According to the World Health Organization, over 1.7 billion people worldwide do not have access to even the most basic sanitation facilities. An even greater number lack access to safely managed sanitation or sewerage systems. The ripple effect leads to some staggering statistics. Almost a million people die annually of preventable, communicable diseases, including almost a quarter of a million children under 5. About a third of the world’s school-aged children, mostly girls, miss class or drop out because of a lack of hygienic resources (a predicament that can lead to embarrassment, harassment, and threats to their safety). These and other sanitation equity-related conditions perpetuate the cycle of poverty, epidemics, and even climate change. The team at change:WATER Labs, led by CEO and inventor, Diana Yousef, hopes to address these with their innovative, waste-shrinking, waterless toilet system, the iThrone. And Tacuna Systems is proud to be part of their efforts.
Project Technical Profile
- Client / Partner: change:WATER Labs
- Application Category: Humanitarian Bio-Tech & Sanitation Engineering
- The Core Technical Challenge: Capturing highly accurate, minute-by-minute mass data to track waste evaporation rates inside non-sewered, waterless toilets within extremely humid field environments (Uganda and Panama) under strict budget limits.
- The Core Social Challenge: Over 1.7 billion people lack essential sanitation facilities, leading to serious health issues and social consequences. To address this, change:WATER developed the iThrone, a waterless toilet solution that evaporates waste, minimizing environmental impact with minimal maintenance costs.
- Hardware Enabler: Multi-sensor arrays (8 load cells per unit), signal-summing junction boxes, and low-noise weight tracking amplifiers using an IP65-rated, budget-optimized design.
The iThrone Concept: Waterless, Evaporative, Portable Sanitation
The idea behind change:WATER’s iThrone system is simple — evaporation. Human waste is mostly water. What if, instead of flushing it using valuable, drinkable water sources, it was desiccated? Could that waterless toilet promote the evaporation of its liquid content, releasing pure water molecules into the atmosphere? What if this process were so efficient that it would leave only a small amount of dry solids? Perhaps these dry solids could be used for energy production, fertilizer, or other useful applications.
The iThrone waterless sanitation system “does its business” exactly through this process, borrowed from the evaporation mechanism found in plants. Each self-contained unit has bags made of a special, 95% compostable micro-porous membrane that collects human waste and releases pure, molecular water, leaving behind just a small amount of residual solids. Bags that collect these solids need to be replaced only once or twice a month, the company estimates, depending on usage. The iThrone operates without any water or external power source. Instead, it derives its required energy from the collected waste itself.
Cost is another advantage of the system. Unlike other portable toilet solutions, the iThrone is cheaply and easily serviceable. Rather than having to pump liquids out of tanks, the iThrone simply requires the collection of these small, dry, compostable bags. And unlike alternatives which have to be emptied almost daily, the waste-shrinking iThrone requires only monthly service. Likewise, the iThrone is less expensive to produce than alternative waterless toilets. These lower production and maintenance price points make the system more accessible to the areas that most need it.
The Challenge: Tracking Real-Time Evaporation in Severe Humidity
With big ideas and big goals, the iThrone team’s next challenge was proof of concept. Live testing was critical. The team chose two infrastructure and climate-challenged environments for this effort: Uganda and Panama.
iThrone Live Testing Take One: Uganda
Just before the global pandemic, the change:WATER team began its pilot test in Uganda.
The results were promising. Unlike composting toilets, the team found that the iThrone portable toilets produced little to no odor, didn’t discharge any waste onsite, and actually shrank daily waste collections significantly. They behaved as expected, turning waste into a small amount of residue. Users were thrilled with their new facilities.
However, the team encountered issues collecting measurements that would allow them to refine their design. “We had good analog data but unreliable real-time data on the amount of waste collected in the system and how fast it was evaporating,” explained Yousef. The team had added load cells (and a power source for them) to measure the waste’s mass reduction over time, but they found that the load cell quality was not up to the task. “The most critical data is minute-by-minute,” Yousef continued. “We needed to understand how the surrounding environmental conditions affect performance in real time.”
Then came the pandemic. The field deployment team had to evacuate from Uganda on March 13, 2020 and put live site testing on hold.
iThrone Live Testing Take Two: Panama
While the world became consumed with managing a global virus, a Central American construction company was busy working on providing adequate housing for indigenous populations in Panama. They were looking for a no-plumbing toilet, and the iThrone stood out as a potential solution to this daunting task.
The change:WATER team welcomed the opportunity to join this effort, but they knew there would be challenges. Unlike Uganda, the Panamanian climate is persistently extremely humid, which could affect the iThrone’s performance. To make any necessary design adjustments for these environmental conditions or malfunctions, Yousef and her team needed to remotely monitor the collection bag’s weight to derive three vital pieces of information: (1) when the toilet was used (indicated by weight increases), (2) any leaks (indicated by rapid weight decreases), and (3) real-time evaporation rates (indicated by slow, predictable weight decreases).
Achieving this required an affordable, high-precision measuring system with liquid ingress protection and a high signal-to-noise ratio. This would ensure low-error results in the damp environment. A robust system utilizing high-quality load cells was key, but load measurement was completely outside the bio-tech team’s expertise. As Yousef recalled, “you don’t know what you don’t know,” and the design team needed help knowing where to start.
Achieving this required an affordable, high-precision measuring system with liquid ingress protection and a high signal-to-noise ratio. This would ensure low-error results in the damp environment. A robust system utilizing high-quality load cells was key, but load measurement was completely outside the bio-tech team’s expertise. As Yousef recalled, “you don’t know what you don’t know,” and the design team needed help knowing where to start.
“You don’t know what you don’t know. Chris (Lange) was responsive to our issues, like a partner. His advice was critical to our project.”
-Diana Yousef, change:WATER
The Solution: A Cost-Effective, High-Ingress Multi-Load-Cell Array
Not sure where to turn, the change:WATER team reached out to our chief engineer, Chris Lange, for advice. “Chris was responsive to our issues, like a partner,” said Yousef. “He was really helpful and his advice was critical to our project.” Interestingly, they came across the Tacuna Systems company website by performing a simple internet search for a particular kind of load cell.
After consulting with Lange, they settled on a design of 8 load cells per toilet, connected via a junction box, with amplifiers. To reduce load cell costs, the team chose units with an IP65 rating, adding further ingress protection in the iThrone design itself. The load cells, data acquisition system and data transport were all powered using solar generation.
iThrone in Panama: A work in progress
To date, the Panama project is ongoing. The builder has incorporated the iThrones in newly-built outhouses behind the principal dwellings and the change:WATER team has established their testing system. Using pilot data, the design team has made some structural improvements to their system. The modified units will be the source of further usage and performance data over the next few months. For completeness, the team also collects feedback from users to influence further design modifications.
In the future, given the promising test results, the units could become part of more formal structures. Meanwhile, the change:WATER team is continuing its development efforts with important partnerships including the MIT Solve initiative and MIT D-Lab.
The Impact: Data-Proven Sanitation for Under-Resourced Communities
While the innovative iThrone is still undergoing design refinements based on live test results, its promise for improving the future is great. In full production, the simple, highly portable waterless toilet will allow access to safe, inexpensive sanitation where it has not existed before. For poor, rural communities, schools in under-resourced areas, and refugee camps, the iThrone’s benefits could be life-changing. Yet even in developed areas, the iThrone could offer a far more environmentally friendly solution to off-the-grid sanitation than what is available today.
Even beyond expanding sanitation options, the change:WATER approach has many upsides. It would lessen the spread of many of the diseases borne by human waste — germs that don’t survive without water. Also, in the absence of water, bacterial methane emissions would significantly diminish, reducing greenhouse gasses from human activity. By eventually replacing other portable toilet options or even flush toilets in areas with modern plumbing, the iThrone could potentially lessen water shortages, pollution and emissions from water treatment facilities, and harmful chemical usage.
In fact, Yousef estimates that the iThrone could address nearly half or more of the 17 Sustainability Development Goals (SDG) outlined by the United Nations. From providing sanitation equity and access, reducing poverty, promoting gender equality, increasing sustainability, and reducing greenhouse gas emissions to promoting economic growth, iThrone is poised to make a significant impact on the planet.
Want to learn more? Go to https://www.change-water.com/.
