September 18, 2008

TOWN OF HINTON, ALTA.

Skidders and a bulldozer clear land in Hinton Alta. for the town’s industrial park.

Hinton becomes first municipality to employ Small Bore Sewer technology in its sewer system

JESSICA KERR

correspondent

A small Alberta town is the first municipality in Western Canada to use an innovative sanitary sewer system.

Hinton, a town of 10,000 located about 300 kilometres west of Edmonton, will use Small Bore Sewer (SBS) technology as part of Canada’s first built-from-scratch eco-industrial park. The system was designed by Ontario-based Clearford Industries.

The $14-million park is being developed on green space and will allow for industrial development of the land without spoiling it.

“I think it shows that we’re leading in this area,” said Renée LaBoucane, economic development manager with the Town of Hinton.

“Other municipalities are looking to us.”

With the SBS system, an individualized primary treatment facility, a clarifier tank, is located on each property.The tank separates the solid and liquid components of the sewage. Once separated, a predominately solids-free liquid effluent is directed by gravity through small-diameter pipes to the final treatment plant. The solid waste left in the tank goes through natural digestion over a residency period of seven to 10 years. During that time, the sludge accumulation rate naturally decreases in annual volume.The system is designed to be flushed every seven years.

The patented sewer system uses fused-joint high density polyethylene (HDPE) for its collection mains, laterals and clean-out access points. HDPE pipes are stronger, more resilient and more flexible than conventional polyvinyl chloride (PVC) sewer pipe.

The company claims the pipes have a design life of 90 years, compared with the 35-year lifespan of PVC pipe. According to the company’s Web site, sludge removed from the clarifier tanks is more homogeneous and more economical to treat once it has digested anaerobically.

The SBS clarifiers are similar in appearance to a standard septic tank, but the design of the Clearford tanks is significantly different. The tanks are pre-built using high-strength concrete in a factory and tested to ensure a water-tight vessel.

The tanks area is made up of two chambers. Primary treatment (solids settling) occurs in the first, larger, chamber. The SBS internal plumbing is designed to reduce the amount of suspended solids without using effluent filters.

Typical sanitary sewer systems are left with about 200 milligrams per litre (mg/l) of suspended solids. The SBS system reduces that to 35 mg/l.

All connections, bends and appurtenances are welded on site to create a sealed, leak-free piping system that eliminates groundwater infiltration into the sewer system and the potential for sewage leaching into the surrounding soil. The use of HDPE pipes allows the company to utilize no-dig, trenchless technology in installing mains and laterals, which minimizing surface and subsurface disruption during construction.

The use of the trenchless technology also minimizes the impact on the environment by preserving surface and subsurface materials. In many cases, environmental construction considerations such as silt screens, dewatering containment and clay trench seals can be eliminated when the lines are installed using horizontal directional drilling. The sewer system is part of a unique project in Hinton.

The 108-acre green industrial park, now known as the Innovista Industrial Park, will be the first park of its kind in the country. There are some eco-industrial parks, but they have been retrofitted from existing industrial parks. Fifty-six per cent of the park will remain treed and the park will include natural walking trails.

In addition, only seven per cent of the development will be covered in roads compared with 12 per cent in a regular industrial park. Construction of the first phase of the project began last fall.

Crews were able to get all of the underground infrastructure in place, as well as some of the waste water treatment and road work, before the ground froze last winter.

In 2005, the Federation of Canadian Municipalities awarded Hinton a $3.3 million grant and a $2.2 million low-interest loan to help build the park.

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