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Self-Contained Solar-Powered Toilet Could Transform Sanitation in Developing World

A team of Caltech engineers is working on the toilet of tomorrow — a self-cleaning, solar-powered toilet that turns human waste into hydrogen and fertilizer, according to FastCoExist. The low-cost, automated toilet could help to revolutionize sanitation systems in the developing world.

The toilet uses a solar panel to power an electrochemical reactor, which breaks down waste into solids that can be used as fertilizer and hydrogen that can be stored in fuel cells to power the reactor during times of low sunlight. A pump sends recycled, purified water back to a reservoir on the top of the toilet. The toilet is completely self-contained (no sewer connection required), and can run off the grid. The system treats wastewater in just three to four hours.

Caltech engineer Michael Hoffman conceived the toilet during his previous experience on toilet-related projected for US Navy wastewater treatment plants and a NASA space shuttle system for urine removal.

In 2011, Hoffman and his team received a $400,000 grant to develop a toilet that can remove human waste for five cents per user per day. The following year, the toilet won the Gates Foundation's 2012 Reinvent the Toilet Challenge, which asked participants to create a safe, affordable and hygienic toilet that could serve the 2.5 billion people around the world who lack access to safe sanitation. In November 2013, toilet maker Kohler joined with the Caltech engineers to help further develop the toilet.

While the team has not yet reached its five-cent goal, the toilet currently costs about 11 cents per user per day if it is connected to the grid, or $1,500 over the 20-year life span of the toilet. The team says is working on using the hydrogen to add extra value to the system.

One of the biggest challenges of building a cheap, efficient and maintenance-free toilet is figuring out how to make the system completely automated, the researchers say. The current goal is to develop a toilet that can work by itself but be remotely monitored. The toilet is designed for easy repairs, but when the system breaks down, local technicians will be needed to fix it. To address this, Caltech is considering a business model that involves training local technicians. To further reduce production costs, the researchers are hoping to utilize local manufacturing resources wherever the toilet is used.

Caltech says two of the solar toilet systems are being tested in India.

Around 2.5 billion people — roughly 40 percent of the global population — do not have access to a toilet. In areas lacking adequate facilities, human waste can contaminate drinking water, which when combined with malnutrition, often causes gastrointestinal infections such as diarrhea. Diarrhea is the second leading cause of death in children under five, and is responsible for killing more than 660,000 children every year, according to the World Health Organization. In Sub-Saharan Africa alone, each day nearly 2,000 children under the age of five perish from the preventable illness.

WaterAid is working with companies large and small to improve access to safe water, improved hygiene and sanitation for 25 million people by 2015. Australian startup Who Gives a Crap gives half of the profits from sales of its eco-friendly toilet paper to WaterAid to build toilets and improve sanitation in the developing world. And earlier this month, WaterAid launched a new $9.3 million global partnership with H&M aimed at improving the health, education and future prospects of students by delivering safe water, sanitation and hygiene education programs in schools throughout the developing world. The goal of the initiative is to not only transform the lives of students by delivering immediate and long-term improvements to health and education, but also to influence national and international policies around the right to safe water and sanitation, H&M says.


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