What’s the Dirt on Resource Regeneration?
Have you ever wandered past a colourful mural with a rendering for a cool new condo development and noticed the huge gaping hole in the ground behind it? Did you ever wonder where all the dirt went after it came out of the hole?
Most people don’t! And most people, like me, are surprised to learn that more often than not, the dirt goes into the back of a truck and gets hauled away to a landfill.
Wait. Why can’t the dirt just get reused for gardening? What about placing it in a farmer’s field?
The excess soil from The Hole is usually a mix of old fill from whatever was there before, sand, gravel, silt, organics like topsoil and tree roots, and perhaps bits of concrete and brick or scrap metal. And as you dig deeper or if you're close to the ocean, you might find salty clay (including blue clay...which is actually grey). Turns out it's not the same soil you'd put on your garden or in a farmer's field. That’s the first reason that dirt from The Hole is often landfilled.
Aside from the physical properties of excess soil that make it unsuitable for reuse, there’s also the potential issue of contamination. Most urban developments aren’t breaking ground on untouched land. They typically involve building something new where something old used to be. As downtown cores expand outward, the sites that come up for redevelopment usually have prior commercial and industrial uses. Auto repair shops. Gas stations. Dry cleaners. Factories. And when a site changes use (from industrial to residential, for example), the soil that sits on the property needs to meet the standard for the new use.
As you can imagine, the soil standard is (and should be) cleaner for places where humans live, versus a place where cars are fuelled. If soil is too dirty for a new site use, the landowner can monitor the soil and hope that contamination will naturally decrease over time. This is why you'll see old gas station sites sitting empty for years. Or they can excavate and pay to have the soil hauled away and disposed of at a suitably permitted facility, which is quicker and more certain—a cradle-to-grave solution. But landfills with permits to receive contaminated excess soils are expensive and typically located far away from cities.
There are no permitted facilities that accept metals-contaminated soils on Vancouver Island; the material needs to be trucked or barged to the Mainland for disposal. The cost for this can run upwards of $150/tonne. Multiply that by the typical ~4000 - 10,000 tonnes of soil that’s excavated to build a condominium parkade, and a developer faces significant remediation costs before construction even begins. Letting the site sit for a few years is often the only viable alternative.
None of this was an especially big deal in years past — if a site was going to be too costly to remediate, you’d simply find a cleaner or better site to build on. But now that land is becoming scarcer and more expensive in and near cities, options are limited and redevelopment of previously developed and potentially contaminated sites (also known as Brownfield Development) is becoming the norm.
There are some big problems with the ‘cradle to grave’ soil lifecycle today. Existing landfill capacity is limited, and new landfills are much harder to site, permit and construct than they were in the past. This drives up the price of soil disposal, making new projects harder and harder to get off the ground, limiting options for things like housing in places where it’s critically needed. Secondly, the growing demand for aggregate to support concrete production and construction projects means more mining for virgin sand, gravel and rock, and more emissions involved in extracting and transporting these materials to the job site. Remember all of that dirt that came out of The Hole? It gets replaced with new concrete and gravel.
At GRT, we saw an opportunity to solve a number of these challenges at the same time. In June 2021 in Nanaimo, BC, we opened the first Resource Regeneration Facility in Canada that is permitted to receive hydrocarbon and metals contaminated soils and dredgeate.
We accept soil by truck or barge, then wash and sort the material, producing clean recycled aggregate products for the construction industry. Our process uses water to wash off contaminants, and screens to separate the components by size and type: rocks, sand, organics, clay. We treat all of the water and reuse it in a closed-loop system. To date, we have processed over 50,000 tonnes of soil and kept 90% of it out of the landfills (sometimes the clay doesn’t wash clean enough to be reused). That 90% of material diverted from the landfill then becomes a useful commodity that’s integrated directly back into the local market, reducing the demand for virgin material.
We’ve been relatively fortunate here in North America that our vast expanses of land and abundant resources have allowed us to carry on cradle-to-graving for as long as we have. But we think it’s time to say goodbye to this linear approach in favour of a more circular solution that’s better for our customers, the people they serve, and most of all, the earth.
To learn more about GRT’s Resource Regeneration Facility, please reach out to our team.
