Effectiveness of biochar application and bioaugmentation techniques for the remediation of freshly and aged diesel-polluted soils

• Published in: International biodeterioration & biodegradation 2021-09, Vol.163, p.105259, Article 105259
• Main Authors: Guirado, María, Garrido-Sanz, Daniel, Pindado, Oscar, Rodríguez-Rastrero, Manuel, Merino-Martín, Luis, Sierra, María José, Escolano, Olga, Rivilla, Rafael, Millán, Rocio
• Format: Article
• Language: English
• Subjects: 16S; Attenuation; Autochthonous bacterial consortium; Biodegradation; Bioremediation; Charcoal; Combination biochar-bioaugmentation; Consortia; Hydrocarbons; Pollution; Pruning; Soil bioremediation; Soil pollution; Soil remediation
• ISSN: 0964-8305; 1879-0208
• DOI: 10.1016/j.ibiod.2021.105259

In order to contribute to a minimum impact on soil biocenosis during the application of in-situ bioremediation techniques, this work assessed the efficiency of a scarcely used combination of biochar and a bioaugmentation based on an autochthonous bacterial consortium. Bioaugmentation-biochar combination was assessed by using soil samples from a polluted site with two pollution scenarios: a) soil with aged diesel, and b) clean soil to which fresh diesel was later added simulating a recent pollution event. The autochthonous consortium, isolated from the aged-diesel soil, was genetically, taxonomically and functionally characterized by these authors in a previous work. The biochar used was obtained from tree pruning residues. In both scenarios, four treatments were carried out under short-term test conditions: i) natural attenuation, ii) biochar, iii) bioaugmentation, and iv) biochar-bioaugmentation combination. Our results show that the bioaugmentation-biochar combination was significantly more effective than the simple treatments. This combination produced more than 20% diesel degradation in both scenarios over twelve weeks. Simultaneously, an increase in bacterial diversity was observed in that period. Therefore, using biochar combined with bioaugmentation suggests synergies that lead to a highly efficient and environmentally friendly bioremediation processes. [Display omitted] •An autochthonous consortium from a diesel-polluted soil, was used in bioaugmentation.•Biochar addition to bioaugmentation significantly improved diesel degradation.•This combined treatment was effective for recent and aged-diesel pollution.•Relationships between bacterial communities and diesel fractions was described.•Bioaugmentation-biochar combination was environmentally-friendly soil bioremediation.