Open defecation is common in regions of the world that suffer from a variety of other issues requiring imminent action, such as poverty and malnutrition. However, providing a swift resolution to the sanitation crisis is important not only because it grants individuals the ability to safely perform a basic human need in the Modern age, but also due to the fact that a lack of sanitation is closely tied with these other issues.
Because of this, in 2013, the United Nations issued a global call to action for the elimination of open defecation by 2025. Similarly, the Bill & Melinda Gates Foundation launched the Reinvent the Toilet Challenge to put an end to this issue in an effective manner. We mentioned this and further background in our past post, Why the World Needs More Toilets, as ISO had been striving to complete this challenge for some time. In fact, international standardization actually has made a major step in fulfilling its goals, through the publication of IWA 24:2016 - Non-sewered sanitation systems - General safety and performance requirements for design and testing.
Just to give a background on the Bill & Melinda Gates Foundation’s Reinvent the Toilet Challenge, it set the criteria for a toilet that:
- Removes pathogens from human waste and recovers valuable resources such as energy, clean water, and nutrients.
- Operates “off the grid” without connections to water, sewer, or electrical lines.
- Costs less than USD 0.05 per user per day.
- Promotes sustainable and financially profitable sanitation services and businesses that operate in poor urban and rural settings.
- Is a truly aspirational next‐generation product that everyone will want to use in developed as well as developing nations.
Each of these stipulations is important, as they allow the new technology to avoid any of the limitations that might be present in the areas that they are to be installed in. For example, a poverty-stricken community might not have access to reliable running water, so installing toilets that operate “off the grid” can be a key factor in establishing their ability to function. And, with costs at the inexpensive $0.05 per person daily, the Reinvent the Toilet Challenge is an attainable solution.
IWA 24:2016, an international workshop agreement that was released in September 2016, brings this conceptual toilet closer to reality through the standardization of its design, installation, and use. With these guidelines, the next-generation toilets can be installed throughout the world with the same effective technical requirements, test methods, and sustainability considerations.
Following the criteria set by the Reinvent the Toilet challenge, the international document specifies a sanitation system that is not connected to a networked sewer system and collects, conveys, and fully treats the specific input, to allow for safe disposal or reuse of the generated output.
IWA 24:2016 conceptualizes the areas in which is concerned through the following figure:
This figure indicates the general cycle of the toilet’s operation, beginning with the input, which can consist of any of the anticipated treatable substances, including urine, feces, menstrual blood, bile, flushing water, and toilet paper, and ending with the outputs, which include the breakdown of these substances and their effects. In compliance with the IWA 24:2016, users should not be exposed directly to the outputs of a previous user, despite the minimal flushing capabilities of toilets that are not connected to the local water network.
From the management of these outputs, it can be seen that the IWA 24:2016 toilets are meant to be designed for the good of the users, something that you obviously might expect with a technology that is intended to improve the quality of life for individuals in less-advantageous communities. The document calls for the appropriate user information to be displayed on the toilet itself, including the expected number of users and uses per day, the expected daily capacity for further input, such as urine or feces, common items that should not be added to the system, and instructions for obtaining service.
However, despite the need for this information to be included, IWA 24:2016 also recommends that the toilets be usable for the illiterate. The users do not need to be made aware of the limitations of the sanitation systems, as long as those behind their design and installation prepare the toilets in accordance with the document’s guidelines. In adherence to these guidelines, the designers should have established the toilet’s sustainability limits off the amount of anticipated users.
IWA 24:2016 also details extensive recommendations on the toilet’s structural integrity and durability. This includes practically all of the anticipated forces and stresses, with considerations placed on external impacts and the effects of corrosive agents. The toilets should be able to function reliably within environments with ambient temperatures between 5°C and 50°C. Any components of the sanitation system located below ground level should be able to resist any geotechnical impacts.
The idea of non-flushing toilets is far from a glamorous subject, but these devices serve as a testament to the abilities of modern technology and innovation. While much attention today is drawn to certain technological advancements, such as those made in computers and clean energy equipment, next-generation toilets, by solving a world sanitation crisis in a reasonable and economic manner, might turn out to be one of the greatest accomplishments of the 21st Century.
IWA 24:2016 - Non-sewered sanitation systems - General safety and performance requirements for design and testing is now available on the ANSI Webstore.
1. International Organization for Standardization (ISO), IWA 24:2016 - Non-sewered sanitation systems - General safety and performance requirements for design and testing (Geneva: ISO, 2016), 2..