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

Abstract

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.