Contaminated dirt at Hamilton water plant will cost millions, delay construction

The city expects nearly 75,000 tonnes of soil befouled with polychlorinated biphenyl (PCBs) to be trucked away from the construction site of Hamilton's water treatment plant by this summer.

The estimated cost of dealing with the PCB-laced dirt at the Woodward Wastewater Treatment Plant is about $18.4 million and months of delay.

We do hope that is it," city water director Andrew Grice said Monday. But I don't expect that to grow much from there in terms of quantity."

The contamination was discovered during the city's roughly $330-million revamp of the Woodward Avenue sewage plant, which releases treated effluent to the Red Hill Creek and Hamilton Harbour.

The source of the PCBs is an old landfill site on Brampton Street that was closed in the 1970s before current hazardous waste laws came into effect.

Of the 75,000 tonnes unearthed so far, about 66,000 is classified as contaminated while 9,500 is hazardous.

The cost to dispose of the more serious hazardous dirt is $1,176 per tonne while the contaminated variety goes for $60 per tonne, noted a staff report before councillors Monday.

To date, the hazardous soil has cost the city about $11 million, project director John Helka told them. So that is a substantial cost that was unforeseen at the time."

The contaminated soil is sent to the Terrapure Environmental dump in upper Stoney Creek, while the hazardous material must be trucked to a more specialized landfill in Quebec.

The construction job is made up three principle contracts:

• $87.5 million for upgrades to the main pumping station;

• $60.9 million for electrical and chlorination improvements;

• $165 million for tertiary treatment that uses disc-filtration technology, bigger aeration tanks and a chlorine contact tank.

This is huge. This is a game changer, really, for the city," Grice told The Spectator.

The improved quality of the effluent leaving the plant will lead to the overall rejuvenation of Hamilton Harbour."

So far, 318,319 tonnes of mostly clean dirt - or about 15,000 truck loads - have been dug up since construction started on the massive project in 2017.

Grice said the city and contractors are following provincial environment ministry regulations to tarp off" the contaminated dirt to stop it from making its way into the creek.

A consultant the city hired to conduct soil and groundwater tests in 2010 didn't detect any PCBs, but a significant amount" was found when the electrical work got underway, Helka said during Monday's water subcommittee meeting.

The city avoided an expected bill of $9 million to deal with that soil through a soil segregation" effort that separated the hazardous and contaminated dirt, reducing the cost to about $1.4 million.

But that put the schedule back several months, and the city expects the contractor to pass the associated costs along through a delay claim," Helka said.

In addition, a significant amount" of more problematic soil was found during the tertiary treatment work, presenting an estimated cost of $17 million.

There are enough funds in the overall budget to cover that, but there may be a requirement" to top it up during the 2022 water-rate budget, Helka said.

The Woodward project's substantial completion" was initially pegged for December 2021, but now work is expected to wrap up in November 2022.

Coun. Lloyd Ferguson praised staff for no lost time due to injury with more than a million worker hours logged so far. You guys need to celebrate that."

Teviah Moro is a Hamilton-based reporter at The Spectator. Reach him via email: tmoro@thespec.com