Case Study: Moving soil, not money - how a site assessment unlocked onsite reuse
When a project has surplus soil, the usual answer is to truck it to landfill. It is rarely the cheapest option. On a recent project, a site assessment let our client keep the soil on site and avoid a large disposal bill.
The problem
Our client had two areas within the same parcel of land, both built on reclaimed fill. One was being converted to sealed hardstand, requiring excavation across its entirety and had several large soil stockpiles sitting on it. The other had been dug out years earlier for a development that never went ahead. Moving soil from one area to the other seemed obvious. But shifting fill without knowing what is in it creates risk for the landowner and the environment. Without data, the safe default would have been to send the soil to landfill.
What we did
We scoped the assessment around one question. Can this soil be safely reused on site? That meant looking at the site's history, how the land will be used, and who or what could be exposed. We dug test pits across both areas and tested the soil for the contaminants highlighted by our conceptual site model.
What we found
The soil was largely clean. There was no asbestos, no fuel or heavy metal contamination, and nothing that posed a risk to people working on or using the site. Low levels of PFAS were found in shallow soil, albeit below the adopted ecological criteria. As such, the results supported reuse. That is where assessment pays off. Screened against the strictest number alone, the soil would have gone to landfill. Assessed in context, it could stay.
Where the savings come from
The biggest saving is avoided disposal. Landfill costs are high and rising, with the state waste levy alone now more than $180 a tonne in metropolitan areas before transport and gate fees. PFAS makes this worse, because fewer landfills will accept it and those that do charge a premium. The second is avoided import. The empty area needed filling anyway, and reusing the site's own soil meant no clean fill to buy, validate and truck in. On top of that come fewer truck movements, a shorter programme and a smaller carbon footprint. The assessment itself cost a fraction of what disposal and import would have.
Is reuse always an option?
No. It depends on what is in the soil and where it is going. Where contamination is significant, reuse is not appropriate. Even then, an early assessment gives you an accurate picture and no surprises at the landfill gate.
The cheapest tonne of soil is the one that never leaves site. If your project has surplus soil or needs fill, talk to us early.
#LandRiskEnvironmental #ContaminatedLand #EnvironmentalRisk #SiteAssessment #SoilReuse
