Thursday, May 11, 2023

Where does all that excavated dirt end up?

There was an illuminating article in the Globe and Mail today about the disposal of excavated dirt from construction sites.

In a city the size of Toronto, and with as much development going on as there is here, an awful lot of soil, dirt and rubble is being moved every day. There is a constant stream of those triple-axle dump trucks moving through and out of downtown (I know because I regularly get stuck behind them). 

I have often wondered what happens to it all. I had some vague notion that most of it still ends up on the Leslie Street Spit, where it provides the base for Tommy Thompson Park and the  nature reserve there. I should probably have known that the truth would not be quite so benign.

The province of Ontario as a whole generates over 25 million cubic metres of excess silt, clay, gravel and other soils each year from construction projects, and most of it is transported by hired haulage companies and subcontractors, often self-employed individuals, which operate under little or no regulation. The cost of managing this excess soil represents as much as 14% of the total costs of construction projects, so it's actually a big deal.

It may surprise you to discover, then - or maybe not! - that those many thousands of truckloads are moved around with little to no documentation or supervision. There are virtually no rules governing where and how this dirt is disposed of. In fact, there used to be literally no rules, but recently Ontario has introduced a public registry detailing the volumes of soil to be excavated, what type and what chemicals it contains, where it us being taken to, and by whom.

To be fair, some of the more responsible contractors have been doing this very thing for years. But many more have not, and, even with the new rules, there is little in the way of supervision and enforcement to ensure compliance. Usually, the process would be as basic as an antiquated system of tear-off paper tickets. 

Furthermore, there are few checks on the content and contamination levels of excavated dirt. Although there have been a few high-profile court cases over the years over misidentified contaminated soil, it is anybody's guess how much other bad stuff has slipped through the net.

Much of the excavated dirt ends up in landfills, where it incurs tipping fees and takes up valuable landfill space. Soils containing known contaminants are supposed to go to licensed treatment facilities for remediation, but not everything goes where it is supposed to (some project managers actually hire students to follow disposal subcontractors to see where they go). Some of it is used on airfields, where is provides a base for runway extensions, and to help fill in gravel pits and quarries. 

But some of it - and we have no idea how much - is just dumped in rural areas, wasteland, flood plains, even environmentally-sensitive wetlands. Very little soil is recycled or reused - although the separation technology exists, it costs money and developers typically don't want to spend money unnecessarily. "Fill brokers", middlemen who match soil generators with users, do exist, but they too cost money and are under-utilized.

The new Ontario laws will certainly help. They set out criteria for reusing excess soil, excavation, soil testing, data tracking and other aspects of soil handling, all managed by a new Resource Productivity and Recovery Authority. The rules are being introduced in phases, e.g. dumping reusable soil in a landfill will not be permitted come 2025. All of this will cost developers more, so they are not happy, although they have already had so many kickbacks from the Ford government that they probably don't feel able to complain too much. 

And still there are questions about enforcement of the new rules. The new regulatory authority still has not issued any penalties, preferring to address issues of non-compliance with "education and outreach". It seems likely that the old "dig-and-dump" policy, utilized officially or otherwise by contractors, may well continue for some time, mainly motivated by economic considerations.

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