Site characterization

In northern France, in the industrial suburbs of Rouen, a former Shell and Petroplus refinery was dismantled and rehabilitated by VALGO.

This site lays beneath the Seine River, on alluvium layers, over a fractured chalky bedrock with a shallow aquifer. Numerous oil spillages were treated or under treatment.

Refining activities, during more than 80 years, left behind:

• Above ground level, superstructures visible from miles away.
• Hydrocarbon residues in all tanks and pipes, on surface and underground, and in the subsoil, especially floating pure phase upon the groundwater (LNAPL).
• Nature of the products: refining convert crude oil into multiple end products, owing very diverse properties regarding penetration, accumulation or attenuation.
• All of them are petroleum hydrocarbons, but viscosities and densities cover a wide range from light essences to heavy tars.

Small pilots

The production of one ton of a selected white rot fungal strain was carried out by Novobiom to implement four distinct soil mycoremediation setups.

• Static configurations in 1 m³ containers with air flow systems: inoculated as well as non inoculated fungal substrate were brought to the contaminated soil with distinct implementations:
  • As a homogeneous mix
  • As a unique layer of fungal substrate
  • As multiple fungal substrate layers
• Dynamic configurations: inoculated and non-inoculated fungal substrate was homogeneously mixed with the contaminated soil and assembled in piles (1 m³), with monthly mechanical mixing, to allow air renewal into the piles.

All configurations were periodically monitored for temperature, water content, electrical conductivity, while gas and soil were sampled for total petroleum hydrocarbons (TPH) quantification.

Full-scale demonstrator

The fungal enrichment production of a specific fungal strain was achieved following two steps using solid state fermentation technology:

• Validation of a specific fungal substrate formulation exploiting lignocellulosic waste: with a specific attention to provide optimal substrate granulometry, structure and chemical composition, enabling substrate pasteurisation and robust fungal growth.
• Validation of substrate colonisation by specific fungal strains to be used for soil mycoremediation, carried out on 18 t of pasteurised fungal substrate.

On July 2023, two 50 t mycopiles with air extraction systems were installed to mimic onsite soil mycoremediation implementation.

• A 7x3x1,5 m bioaugmented pile with strain specific inoculated fungal substrate (from the production scale-up trial).
• A 7x3x1,5 m biostimulated pile with non inoculated substrate.