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PeerJ. 2019 Aug 1;7:e7389. doi: 10.7717/peerj.7389. eCollection 2019.

Bioremediation of engine-oil contaminated soil using local residual organic matter.

Author information

1
Département de sciences biologiques, Université de Montréal, Montréal, QC, Canada.
2
Akifer, Boucherville, QC, Canada.

Abstract

Soil remediation industries continue to seek technologies to speed-up treatment and reduce operating costs. Some processes are energy intensive and, in some cases, transport can be the main source of carbon emissions. Residual fertilizing materials (RFM), such as organic residues, have the potential to be beneficial bioremediation agents. Following a circular economy framework, we investigated the feasibility of sourcing RFMs locally to reduce transport and assess possible bioremediation efficiency gains. RFMs were recruited within 100 km of the treatment site: ramial chipped wood (RCW), horse manure (MANR) and brewer spent grain (BSG). They were added to the land treatment unit's baseline fertilizer treatment (FERT, "F") to measure if they improved the remediation efficiency of an engine oil-contaminated soil (7,500 ± 100 mg kg-1). Results indicate that MANR-F was the only amendment more effective than FERT for petroleum hydrocarbons (PHC) reduction, while emitting the least CO2 overall. RCW-F was equivalent to FERT but retained more moisture. Although BSG contributed the most nitrogen to the soil, BSG-F retained excessive moisture, emitted more volatile organic compounds, contained less soil O2, and was less effective than the baseline treatment. Significantly more of the C16-C22 fraction was removed (63% ± 22%) than all other fractions (C22-C28, C28-C34, C34-C40), which were equally removed. Microbial community-level physiological profiling was conducted with Biolog Ecoplates™, and catabolic diversity differed between treatments (utilization rates of 31 carbon sources). MANR-F has the potential to increase PHC-remediation speed and efficiency compared to inorganic fertilizer alone. Other RFM promote moisture retention and diverse microbial catabolic activity. A variety of RFM are present across the globe and some can offer low-cost amendments to boost remediation efficiency, while reducing treatment time compared to traditional fertilizer-only methods.

KEYWORDS:

Bioremediation; Circular economy; Petroleum; Residual organic matter; Valorisation

Conflict of interest statement

Marc Amyot is an Academic Editor for PeerJ. This work was conducted by a Ph.D. student, Kawina Robichaud, as part of a governmentally-funded internship program in a private company (Akifer), aimed at better training graduate students. Akifer provided the experimental units, funded some of the analyses and provided expert advice. Akifer do not benefit in any way from this publication and they simply agreed to it for the benefit of the graduate student who will use this paper as part of her thesis. Miriam Lebeau and Sylvain Martineau are employed by Akifer Inc.

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