Water-free toilets? These ideas are redefining sanitation

From agriculture to protecting biodiversity and safeguarding human health, water is essential to all aspects of life. Yet, 3.6 billion people still live without access to safe sanitation, posing a risk to their well-being, the environment, and economic development.

Thankfully, science and innovation are stepping in to ensure that this basic need becomes accessible, safe, and sustainable for all. One of the latest breakthroughs comes from a NASA scientist: a toilet that mimics the evapotranspiration process of plants to eliminate waste. Another innovation transforms waste into fertilizer.

What will you learn in this article?

• The global sanitation crisis
• A toilet that evaporates waste almost entirely
• Dry toilets: sanitation without water

Lack of sanitation: A crisis for millions

Sanitation is not just about health, but also about dignity and opportunity. Proper sanitation prevents infectious diseases, allows for dignified menstrual management, and generally improves quality of life while promoting a cleaner and safer environment.

However, 46% of the global population still lacks access to safely managed sanitation services, according to UN data, creating significant barriers to sustainable development. In rural and remote regions, such as parts of Africa and Latin America, these challenges are exacerbated by logistical difficulties and resource shortages.

Despite the obstacles, there are individuals and organizations working tirelessly to carve out new solutions, transforming societies. Notable examples include the inventive work of Diana Yousef and the initiative by the acciona.org foundation in Mexico.

                           "46% of the population still lacks access to safely managed sanitation services."

The toilet that evaporates waste almost entirely

Many communities still do not have access to hygienic, safe, and sustainable sanitation. The main culprit? Something as basic as the lack of sewage infrastructure.

Diana Yousef, an American scientist with Egyptian roots, and her team at change: WATER Labs have addressed this issue on a molecular level. Drawing on her experience with NASA—where she used breathable materials to recycle wastewater on the space station—Yousef developed a toilet that does not flush waste with water. Instead, it evaporates the waste, reducing its volume by 95%. The waste is deposited into a bag fitted with a membrane that evaporates and absorbs it, turning most of the waste into clean water vapor. This method also cuts down on odors and reduces contamination risks.

The process mimics what we see in nature: plants absorb water from the soil and release it as vapor through their leaves in a process called transpiration. This solution not only promises improved hygiene and health in regions lacking sanitation but also reduces the carbon emissions associated with waste transport by minimizing the need for frequent collection.

Dry toilets: A sanitation solution for water-scarce communities

Another initiative, led by the acciona.org foundation, focuses on reducing the number of people without access to safe sanitation. Since 2018, the foundation has provided solutions to remote populations in countries like Mexico. Through its EncASa program, it installs dry toilets in rural communities in Oaxaca. This sustainable and practical option ensures access to sanitation with dignity in remote areas.

A dry toilet does not require water like traditional toilets. Instead, waste is covered with a mixture of lime and soil, which not only prevents odors, insects, and disease spread but also transforms the waste into natural fertilizer.

Dry toilets represent more than just an alternative; they are a paradigm shift. Designed with sustainability and circularity in mind, this solution is a catalyst for change, offering safe sanitation without polluting or relying on water—a precious and scarce resource in many of these regions.

In a world where inadequate sanitation leads to disease and environmental harm, dry toilets offer an effective, eco-friendly solution. They also contribute significantly to the Sustainable Development Goals, particularly SDG 6, which aims to ensure clean water and adequate sanitation for all.

If this topic interests you, read more about acciona.org’s project in this feature article.

Yousef’s and acciona.org’s efforts are prime examples of how innovation and cross-societal collaboration can change lives. Both initiatives underline the need to approach the sanitation crisis from a holistic perspective, where technology and sustainability work together to create lasting, positive change.