Using prototypes to enable development of commercially viable field scale contaminated site remediation processes

Soil structure was damaged from solvents and localised heating after a large fire which had potential to limit bioremediation of an industrial site. Laboratory prototypes (biopile, bioflushing, bioreactor, slurry reactor) for treating the site contamination were developed. After successful laboratory testing (96% removal of main contaminant, phenol), the bioflushing prototype was then applied in the field. Field prototype removed 95% phenol using a small scale 2000 L bioreactor. Field trial was then scaled to commercial clean-up. Intensive soil grid sampling after 600 days treatment revealed hotspots of solvents remaining as well as the heterogeneity in the subsurface, however overall concentrations were substantially decreased below the initial assessment. The process decreased initial soil phenol concentrations of approximately 500 mg/kg (pre-treatment area average) to 75 mg/kg across the most contaminated areas. Phenol toxicity increased with depth and is linked to increasing oxygen deficit. The study demonstrated the prototyping process enabling site clean-up and scaling for bioremediation at the industrial site, provided certainty for site owner on treatment elements and achieving improved environmental and commercial outcomes.