Waste to Fertilizer at the UBC Botanical Garden

Creating a closed-loop system, returning solid and liquid waste back to ecosystems as nutrient-rich soil and fertilizer.

The UBC Botanical Garden, in partnership with the Biogenic Architecture Lab at the UBC School of Architecture and Landscape Architecture (SALA), has developed a proposal to incorporate a state-of-the-art mushroom-based waste separating toilet system at the entrance of the canopy walk. The composting toilet will not only provide a better experience to the user but create a closed-loop system returning solid and liquid waste from the toilet back to the ecosystem in the form of nutrient-rich soil and fertilizer, aligning with the Garden’s goals of environmental stewardship. Funding from the Campus as Living Lab program will enable initial testing of the mushroom-based composting toilet during Summer 2025 and beyond. The toilet will eventually replace an existing chemical toilet on the site that requires weekly servicing throughout the year.

Benefits of Waste Separation

Waste separating toilets are a proven alternative to flush and chemical toilets. They work by separating liquid from solid waste, enabling onsite conversion of solid and liquid waste to valuable fertilizer that can be used to enrich local soils. Waste separating toilets operate naturally, without the need for water, electricity, or other inputs. It is estimated that the project will generate approximately 600L of valuable soil and 2000L of liquid fertilizer per year that can be used for operations and maintenance at the Botanical Garden, reducing overall reliance on energy-intensive fertilizers in keeping with ecological sustainability goals at the garden.

Incorporating New Research: A Phased Approach

The project incorporates innovative research at SALA and UBC Microbiology to develop the MycoToilet, the world’s first toilet to use mushrooms and thermophilic microorganisms to help break down waste naturally and efficiently. The first phase of the project consists of a 6-week pilot project to test the MycoToilet at the Botanical Garden, which will be funded through the Campus as a Living Lab program at UBC. The toilet enclosure at the Botanical Gardens will aid in the full-scale development and testing of the MycoToilet with the goal of expanding its use beyond that of the Garden to provide solutions for contexts such as remote communities in Canada and refugee camps without access to centralized sewerage systems.