About 2.5 billion people use unsafe toilets or defecate in the open. Unsafe methods to capture and treat human waste result in serious health problems and death. Food and water tainted with fecal matter result in 1.5 million child deaths every year. Most of these deaths could be prevented with the introduction of proper sanitation, along with safe drinking water and improved hygiene.

The flush toilet of today was invented in the 18th-century and requires significant amounts of sewer infrastructure and water. In June 2011, the Bill & Melinda Gates foundation awarded eight universities grants of approximately $400,000 to leverage, in one year, advances in science and technology to create a waterless, hygienic toilet that is safe and affordable for people in the developing world.

Earlier this week the winners of the Reinvent the Toilet Challenge were announced. Below you will find a brief overview of the issues, goals of the challenge and results from the eight universities.

 

 

 

 

 

 

 

 

 

 

 

In June 2011, the foundation awarded eight universities grants of approximately $400,000 to leverage, in one year, advances in science and technology to create a waterless, hygienic toilet that is safe and affordable for people in the developing world. These grantees were eligible for the Reinvent the Toilet Challenge awards that were announced on August 14, 2012. Awards include: First Prize: $100,000; Second Prize: $60,000; Third Prize: $40,000.
 
Reinvent the Toilet Challenge aims to:

– Address the failures of the 18th-century toilet, which is not meeting the current needs of 2.5 billion people who lack access to sanitation
– Support upstream research and development of a toilet that:

i. Is hygienic and sustainable for the world’s poorest populations
ii. Has an operational cost of $0.05 per user, per day
iii. Does not discharge pollutants, but instead generates energy and recovers salt, water and other nutrients
iv. Is designed for use in a single family home

– Create a toilet that does not rely on water to flush waste or a septic system to process and store waste
– Create a toilet that is the basis for a sanitation business that can be easily adopted by local entrepreneurs living in poor urban settings

 

 

 

 

 

A toilet that converts human waste to fuel gas
Delft University of Technology, The Netherlands

A toilet system that applies microwave technology to transform human waste into electricity. The waste will be gasified using a microwave-induced plasma. This process will yield synthesis gas (syngas), a mixture of carbon monoxide and hydrogen. The syngas will then be fed to a solid oxide fuel-cell to generate electricity.

 

 

 

 

Diversion for safe sanitation
Participating organizations: Eawag: Swiss Federal Institute of Aquatic Science and Technology; EOOS , Switzerland

A functional model of a urine-diverting toilet that recovers water for flushing. The urine and feces will be safely transported to a decentralized processing center. The water used for cleaning will be recycled by a gravity-driven biological membrane.

 

 

 

 

A toilet that sanitizes feces and urine to recover resources and energy
University of Toronto, Canada

A technology for treating solid waste streams through mechanical dehydration and smoldering (low-temperature, flameless combustion) that will sanitize feces within 24 hours. Urine will be passed through a sand filter and disinfected with ultra-violet light.

 

 

 

 

A urine-diverting combustion toilet
National University of Singapore, Singapore

A toilet that uses biological charcoal (biochar) to dry and combust feces. The heat generated will be used to extract water from urine by boiling it under pressure. The system can be fitted with activated carbon and exchange resin to recover highly purified water.

 

 

 

 

A community bathroom block that recovers clean water, nutrients, and energy
University of Kwazulu-Natal, South Africa

A toilet system that can safely dispose of pollutants and recover materials such as water and carbon dioxide from urine in community bathroom blocks. The system will separate the urine from the feces and extrude the feces into thin strands for faster drying and stabilization.

 

 

 

 

A toilet that produces biological charcoal, minerals, and clean water
Loughborough University, United Kingdom

A toilet that transforms feces into a biological charcoal (biochar) through hydrothermal carbonization (decomposition at high temperatures without oxygen and in water) of fecal sludge. The proposed system will be powered from heat generated by combusting the produced biochar and will be designed to recover water and salts from feces and urine.

 

 

 

 

A solar-powered toilet that generates hydrogen and electricity
California Institute of Technology, USA

A self-contained, solar-powered toilet and wastewater treatment system. A solar panel will produce enough power for an electrochemical reactor that is designed to break down water and human waste into hydrogen gas. The gas can then be stored for use in hydrogen fuel cells to provide a backup energy source for nighttime operation or use under low-sunlight conditions.

 

 

 

 

A sanitation system that converts human waste into biological charcoal
Participating organizations: Stanford University and the Climate Foundation, USA

A self-contained system that pyrolyzes (decomposes at high temperatures without oxygen) human waste into biological charcoal (biochar). After the fair, the system will be shipped to Nairobi to process two tons of human waste daily, at a facility located in the slums.

 

 

 

 

 

California Institute of Technology in the United States received the $100,000 first prize for designing a solar-powered toilet that generates hydrogen and electricity. Loughborough University in the United Kingdom won the $60,000 second place prize for a toilet that produces biological charcoal, minerals, and clean water. University of Toronto in Canada won the third place prize of $40,000 for a toilet that sanitizes feces and urine and recovers resources and clean water. Special recognition and $40,000 went to Eawag (Swiss Federal Institute of Aquatic Science and Technology) and EOOS for their outstanding design of a toilet user interface.