April 27, 2006

Emerging Technologies

‘Sewer from hell’ tamed by portable pump system

WARREN FREY

staff writer

RICHMOND, B.C.

For the city of Richmond, B.C., a “sewer from hell” turned into a chance to create a new way to deal with wastewater.

Richmond experienced a local state of emergency in January of 2005, when a sinkhole opened up on the No. 3 Road, causing structural damage to nearby buildings. Since then, city engineers have been working on a way to prevent a similar disaster, and they’ve come up with a tiny and portable solution.

Jim V. Young, an engineer for the City of Richmond and Naresh Koirala, from Golder Associates, will elaborate on their innovative use of technology at a seminar on emerging technology May 1 at the British Columbia Water and Waste Association’s annual general meeting in Whistler, B.C. The title of their address is “Another Sewer from Hell — the Richmond Perspective.”

The City of Richmond has recently used an innovative “grout curtain” method to protect surrounding buldings while lowering the water table. The curtain, which replaces the more common sheet piling technique, consists of a series of holes cored into the ground and filled with concrete, preventing water from passing to the foundations of the buidlings and causing structural damage.

“It’s basically a portable pump station that fits right in a manhole. It’s built, and it’s ready to go,” Young said.

With the new system, a blocked sewer anywhere in Richmond can be brought back into operation quickly, and the pump is easily operated remotely from a central location. The device consists of a five-horsepower pump installed inside a can the size of a manhole lid. The pump then rests on the manhole bench at the bottom of the sewer, and the pump is hooked into the piping system.

“From there, we can bypass sewage to different parts of the system. It took us years to come up with the idea and work on it, but only a week to actually build,” Young said with a chuckle.

Currently, Richmond has three of the units ready for deployment.

While the conventional wisdom is that since Richmond is below sea level, therefore sewer problems are more difficult to deal with, the truth is that it’s a blessing in disguise, Young said.

“When you have a blocked sewer, the system essentially becomes a big storage reservoir, which we couldn’t do if we were above sea level. In someplace like North Vancouver, where there’s a lot of elevation, that just wouldn’t be possible,” he said.

The pump system isn’t the only innovation Richmond has brought to wastewater management.

Richmond’s engineering department has also created a “grout curtain,” which replaces sheet piling and dewaters the ground without causing structural damage to surrounding buildings, Young said.

This system works by injecting holes in the ground, filling them with grout, and continuing the process until a “wall” is created.

Richmond’s use of the grout curtain is a first for the Lower Mainland, Young said.

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