Bioremediation is considered an innovative technology, essentially because current knowledge concerning the fundamental mechanisms of biodegradation does not allow for a large and safe application of biotechnology. Pre-assay and ongoing monitoring of biotechnology in the laboratory can provide the basic scientific and technical information which assist to improve the efficiency in the field.
Two soil bioremediation projects were implemented with parallel assistance of laboratory simulations: (1) The Soil Recycling Demonstration Plant at the Toronto Harbour and (2) The soil decontamination of a Montreal refinery site. The clean-up of the first site is complete while the second is still in progress.
Both sites are highly contaminated with petroleum hydrocarbons (20–30% Oil and Grease) and heavy metals (e.g. >600 ppm of Pb). The remediation techniques included combined physico/chemical and bioremediation processes in order to tackle both types of contamination. Biostimulation was simulated in large bench-scale reactors in both bio-slurry and solid state form depending on the requirements of the project.
The bioremedmtion controlling parameters which have been assessed in these studies include: a) screening of reagents, b) optimization of nutrients and oxygen dosages (concentrations, mixing gradients, contact time), c) effects of hydrocarbon/soil ratios, d) biodegradation pathways and persistence of products, e) microbe family strains and the effects of redox and pH on population growth.
The results showed that valuable scientific and practical information can be obtained from laboratory experiments performed on actual contaminated soils. The major practical advantage being the greater flexibility they provide at lower expense.