August 29, 2008

The Leamington UV building was included in the first stage of development when upgrades at the facility began in 2004.

CH2M HILL

This is how the Leamington site looked after the first phase of massive upgrade to its facility was completed. Above is the biofilter facility.

Overlapping phases provide cost-saving options in Leamington, Ontario project

Upgrades are main phase of project started in 2003 to revamp system

MARY BAXTER

correspondent

LEAMINGTON, ON

One of the largest development projects the municipality of Leamington has ever undertaken is nearly ready to get under way.

Designs for the introduction of primary and secondary clarifiers as well as a conventionally activated sludge plant to the town’s pollution control centre are in the final stages, says Leamington’s manager of environmental services.

“It’s a big project for us,” says Kit Woods. “We’re estimating a two-year construction process,” that could begin as early as this November, depending on when the final drawings are approved and the job is put out to tender. The project will also involve adding new effluent bar screens and grit removal systems to the plant’s headworks.

It’s the main phase of the $32-million upgrade that was first envisioned in 2003 as part of a master plan to upgrade the municipality’s sewer collection and treatment system.

The centre currently consists of two separate extended aeration plants with a single outfall to Lake Erie and a biosolids facility that dewaters, stabilizes and stores sludge until it can be land applied.

Woods and Ryan Connor of CH2M Hill, the prime consulting engineering firm on the project, say the work is being driven by aging infrastructure and population growth.

“Some of the plant is quite old and difficult to maintain,” notes Woods.

As well, the existing plant can only handle so much wastewater flow, says Connor. “They do preliminary treatment and disinfection, but they can’t treat everything if there’s a heavy rain event or whatnot.”

Work on the upgrade actually began in 2004 with an expansion of the plant’s biosolids facility, the construction of a new administration building and the introduction of ultraviolet disinfection to replace the use of chlorination to disinfect water. The work was carried out by St. Thomas-based HIRA Limited, General Contractors.

In 2006, work started up again with an addition made to the biosolids facility, an introduction of a new polymer system as well as two new centrifuges to separate heavier solids from the wastewater. The work was carried out by Ruscom Station, Ontario-based Facca Inc.

While the first two stages have enhanced the current system, it’s expected the next round of construction will transform how the wastewater is processed.

Woods explains this next stage was initially envisioned as three separate phases and the initial vision of implementing the project involved six phases with each costing roughly $10 million. The conversion of one of the aeration lagoons into storm water lagoon storage, to reduce storm water bypassing the plant, is a major focus of the final project phase.

The decision was made to combine the third, fourth and fifth phases of the project because of operational interdependency of the equipment introduced in each. Synchronizing the new equipment’s warranties was another factor, says Woods. Combining the phases also means cost savings due to economy of scale and administering one rather than three contracts.

Obtaining more than $13 million in provincial and federal funding has helped make the decision to combine the phases feasible, says Connor.

In terms of challenges, he says the facility’s available footprint created some head scratching to figure out how to “fit everything in” during the design process.

He envisions staging construction as being one of the next significant hurdles, pointing out that the facility will be operating as work takes place. Much of the construction will take place in an area that’s uninhabited but staging will come into play when doing the tie-ins at the plant’s headworks facility where older equipment will be replaced.

“We will have to stage that carefully,” he says, noting contractors will also have some deep excavation to do. The presence of lots of underground services will also mean having to progress carefully during excavation, he adds.

Woods agrees having construction going on as the existing facility is operating will be a major challenge.

“We’re lucky in that we can pretty much build the new facility in totality while keeping the old facility running,” he says.

One unknown factor is the impact of any upward changes in material or fuel costs and how much the municipality will be competing with other projects for its labour force. Already, inflation has helped to bring up the project’s original price tag of $30 million to about $32 million, Woods says. “So we really won’t know until we actually tender it what the final design amount will be.”

As far as obtaining both contractors and workers to do the project, he points out the community is positioned between Chatham and Windsor and will likely draw manpower from both of the larger communities.

Ultimately, however, both anticipate the project to unfold smoothly.

“Everything that we have decided on (in terms of unit equipment) is proven in other applications,” says Connor. “So we are not the guinea pig of any one technology, but everything that we’re doing is of the modern design; we’re not held back by anything.”

What makes the project a little different, he says, is the ongoing relationship the municipality has had with CH2M Hill and Stantec Inc. CH2M Hill worked on the master plan and led the first phase while Stantec led the second. The two engineering firms are involved in the upcoming stage with CH2M Hill acting as the project consultant and Stantec handling the civil, structural and electrical work.

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