August 28, 2008

PATRICK McCONNELL

The historic Rideau Canal, above, will see some changes to its landscape in coming months as the Smith Falls water treatment facilities are built on a tiny piece of land on its banks. Although small, the facility will have a big production capacity of 19 million litres when the plant is operational next summer.

Innovation

Small plant in Smith Falls, Ontario is big on unique features

Processing features finalized during two design stages

DON PROCTER

correspondent

SMITH FALLS , ON

In the world of water treatment facilities, the Smith Falls Water Treatment Plant is tiny. Situated on a very small parcel of land on the banks of the Rideau River, it will have a production capacity of 19 million litres when construction is completed next summer.

Small as it is, the plant is a complex project largely because it incorporates a number of modern treatment process technologies a plant could have these days, says Zoran Filinov, project manager, R.V. Anderson Associates Limited (RVA), the plant’s designer.

Among its features is the AquaDAF, a proprietary dissolved air floatation (DAF) treatment, which is the very first application of its kind in Ontario, he says.

The project had to be designed twice before it could proceed. The original design was tendered at $33 million, which was much higher than the town’s budget, even though the province and the feds kicked in $6.6 million each through the Canada-Ontario Municipal Rural Infrastructure Fund (COMRIF).

To pare the budget, RVA produced a new design. It replaced the mechanical thickening equipment with a simpler decanting system in the backwash equalization tank and placed Granular Activated Carbon (GAC) caps in the filter cells, in lieu of the ozone system for taste and odour control, among other revisions.

Overall, the redesign reduced the building footprint by about one third. A similar reduction was applied to the inground reservoir capacity. Those and other changes brought the price down to $21.8 million, still $3 million over the town’s original budget but a number it could live with, explains Filinov.

“Although we reduced the size of the original building’s square footage by about one third,” he says, “the design of the building and the treatment process allows space for the addition of the removed processes or for future expansion.”

In addition to the AquaDAF preliminary treatment, the plant treatment process comprises dual media gravity filters with GAC caps, primary disinfection with ultraviolet light; secondary disinfection with chlorine and a residue management system. It operates with a high lift pumping station and features a 2,200-cubic-metre, in-ground concrete reservoir.

“We wanted to meet all the current regulations and provide and anticipate any potential future changes in direction in the (water treatment) regulations,” says RVA’s project manager.

Tighter environmental regulations and technological changes in system design have made engineering even small plants like Smith Falls’ a complex job, he points out.

Filinov says from the outset the project was fettered by obstacles. A record snowy winter, ice jams that caused river flooding and record rainfalls hampered the project’s start, but Ottawa-based contractor Thomas Fuller Construction Co. Limited has managed to keep the project on schedule.

The project is to be completed by the summer of 2009.

Before choosing to build the new facility, the town had considered simply updating an existing one, but opted against a retrofit of the antiquated plant (the oldest portion dated to the 19th Century) because of the high cost and expansion constraints.

The new plant will be something of a showpiece in Smith Falls. Because the Rideau Canal is a Canadian National Historic Site, RVA and the town worked with Parks Canada and the Rideau Valley Conservation Authority to maintain the historical integrity of the site. Additionally, it will feature landscaping and a public river wall and walkway where the plant abuts with the river.

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