Innovations in toilet technology and sewage systems

Think about the toilet, that insignificant porcelain bowl that discreetly disposes of our waste multiple times a day. It’s not a design darling, nor is it a piece of technology that receives frequent dazzling improvements (though options like dual flushing, seat warming, and electronic bidets can surely make it more luxurious).

However, many designers, environmental engineers, and sanitation specialists wanting to bring about a paradigm change contend that toilets, along with our entire approach to sewage, are in dire need of modernization.

According to CNN, the Environmental Protection Agency (EPA) states that roughly one-third of indoor water use in US households is attributed to our wasteful practice of flushing. The use of water toilets has become more risky in many parts of the world because of climate change, which is bringing harsh droughts and flooding that overflow septic tanks and back up sewers. Innovation is especially needed in areas without access to running water or in disaster areas.

There may be a benefit to reevaluating our waste management practices: waste can be recycled to produce electricity, heat, and fertilizer.

“Waste is not waste, it’s a resource,” stated Finnish architect and artist Arja Renell, who introduced the subject to the Venice Architecture Biennale as the curator of her nation’s pavilion the previous year. Although she was not an authority in the field, she was concerned to discover that a portion of Venice’s wastewater is dumped straight into its canals and wanted to highlight the “dry” toilet as a circular approach to sanitation.

finnish dry compost toilet

Renell told CNN over a video call that dry toilets, also known as “Huussi” in Finnish, are very common in remote summer cottages in Finland. They separate urine from stool and are vented to keep odors out. After using the restroom, users add peat or sawdust to the toilet bin. When the bin is filled, they transfer the waste over several months to a larger, airtight container to ensure that any microbes are eliminated.

Instead of using the typical synthetic fertilizer that emits greenhouse gases, the residual material, which is rich in nitrogen and phosphorus, can be used as a natural fertilizer.

Those who live off the grid will be familiar with the dry composting process. In the US, people who cannot afford to build a neutralizing septic tank—which may cost thousands of dollars—or live in rural residences without access to a sewage system have traditionally constructed dry compost toilets as an alternative to flush toilets. According to environmental engineer Kelsey McWilliams, whose company Point of Shift installs circular sanitation systems around the nation, the demand for sustainable solutions will only increase in regions affected by flooding or drought.

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“There are multiple states right now where people are working on changing the current building codes to allow not only compost toilets but more innovative solutions for people who want them,” she said. “Septic tanks are great—they served a purpose. They’re a very old type of technology, and they still generally protect our wells from human waste and bacteria. But there are better solutions.”

However, there are several obstacles to overcome before dry compost toilet use can be widely adopted, ranging from county or state laws to individual preferences. Installing and maintaining them in urban environments can be challenging, especially for larger homes than single-family homes. There’s also the issue of time: Many people may be put off if they have to wait up to a year for their waste to be safely recycled, and the repulsive feeling may be difficult to overcome.

“It’s asking people to care about something that they’re biologically attuned to be averse to,” McWilliams said.

Disappearing act

However, what if your waste could largely vanish from your toilet? Change:WATER Labs, a startup run by scientist and entrepreneur Diana Yousef, is posing this question to patent an evaporative material that has the potential to minimize waste buildup by up to 97% in a single day.

“We have developed a technology that we lovingly term ‘shrink wrap for crap,’” Yousef explained.

The “iThrone,” a low-cost, completely waterless portable toilet from Change:WATER Labs, holds human waste in a bag lined with special material. Yousef stated that the remaining material only needs to be recovered once every one to two months, but it still needs to be gathered and processed because it is recyclable but not neutralized.

The iThrone has been tested in disadvantaged communities in Uganda and Panama that lack access to safe sanitation since it was founded in 2018 by the Humanitarian Grand Challenge, an international acceleration award. Change: WATER Labs intends to expand the project’s scope. About 3.5 billion people, or 43% of the world’s population, were estimated to lack access to a toilet or latrine that was connected to wastewater treatment or safe disposal by the WHO and UNICEF’s Joint Monitoring Programme last year. Of those, almost a billion use buckets or dangerous pit latrines, or they defecate outside.

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“When you shrink the waste at the point of production, essentially, you do a better job of containing it hygienically, so it cleans up communities”, Yousef said. “But then, on top of that, you are not using, or polluting, any water.”

Excrement isn’t currently processed by the iThrone, but Yousef claims that as time goes on, the device will “get more sophisticated” and that in the future it might be able to turn evaporated moisture from urine or feces into drinkable water or turn the leftover stored waste into renewable energy.

“I don’t think anyone living in a house with a flush toilet is within five or 10 years of saying, ‘Yeah, I want to give that up,’” she said. “But there are so many other applications. And they’re not all just for low-income or distressed, fragile populations. There’s public sanitation, green building, transportation. And there are so many places where people are tied to septic tanks.”

Upcycling waste

Sewer systems that are well-developed in cities can cause drastic changes that are invisible. For instance, San Francisco now mandates that new construction over 100,000 square feet have on-site wastewater recycling facilities, even as California struggles with an increasingly severe drought. Local startup Epic Cleantec is expanding its system to residential buildings, corporate campuses, factories, and hotels around the state. Epic Cleantec developed the first graywater reuse system in the city in the opulent high-rise Fifteen Fifty.


Meanwhile, a conventional sewage plant in a brand-new coastal development in the Swedish city of Helsingborg has undergone a complete makeover to become a cutting-edge new treatment facility known as RecoLab, which stands for “Recovery Lab.” RecoLab is a striking structure that uses air vents to dissipate odors. It is connected to all buildings in the new district via a three-pipe system that recycles and separates water that contains human waste (also known as blackwater) from low-water vacuum-based toilets, graywater from washing machines and bathtubs, and organic matter from food disposal systems. When the housing complex is finished in 2030, RecoLab will provide homes for 2,500 people.

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“When you’re ‘source-separating’ the wastewater, it’s the same principle as when you’re separating plastic from metal—it’s easier to recycle,” explained Amanda Haux, business developer at RecoLab.

“Ninety-four percent of the wastewater in our cities is actually very easy to clean,” she said, but mixing in blackwater contaminates what could be a reusable resource.

RecoLab converts nitrogen and phosphorus from human waste and food compost into fertilizer pellets at a nearby facility, just like dry composting toilets do. While recycled water is used in the community swimming pool, biogas from recycled waste is converted for use as heating. Because of stringent Swedish government laws prohibiting the reuse of wastewater for human use, the plant does not currently recycle graywater. Haux, though, is hoping that will change—especially in cities where climate change may make water shortages more frequent.

Haux intends to someday build a rooftop garden and restaurant on RecoLab’s property, using its recycled water and fertilizer to grow ingredients, in order to showcase the project’s circularity. “The purpose is to raise awareness about wastewater as a resource. We shouldn’t hide it away in our cities,” she said. “This is actually a low-hanging fruit when we’re talking about circulation.”

Renell invited Haux to present at RecoLab at a fall seminar on innovative waste management techniques during the Venice Biennale. Even though they are on different ends of the spectrum, a large-scale urban sewage system and a simple dry toilet are both solutions to the same issue.

“So many people get so excited about this topic,” Renell said. “Of course, the urban scale feels a bit more daunting, but even within that, there are these amazing examples going on.”

“Going to the toilet needs to be quite simple,” Renell said. “If we want to compete with the current system, we need to provide something equally easy.”