Ecopiling: a combined phytoremediation and passive biopiling system for remediating hydrocarbon impacted soils at field scale.

Kieran J Germaine,Xuemei Liu,Jer Keohane,Samuel Kiwanuka,John Culhane,David Ryan,David N Dowling,John Byrne,Richard D Lally

doi:10.3389/fpls.2014.00756

Kieran J Germaine, Xuemei Liu + Show 7 more

Open Access

https://doi.org/10.3389/fpls.2014.00756

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Abstract

Biopiling is an ex situ bioremediation technology that has been extensively used for remediating a wide range of petrochemical contaminants in soils. Biopiling involves the assembling of contaminated soils into piles and stimulating the biodegrading activity of microbial populations by creating near optimum growth conditions. Phytoremediation is another very successful bioremediation technique and involves the use of plants and their associated microbiomes to degrade, sequester or bio-accumulate pollutants from contaminated soil and water. The objective of this study was to investigate the effectiveness of a combined phytoremediation/biopiling system, termed Ecopiling, to remediate hydrocarbon impacted industrial soil. The large scale project was carried out on a sandy loam, petroleum impacted soil [1613 mg total petroleum hydrocarbons (TPHs) kg-1 soil]. The contaminated soil was amended with chemical fertilizers, inoculated with TPH degrading bacterial consortia and then used to construct passive biopiles. Finally, a phyto-cap of perennial rye grass (Lolium perenne) and white clover (Trifolium repens) was sown on the soil surface to complete the Ecopile. Monitoring of important physico-chemical parameters was carried out at regular intervals throughout the trial. Two years after construction the TPH levels in the petroleum impacted Ecopiles were below detectable limits in all but one subsample (152 mg TPH kg-1 soil). The Ecopile system is a multi-factorial bioremediation process involving bio-stimulation, bio-augmentation and phytoremediation. One of the key advantages to this system is the reduced costs of the remediation process, as once constructed, there is little additional cost in terms of labor and maintenance (although the longer process time may incur additional monitoring costs). The other major advantage is that many ecological functions are rapidly restored to the site and the process is esthetically pleasing.

Highlights

Bioremediation may be defined as the use of biological systems to degrade or remove pollutants from contaminated environments
The objective of this study was to investigate the effectiveness of a combined phytoremediation/biopiling system, termed Ecopiling, to remediate hydrocarbon impacted industrial soil.The large scale project was carried out on a sandy loam, petroleum impacted soil [1613 mg total petroleum hydrocarbons (TPHs) kg−1 soil]
To try to address this, as part of our study we describe the combined use of phytoremediation and biopiling in a process termed Ecopiling

Summary

Introduction

Bioremediation may be defined as the use of biological systems (micro-organisms, plants, or enzymes) to degrade or remove pollutants from contaminated environments. Biopiling involves the heaping of contaminated soils/dried sediments into piles and stimulating the biodegrading activity of aerobic microbial populations by creating optimum or near optimum growth conditions within the pile (Jørgensen et al, 2000; Li et al, 2004). This includes the introduction of oxygen through aeration, adjusting pH and moisture levels, and addition of nutrients (nitrogen and phosphorus). As a consequence of these optimum growth conditions, the enhanced microbial activity results in the degradation of the bioavailable organic pollutants (Gomez and Sartaj, 2013). The effectiveness of biopiling has been successfully demonstrated at laboratory and field scale for a number of different types of hydrocarbons (Rojas-Avelizapa et al, 2007; Gomez and Sartaj, 2014; Xu et al, 2014)

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