The number one challenge associated with most site remediation designs and methodologies is that 90-95 per cent of all environmental contaminants are present in an adsorbed phase onto soil and bedrock surfaces within both saturated and unsaturated zones. Contaminants, including hydrocarbons (LNAPL), chlorinates (DNAPL) and heavy metals, are sorbed onto the substrates and so have reduced mobility and low water solubility. These factors greatly limit the availability of the subject contamination for extraction or treatment during in-situ and ex-situ remediation treatment.
This condition is further exasperated when the contamination is in fine-grain soil media, from silty sand to silty clays, which greatly reduces permeability and increases the surface area onto which the contaminants may absorb. The absorbed contamination will often exhibit reduced mobility and limited availability for treatment using many common technologies and processes.
This reality limits the effectiveness of several soil and groundwater remediation technologies. These include in-situ pump and treatment (P&T), bioremediation of recalcitrant compounds and chemical oxidative and chemical reductive treatment approaches, both onand off-site. As a consequence, site remediation can be much longer than desired and exceed even the best of cost estimates, a source of considerable frustration for many clients. If we could overcome contaminant adsorption, we could improve most forms of soil and groundwater remediation.
Water is often viewed by engineers and scientists as a single molecule of H2O, when in fact it is not. It is actually a conglomeration of water molecules called ‘clusters’ due to the attractive force called ‘hydrogen bonding’ that exists between neighboring water molecules. Hydrogen bonding gives rise to water’s surface tension of 72 dynes, which is very strong for a liquid and explains why water beads on a surface. If we could reduce the size of water clusters and lower surface tension, the effective permeability (K) of water would increase for fine grain soil and bedrock.
Applying Ivey-sol surfactants
That’s where Ivey-sol’s Selective Phase Transfer Technology comes in. The technology is comprised of several non-ionic surfactant formulations that work at the molecular level to selectively desorb and encapsulate contaminants from soil and bedrock surfaces, groundwater and solid waste. It has also proven very effective at liberating into solution petroleum hydrocarbons, Polycyclic Aromatic Hydrocarbons (PAH) and Poly Chlorinated Biphenyl’s (PCB), plus chlorinated solvents, MTBE and heavy metals.
The approach makes the desorbed contaminants more hydraulically available for extraction by pump and treatment; more bio-available for bioremediation; and by increasing the dissolved aqueous-phase contaminant concentration it improves their chemical availability for oxidative and/or reductive treatment.
Ivey International founder and CEO George Ivey said 90-95 per cent of small to medium size sites in North America have been successfully remediated in less than 18 months on average, with many completed in less than a year. The selected surfactant is typically applied through injections wells if on-site or mixed with the soil and water in a rotation treatment unit if off-site.
A service station case study in Canadian Environmental Protection magazine expected substantial savings. SteveWasson of oil and gas industry specialist Key Safety Services said: “This process is very cost effective and will save between C$40,000 to $60,000 [$47,000 to $71,000] compared to the closest available technology that we are aware of.” Ivey is now keen to break into the Australian market and has been talking to a number of companies about testing the product on local soils. He will present at Enviro 06 in Melbourne in May.