Tech + Health

04.05.14

Toilet Made for Densely Populated Settlements Turns Waste Into Dollars

Sanergy, a company founded by MIT students, distributes toilets specially designed for crowded areas. The toilets not only help people stay healthy, but they help communities make money.

About half of Nairobi’s 3.3 million people don’t have access to piped water or a sewage grid. Put simply: this is a public health catastrophe that disproportionately harms women and children. Water and sanitation development projects are legion in the informal settlements of Nairobi, and yet the basics of sanitation—access, affordability, and cleanliness—barely exist.

Sanergy, a for-profit/non-profit hybrid started by five MIT students in 2011, may change that. It manufactures and distributes toilets designed specifically for dense, urban informal settlements, then collects the resulting waste and processes it into high-value byproducts like fertilizer, which can be sold to local farmers. Its model has the potential to sustainably improve sanitation in dense, urban areas unequipped with a proper sewage grid.

“There's still not a clear answer for how you actually build a sustainable sanitation network in urban slums," Lindsay Stradley, one of Sanergy’s five co-founders, told me in an interview at its office in Mukuru Kwa Ruben, an informal settlement a few kilometers south of Nairobi’s central business district. One question in particular drew the team in, she said: “How do you harness the waste that comes out of sanitation—and now is a huge cost center—and turn that into a source of revenue to sustain not just the operations but potentially a whole community?”

In other words: how do you turn human waste into human welfare?

With a proper, piped sewage grid, this is relatively straightforward: waste is channeled to a central location where it can be sorted, disinfected, and treated with microorganisms, then sold as a high-value byproduct like fertilizer or biogas. New York City’s 6,000 miles of pipes, for example, move 1.3 billion pounds of wastewater to 14 treatment plants each day, resulting in 2.4 million pounds of “biosolids.” Some is sold as a liming agent, and some is disposed of in landfills (though it used to be sent to Colorado to fertilize crops).  

Without a sewage grid, waste collection would need to be sanitary, simple, and efficient—an impossible ask of traditional pit latrines. Waste must be periodically removed from the pit, which most often involves modern-day night-soil men who bale it out, bucket by bucket.

Sanergy designed a toilet to allow quick, clean waste removal. Rather than using a pit, the toilet has two blue modular plastic jugs that collect waste during the day, and are efficiently removed and replaced with clean ones each evening by its logistics team.

To install its “Fresh Life Toilets” in communities, Sanergy employs a microfranchising model, allowing entrepreneurs to purchase and run the toilets as independent businesses. Fresh Life Operators, or FLOs (Sanergy’s term for its microfranchisees) receive advising, discounts on sanitary products, and other forms of support from the organization, but otherwise “they own it, they operate it, [and] their success is their own,” Stradley said.

FLOs purchase Fresh Life Toilets for 50,000 Kenyan shillings (about $580—the manufacturing cost), and can buy additional toilets at a discount. Unfortunately, many prospective FLOs don’t have that kind of money, and accessing credit can be very difficult for the chronically unbanked settlement population. This was a significant challenge to Sanergy’s model until it partnered with Kiva in September 2012. Since then, dozens of FLOs have received loans to purchase toilets.

The toilet was designed to have a very small footprint—just three feet by five feet—so it fits on an individual’s plot of land. After manufacturing pre-fabricated components at its headquarters, Sanergy engineers install a toilet on the FLO’s land, and it is immediately ready for use.

Currently, there are 365 Fresh Life Toilets in Mukuru Kwa Ruben and other settlements, owned by 190 FLOs. The toilets provide hygienic sanitation to about 15,000 residents each day, and 2,050 tons of waste has been collected in the past two years.

Simon Stumpf, a Regional Representative for Ashoka East Africa, which elected co-founder David Auerbach as an Ashoka Fellow in 2013, told me in an email interview that Sanergy’s model “may not sound that innovative at first, but this is the key Sanergy insight. It has to be all three: Affordable. Accessible. AND hygienic… they are proving that ‘good enough’ isn’t good enough anymore.”

Other solutions manage to hit one or two of these needs, but Sanergy is unique in its ability to achieve all three at once. One popular alternative model is a “sanitation block”: a large structure that houses multiple toilets and often includes hot showers. Some sanitation blocks, like the “bio-centers” constructed by Umande Trust, even generate biogas from the waste. But these blocks are large by definition and by necessity, so finding space for them in cramped, congested informal settlements is an issue, as sanitation block-builder Maji na Ufanisi (Water and Development) has found. The blocks are also quite expensive at $30,000 each.

Most importantly, access is still a problem for those that live far from a block. If you don’t solve the access problem, you don’t solve the sanitation problem. The small footprint of Sanergy’s toilet allows for it to be placed just about anywhere, which allows for more efficient allocation of toilet supply.

Typical pit latrines are often inaccessible and unclean. Pit latrine operators simply don’t have the inherent incentive to keep them clean; sanitation is an added expense, and owners have a captive market. As a mission-oriented organization, Sanergy cares about offering hygiene and a clean environment for customers. When FLOs purchase a toilet, they agree to keep it well-stocked with sanitary products like toilet paper and soap. If they don’t, a Sanergy employee will work with them to fix the problem.

Alex Wekesa, a 26-year old employee of Sanergy, also owns two Fresh Life Toilets near his home in Mukuru Kwa Ruben (it’s not uncommon for Sanergy employees to also be FLOs). Before working at Sanergy, Alex did what many residents of informal settlements do: he strung together an array of side jobs—barber, driver, launderer—to make ends meet. Unlike many of his neighbors, though, he completed university, which allowed him to get a more stable job. He used his savings to become a FLO.

As we were walking through the congested, uneven, dirt streets, narrowly dodging the schoolchildren running around after school, I asked Alex why he decided to become a FLO. “The sanitation in my area is very bad,” he said simply. “And the pay helps me to pay for my brother’s schooling.” In return, his brother is his employee, operating the toilets while he is away.

A long, narrow alleyway lined with corrugated aluminum homes led to Alex’s two immaculately clean toilets. He charges four shillings per adult use (about $.05) and two shillings per child use (market rates in the area), but was quick to point out, “if someone doesn’t have the cash, I let them use the toilet and they can pay back later.”

Alex‘s location is perfect for the toilets—a main thoroughfare with lots of foot traffic—so he didn’t have an issue attracting customers. He had so many, actually, that it made sense to purchase another Fresh Life Toilet, and now about 100 customers visit his toilets each day.

Alex pays an annual leasing fee, and must commit to keeping the toilets clean and well-stocked with soap and other sanitation products, but otherwise is free to run his business as he sees fit.

Other FLOs have had more trouble than Alex. Some simply haven’t had enough demand, and others have managed their toilet or their money poorly, and have defaulted on their Kiva loans. To prevent defaults and failures, Sanergy carries out extensive market research ahead of entering a new neighborhood, and the model itself works against failure: because the FLOs are in business for themselves, they are incented to do well.   

After collecting the waste, Sanergy’s logistics team brings it to a central processing facility in Mukuru Kwa Ruben, where it is weighed and placed in large bins. It is monitored, tested, and treated, and becomes fertilizer after about eight months. The most pressing question is whether Sanergy’s fertilizer, which is up to the safety standards of the Kenya Bureau of Standards and the World Health Organization, will be competitive on the Kenyan marketplace.

Many external individuals and organizations are optimistic about its chances. Sanergy has racked up accolades, awards, and investment for its model; it was even the first recipient of the WASH for Life Award, a $100,000 grant given by USAID’s Development Innovation Ventures in partnership with the Bill & Melinda Gates Foundation. These grants and private investments have allowed Sanergy to build up its network of toilets and to experiment with its fertilizer production, but for it to be financially sustainable it will need to sell a quality product. Initial testing of the fertilizer was positive; the Sanergy plot yielded 30% more sorghum than a non-fertilized plot. While Sanergy’s fertilizer has not yet been tested against other fertilizers, the organization believes that it will be competitive with organic fertilizer on the Kenyan market.

There’s a deep potential market for fertilizer in Kenya. On average, the country’s farmers use only 35 kilograms of fertilizer per hectare of arable land—higher than the region’s average, but a fraction of what is used in other developing countries. It is highly likely that using fertilizer would increase yields and incomes, and while under-use stems from disparate causes, behavioral economists have found strategies that significantly increased its use.

In order to guarantee consistent supply for its customers, Sanergy needs to grow its network of toilets and its capacity “by three or four times,” Auerbach said recently. But scaling presents new challenges. Most visibly, it needs somewhere to put all of the waste. The current fertilizer production process is “hugely space-intensive… as we grow, it’s becoming completely not feasible” Stradley told me.

A recently-purchased machine can cut the treatment period from eight months to one week, which should reduce the amount of space needed and help the organization ensure a consistent supply of fertilizer for its customers. 

As the density of toilets increases in Mukuru Kwa Ruben and the other nearby settlements, it will also need to expand, which will, at a minimum, force the logistics team to go longer distances to collect the waste, and could require additional processing facilities. This isn’t an immediate concern—there is a lot of room to grow in its current locations—but it will be a challenge in the future.

This year, it will begin to sell its fertilizer to farmers, and aims to have 1,000 toilets in use by the end of 2015.