Publication on SOIL’s composting method by the CDC and Emory University

Here at SOIL, we’re dedicated to basing our strategic objectives, protocols and procedures, and design iterations on careful research and data. We also make an effort to share our lessons and progress with the global ecological sanitation community. That’s why we’re so pleased that a scientific paper on our work has been published!

“Ascaris and Escherichia coli Inactivation in an Ecological Sanitation System in Port-au-Prince, Haiti” was released on May, 2015 by David Berendes with co-authors from the Centers for Disease Control and Prevention (CDC) and Emory University.

This publication is a powerful validation of SOIL’s work in Haiti, as it demonstrates the efficacy of our thermophilic composting system in pathogen inactivation. In other words, heat-loving bacteria quickly eradicate the dangerous pathogens in human poop through SOIL’s method of composting.

After poop is dumped into bins at our waste treatment sites, naturally occurring bacteria go to work breaking down biological material. During that initial period, known as the thermophilic stage, the bacteria can generate temperatures up to 160° F! If left alone without watering and encouraging aeration, the compost piles could actually start to smolder! While those helpful bacteria flourish in high temperatures, dangerous pathogens cannot survive – which is what makes SOIL’s composting process so effective.

Researchers tested that effectiveness by measuring the die-off rates of E. coli and Ascaris lumbricoides eggs over time. E. coli is often used as an indicator of fecal contamination, and Ascaris lumbricoides is generally recognized as the most difficult human pathogen to kill even with high temperatures like those found in SOIL’s system. This means that if SOIL’s system is able to neutralize Ascaris eggs, all other pathogens will be taken care of as well!

The CDC/Emory researchers found that there was a 99.99% reduction in E.coli to well below acceptable levels within sixteen weeks, and viable Ascaris eggs were rendered non-viable within just six weeks. This means that SOIL’s finished product, which goes through a full 36-50 weeks of composting, goes well beyond the time needed for complete pathogen die-off.

While SOIL has continued to make significant improvements to our composting model since the data for this study was collected in 2012, these results confirm that SOIL’s composting process safely transforms the waste emptied in our compost bins to a final product ready for reuse. Having published research from the CDC to back it up increases the credibility of EcoSan and shares important insights that can be applied globally. As the authors state, “This study is one of the first to document efficacy of an ecological sanitation system under field conditions and provides insight into composting methods and monitoring for other international settings.”

As 2.5 billion people around the world still lack access to improved sanitation, topsoil critical for agriculture is eroding, and fresh water resources are increasingly scarce, EcoSan systems like SOIL’s are a viable solution for treating human waste.

Thank you to the researchers of this publication, to the CDC, and to Emory University!

You can read the full article here.