Decoding Design

Safe sanitation systems close the loop on poop

Posting in Architecture

Human waste is a major threat to public health, but it's also a rich resource. These closed-loop systems are capturing that value while improving public health.

Today is the 10th annual World Toilet Day. Sponsored by the Singapore-based World Toilet Organization, the event is meant to build awareness about the risks that lack of sanitation present to the physical, emotional and psychological health of 2.6 billion people around the world.

Fortunately, poor sanitation is receiving an increasing amount of attention from NGOs, academics and other problem-solvers around the world. But there's time to waste, since lack of hygiene contributes to diarrheal diseases that claim the lives of 1.5 million poor children each year.

Earlier this year, The Gates Foundation awarded a total of $3 million to researchers at 8 universities as part of its Reinvent the Toilet competition. Unlike the innovations that are taking place with flush toilets, these grants are aimed at designing, developing and prototyping waterless, hygienic toilets that costs less than $0.05 per user per day.

The foundation also awarded a $4.8 million grant to the London School of Hygiene and Tropical Medicine (LSHTM) for a project called Sanitation Ventures. For it, researchers are developing ways to speed up the decomposition process in pit latrines. Organisms such as tiger worms, placed near the surface of the latrines, can effectively increase the speed of composting. Beneath that, in a filtration bed, liquid waste is further treated by aerobic bacteria. The end protect is a treated sewage material that can later be used as a fertilizer.

And if that sounds gross, well, get over it. Human-waste-based fertilizer has been used in many parts of the world for centuries. The key is to process it correctly -- at the right temperature and for enough time -- to ensure that all pathogens are eliminated.

In fact, aside from better public health, one of the major benefits of developing sanitation solutions for the developing world is creating an end product with value, such as fertilizer or biochar for energy.

The folks at PeePoo have been working on this, in a very low-tech way, for many years and a pilot program in Kenya is showing that it could create a viable business model through a closed-loop system that allows people living in poverty to collect their waste in compostable bags that are then turned into fertilizer.

In Haiti, where only 15 percent of those living in rural areas have access to sanitation systems, ecologist Sasha Kramer and engineer Sarah Brownell co-founded Sustainable Organic Integrated Livelihoods, or SOIL, in 2006. SOIL installs composting toilets that provide a means for Haitians living in poverty to use clean, safe lavatories - something that become even more vital following the 2010 earthquake.

SOIL uses a simple and effective design for its toilets. Near the front part and just unde the toilet seat, there's a smaller bowl where the urine is collected. The poop, coming, as it does, from the rear, falls into a larger container below the seat. The feces are then collected and brought to a composting facility. Because the urine is diverted from the poop, the poop is easier to transport and is less malodorous than it would otherwise be.

The project has so far created 100,000 gallons of compost that is starting to be applied to crops.

And at the Safe Haven orphanage in Thailand, Norwegian firm TYIN tegnestue has employed smart architectural solutions to create bathhouses that improved sanitation for the resident children.

Photos: Flickr/Gino; SOIL

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Mary Catherine O'Connor

Contributing Writer

Mary Catherine O'Connor has written for Outside, Fast Company, Wired.com, Smithsonian.com, Entrepreneur, Earth2Tech.com, Earth Island Journal and The Magazine. She is based in San Francisco. Follow her on Twitter. Disclosure