Department of Civil and Environmental Engineering, University of Alberta, Edmonton, Alberta T6G 1H9, Canada.
Department of Civil and Environmental Engineering, University of Alberta, Edmonton, Alberta T6G 1H9, Canada; Department of Civil Engineering, New Mexico State University, Las Cruces, NM 88003, United States.
Water Res. 2018 Apr 15;133:310-318. doi: 10.1016/j.watres.2018.01.001. Epub 2018 Jan 5.
In this study, a fixed-bed biofiltration system (biofilter) that utilized indigenous microorganisms was developed for the reclamation of oil sands process-affected water (OSPW). With the assistance of quantitative polymerase chain reaction (qPCR) and confocal laser scanning microscopy (CLSM), indigenous microorganisms from OSPW were able to attach to the surface of sand media and form biofilms. The number of total bacteria on the biofilter media reached a steady state (10/g) after 23 days of operation. Ultra Performance Liquid Chromatography/High Resolution Mass Spectrometry (UPLC/HRMS) analysis showed that 21.8% of the classical naphthenic acids (NAs) removal was achieved through the circulation of raw OSPW on the biofilter for 8 times (equivalent to a hydraulic retention time of 16 h). When ozonation with utilized ozone dose of 30 mg/L was applied as pretreatment, the classical NAs in the ozonated OSPW were removed by 89.3% with an accelerated biodegradation rate of 0.5 mg/L/h. Compared with other biofilm reactors such as moving bed biofilm reactor (MBBR), ozonation pretreatment could benefit the biodegradation of NAs in the biofilter more (classical NA removal: 89.3% vs. 34.4%), especially for those with high carbon number and cyclicity. The combined ozonation-biofiltration process could remove 92.7% of classical NAs from raw OSPW in 16 h. Although both ozonation and biofiltration alone did not show degradation of oxidized NAs from raw OSPW, the combined process led to a 52.9% and 42.6% removal for O-NAs and O-NAs, respectively, which were the dominant oxidized NA species in OSPW. Metagenomic sequencing analysis showed that Rhodococcus was the dominant bacterial genus on the sand media, which may play a crucial role during the NA biodegradation. With the advantage of high NA removal efficiency, the combined ozonation-biofiltration process is a promising approach for NA degradation and shows high potential to be scaled up for in-situ OSPW treatment.
在这项研究中，开发了一种利用土著微生物的固定床生物过滤系统（生物滤池），用于处理油砂加工废水（OSPW）。借助定量聚合酶链反应（qPCR）和共聚焦激光扫描显微镜（CLSM），从 OSPW 中分离出的土著微生物能够附着在沙质介质的表面并形成生物膜。在运行 23 天后，生物滤池中的总细菌数量达到稳定状态（10/g）。超高效液相色谱/高分辨率质谱（UPLC/HRMS）分析表明，通过将原始 OSPW 在生物滤池中循环 8 次（相当于水力停留时间 16 小时），实现了 21.8%的经典环烷酸（NA）去除。当应用 30 mg/L 的臭氧作为预处理进行臭氧氧化时，臭氧氧化 OSPW 中的经典 NAs 去除率为 89.3%，生物降解速率加速至 0.5mg/L/h。与其他生物膜反应器（如移动床生物膜反应器（MBBR））相比，臭氧预处理更有利于生物滤池中 NAs 的生物降解（经典 NA 去除率：89.3%对 34.4%），特别是对那些高碳数和多环的 NAs。组合臭氧-生物过滤工艺可在 16 小时内从原始 OSPW 中去除 92.7%的经典 NAs。虽然臭氧氧化和生物过滤单独处理均未显示出对原始 OSPW 中氧化 NAs 的降解，但组合工艺分别导致 O-NAs 和 O-NAs 的去除率达到 52.9%和 42.6%，这两种物质是 OSPW 中主要的氧化 NA 物质。宏基因组测序分析表明，在沙质介质上，优势细菌属为 Rhodococcus，它可能在 NA 生物降解过程中发挥关键作用。由于具有高 NA 去除效率的优势，组合臭氧-生物过滤工艺是一种有前途的 NA 降解方法，具有很大的潜力用于原位 OSPW 处理。
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