Thermochemical characterization of post-phytoremediated vetiver (Vetiveria zizanioides (L.) Nash) root and shoot for their prospective bioenergy potential

Enhanced phytoremediation of atrazine-contaminated soil by vetiver (Chrysopogon zizanioides L.) and associated bacteria

This work aimed to validate the removal of total petroleum hydrocarbons (TPH) in a pilot system (on-site). Six piles of oil-contaminated soil were treated with 1) bioremediation (BIO) by three simultaneous technologies (bioaugmentation (bacterial consortium), phyto- (Panicum maximum) and vermiremediation (Pontoscolex corethrurus)), and compared with 2) natural attenuation (NA). Removal of alkanes, polycyclic aromatics (PAH), total petroleum hydrocarbons (TPH), and bacterial diversity were evaluated at 0, 35, 70, and 112 days. Biomass and number of shoots of P. maximum, the secondary vegetation, and the abundance of meso and macrofauna were measured initially and at the end. After 112 days, BIO significantly removed more alkanes (76%), PAH (68%), and TPH (76%) than NA treatment (23%, 19%, 24%). P. maximum biomass increased significantly (300%), with 97.3 ± 11.8 shoots m−2. After 112 days, the secondary plants Lippia dulcis, Taraxacum officinale, Bidens pilosa and bacterial phylum Actinobacteria (18%) were the most abundant. The abundance of the earthworm Protozapotecia australis was reduced, while the most abundant group of mesofauna was Acari (56%–71%). This combination of technologies improved the development of grass and secondary plants, which generated a more favorable microhabitat for soil organisms to remove TPH more efficiently. 

Hydrocarbon bioremediation in a pilot-scale: A combination of bioaugmentation, phytoremediation, and vermiremediation

Abstract Diesel oil is known to be one of the major petroleum products that can pollute water and soil. Soil pollution caused by petroleum hydrocarbons has substantially impacted the environment, especially in the Middle East. In this study, modeling and optimization of hexadecane removal from soil was performed using two pure cultures of Acinetobacter and Acromobacter and consortium culture of both bacterial species using artificial neural network (ANN) method. Then the best ANN structure was proposed based on mean square error (MSE) as well as correlation coefficient (R) for pure cultures of Acinetobacter and Acromobacter as well as their consortium. The results showed that the correlations between the actual data and the data predicted by ANN (R2) in Acromobacter , Acinetobacter and consortium of both cultures were 0.50, 0.47 and 0.63, respectively. Despite the low correlation between the experimental data and the data predicted by the ANN, the correlation coefficient and the precision of ANN for the consortium was higher. As a result, ANN had desirable precision to predict hexadecan removal by the cobsertium culture of Ochromobater and Acintobacter . 

/pdf/modelling-of-n-hexadecane-bioremediation-from-soil-by-slurry-21agdewb.pdf

Modelling of n-Hexadecane bioremediation from soil by slurry bioreactors using artificial neural network method

Remediation of crude oil-impacted areas is a major pervasive concern in various environmental conditions. The major aim of this study was to investigate the collaboration of vetiver grass (Vetiveria zizanioides L.) and petroleum hydrocarbon-degrading bacteria to clean up contaminated soils. Vetiver grass and five native bacterial isolates were used in one consortium to remediate contaminated soil by crude oil at various concentrations (2.0, 4.0, 6.0 8.0, 10, and 12.0% woil/wsoil). The presence of isolated bacteria caused a significant (p < 0.05) increment of root-shoot ratio of vetiver in contaminated soils in comparison to non-contaminated soil. The combination of vetiver and bacterial consortium revealed efficient dissipation of more than 30% of low-molecular-weight polycyclic aromatic hydrocarbons (PAHs) and more than 50% of high-molecular-weight PAHs in all crude oil concentrations. The removal of n-alkanes in the simultaneous presence of the bacteria and plant was more than 70.0% at 10.0% of oil concentration, whereas the removals in control were 20.7, 13.7 and 9.2%, respectively. The hydrocarbons dissipation efficiency of applied treatments decreased at 12.0% of contamination. It is concluded that a combination of vetiver grass and the isolated bacteria could be a feasible strategy for remediation of crude oil-polluted soils. Novelty statementDetermination of the responses of vetiver grass under different crude oil concentrations is one of the novelties of the present study, which is helpful for demonstrating plant tolerance on polluted environments. Also, it adds information about the potential of this grass to clean up crude oil-polluted soils solely as well as in the presence of promising selected bacterial strains.

Evaluating the bio-removal of crude oil by vetiver grass (Vetiveria zizanioides L.) in interaction with bacterial consortium exposed to contaminated artificial soils

Zahra Kiamarsi

Papers

Evaluating the bio-removal of crude oil by vetiver grass (Vetiveria zizanioides L.) in interaction with bacterial consortium exposed to contaminated artificial soils