November 14, 2008

EPCOR

The sewer treatment plant in Sooke, B.C. was built so it can be expanded to accommodate a growing population.

Sooke sewage treatment facility leaves the door open to expansion

SHANNON MONEO

correspondent

Sooke’s new P3 (public-private partnership) sewer system was built with expansion in mind. Already the system is extending its reach as new development proceeds in the community of 11,000.

In December 2005, the $23.5-million joint project between the District of Sooke and Edmonton-based Epcor began collecting sewage through 27 kilometres of lines.

It is augmented by three lift stations, which deliver sewage to the treatment plant where effluent is pumped 1.7-km out into the Strait of Juan de Fuca.

The system serves about 30 per cent of the municipality’s 56-square-km land base.

“When the system was built, it was to bring it to the greatest amount of properties for the least amount of cost,” said District of Sooke finance director Dave Devana.

“It provides us with a lot more opportunities for targeted growth within a specified area. The beauty of our system is, it’s expandable.”

Sooke, located 35 km west of Victoria, built its system with an $11.6-million Canada-B.C. Infrastructure grant, an $8.8-million debenture debt and $2.6-million contributed by nine developers eager to be connected to the system.

At the west end of Sooke, Brian Butler, one of the developers who bought-in, is overseeing development of Erinan Country Estates.

Also head of Butler Brothers Supplies, Butler paid about $200,000 to have the sewer line extended to his 245-hectare property, where about 80 hectares are slated for development.

He thought it made good business sense to pay for the line because building a standalone sewage system for the high-end residential and commercial development would have been economically prohibitive.

“The sewer system decreased our costs substantially,” Butler said.

Current system capacity is 4,000 Single Family Equivalents (SFE). Roughly 2,500 SFE are hooked into the system where the peak capacity is a daily 3,000 cubic metre flow.

Once current capacity is exceeded, a second treatment bay will be built, adding another 2,000 SFE to the system.

The existing wastewater treatment plant can handle one further 2,000 SFE expansion, bringing the total SFE to 8,000 or serving about 16,000 people.

Devana figured the “grow with us” sewer system should last the community for quite a few years.

The president of Victoria-based Chew Excavating said that Sooke’s sewer project was one of the most challenging undertakings his company, in charge of construction and design, has faced.

It was also Chew’s largest project to date.

“It was exceptionally complex,” Bruce Dyck said.

To finish the project by June 2006 (to coincide with Sooke’s taxation requirements), Chew had to avoid down time.

Design work (aided by Stantec Consulting) kept one step ahead of the actual labour.

“The challenge was keeping everyone busy,” said Dyck, who began working for Chew in 1991 as an estimator. At the project’s peak, 60 Chew employees were in action.

Epcor’s Vancouver Island operations manager said that the “tight” working relationship between the municipality, Chew, sub-contractors and Epcor eliminated time lags.

When a municipality takes on such a project solo, delays related to design and construction can occur, Tami Wetmore said.

“With the P3, all the pieces were brought together seamlessly,” she said.

There were challenges though.

Streets had to be dug up to connect homes and businesses, so traffic was disrupted.

Environmental hurdles also surfaced, including several creek crossings and construction of the marine outfall by the contracted sub-trade, Vancouver-based Can-Dive Construction.

The outfall line was brought from the treatment plant and then buried 10 metres past the lowest tidal point.

The outfall was then weighted with a concrete overlay and settled on the ocean floor, a distance of 1.7 km, to a depth of 30 metres.

Epcor was paid $21-million for completing the project on time.

Of that total, Chew, which completed its work five months ahead of schedule in January 2006, was paid $14-million, Dyck said.

Homeowners had to pay to decommission their septic fields and also had to pay for their service connection.

Costs varied, depending on the distance and terrain, but the average hook up cost was about $5,000 per household, said Sooke’s engineering director Darcey Kohuch.

The collecting system delivers sewage to the treatment plant on Sooke’s west side where 90 per cent of total suspended solids are removed.

Other contaminants are also screened out.

Primary treatment is via a screen which removes large debris in the sewage. The second step involves a tank where grit such as pebbles and sand are removed.

Secondary treatment involves moving the sewage to the sequencing batch reactor where active bacteria consume organic matter, in a tank known as a digester.

A centrifuge de-waters the sludge, which gets trucked to a landfill.

Once the digester has finished its work, the effluent receives ultra-violet light disinfection to neutralize harmful bacteria.

Finally, the effluent is piped to the marine outfall.

Last year, the District of Sooke and Epcor received the C.W. Chuck Wills Award for Innovation and Excellence in Public-Private Partnerships.

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