Bacterial treatment of soils lightly contaminated with Total Petroleum Hydrocarbons (TPH) and Volatile Organic Compounds (VOCs) is an established soil remediation technique and has been undertaken at the Sugar House Island development site.
The treatment of Polycyclic Aromatic Hydrocarbons (PAH) has proved significantly more difficult for the construction industry and material with this classification is typically landfilled.
Recent laboratory studies have indicated that mycelium ‘sweats’ associated with various fungal species may split PAH molecules into simper compounds making them more bio-available for bacteria to metabolise. A recent paper published in ‘Frontiers of Microbiology’ provides useful information on the subject based on a series of laboratory scale trials.
John F Hunt have designed and implemented a treatability trial employing three different commercially available bacteria additives and three specifically selected fungal species to determine the feasibility of treating PAH contaminated soils on a large scale. This has involved the construction of 13No 300m3 windrows, each inoculated with various combinations of bacteria and fungi. These are subject to regular monitoring and sampling.
If the myco-remediation (fungal-based soil treatment) is successful and PAH concentrations are reduced (by typically 75%), the material will be suitable for reuse. This will negate the need to export 3900m3 of soil to landfill, saving an estimated 380 wagon movements, thereby significantly reducing the carbon footprint of the works.
To find out more, click on the link below.
Monitor Report. John F Hunt. London. August 2018.