Landfill Interim Closure and Biocover Fabrication

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Regional District of Nanaimo

The Regional District of Nanaimo (RDN) owns and operates a Regional Landfill.  Concurrent with the development of the landfill, the interim closure of approximately 2.1 hectares of the landfill was required.  A goal of the project was to maximize the use of on-site residuals and biosolids generated at the landfill and within the regional district to produce a fabricated soil amendment to be used in lieu of topsoil within the closure system.  Another goal of the project was to have the fabricated soil amendment operate as a biocover, a system that would support the growth of methanotrophic bacteria that would consume fugitive methane emitted from the landfill. 

SYLVIS designed a fabricated soil biocover for use on top of the closure system.  Biosolids were identified as a key component of the fabricated soil to provide the necessary nutrients and organic matter to facilitate the establishment of methanotrophs and a sustainable vegetative cover.  SYLVIS also prepared a Land Application Plan for use of biosolids on the site, and designed the specifications for the cover system and fabricated the biocover for placement and seeding.  Class A and B biosolids produced locally by the RDN were used in combination with ground construction and demolition wood waste to fabricate approximately 3,000 m3 (4,000 yd3) of biocover/fabricated soil.  SYLVIS provided turn-key services to the project by fabricating the required biocover on-site.

The project demonstrated the ability to provide cutting-edge applied science and innovation within complete turn-key services for residuals management.  In this particular project, SYLVIS evaluated the use of residuals, formulated optimal feedstock combinations, secured regulatory approval for residuals use, and fabricated the biocover soil.  SYLVIS, in conjunction with other agencies, is continuing to explore the ability of biocovers and fabricated soil systems to reduce fugitive methane emissions from landfills.