Remediation of Organically Contaminated Soil Through the Combination of Assisted Phytoremediation and Bioaugmentation

Abstract

Here, we aimed to bioremediate organically contaminated soil with Brassica napus and a bacterial consortium. The bioaugmentation consortium consisted of four endophyte strains that showed plant growth-promoting traits (three Pseudomonas and one Microbacterium) plus three strains with the capacity to degrade organic compounds (Burkholderia xenovorans LB400, Paenibacillus sp. and Lysinibacillus sp.). The organically contaminated soil was supplemented with rhamnolipid biosurfactant and sodium dodecyl benzenesulfonate to increase the degradability of the sorbed contaminants. Soils were treated with organic amendments (composted horse manure vs. dried cow slurry) to promote plant growth and stimulate soil microbial activity. Apart from quantification of the expected decrease in contaminant concentrations (total petroleum hydrocarbons, polycyclic aromatic hydrocarbons), the effectiveness of our approach was assessed in terms of the recovery of soil health, as reflected by the values of different microbial indicators of soil health. Although the applied treatments did not achieve a significant decrease in contaminant concentrations, a significant improvement of soil health was observed in our amended soils (especially in soils amended with dried cow slurry), pointing out a not-so-uncommon situation in which remediation efforts fail from the point of view of the reduction in contaminant concentrations while succeeding to recover soil health.

Rhizoremediation as a green technology for the remediation of petroleum hydrocarbon-contaminated soils

“…Although some successful examples on the application of a single microbial strain in rhizoremediation are available, strong evidence shows that the bioaugmentation with a consortia is generally more efficient than individual strains for TPH degradation (Anza et al 2019;Dealtry et al 2018;Rodriguez-Campos et al 2019). Some of the desired properties for the microbial consortia for rhizoremediation that have been recommended include being able to handle abiotic stress, particularly contaminant stress, and being able to grow to the desired density under stressful conditions (Calvo et al 2014;Yang et al 2009).…”

Reduction of the soil environmental impact caused by the presence of total petroleum hydrocarbons (TPH) by using Pseudomonas sp.

“…One of the techniques used today for recovery of hydrocarbon contaminated soils is bioremediation in which bacteria are used for effective biodegradation of total petroleum hydrocarbons (TPH) (Quintella, Mata & Lima, 2019). Today, due biological and technological advances, it is much easier to resort to any of the bioremediation processes such as phytoremediation, biostimulation, bioaugmentation, among others; where they use living organisms to treat environmental pollutants (Paredes-Páliz et al, 2016a;Anza et al, 2019).…”

Effects of biological pre-treatment of lignocellulosic waste with white-rot fungi on the stimulation of 14C-phenanthrene catabolism in soils

“…Previous studies have reported the stimulation of these enzymes by lignocellulosic biomass amendment, including the improvement of soil quality, mainly in PAH-contaminated soils (Tejada et al, 2008;Anza et al, 2019). Very few studies have investigated the addition of organic waste in PAH-contaminated soil with enhanced biodegradation using lignocellulosic material-immobilized WRF (Mohammadi and Nasernejad, 2009;Ros et al, 2010;Lukić et al, 2016), but very few investigations have been reported on PAH degradation in contaminated soils after amendment with biologically pre-treated lignocellulosic waste materials, such as spent brewery grains (SBGs).…”