The idea of composting the collective mass of Bowen Island’s household food scraps and garden waste was enthusiastically researched by the municipality’s former Solid Waste Resource Management Advisory Committee (SWRMAC) with the primary objective to reduce our carbon foot print. However, in 2013 the committee concluded that there was no clear path to accomplishing this goal. Former SWRMAC member Pete Taggart and council’s liaison to the committee, Cro Lucas, have recently investigated an alternative system that they claim could make the idea of processing the island’s food scraps on island a realistic possibility.
In a presentation made to council on Monday, Taggart explained that although SWRMAC wanted to encourage composting on a commercial scale on Bowen the committee couldn’t find an economic way of doing so. He said there was one technique that the Committee was aware of, and which, in hindsight, deserved greater attention. This process is known as the Gore technique.
In a later interview, Taggart said that this technique came to his attention again through a presentation offered to professional engineers. When the presentation was postponed, Taggart contacted the individual who was lined up to give it.
“Mateo Ocejo is the director of Net Zero Waste, a company that builds and runs these systems,” says Taggart. “I advised him that we would want to see, touch, and smell one of his operations.”
Taggart emphasized the importance of site visits to gain first hand knowledge of potential problems relating to the presence of vermin, birds or offensive odours.
Taggart and Councillor Cro Lucas made a visit to the company’s site in Abbotsford at the end of March.
“We were impressed by the simplicity of this system,” says Taggart. “It looks great environmentally, socially it doesn’t create problems and it might provide some jobs. Economically it is too early to say, but certainly, building this system would be less expensive than the other options considered.”
The Gore Cover System for commercial composting has been installed in almost 200 locations worldwide and a number of those locations are in Canada, including Pemberton, Abbotsford, Sechelt and Chemainus.
Taggart says the basic materials required to build such a system are asphalt or concrete pads, concrete blocks and tent-like material that is similar to what is used to make Gore-tex outdoor apparel. A small process building may be required together with a platform scale and modest modular office.
“The other systems we looked at [through SWRMAC] all required large buildings with complex ventilation systems,” says Taggart. “They also required expensive equipment to treat and mix the waste before it goes into the composting system. Although we’ve suggested that a mixer should be purchased if a Gore system were built on Bowen, it may not be necessary. In Abbotsford, they take everything that people drop off, they don’t shred or chip anything, they just throw everything whole into the composting system and it seems to work well.”
It is a closed system, which means there are virtually no offensive odors. By covering the initial phases of the process, the amount leachate produced is minimal, and is recycled to the feed of the process.
“The process takes eight weeks, with the organic waste being moved through two covered areas for six weeks, and then being left open for another two weeks. After that, the material is sifted through a screen. Chunks that are left behind in the screen go back to phase one of the process for more composting, and the rest of the compost can be left out for several months to cure,” says Taggart. “After that, you send samples to a lab that will test for pathogens. The times required to process Bowen’s organics may vary, based on differences in composition. Once you get a clean bill from the lab you can sell the stuff as Grade A compost, I don’t know how much Abbotsford sells their compost for but elsewhere it is sold for $25 - $30 per yard.”
Taggart and Lucas say that, based on their estimates, the municipality could break even in seven or eight years if it invested in this kind of composting system. Taggart stresses that the cost estimates and economic assumptions applied are very approximate, pending preliminary engineering studies.
“It currently costs approximately $160 to ship a tonne of organic waste to the North Shore Transfer station, and pay for the tipping fee,” says Taggart. “Tipping fees are going up, and the cost of taking this material on the ferry has risen 38 percent in the past five years with an 8 percent rise just this year. So far the ferry is not the most significant cost when it comes to this operation, but if things keep going like this it could become a major cost component.”
According to their preliminary calculations, which include the capital costs of building the system, amortization and the financial benefit that would come from selling the compost at the end of the process, the cost of processing organics locally with this system would come to approximately $110 - $120 per tonne.
Taggart requested that council make a resolution to spend up to ten thousand in order to fund the first two phases of a study that would determine the environmental, social and economic viabilities of a Gore Cover composting system on-sland.
Councillor Alison Morse suggested that such a project would be better undertaken by the private sector, leading council to make a directive to staff to develop an Expression of Interest for the treatment of commercial and residential organic waste on Bowen.
