INNOVATION November-December 2012

f ea t u r e s

Cranbrook Wastewater Treatment Upgrades Build on Sustainable Solutions for a Growing Population

Jean Sorensen

Expanding with Sustainability in Mind When the sewage treatment system had reached its capacity and could no longer comply with environmental requirements or provide for the city’s future growth needs, engineering firm AECOM responded to the City of Cranbrook’s request for propos- als in 2009 to upgrade and expand the whole system. The project work involved improving treated wastewater quality to meet or exceed BC Ministry of Environment guidelines, building capac- ity to handle 25 years of growth, replacing failing infrastructure with high efficiency systems that limit environmental damage, preserving archeological sites, and maintaining and improving the sustainability features of the system at a price point the city could afford. AECOM’s efforts on the project won it APEGBC’s 2012 Sustainability Award. “One of the main challenges was to deliver the project, right from the beginning to the end, on the same sustainability basis,” says AECOM senior project manager and project leader Shawn Pillai PEng. He wanted it to mirror the concept found in the

The City of Cranbrook, located in BC’s Kootenay region, has taken sustainability to a new dimension that is attracting Canada-wide attention. Quite simply, it has taken its treated sewage water and turned it into an irrigation product that is sprayed onto cattle grazing lands. With the result, Cranbrook has forged a thriving cattle industry and is also now looking into opportunities for providing highly treated sewage effluent as a source for irrigating high-density fibre forest lands. For 40 years, it operated a simple system. Sewage goes into it primary breakdown system—three, side by side, cell-like treatment lagoons where bacterial action breaks it down before a transfer station sends treated effluent wastewater to one of two storage ponds (No. 1 and 2) nine kilometres away. When irrigation water is needed, an irrigation pump station sends stored water through an underground piping system to spray pivots which irrigate crop and pasture fields. Cranbrook had a system ahead of its time when it started and operated at a fraction of the cost of a mechanical wastewater treatment plant.

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