Q&A: A how-to guide to mushroom toilets, by the team that made one
A Campus as a Living Lab team of faculty, staff, and students explain how a new composting toilet uses mushrooms – instead of water, electricity and chemicals – to break down human waste into safe, nutrient-rich compost soil.
Untreated human waste is a leading cause of disease and mortality among the 2.3B people who lack access to adequate sanitation globally1. Current centralized approaches to waste treatment are energy intensive and require significant amounts of water. While decentralized approaches, such as chemical toilets, reduce energy and water use, they require toxic chemicals which create economic, operational and disposal challenges.
That’s why a team of faculty, staff, and students at UBC have been working on the development of a fully biodegradable process for composting toilets that speeds the decomposition of waste and eliminates the need for energy and chemical inputs.
Q. How did interdisciplinary collaboration—linking architecture, microbiology, and campus operations—shape the project?
A. This project was transdisciplinary from its initial conception. It grew out of a competition that included students from four different faculties at UBC. The proposal, which won the Biodesign Challenge in 2019, proposed a mycelium-based toilet for intended for refugee camps. The entry proposed a new conceptual framework for approaching waste that was beyond any single discipline. It would not have occurred had we not had a team that represented so many diverse fields.
Actually realizing the vision as a working prototype required a different kind of interdisciplinary collaboration – which included laboratory testing at the Hallam Lab at UBC Microbiology and Immunology, as well as designers working at the Biogenic Architecture Lab at UBC SALA.
JOSEPH DAHMEN, ASSOCIATE PROFESSOR, FOUNDER OF BIOGENIC ARCHITECTURE LAB, SALA, APPLIED SCIENCE.
Q. How did working on the MycoToilet shape your perspective on sustainability? What did you learn about linking research to real-world challenges?
A. The MycoToilet project allowed me to gain first-hand experience with how designers can collaborate with microbiology and other researchers, to generate new ways of making the built environment more sustainable.
“Through the process of growing material – working with something that is literally alive – you develop a strange relationship with this unique non-human actor. You have to quickly learn to accept its autonomy, and work with it, instead of control it.”
Mycelium bio-composites and other similar materials are only recently starting to scale up and become commercially available, but there are challenges related to the consistency of growth, the adaptability of the building industry, and public perception.
CHRISTY-ANNA CHUNG, RESEARCH ASSISTANT, M.ARCH CANDIDATE, SALA, APPLIED SCIENCE
A. Mycotoilet allowed me to apply some of the sustainability concepts I was learning in school to an actual project with impact. While the project is supported by a strong scientific idea, it is the design of the enclosure itself that I think best describes the sustainability through material and form. It allows the inhabitants to not only engage with sustainability as a concept, but link their actions into positive environmental impact.
The Mycotoilet project exposed me to a whole new way of thinking about the role of architecture in ecological systems and gave me the connections and skills to launch a career I didn’t even know existed just over three years ago.
ISOBEL MCLEAN, RESEARCH TECHNICIAN, HALLAM LAB, FACULTY OF SCIENCE
A. By involving the contractors in the design process, we were able to shift from CLT (cross-laminated timber, which relies on adhesives), to a newer technology DLT (dowel-laminated timber) which uses neither nails nor glue. Its ability to come apart means that the MycoToilet can contribute to a circular economy at the end of its life.
I think this is the greatest take-away for me, the ability to learn from and design in response to the interdisciplinary members of a team, which enabled us to advance the studies of DLT, but also gave a local business the opportunity to create their first-ever DLT product.
JAMI HOLDEN, RESEARCH ASSISTANT, M.ARCH CANDIDATE, SALA, APPLIED SCIENCE
Q. What were some practical considerations in bringing Mycotoilet to the Garden?
A. We had to consider the best location for the Mycotoilet that would support visitors to the Garden Tree Walk, and how to install it without damage to valuable plant collections in the area.
Our Botanical Garden Horticulturists helped support with preparation of the area which meant transplanting and protection of plants, base preparation and landscaping restoration around the MycoToilet. One of the biggest challenges we were involved with was the movement and placement of the mostly pre-assembled structure into the garden. While challenging to protect our collections, there was great collaboration between Joe’s team, UBC Plant Operations and the Botanical Garden.
We also helped with the installation of the green roof planting and will be installing irrigation a later date to maintain plants for that green roof. Our Curator of the Asian Garden, Andrew Hill, was instrumental in coordinating efforts between Joe’s team and the Botanical Garden crew.
BRENDAN FISHER, HEAD TRADES - HORTICULTURIST, UBC BOTANICAL GARDEN
Q. How did you support the project team throughout the lifecycle of the project?
A. The Campus as a Living Lab program, managed by the Sustainability Hub, provided both funding and a structured platform that enabled the researchers, students, and operations staff to work together effectively.
I expected to help with turning an ambitious concept into a practical demonstration. But what surprised me is how the project has grown and evolved over time into something long-term. It began as a pilot, but with strong support from the Botanical Garden is now developing into a full-scale mycelium composting toilet intended to permanently replace a chemical unit.
Looking forward, I hope this project sets a strong example and encourages more researchers, staff, and external partners to collaborate through Campus as a Living Lab.
ANTHONY AN, RESEARCH MANAGER, SUSTAINABILITY HUB
Q. What lessons or skills from this project do you expect to carry forward into your future studies or career?
A. I use almost all the technical skills that I learned throughout the project daily. However, in working with Joe Dahmen and Steven Hallam, I think the most important lesson that was modelled throughout the project was that it won’t be a singular discipline that comes up with the solutions to the complex problems that we, as a society, are currently facing.
“Working in this transdisciplinary mode created something with the possibility for much greater impact than either architecture or microbiology could have proposed alone, and it was the willingness of everyone on the team to take the time to communicate and listen to each other’s perspectives that made it possible.”
Being willing to listen to people with other forms of knowledge and work towards creative solutions together is what brought the concept of the Mycotoilet together several years ago, and it is also what made it a reality today.
ISOBEL MCLEAN, RESEARCH TECHNICIAN, HALLAM LAB, FACULTY OF SCIENCE
Q. The MycoToilet was inspired in part by the Garden’s goal of ‘demonstrating sustainable practices’. What made you choose this project above others?
A. Sustainability was the primary reason, but also the innovative and botanical nature of the toilet were both important factors, as were the opportunity to collaborate with other UBC departments and our ability to share the costs with the designers.
DOUGLAS JUSTICE, ASSOCIATE DIRECTOR, HORTICULTURE AND COLLECTIONS, BOTANICAL GARDEN
Q. How do you see the MycoToilet improving operations compared to the chemical toilet it is intended to replace?
A. We see an opportunity for improving operations that should result in both cost savings and environmental benefits. Chemical toilets were trucked in and out of the garden seasonally and weekly truck service was required to vacuum out and clean.
“Allowing this new structure to become part of the Botanical Garden’s regular cleaning schedule with UBC Custodial will provide some cost savings – and more importantly reduce the environmental impact of multiple truck visits into the garden for cleaning and service.”
BRENDAN FISHER, HEAD TRADES - HORTICULTURIST, UBC BOTANICAL GARDEN
Q. What opportunities do you see to scale this technology to other contexts — such as urban parks or remote communities?
A. Part of the reason for developing the full-scale prototype at the Botanical Garden is to demonstrate the modular toilet to municipalities and the provincial government. Connecting to plumbing typically accounts for around half the cost to develop a public toilet. In parks or other locations far from plumbing the percentage cost can be significantly higher.
The modular waste-separating toilet we’ve developed incurs none of these costs, with servicing requirements that can be as low as 3-4 times per year. This could be an excellent solution when connecting to centralized systems is difficult or costly.
JOSEPH DAHMEN, ASSOCIATE PROFESSOR, FOUNDER OF BIOGENIC ARCHITECTURE LAB, SALA, APPLIED SCIENCE.
Learn more about UBC’s Campus as a Living Lab program, the UBC Botanical Garden, the Biogenic Architecture Lab, the Hallam Lab and UBC School of Architecture + Landscape Architecture,