Somewhere between a botanical garden and a tree walk at the University of British Columbia, there’s a cedar-clad wooden structure with a green roof, a lighted interior, and a ramp for wheelchair access.
It smells like the forest. It looks like a piece of thoughtful architecture. And inside its back wall is something no public toilet has ever used before: a chamber lined with live mushrooms that absorb odor, speed up decomposition, and turn human waste into usable compost without a single drop of water, gram of chemical input, or connection to any plumbing system. MycoToilet, developed by researchers in the UBC School of Architecture and Landscape Architecture and the Department of Microbiology and Immunology, will launch at the UBC Botanic Garden in September 2025.
It is the first of its kind anywhere in the world, and the problem it is trying to solve is much larger than any problem on a single campus.
A global sanitation crisis that makes mushroom-powered waterless technology sorely in demand
The scale of the sanitation problem that technologies like MycoToilet are designed to address is truly staggering. A 2024 review published in the ISME journal by Oxford Academic found that more than two billion people do not have access to adequate sanitation, a number the UBC campus estimates as a MycoToilet Living Lab Project Summary at 2.3 billion, with 450 million people restricted from open defecation altogether.
Untreated human waste is a major cause of preventable disease and child mortality throughout the developing world.Mainstream solutions have serious limitations. Centralized wastewater treatment is energy-intensive, water-intensive, and requires significant investments in infrastructure that many municipalities and rural communities cannot afford. Chemical toilets, the portable units most commonly used in parks, construction sites and event spaces, rely on formaldehyde and other toxic chemicals that require the waste to be treated as hazardous materials at the disposal stage.
Traditional composting toilets are considered a cleaner alternative in principle, but have historically suffered from odor problems, inconsistent decomposition, and operational reputations that have made municipalities reluctant to adopt them on a large scale.
What is mycelium and how do fungi break down human waste faster than standard composting
MycoToilet’s primary innovation is to replace the standard composting process with a process based on mycorrhizal mycelium, a dense, thread-like root network that forms the vegetative body of the fungus, which is different from the fruiting body that appears above ground. According to a 2023 review on fungal remediation published in the Journal of Applied Science, fungi produce powerful extracellular enzymes capable of breaking down complex organic compounds, including lignocellulosic biomass, hydrocarbons, and biological waste, into simpler compounds that microbial communities can then process further.
This enzymatic ability is what makes mycelium particularly suitable for decomposing human waste.“Fungals are very good at breaking down biomass, including human and animal waste,” Dr. Stephen Hallam, a professor in the Department of Microbiology and Immunology at UBC, said in UBC’s official announcement. “They produce enzymes that convert substances into simpler compounds while supporting microbial communities that speed up the decomposition process.
No need to add water, electricity or chemicals.”The UBC Living Lab project summary notes that decomposition of harmful mycelium-based pathogens takes approximately half the time of traditional composting toilets, a significant operational advantage for a system designed to be maintained on a simple schedule. Laboratory tests of mycelium liners have shown that they remove more than 90 percent of odor-causing compounds, addressing the largest practical barrier to toilet adoption in public and community settings.
How the MycoToilet system separates waste, removes odors, and produces fertilizer and compost
MycoToilet works by first designing the class. Liquid and solid waste are divided at the deposit point, with solid waste directed to a mycelium-lined compost chamber at the rear of the structure. Fungi and the thermophilic microbial communities they support break down the solid aerobically, that is, in the presence of oxygen, preventing the anaerobic conditions responsible for the odors and methane production that plague poorly designed composting systems.A low-power fan keeps air circulating through the ventilated cedar structure, and the roof design supports negative temperature regulation. The four maintenance visits a year the system requires are deliberately scheduled rather than reactive, a design choice that project leader Professor Joseph Damen of UBC’s School of Architecture and Landscape Architecture describes as deliberate: “We’ve eliminated the uncertainty that could scare municipalities away from composting toilets and solved it. The schedule is set, ventilation is integrated, and everything is working as it should.”
“When fully operational, MycoToilet is expected to produce approximately 600 liters of nutrient-rich soil compost and 2,000 liters of liquid fertilizer annually. The nutrient recovery numbers are significant: A study published in the ISME journal found that well-managed composting of human feces can recover up to 91 percent of the nitrogen, 83 percent of the phosphorus, and 59 percent of the potassium found in waste nutrients, which, if returned to agricultural soil, reduces reliance on synthetic chemical fertilizers.
Architecture and materials used in the design of MycoToilet at the UBC Botanical Garden
The physical structure of MycoToilet is as intentional as its biological system. Prefabricated wood panels form the primary structure, with a naturally rot-resistant cedar exterior that has been charred in a traditional Japanese technique called shou sugiban to give it additional antimicrobial properties. The green roof supports native plants and local wildlife habitat. The interior combines wood and stainless steel finishes with odor-absorbing mycelium chambers, designed by Dahmen to replace the look and smell typically associated with composting toilets with something closer to a forest shelter.“We wanted to transform the daily routine that everyone knows into a fun experience that reminds us of our connection to environmental cycles,” Dahmen said. The structure blends into the Botanical Garden’s forest environment, is fully wheelchair accessible via a ramp, and is designed to be modular and transportable, a design feature that has direct implications for deployment in parks, remote communities, and areas without plumbing infrastructure.
What a six-week beta test and future research will determine about scaling MycoToilet
The six-week pilot program that began at the end of September 2025 is testing the MycoToilet under real-world use conditions, with researchers from both SALA and the Department of Microbiology and Immunology monitoring how fungal and microbial communities interact as the system processes actual human waste at scale.If the pilot shows consistent performance, the self-contained, chemically clean, low-maintenance nature of the system positions it as a reliable alternative to chemical toilets in parks and public spaces and potentially a useful sanitation option for communities that need it most. Toilets that require no water, no chemicals, and no sewer connections, requiring only four maintenance visits a year, while converting their waste into agricultural inputs, is a proposition fundamentally different from anything currently widespread.
Whether it can reach this range is what research must now answer.
