Water For All

Dawson Creek’s commitment to sustainability is reflected in such projects as a reclaimed water plant, built through a unique partnership with Shell.
Water For All
The Dawson Creek Public Works team includes, from left, Kevin Henderson, director of Infrastructure and Sustainable Development; John Kalinczuk, water resource manager; and Kerry DeVuyst, water treatment plant operator.

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The City of Dawson Creek is located in northwest British Columbia on the western edge of the prairies, almost 750 miles from Vancouver. In a region susceptible to drought, the city’s water supply must sustain more than 11,000 people, along with cattle ranches and local industries, including oil and gas.

A focus on sustainability — both financial and environmental — is helping the community prepare for the future and has generated a novel partnership with energy company Shell to develop its reclaimed water resources.

The area was first settled in the late 1800s and the city grew on grain and the construction of a railroad by the Northern Alberta Railways in 1930. During World War II, Dawson Creek became Mile Zero of the Alaska Highway, a transportation corridor built to connect Alaska with the U.S. mainland.

Newer Infrastructure Benefits City

“Much of our sewer and water infrastructure was built after the U.S. Army established the town as its base in World War II,” says Kevin Henderson, the city’s director of Infrastructure and Sustainable Development. “With a relatively new infrastructure, we’re in a unique position to learn from the infrastructure problems in older cities such as Toronto and Montreal.”

The water system is 75 percent PVC and 25 percent asbestos cement. “We used to use cast iron, but that was replaced in the 1970s and 1980s,” says Henderson. “The high sulphate content of the soil eats up cast iron like crazy.”

Water lines must be buried at least 9 feet deep to avoid frost. Underneath roads, frost is driven particularly deep, putting extra pressure on water pipes. There, pipes may be buried as deep as 12 feet. Leaks are rare, however, and are identified by visual inspection or the department’s supervisory control and data acquisition (SCADA) system.

“We’re in a good spot now,” says Henderson. “We may only have to respond to couple of mainline leaks per year.”

Internal crews handle the repairs, but rely on outside contractors to provide shoring and excavation, considering the depth of the mains. New mainline construction is also outsourced.

Three pumping stations convey water to three reservoirs with a capacity of more than 190 million gallons — about a three-month supply. After the water is processed at the city’s Class IV water treatment plant, a fourth reservoir can hold up to 2 million additional gallons of treated water. During hot summer months, water demand can approach 3 million gallons per day.

Water Is Precious

The community relies on surface water drawn from the Kiskatinaw River, a shallow waterway susceptible to drought.

“The river level may fluctuate and with a good rain come back up again, but we recognize that water is a precious commodity,” says Henderson. “City Council has been very progressive in supporting efforts at sustainability across all departments. While we’re active on the education side  in promoting water conservation, metering all accounts and pricing water to reflect our costs provides the most significawnt way to promote careful use of water. Sustainability is not only important as an environmental concept, financial stability is essential to running an efficient water system.”

The city’s wastewater infrastructure consists of almost 70 miles of sanitary sewer pipe ranging from 8 to 30 inches in diameter. An entirely separate stormwater collection system consists of 22 miles of pipe ranging from 12 to 48 inches in diameter. The system also includes a Vactor truck dumping station where domestic wastewater is hauled in from rural areas for disposal and treatment.

All wastewater is first treated through a sewage lagoon system. It passes through two anaerobic ponds, two aerobic ponds and one large wetland polishing pond before being released to nearby Dawson Creek, the waterway after which the city was named.

Oil And Gas Pushes Growth

The region relies primarily on four economic drivers — retail, tourism, agriculture, and oil and gas. Unconventional oil and gas exploration began to ramp up in the area in 2003. Companies such as Shell are bringing major economic benefits to the area and employing local residents. Shell is pursuing the production of natural gas from the Montney shale gas formation in the Sunset-Groundbirch area about 30 miles west of the city. However, energy companies are also major water customers, using significant volumes of potable water for hydraulic fracturing.

“After a significant drought in 2006, we were looking for ways to supply the oil and gas industry and struck on the idea that we could use our treated effluent as a resource, if we provided some additional tertiary treatment that would make it an acceptable product for hydraulic fracturing,” says Henderson. “We then came up with some conceptual designs for a treatment plant to divert some of the 6,000 cubic meters of effluent we discharged each day.”

Shell representatives heard about the plan and approached Dawson Creek with a proposal. If the city would set aside a certain volume of reclaimed water for use by Shell, the company would fund a substantial portion of the construction budget of the new facility.

“When Shell heard about the opportunity to partner with the City of Dawson Creek we saw an innovative project that would not only address residents’ concerns about water use and truck delivery traffic, but would meet our overall objective of reducing the amount of freshwater we use in our operations,” says Carson Newby, Groundbirch community affairs with Shell Canada Energy. “Our partnership with Dawson Creek is unique for the area and a first for Shell Canada.”

SAGR Cells For Additional Treatment

The additional treatment required to prepare the water for use in hydraulic fracturing involves processing the effluent through three Submerged Attached Growth Reactor (SAGR) cells supplied by Nelson Environmental of Winnipeg, Manitoba. A newer technology used for municipal water treatment, the cells employ a gravel medium supplied with air and microorganisms. The treatment breaks down any stubborn bacteria and neutralizes remaining ammonia. The cells have a layer of insulating mulch at the surface which prevents ice formation in the bed, allowing the system to treat wastewater that is near freezing (less than 0.5 degrees C)

That treated water is pumped into what is now known as the Dawson Creek Reclaimed Water Project, where it’s subjected to further treatment through chemical coagulation, mechanical mixing and disc filtration. After the addition of sodium hypochloride, the water is collected in a wet well and pumped to a nearby Shell building.

The plant was designed to produce 4,500 cubic meters of reclaimed water per day. Under an agreement negotiated in 2010, Shell would fund $16.5 million of the plant’s $18 million price tag. In exchange, Shell would receive the rights to the first 3,400 cubic meters of water reclaimed each day.

“Under the agreement, we could keep the additional reclaimed water as needed, sell it to other customers, or use it for the city’s own purposes,” says Henderson. “On days that Shell couldn’t use its allotment, ownership of that volume of water would revert to the city.”

Shell Pumps Waer To Gas Fields

The Shell building is a self-contained pumping station, designed to pump the water directly to the gas fields through a 30-mile carbon steel pipe surrounded by an HDPE continuous fused liner. The pipeline completely eliminates trucking of water from the city to the drill site, which totaled about 2 million miles driven annually.

Despite the benefits offered by the deal, not all residents initially approved of the idea.

“Some people felt we should have built the plant ourselves so that we could collect all of the revenue from the sales of reclaimed water,” says Henderson. “It was our contention that Shell was taking all of the risk while we would still collect the revenue from additional reclaimed water sales — a solid win-win.”

Dawson Creek was required to amend its municipal sewage discharge permit with the British Columbia Ministry of Environment to allow the use of reclaimed water for fracking.

“Although we wanted to use some of that reclaimed water for park irrigation, dust control, cleaning and our municipal sanitary sewer flushing program, for now, the permit only allows us to use it for hydraulic fracturing,” says Henderson. “The regulatory aspect of the program is a learning curve.”

The plant was commissioned in September 2012. To date, Shell has frequently drawn less than its daily allotment from the reclaimed water plant, leaving the city free to sell the water to other energy companies.

For its part, Shell now relies exclusively on the reclaimed water for its oil and gas operations nearby.

“With respect to our Groundbirch venture, the Peace River some 30 miles away was a significant natural water source,” says Newby. “But in light of Shell’s move to intensive recycling of fracture fluids and the reclaimed water supply from the City of Dawson Creek, we no longer draw from natural water sources for hydraulic fracturing activity in Groundbirch.”

Dawson Creek continues to sell its excess reclaimed water to other energy companies operating in the area.

“The only glitch we’ve run into so far is that some drilling companies are very specific about the water they want to use for their fracturing,” says Henderson. “One company has told us they’d like the water to contain fewer sulphates. We occasionally still discharge reclaimed water into the creek when there are no customers for it, but the water we do discharge is of much higher quality than anything we were discharging before. It’s a beautiful thing.”

More Information

Nelson Environmental Inc. - 204/949-7500 - www.nelsonenvironmental.com

Vactor Manufacturing - 800/627-3171 - www.vactor.com


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