From pit to Pivot Fuel: sourcing fecal sludge from informal communities

Hello World (...or the tiny subset thereof who are Pivot Updates readers)! It's been long. We're still here, and doing great in fact.  In our six months of silence we've been up to a lot! Like bringing on our new CTO, selling more fuel to more customers, making major strides in the performance of our dewatering process, raising money, and launching an effort to source fecal sludge from poor communities in Kigali, which you can read all about below.

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Over the past 4 months, with support from the Osprey Foundation and Stone Family Foundation, Pivot has established a fecal sludge sourcing team whose mission is collecting human waste from Kigali’s slums and delivering it to the Pivot Works factory for processing into fuel. The team is tasked with developing a reliable and cost-effective model for harnessing this waste in order to drive up Pivot Fuel production and drive down the public and environmental health impacts of poor sanitation in Kigali’s poor communities.

Prior to Pivot’s intervention, when pit latrines filled most families either sealed them and constructed a new one, or hired manual emptiers to excavate the pit and dump its contents into the environment – an illegal practice, of course. Illegal emptying and dumping practices are particularly common in dense informal areas, where space constraints preclude digging new latrines.

Our strategy for collecting this waste began with identifying existing emptiers in target communities and getting them bought-in to collaborating with Pivot.  To improve the health and safety standard of their work, Pivot replaced street clothes and shovels with head-to-toe personal protective equipment and mechanical emptying devices (E-Vacs) for the emtyping teams.  And now, instead of dumping the fecal sludge into the environment, the emptiers pump into barrels, which they bring to our transfer station.

Our working model

In the current iteration of the service model, pit emptiers work in teams to break the latrine slab, remove the trash (averaging 15% of total material by weight), and pump fecal sludge into 50-L barrels. A typical latrine yields about 50 barrels, which they carry via push-carts to a Pivot transfer station located in the community. Once the transfer station fills, Pivot collects the barrels of sludge and transports them to their factory.

 Bringing E-Vac pump and 50-L barrels to pit in preparation for emptying.

Bringing E-Vac pump and 50-L barrels to pit in preparation for emptying.

 Coping with steep terrain of Kigali, pit emptying underway.

Coping with steep terrain of Kigali, pit emptying underway.

 Loading full barrels into the truck for transport to Pivot Works factory.

Loading full barrels into the truck for transport to Pivot Works factory.

It’s a win-win for Pivot and Kigali’s network of informal waste workers; the improved equipment and safe removal of waste from the communities legitimizes the work of the emptiers, and allows them to openly market their services. In turn, Pivot Works is benefiting from the large household demand for pit emptying and ever growing volumes of sludge being delivered to our factory.

Lest this sounds like the entrepreneurial opportunity you’ve been looking for, pit emptying is extremely hard work and keeping finances in the black takes a tailor-made, perfectly optimized solution.  Take “the land of 1000 hills’ ” topography for example, the terrain in Kigali’s informal settlements is so steep and treacherous that our push carts can’t always access the pits.  This means that the 50 or so 50-L barrels filled with fecal sludge often need to be manually carried from the pit to the transfer station. One. By. One.  A time consuming, hugely labor-intensive, and expensive undertaking.

In addition to tracking the financial and technical success of our service models, we’re investing in monitoring and evaluations tools to characterize risks associated with our process and hold us accountable for achieving the public health outcomes that we envision. As part of our collaborative work with the UC Berkeley's School of Public Health, we are quantifying community and worker exposure at all stages of the waste-to-fuel supply chain. During empties we monitor levels of microbes, particulate matter, and toxic gases in different work zones and then use modeling tools to estimate the short- and long-term health impacts of these exposures. Understanding the types of exposures that occur as a result of different types of activities can help us optimize our process in a way that prioritizes public health alongside other cost and performance indicators.

What's next?

With household demand confirmed and a basic working model, Pivot is focused on cutting the end-to-end cost of the service from pit emptying to delivery of the sludge to Pivot Works.  Ultimately, our goal is to devise a service model that is affordable for Kigali’s poorest residents while also covering its operating costs.  Pivot Works, meanwhile, will absorb the cost of processing pit sludge, which they can recover through revenue generated from the resultant fuel. 

Major cost reduction is a challenging feat, but we’ve got a few ideas up our sleeves.  Think: replacing barrels with portable pumps that can overcome large head and long distances and deliver sludge directly to a roadside tanker. Think: trash incorporation into Pivot Fuel to increase the value of the material recovered from an individual pit. Thinking creatively we are, and we’ll be back soon with the details.