Oil-Contaminated Soil Remediation with Biodegradation by Autochthonous Microorganisms and Phytoremediation by Maize (Zea mays)

Abstract

Biological methods are currently the most commonly used methods for removing hazardous substances from land. This research work focuses on the remediation of oil-contaminated land. The biodegradation of aliphatic hydrocarbons and PAHs as a result of inoculation with biopreparations B1 and B2 was investigated. Biopreparation B1 was developed on the basis of autochthonous bacteria, consisting of strains Dietzia sp. IN118, Gordonia sp. IN101, Mycolicibacterium frederiksbergense IN53, Rhodococcus erythropolis IN119, Rhodococcus globerulus IN113 and Raoultella sp. IN109, whereas biopreparation B2 was enriched with fungi, such as Aspergillus sydowii, Aspergillus versicolor, Candida sp., Cladosporium halotolerans, Penicillium chrysogenum. As a result of biodegradation tests conducted under ex situ conditions for soil inoculated with biopreparation B1, the concentrations of TPH and PAH were reduced by 31.85% and 27.41%, respectively. Soil inoculation with biopreparation B2 turned out to be more effective, as a result of which the concentration of TPH was reduced by 41.67% and PAH by 34.73%. Another issue was the phytoremediation of the pre-treated G6-3B2 soil with the use of Zea mays. The tests were carried out in three systems (system 1—soil G6-3B2 + Zea mays; system 2—soil G6-3B2 + biopreparation B2 + Zea mays; system 3—soil G6-3B2 + biopreparation B2 with γ-PGA + Zea mays) for 6 months. The highest degree of TPH and PAH reduction was obtained in system 3, amounting to 65.35% and 60.80%, respectively. The lowest phytoremediation efficiency was recorded in the non-inoculated system 1, where the concentration of TPH was reduced by 22.80% and PAH by 18.48%. Toxicological tests carried out using PhytotoxkitTM, OstracodtoxkitTM and Microtox® Solid Phase tests confirmed the effectiveness of remediation procedures and showed a correlation between the concentration of petroleum hydrocarbons in the soil and its toxicity. The results obtained during the research indicate the great potential of bioremediation practices with the use of microbial biopreparations and Zea mays in the treatment of soils contaminated with petroleum hydrocarbons.

Evaluation of the Effectiveness of Bioaugmentation-Assisted Phytoremediation of Soils Contaminated with Petroleum Hydrocarbons Using Echinacea purpurea

“…The bacterial and fungal strains used in the microbial consortia had proven abilities to metabolize petroleum hydrocarbons and did not exhibit pathogenic properties. A detailed description of the design of microbial consortia B1 and B2, along with the method of identification of the strains of bacteria and fungi present in them, is provided in a previous article [17]. More information about the microbial consortia used in the research is available in Supplementary Materials.…”

“…It has been proven that aged soils containing a greater variety of contaminants, with higher concentrations of xenobiotics, undergo the treatment process more slowly than freshly contaminated soils with a single type of contaminant. For real soils with a wide spectrum of contaminants, the efficiency of phytoremediation alone may be too low [17]. Therefore, it is critical to find a new, efficient and economically beneficial approach to the phytoremediation process.…”

“…It should also be remembered that in order to ensure the best possible efficiency of the bioaugmentation process, it is advisable to use inoculants developed on the basis of selected micro-organisms isolated from the natural environment. This avoids antagonistic interactions with naturally occurring micro-organisms in the tested soil [17]. In addition, substances can be added to the inoculant to ensure better microbial growth by providing an easily assimilable carbon source or using a natural biosurfactant, such as γ-PGA [3,17,62,63].…”

“…This avoids antagonistic interactions with naturally occurring micro-organisms in the tested soil [17]. In addition, substances can be added to the inoculant to ensure better microbial growth by providing an easily assimilable carbon source or using a natural biosurfactant, such as γ-PGA [3,17,62,63].…”

Geotechnical evaluation of residual granitic soils contaminated with gasoline

“…Remediation techniques were widely studied for oil removal in soils [10] [11], [12] have removed 12-22% of oil content in soil samples using organomineral sorbents like biofertilizer and aluminum alloys activated by tin, gallium, and indium, besides phytotoxicity decreased with the treatment. Wojtowicz et al [13] have reached 31% of biodegradation using autochthonous bacteria and fungi inoculation, and Zhao et al [14] observed 52% removal of crude oil due to bacterial consortium when for a 60-day period. Ambaye et al [15] and Michael-Igolima et al [16] have reviewed the challenges and perspectives over hydrocarbon-contaminated soil remediation aspects, and highlighted nanotechnologies and biosolutions as emerging technologies, linked to thermal desorption [8], electrochemical methods, advanced oxidation processes [17] [18], and permeable active barriers [19] [20] [21] [22].…”