bacteria - metabolism; Biodegradation, Environmental; Biofilms; Biofilms - drug effects; Bioreactors; Carboxylic Acids - chemistry; Confocal; Extraction and Processing Industry; Genes; Genes, Bacterial; Industrial Waste; Integrated fixed-film activated sludge (IFAS); Oil and Gas Fields; Oil sands; Oil sands process-affected water (OSPW); Ozonation; Ozone - chemistry; Parents; Raw; Sewage; Waste Disposal, Fluid - methods; Waste Water - chemistry; Water Pollutants, Chemical - chemistry
• ISSN: 0043-1354; 1879-2448
• DOI: 10.1016/j.watres.2015.08.019

Two integrated fixed-film activated sludge (IFAS) reactors were operated continuously to treat raw (untreated) and ozonated (30 mg/L) oil sands process-affected water (OSPW). After 11 months, 12.1% of the acid extractable fraction (AEF) and 43.1% of the parent naphthenic acids (NAs) were removed in the raw OSPW IFAS, while 42.0% AEF and 80.2% of parent NAs were removed in the ozonated OSPW IFAS. UPLC/HRMS analysis showed that NA biodegradation significantly decreased as the NA cyclization number increased. Confocal laser scanning microscopy (CLSM) results showed that the biofilm in the ozonated OSPW IFAS was significantly thicker (94 ± 1.6 μm) than the biofilm in the raw OSPW IFAS (72 ± 2.8 μm) after 283 days of cultivation. The quantitative polymerase chain reaction (q-PCR) revealed that the abundance proportions of both nitrifier genes (AomA, NSR and Nitro) and denitrifier genes (narG, nirS, nirK and nosZ) within total bacteria were significantly higher in biofilms than in flocs in the raw OSPW IFAS system, but a different trend was observed in the ozonated OSPW IFAS system. [Display omitted] •The combined ozonation and IFAS biodegradation effectively removed COD and AEF.•Two types of biomass (biofilms and activated sludge flocs) were applied to the degradation of oil sands process-affected water.•UPLC/HRMS analysis showed that biodegradation of parent NA was dependent on the n number and -Z value.•Similar microbial community structures in activated sludge flocs and biofilms were observed in two IFAS systems.