The presence of heavy metals in soils and waters associated with former industrial activities is a common environmental problem. Heavy metal contamination may pose risks and hazards to humans and the ecosystem through direct ingestion or contact, the food chain, drinking of contaminated groundwater, reduction in food quality and land tenure problems. Heavy metals cannot be destroyed and therefore can persist in the environment for a long period of time.
Typical remediation technologies considered for reducing the harmful effects at heavy metal impacted sites often include:
Excavation and physical removal – whilst relatively rapid, this presents the most expensive and unsustainable option.
Stabilisation – binding heavy metals in-situ so not readily absorbed by plants, animals. It can be half the cost of ‘dig and dump’ but constrained by programme and space.
Phytoremediation – plants can be used to prevent wind and water erosion that spread contamination. Potentially less than a quarter of the cost of exaction but takes time to accomplish.
Soil Washing – an expensive treatment option that utilises specialist water based plant to ‘scrub’ contaminated soils. This produces concentrated contaminated sludge and large volumes of wash water.
In response to the limitations provided by these remedial methods, Dunton Environmental has developed Regener8-19 to target heavy metal contaminants in soils. This rapid treatment approach induces chemical reactions within the soil to form stable, inert compounds that no longer present a risk to the environment.
The technique has been successfully implemented on a number of projects throughout the UK. One recent example, includes the rapid treatment of 10,000m3 of Lead impacted soils for Crest Nicholson (Case Study). The process reduced the total Lead concentrations by 72% and the leachate values by 93% within 2 weeks of product application. The process diverted all waste from hazardous landfill and enabled the safe re-use of materials on-site.
Dunton also operates a number of off-site Soil Treatment Facilities across the UK where such remedial techniques can also be implemented. Waste arisings that would otherwise be disposed of at landfill can now benefit from these tax-free and sustainable waste management centres.