TNRD’s biosolids response


To the editor:

The Thompson-Nicola Regional District will be using Metro Vancouver biosolids as part of two innovative technologies for closing the landfills in Barriere, Clearwater and Chase.  Both technologies will reduce the carbon footprint of these sites that will be closing in the next two years, and will be replaced with more environmentally friendly eco-depots – in Clearwater, Pritchard and Louis Creek.

Metro Vancouver and the TNRD have partnered for this project because it offers unique opportunities for both regions to participate in new methane control technology using waste products to treat waste products. The TNRD recently received an environmental award from the Union of BC Municipalities for this groundbreaking work.

The TNRD is not applying the biosolids – compost-like material which contain microbes that naturally convert methane gas into carbon dioxide – directly to the ground. These biosolids, approved for landfill closure use, meet the requirements of the Organic Matter Recycling Regulation. In the case of the methane oxidation beds, biosolids from both Metro Vancouver and the Good Earth Company in Merritt will be mixed with wood chips to create a composted growing medium that supports the microbes needed to metabolize the methane emitted from the landfills.  Methane is 21 times more potent than carbon dioxide as a greenhouse gas. The biosolids added to create the compost provide the nutrients that are needed for the composting process, which helps reduce the carbon footprint of the closed landfill.

A second aspect of the landfill closure projects involves reclamation of the area of the landfill where solid waste was deposited by placing a final cover of soil on the landfill. The final cover soil is a two part system, the first is a one meter thick layer of mineral soil over the refuse. The second is a thick organic topsoil layer. This topsoil is created by mixing sand, chipped wood waste, sawdust and biosolids. Again, the biosolids are required to provide the nutrients needed to support plant growth.  A secondary benefit of the thick topsoil layer is its capacity to absorb and oxidize fugitive emissions of methane.  So combined with the methane oxidation beds more than 80 per cent of methane generated by the landfill after closure will be captured, greatly reducing the overall impact of landfill emissions on the atmosphere.

There will only be one application of biosolids as part of this landfill closure projects. The previous application at TNRD sites was done as part of a progressive closure of the steep slopes at the landfills.  The steep slopes are not included in the current closure plans as they have already been completed.

The TNRD is not proposing to treat any other areas in or near the District of Barriere with soil that contains Metro Vancouver biosolids. The TNRD has submitted a land application plan to the Ministry of Environment to apply Metro Vancouver biosolids within the footprint of the Barriere landfill.

Don May, manager of Environmental Health Services

Thompson-Nicola Regional District