Wasted* On Purpose: Developing More Sustainable Human Waste Management Practices

We all pee and we all poop, but most of us rarely consider what actually happens to our waste (and would rather not talk about it). Human waste is a double-edged sword: it can be a pollutant but it also contains valuable nutrients that can be harnessed for good. The problem with human waste right now is that existing waste management practices are antiquated and vulnerable to climate change, creating more of a pollution risk and less opportunity to capture nutrients.

Unsustainable Waste Management

Many of the impacts of climate change are now posing stressors that go beyond what our built environments were designed to handle. Climate impacts such as increased storm frequency, excessive rainfall and/or drought, and rising temperatures are curtailing the integrity of existing waste management systems and leading to leakages, public health risks, water quality deterioration, and other adverse social, cultural, and economic impacts.

Often placed in coastal regions for ease of effluent discharge, wastewater treatment plants are vulnerable to coastal flooding and sea level rise. For example, the aftermath of 2017's Hurricane Harvey left 40 wastewater treatment plants in Texas inoperable.¹ But people don’t stop pooping when facilities go down; untreated waste leaks out, causing biodiversity loss, aquatic dead zones, and public health crises.

A 2021 study² estimated that wastewater adds as much as 6.2 million tons of nitrogen from waste to coastal waters around the world, an amount equivalent to nearly 40% of total nitrogen inputs from agricultural runoff. Nitrogen–a core component of human waste–is one of the worst ocean pollutants. When present in excess, nitrogen can deprive ocean life of oxygen, creating dead zones and spurring massive toxic algal blooms. Current wastewater practices also contribute greenhouse gasses³ such as CO₂, CH₄, and N₂O to the atmosphere both directly through biological processes and indirectly via energy consumption. In this way, wastewater management practices may also exacerbate climate change⁴.

Poor waste management also poses problems to human health. Across the United States’ rural south, inadequate sanitation services have been associated with the resurgence of neglected tropical diseases like hookworm⁵, previously believed to be eradicated from the country. These sewage failures often disproportionately affect low income communities of color⁶ making waste management an environmental justice issue as well as a public health concern.

While waste management certainly has the potential to exacerbate environmental problems, human waste is also rich in nutrients⁷. Traditional waste management practices sometimes harness these nutrients, but there is potential to make the practice of capturing these nutrients and recycling them into different systems, such as fertilizer for agriculture⁸, a common practice.

‍

Addressing The Problem

Thor Retzlaff and Taylor Zehren, co-founders of Intrepid, a purpose-driven media production company, first began to think more about waste after members of their team confronted waste management problems on an expedition to Everest Base Camp in November 2018.

Retzlaff is a skier, high-altitude mountaineer, storyteller, and entrepreneur. Zehren is a social impact entrepreneur and outdoorswoman who focuses on circular systems development. Together with their friend Brophy Tyree, an explorer and entrepreneur focusing on protecting natural places, the three began reflecting on their experiences with waste management around the world.

“At one point, I was living in Bariloche, Argentina,” Zehren recalls. “I was doing a lot of rock climbing in one particularly narrow canyon. There were no sanitation options and people’s waste was everywhere – brown trouts and toilet paper lily pads behind every rock. Then, during monsoon seasons, big storms would come through and wash everything down to the river, where it acted as a pollutant, creating harmful algal blooms and other health concerns.”  

What Zehren was observing in South America was not a localized issue but a widespread problem globally, even in places where there is wastewater infrastructure. In fact, sometimes wastewater infrastructure actually exacerbates the problem by concentrating large volumes of waste in outdated structures often placed in more vulnerable locations.

In response to the widespread problems of waste management they were observing and what they subsequently learned about issues with waste management on a global scale, Retzlaff,  Zehren, and Tyree decided they had to do something. In 2019, the trio founded Do Good Sh*t, a non-profit devoted to reducing the harmful impacts of human waste on the environment and surrounding communities by deploying sustainable sanitation systems.

Over the next two years Retzlaff, Zehren, and Tyree connected with key experts across the field of waste management. From working with Geoff Hill, director of Toilet Tech Solutions who holds a PhD in Remote Site Human Waste Management–to modeling a nutrient reclamation urine processing facility with advice from Stanford Chemical Engineer William Tarpeh, the team began to gain their own expertise in waste management.

But then the COVID-19 pandemic hit, derailing the momentum behind Do Good Sh*t and curtailing the team’s ability to move their international sustainable sanitation projects forward. Rather than let this stop them, Tyree, Retzlaff, and Zehren pivoted their focus. With Do Good Sh*t, they had focused on improving backcountry sanitation, but they realized the problem existed at a much bigger scale and not just in remote areas. The trio began to consider how to address waste management in the frontcountry in a way that could harness the nutrients of waste, bolster climate resilience, and minimize environmental impacts.

“We noticed that the problem with domestic wastewater infrastructure in the United States was acute,” says Tyree. “And we knew that the principles of nutrient recovery could be applied everywhere that people go to the bathroom, not just in the mountains, so we started to think about how to expand our work to have a broader impact.”

In August 2020, Retzlaff attended a summit hosted by the Rich Earth Institute to learn more about the market value of upcycling nutrients and the positive environmental co-benefits of waste separation.

“After this, we had the epiphany that urine is valuable,” Retzlaff says. “Urine is essentially liquid gold in terms of nutrients.”

Combining the work of Do Good Sh*t with their newfound realization that urine recycling could provide a more sustainable fertilizer source, Retzlaff, Tyree, and Zehren hatched the idea behind Wasted*.

“We wanted to bring urine recycling, circular sanitation, and nutrient recovery to the world in a way that was scalable,” Tyree explains. “So we looked at all the environments where we could deploy this urine diversion and nutrient recovery technology and just saw porta-potties as the best place for innovation and transformation. Because all the waste from portables is moved around above ground you can easily deploy and iterate upon novel treatment technologies without having to retrofit underlying piping as you would have to if you were modifying the built environment.”

With Tyree serving as the Chief Executive Officer, Zehren as the Chief Operating Officer, and Retzlaff as the Chief Momentum Officer—Wasted* was born.

Climate Resilient Sanitation

The Wasted* team’s impact priority is on developing more climate resilient waste management.

“The climate is changing and it's going to be hard to stop that from happening,” Tyree said. “So we wanted to look into how we can support a world where humanity is not just surviving but thriving in harmony with all life on earth. The goal is to create systems that foster the conditions for symbiosis and coexistence of all life on the planet.”

The spillage, outages, and environmental contamination characteristic of existing wastewater infrastructure are only expected to grow as climate change accelerates. By 2100, sea level may rise by as much as 2 meters¹⁰ across the contiguous United States. With just 90 centimeters of sea level rise, as many as 10 million Americans could lose access to wastewater services¹¹. Furthermore, climate change may displace more than 1 billion people by 2050¹² which would disproportionately stress sanitation infrastructure which is not prepared for such massive spikes in demand. Mass displacement may also increase the need for portable sanitation specifically to support more transient populations.

“Regardless of how we attempt to mitigate climate change moving forward, we are at a point in history where we also need to focus on resilience and adaptation,” says Zehren. “Wastewater treatment is one of our most vulnerable pieces of infrastructure. Traditional wastewater treatment sites are big, expensive, and antiquated, and most were not designed to take into account the storm cycles and sea level rise we’re already seeing today.”

The price of updating existing wastewater infrastructure to adapt it to impending climate changes is high: the cost is estimated at around 1 trillion USD over the next two decades¹³. Rather than focus on addressing the antiquated existing system, however, Wasted* is innovating in the portable space. By creating decentralized wastewater infrastructure and focusing on the portables industry which can be easily adapted, Wasted* is creating a more climate resilient and adaptable waste management ecosystem in the portables industry which can then inform and potentially support waste management in the built environment. Diverting volume, nutrients and other treatment stressors away from centralized plants can help support and alleviate strain on existing infrastructure. The Wasted* team believes that their model may be even more relevant across different contexts as climate change accelerates and displaces communities across the world.

“We can leverage the same technology we’re implementing in municipal settings to provide portable sanitation in climate-affected contexts,” explains Tyree. “Contexts such as new developments, particularly climate-vulnerable municipalities, and even refugee camps.”

Using Waste To Support Regenerative Agriculture

In addition to focusing on bolstering climate resilience, the Wasted* model also supports regenerative agriculture by harnessing the nutrients contained in human waste and bringing them to the point of use where the nutrients from pee and poop are then processed for use as fertilizer.

While the development of synthetic fertilizers has bolstered agricultural production globally, the use of these fertilizers comes at an environmental cost. Global fertilizer production is estimated to contribute to 1.4% of annual CO₂ emissions and fertilizer use is a major non-CO₂ source of greenhouse gas emissions¹⁴. Furthermore, mining for the minerals needed for synthetic fertilizer use (i.e. phosphorus) can be geopolitically contentious¹⁵ as countries compete for control of mineral resources¹⁶ to support fertilizer production.

Biosolids (aka human waste) offer an abundant, low cost, nitrogen-rich fertilizer option so one recycling pathway for Wasted* is to transport human waste to places where the waste can be treated, tested, and processed into biosolids to support agriculture. A comparison of using biosolids versus no fertilizer on grasslands in British Columbia yielded striking results. The grass plot fertilized with biosolids produced much more grass than the unfertilized land.¹⁷

Another option for transforming waste into fertilizer is to harness the raw nutrients in urine. Human urine contains many of the key nutrients in fertilizer¹⁸ and efforts are underway at the Rich Earth Institute and beyond to explore how to harness these nutrients in the most effective and efficient way for use in place of synthetic fertilizers.  

With this in mind, Wasted* collects urine in containment which eliminates the need to add harsh chemicals later in the processing phase. Separating pee and poop at the source also helps maintain the integrity of the nutrients. The urine and the nutrients it contains can then be transported to processing facilities where the nutrients can be harnessed and recycled as fertilizer to support agriculture. Reusing the nutrients from waste also prevents these nutrients from running off into surrounding environments.

“We strongly believe in the importance of circular sanitation,” says Retzlaff. “Closing the loop is what Wasted* is all about.”

By addressing the topic of human waste head on, Wasted* is also pushing back against the stigma around human waste to highlight waste as a cost-effective, accessible source of nutrients.