The market
Today, the global market for water-based sanitation products and services is estimated at $124 billion. While 1.6 billion more people have gained access to water and sanitation since 1990, a total of 2.5 billion still lack access. This number has remained unchanged over the past three decades due to population growth. The United Nations Millennium Development Goals (MDGs) propose doubling aid and investment to address the fact that one in four people in developing countries lacks any form of sanitation at all. In South Asia, approximately 65% of the population practices open defecation. The city of Mumbai has 82 people for every toilet: there are more mobile phones in India than toilets. The market potential for meeting "toilet needs" is estimated at over $400 billion, based on existing costs, business models, and the number of people not yet reached.
Although the first patented self-cleaning vortex toilet bowl dates back to 1907, it wasn't until the 1950s that the modern toilet design became standard. As water-based sanitation became more widespread, the use of drinking water for flushing toilets became one of the most inefficient uses of this precious resource. Today, 25 to 40 percent of domestic drinking water is used for something that doesn't require drinking water at all. The scale of this consumption is illustrated by the 45 million toilets in British homes, which use approximately two billion liters of fresh water every day. During the FIFA World Cup, local authorities work to keep the water flowing for the millions of people who flush during the 15-minute halftime break.
We overlook the fact that each infected person could release up to 10 billion viruses per day. If viruses are transmitted through water, there is an urgent need to use chemicals to control the spread of disease. Even if chemicals were to kill 99.99% of all bacteria and viruses, approximately one million viruses would still continue to spread.
Just one is enough to infect someone. Given that the scarcity of domestic water is driving the installation of 12,500 water purification systems worldwide, and that converting salt water into drinking water is very energy-intensive, the use of water for sanitation and the growing demand for fresh water must be fundamentally rethought. This presents an opportunity to introduce innovations to the market
Innovation
The overhaul of sanitation systems has attracted few top-level engineers. Toilets have undergone numerous redesigns, with prices dropping to as low as $30 per unit—cheaper than a cell phone—and water consumption limited to just 3 liters, and even 1.5 liters per use. Excrement disposal facilities such as septic tanks, flush toilets, and pit latrines are known as improved sanitation systems, which essentially shift the problem and continue to rely on potable water for flushing.
When Dr. Mats Wolgast, a professor of sanitation and a physician by training, studied waterborne diseases, he realized he was caught between the desire to lead a "no toilet, no wife" campaign—which leads women in developing countries to reject suitors if they cannot provide a toilet for a household—and the cultural anachronism that compels them to use drinking water for flushing. He studied human physiology and designed a simple system that separates liquids from solids, preventing them from mixing with water. Liquids are collected in a separate urine reservoir, while solids are deposited in a container and left to dry.
As a doctor, he focused on controlling bacteria and viruses, while respecting the desire to stick with the flush. He designed a separation system based on the Aquatron vortex directly beneath the toilet, ensuring rapid and complete separation of solids and water. The solid matter dries within hours, eliminating the risk of disease transmission. Mr. Wolgast further developed his original idea for a dry toilet, adding a black chimney to the inner chamber by applying the laws of physics. When the chimney heats the air, which expands and rises, a negative pressure is created inside the toilet, drawing air from the room into the chamber. This simple and ingenious system, requiring neither a fan nor electricity, has never failed: the air is fresh and clean without the need for artificial air coolers.
The first cash flow
While many toilet designs exist, the key professionals to convince are, first and foremost, the building architects. Dr. Wolgast worked closely with Anders Nyquist, who then had to convince his clients. The first to adopt the new system was the village of Rumpan, near Sundsvall, Sweden, where the toilets were tested. This collaborative effort further simplified the design. After several years, Anders concluded that the time was right for a large-scale project. Laggarberg School in Timrå, north of Sundsvall, adopted the system for the school in 1995. The annual solid waste generated by a school of 150 children amounts to less than 300 kilograms of dry mass, and there has never been a complaint of odor. Perhaps most importantly, the solid waste is high-quality compost that is sold to local farmers, generating a small additional income. Urine is collected in an underground tank. One unit is mixed with 10 parts water and used as fertilizer on the neighboring golf course.
The opportunity
Mats Wolgast and his colleagues decided that the best of their designs should be commercialized. A number of companies acquired the rights, and many architects familiarized themselves with the waterless system. The least expensive model, however, was transformed into an "open-source toilet," meaning that anyone interested can download the designs for free from the internet and "do it themselves." Anders Nyquist, who is not only an architect but also a carpenter, added his knack for "keeping things simple." The ultimate success of the designs is confirmed by the desire of people in Latin America, Africa, and Asia to produce their own dry, separate toilets, transforming one of humanity's greatest challenges—clean water and sanitation—into an opportunity for local entrepreneurs to use local materials and simple tools for manufacturing, while ensuring sanitation at a fraction of the current cost. That's innovation.
