Leading Edge Technology Manages Cheakamus Wastewater

Article courtesy of BC Hydro internal publication "Keeping Current"11-08-2011

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 Lower Mainland Generation’s Cheakamus Sewage Upgrade Project is “Minding our Footprint” using leading edge, environmental technology to construct wetlands that manage the wastewater system at the Cheakamus Powerhouse. “Basically, it’s a human-made wetland like you’d see in a pond. The system reclaims sewage waste later using peat in what is known as a Vegetative Tertiary Filter (VTF),” said George Aung Thin, Project manager.

Right: The Vegetative Tertiary Filter comprised of native plants and protected by local rocks.

The peat that the system uses regenerates itself from the roots of the native species of plants in the final stage. The peat gives the VTF its natural advantage over conventional systems. Since peat can have up to 30,000 times more surface area than coarse sand it creates a vast area that provides attachment space for microbes to form a community that consumes the remaining dissolved compounds.

 A VTF will typically have an excess of three million cubic centimetres of peat and therefore, three quintillion (3X1015) microbes. Microbes consume and break down the more than 100,000 compounds found in domestic wastewater that would otherwise contaminate surface and ground waters and are causing ecological havoc in our lakes and oceans. “The system consists of a trash tank, pump chamber and the VTF, which looks a bit like an English Garden,” said Alexis Hall , local Natural Resource Specialist. Alexis contributed greatly to the project, selecting native plant species to populate the VTF and a set of high -efficiency toilets that will reduce water use but have the ability to flush a potato.

“Although I hope no one would ever drop a potato into the toilet,” added Alexis.

 

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Above: A conceptual drawing of the wastewater reclamation system setup.

Curt Kerns of WetlandsPacific Corp. also helped with the installation. WetlandsPacific holds the patent on the revolutionary constructed wetlands waste water management system. “It is the last five per cent of sewage contaminants that the VTF removes [which other systems can’t] that could wreak ecological havoc,” said Curt Kerns. “The VTF prevents disasters such as algae blooms, endocrine disrupting compounds destroying fish populations and oxygen starvation in bodies of water.” The VTF system is biologically sophisticated yet mechanically simple and has a lot of advantages over conventional septic tank and weeping tile arrangements:

  • The VTF takes up less than a quarter of the space of a conventional septic system;
  • Maintenance is a simple inspection;
  • Robust native plant growth replaces peat as it decays ensuring a sustainable system; and
  • Peat removes trace compounds even municipal treatment does not (i.e. removing non detectable fecal coliform and protecting groundwater from nitrate contamination)

For more information on the Vegetative Tertiary Filter