Exploiting the intrinsic hydrocarbon-degrading microbial capacities in oil tank bottom sludge and waste soil for sludge bioremediation

Abstract

In this study, biological methods (biostimulation and bioaugmentation) were used to treat oil tank bottom sludge contaminated soils to total petroleum hydrocarbon (TPH) levels suitable for landfill disposal. The sludge's hydrocarbon-degrading microbial capacities were initially compared to those from other contaminated environments using culture-based methods. Results indicated that a fungus, Scedosporium dominated the sludge microbial community. Its application in a nutrient formulation resulted in greater reduction in oil tank bottom sludge viscosity (44 %) and residual soil hydrocarbon compared to hydrocarbonoclastic microorganisms from other sources (26.7 % reduction in viscosity). Subsequent field-based experiments showed greater TPH reduction (54 %) in fungal-nutrient-treated sludge-waste soils than in naturally attenuated controls (22 %) over 49 days. 16S ribosomal ribonucleic acid and internal transcribed spacer regionbased polymerase chain reactions and denaturing gradient gel electrophoresis analyses showed minimal effects on the microbial communities during this time. TPH reduction to landfill disposal levels occurred at a slower rate after this, falling below the 10,000 mg kg -1 legislated TPH disposal threshold earlier in amended samples (91.2 %; 9,500 mg kg -1 ) compared to the control (82 %; 17,000 mg kg -1 ) in 182 days. The results show that the intrinsic hydrocarbon-degrading microbial capacities in sludge are better suited for sludge degradation than those from other sources. The substantial TPH reduction observed in control samples demonstrates the beneficial effects of natural attenuation with waste soils for oil tank sludge treatment. Microbial capacities in sludge and treated waste soils can therefore be successfully employed for treating oil tank bottom sludge.

Diagnosing bioremediation of crude oil-contaminated soil and related geochemical processes at the field scale through microbial community and functional genes

“…Oil contamination in water and soil is a worldwide environmental problem (Lu et al 2014), posing a huge threat to human health and natural ecosystems (Chen et al 2015). Compared with physical and chemical remediation, bioremediation is regarded as the optimal method for remediation of oil-contaminated soil because it is inexpensive, efficient, and applies environmentally friendly processes (Adetutu et al 2015). The successful application of bioremediation techniques, such as bioaugmentation, biostimulation, and phytoremediation, for remediating oil spills was reported in numerous studies (Adams et al 2015;Cai et al 2016;Mrozik and Piotrowska-Seget 2010;Yavari et al 2015).…”

Bioremediation of Hydrocarbon-Polluted Soil: Evaluation of Different Operative Parameters

“…These contaminants can be accumulated in soil due to their low degradation rates, affecting the physical, physiological, and biochemical properties of this valuable resource [9][10][11]. Furthermore, hydrocarbon pollution poses serious risks to human health [12][13][14][15], due to the toxic effects (e.g., mutagenicity and carcinogenicity) and the capability to move through the food chain [16,17]. Hence, special attention is required not only to remediate this pollution and prevent their threats to humans and ecosystems but also to recover the polluted areas and give them back to local communities for safe use [18][19][20].…”

Effective Removal of Alkanes and Polycyclic Aromatic Hydrocarbons by Bacteria from Soil Chronically Exposed to Crude Petroleum Oil

“…Short and long-chain alkanes and PAHs were the most common components of crude oil. Many organisms utilize these components as carbon and energy sources (Zawierucha et al, 2014;Adetutu et al, 2015;Ahmad et al, 2015). Despite their hydrophobicity, long-chain alkanes and PAHs can be degraded by microorganisms but at a slower rate (Chen et al 2017b).…”