The GCH4

V. S. Gardiner

The GCH4 is a toilet with a waterless, mechanical system for packaging and transport. It creates an urban infrastructure in which human waste becomes energy and fertilizer. The toilet uses a biodegradable lining material to transfer and contain excrement inside an odorless, sealed cartridge, which the user periodically wheels to an outdoor biodigester in exchange for methane gas. An experiment in collaboration with chemical engineers at Imperial College London showed that the lining, which is
made from carbon-rich organic material, doubles the methane output of human waste. The lining also serves the crucial purpose of freeing the user and the toilet from fecal contamination. The biodigester creates liquid fertilizer as a secondary byproduct to be emptied once a week. Using low-tech means to turn human waste into high-value commodities, the GCH4 creates an economic cycle in which waste treatment pays for itself. Just as mobile phones have rendered landlines obsolete, this infrastructure could substitute plumbing. The GCH4 solutions: Problem: Most dry toilets today are built on the Eco-San model, which involves urine diversion and composting, and is not practical for dense urban environments. Solution: The GCH4 offers all the ease of a flush toilet, and requires no fixed installation. It can go anywhere. Problem: The big challenge facing waterless systems is transport of fecal matter, because feces sticks to everything, even, as microbiologists have told me, nanosurfaces. Solution: The GCH4 creates a transport infrastructure based on motivation. People will carry the cartridge a short distance when the process is clean and the reward is high-valued fuel. Problem: Communities formerly deprived of toilets don’t properly maintain newly installed dry toilets. Solution: A user-friendly design provides cooking fuel, which is locally, immediately useful. This creates ample incentive for people to maintain their toilet systems. Problem: Biodigesters that harvest human waste generally don’t produce enough methane, because the Carbon to Nitrogen ratio of human waste is too low. Solution: The biodegradable lining, made from carbon rich materials, doubles methane production. A refillable commodity made from renewable resources, the lining helps to create a sustainable business model.

Describe the critical need your solution addresses.

The GCH4’s underlying technology is well-established: anaerobic biodigesters have existed for decades, and biodegradable plastic films are rapidly developing. The innovation lies in using such materials as a conduit, in a user-friendly, low-cost embodiment appropriate for bottom-of-pyramid markets in need of sanitation.

The prototype proved the GCH4’s two central principles. First, a low-tech but high-function cam system carries waste into a lower cartridge, seals off the opening, and stops odor from escaping. Second, the lab-scale biodigester has shown that the biodegradable packaging material doubles the methane production of human waste.

Now the design needs completion: a refined cartridge system, and a flat-pack toilet that uses minimum materials.

The Challenge money is needed to fund my work in collaboration with a mechanical engineer who has more experience in production. I estimate that our combined salaries will be $36,000, to complete the design within 1 year. Our budget for design iterations will be $44,000. The remaining $20,000 will go towards marketing the product and mocking up a transportation paradigm in consultation with economists.

I am currently at the World Toilet Summit in Macau and have established relationships with leaders of sanitation provision in Asia and Africa, along with the Asian Development Bank which provides grants for onsite sanitation initiatives, which will be of use when the product is ready. I have found potential locations for the field test, and manufacturers who expressed interest in partnering when the design is more complete.

At that point we will manufacture a small run and distribute toilets in an urban environment where a biodigester is already in use, such as a Sulabh in India. Alternatively, we will set up a standard digester in a different location. We will optimize an economy of cartridge transport, and the toilet will be ready for mass production.

Explain your initiative in more depth and its stage of development.

The GCH4 is a great fit for the Buckminster Challenge, as it offers a multi-layered solution to the Global Sanitation Crisis. 2.6 billion people are currently without toilets. Fecal contamination of water supplies causes approximately 7 thousand deaths every day, mostly children.

The GCH4 system addresses dire issues through the offering of a carbon-neutral energy source. That is what makes it a trimtab. A simple toilet will create new economy around sanitation, solving a notoriously difficult problem for policy makers and engineers alike.

A host of sites are available for the first field test—in South Asia, most cities are only 80% sewered, and slums account for 30-60% of new growth.

How does your strategy and approach respond creatively and comprehensively to key issues?

The GCH4 was my degree project for a Masters in Industrial Design Engineering (’08), a joint program between the Royal College of Art and Imperial College of science, geared towards engineering graduates. While I was the first to attend the course with a degree in Comparative Literature (Stanford University, 1999), I have an intuitive command of engineering principles and a strong capacity for problem-solving and building test rigs. My contribution to the project is the same vision that has seen it to this point.

My mantra is ‘collaborate or die.’ I conducted lab tests for the GCH4 with Ioannis Vyrides, a chemical engineering PhD at Imperial College. Currently consumed with project promotion and funding acquisition, I have not formally sought a mechanical engineer collaborator, but I will find one.

The GCH4 was a finalist for the Innovation RCA and Terence Conran prizes. It has since been selected for the 2008 World Toilet Summit in Macau and the 2008 St. Etienne Design Biennial in France. It garnered interest from the designer Tom Dixon, who offered his workspace to set up a toilet system in the future.

My current objective is to get the toilet to those who need it most.