The Blue Economy - CASE 19: Dry and Separation Toilets
This article introduces innovations to improve sanitation and reduce water consumption as one of the 100 Blue Economy innovations, known as ZERIʼs philosophy in action. This article is part of a broad effort by the author and the designer of the Blue Economy to stimulate open-source entrepreneurship, competitiveness and employment. Researched, Written and Updated by Professor Gunter Pauli.
The Blue Economy Inspired Series
Dry and Separation Toilets:
A Sustainable Solution to
Sanitation and Water Conservation
Written by; Shelley Tsang, 2024.
In today’s world, sanitation and access to clean water have become critical priorities, as nearly 2.5 billion people lack proper sanitation. As this challenge persists, experts and innovators are exploring new solutions to reduce water dependency and improve hygiene through technological and design innovation. One approach gaining attention is the dry and separation toilet system. This technology not only addresses sanitation needs but also significantly reduces water consumption. It’s a promising example of the "Blue Economy" approach—an economic model that aims to improve sustainability, entrepreneurship, and job creation.
The Sanitation Market and the Need for Innovation
The global sanitation market, estimated at $124 billion, is primarily based on water-based systems. Since 1990, approximately 1.6 billion people have gained access to improved water and sanitation facilities. However, due to population growth, this effort has not been enough; around 2.5 billion people, predominantly in developing countries, still lack access to proper sanitation. A staggering 65% of people in South Asia continue to rely on open defecation, leading to serious public health concerns. In some urban areas, such as Mumbai, India, the lack of facilities is even more severe, with 82 people sharing a single toilet.
The demand for improved sanitation is immense, especially in rapidly growing economies. The United Nations Millennium Development Goals (UNMDG) have underscored the importance of addressing this challenge by calling for increased funding and innovation. Access to sanitation impacts numerous sectors: public health, environmental health, economic productivity, and social equity. Meeting the demand requires an estimated $400 billion investment—a figure that reflects the urgency and potential market opportunity for companies to introduce innovative and sustainable sanitation solutions.
The Problem with Water-Based Sanitation
Water-based toilets have become the norm in developed countries, with flush toilets consuming between 25-40% of domestic water. A traditional flush toilet typically requires a significant amount of potable water to function, which is highly inefficient considering the global scarcity of clean water. For instance, in the United Kingdom alone, approximately 45 million toilets consume about two billion litres of water each day. During events such as the FIFA World Cup, authorities face additional strain as millions of people flush their toilets simultaneously during breaks.
The water used in these systems is often mixed with pathogens from human waste, necessitating chemical treatment to prevent the spread of diseases. These chemicals, while effective in killing bacteria and viruses, contribute to environmental degradation. Even with robust treatment, viruses and bacteria may still spread, highlighting the limitations of water-based sanitation. Furthermore, the growing need for desalination systems to produce potable water intensifies the energy burden, underscoring the unsustainable nature of current practices.
The Innovation: Dry and Separation Toilets
The dry and separation toilet concept emerged as an alternative that not only addresses sanitation but also minimizes water use. Dr. Mats Wolgast, a professor of sanitation and medical doctor, sought to rethink the traditional toilet system by eliminating water as a necessity. Dr. Wolgast’s research focused on separating liquids and solids in human waste, inspired by the inefficiency of flushing with potable water. This separation avoids mixing waste with water, simplifying the sanitation process and reducing water dependency.
Dry and separation toilets operate through a design that collects urine and solid waste separately. Urine is directed to a dedicated tank, while solid waste is contained in another chamber where it dries naturally. This drying process reduces the volume of waste and minimizes the risk of bacterial and viral spread, as dried waste is less conducive to pathogen survival. To maintain hygiene, Dr. Wolgast incorporated the Aquatron vortex separator beneath the toilet. This device allows solids and liquids to flow in different directions, ensuring complete separation without relying on electricity or complex mechanics.
In addition to these features, Dr Wolgast designed an efficient ventilation system that includes a black chimney within the toilet chamber. The chimney warms the air inside, creating a pressure differential that continuously draws fresh air into the toilet, thereby preventing odours. This design eliminates the need for fans or artificial fresheners, making it a low-energy, self-sustaining system.
The First Applications and Cash Flow
To bring his vision to market, Dr. Wolgast collaborated with Anders Nyquist, a renowned architect, to develop prototypes and test the dry and separation toilets in various environments. One of the earliest adopters was the Rumpan village in Sundsvall, Sweden, where residents evaluated the system's performance and provided feedback for further improvement. This pilot project showcased the practicality and durability of dry toilets, proving them to be a viable alternative in communities with limited water access.
In 1995, Nyquist introduced the system to the Laggarberg School in Timrå, northern Sweden. The school, with 150 students, generated less than 300 kilograms of dry waste annually, which was odour-free and produced no complaints from users. Importantly, the dried waste was easily converted into quality compost, offering the potential for a secondary revenue stream. The collected urine, when diluted with water, could also serve as a nutrient-rich fertilizer for nearby agricultural areas. This closed-loop approach exemplified sustainable waste management and underscored the economic potential of dry and separation toilets.
A New Opportunity for Sustainable Development
The success of these early applications highlighted the potential for wider adoption, especially in developing regions where water scarcity and poor sanitation are prevalent. Dr. Wolgast and his team decided to make certain designs open-source, allowing communities in Latin America, Africa, and Asia to access blueprints and fabricate the toilets locally. This approach promotes entrepreneurship, enabling local businesses to manufacture and distribute dry toilets at a fraction of the cost of conventional systems.
By using readily available materials and simple fabrication techniques, communities can produce low-cost sanitation solutions tailored to their specific needs. This model reduces the dependence on imported sanitation products, enhances local job creation, and aligns with the principles of the Blue Economy, where innovation meets environmental and social responsibility.
Environmental and Economic Impact
The environmental benefits of dry and separation toilets are significant. By eliminating water as a necessary component, these toilets reduce the strain on freshwater resources and lower the energy requirements associated with water purification and transportation. Furthermore, the natural drying process diminishes the presence of pathogens, reducing the need for chemicals and preventing potential contamination of water bodies.
In addition to environmental advantages, dry toilets offer an opportunity for economic growth. The compost generated from dry toilets provides a valuable resource for agriculture, supporting local food production and reducing the reliance on chemical fertilizers. As seen in the Laggarberg School example, the urine from separation toilets can be repurposed as an eco-friendly fertilizer, creating additional revenue for users and promoting sustainable agricultural practices.
The separation toilet model also aligns with the goals of urban sustainability. Modern cities face immense challenges in managing water resources and sanitation infrastructure. As urban populations grow, so does the demand for efficient waste management systems. Dry toilets offer an alternative solution for urban developers, particularly in areas where conventional sewage systems are financially or logistically unfeasible.
Challenges and Future Prospects
While the benefits of dry and separation toilets are clear, widespread adoption faces certain challenges. Changing public perceptions of sanitation and addressing cultural stigmas associated with non-flush toilets require educational efforts and strategic communication. Additionally, local governments and policymakers need to support alternative sanitation systems through subsidies, incentives, and inclusion in regulatory frameworks.
Technical improvements are also essential. As the technology develops, engineers are exploring ways to enhance the separation and drying processes further and to integrate digital sensors that monitor waste levels, alerting users when it’s time for maintenance.
Conclusion: Toward a Blue Economy of Sanitation
The concept of dry and separation toilets exemplifies how innovative design and sustainable practices can address one of the world’s most pressing sanitation challenges. By reducing reliance on water and converting waste into resources, this technology supports environmental health, public health, and economic opportunity. This approach aligns with the Blue Economy principles of sustainability, resource efficiency, and local empowerment.
As communities and industries recognize the potential of these systems, dry and separation toilets could transform sanitation, contributing to a cleaner, healthier, and more sustainable future. Through collaborative efforts, open-source sharing, and local entrepreneurship, this innovative approach has the potential to redefine global sanitation and set a new standard for eco-friendly waste management solutions.
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