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Rick Gould

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The High-Tech World of Toilets

To aid global sanitation, ISO 31800 will certify the design, performance, and testing of toilets that function off the grid

Published: Thursday, June 6, 2019 - 12:03

Well over half the world’s population does not have access to safe sanitation. For many people, this means the indignity and risks that come of having no toilets. The answer, it seems, lies in new sustainable treatment plants. The International Organization for Standardization (ISO) and the Gates Foundation have joined forces to show how clean toilets and standards can change people’s lives forever.

In 2010, the United Nations formally declared that access to clean water and safe sanitation are fundamental human rights. Aligned to this, the United Nations’ Sustainable Development Goal Six (SDG 6), which states that everyone should have access to safe sanitation by 2030. This, in turn, would eliminate open defecation, which billions must still endure. According to the Joint Monitoring Program for Water Supply and Sanitation, the official United Nations mechanism tasked with monitoring progress toward SDG 6, 2.3 billion people lack any form of sanitation at all, and more than 200 million tons of human waste go untreated each year.

In the developed world, most if not all people take advanced, interconnected sewerage and wastewater treatment systems for granted, while in the developing world, 90 percent of sewage ends up in lakes, rivers, and oceans. This causes pollution that creates a health hazard for animals, plants, and people. “Sixty percent of the human race does not have access to safely managed sanitation,” reveals Sun Kim, a program officer at the Bill & Melinda Gates Foundation and chair of project committee ISO/PC 318, in charge of developing a standard for community-scale sanitation systems.

Moreover, clean water and sanitation are closely connected because uncontrolled sewage frequently contaminates water resources, with often devastating consequences. “If we don’t have safe sanitation, then clean water will get tainted,” observes Kim. Shockingly, 1.8 billion people globally use a source of drinking water contaminated with feces. Hence, it is not surprising that, according to the World Health Organization, unclean water and poor sanitation are the world’s second biggest killer of children. How can we solve this conundrum?

Nonsewered solutions

Building conventional types of interconnected sewers and waste treatment systems is one answer to the problem, yet these require huge amounts of money and time to build—two resources that are not easily available in the developing world. Is there a way to create nonsewered systems that do all the things these big systems do without the cost and infrastructure? “We believe the answer is yes,” says Kim. In fact, ISO and the Gates Foundation are achieving this together through the work of ISO/PC 318, whose secretariat is held by the national standards bodies of the United States and Senegal under an ISO twinning arrangement.

Managed sanitation systems without interconnected sewers are known as nonsewered sanitation systems. Following significant support from the Gates Foundation, ISO began by developing International Workshop Agreements (IWAs) on the subject. The Gates Foundation promotes and sponsors research and investment in areas such as education, agriculture, global health, and sanitation for the developing world, whilst ISO can help get targeted specifications to market in less than a year using the fast-track process offered by an IWA.

Villagers line up with plastic canisters to get safe water from a public water well in Nyarusiza, Uganda.

Although IWAs often evolve into fully fledged ISO standards, they provide much-needed solutions in the meantime. IWA 24 specifies general safety and performance requirements for the design and testing of nonsewered sanitation systems. It served as the basis for ISO 30500, an international standard for small-scale, safe, self-contained, and self-sufficient toilets complete with fecal treatment, that was published in October 2018.

ISO/PC 318, meanwhile, developed IWA 28 for community-​scale systems that can treat the waste from tens of thousands to hundreds of thousands of people using stand-alone toilets that function “off the grid.” IWA 28 specifies requirements for the design, performance, testing, certification, and operation of independent, self-contained, and energy self-sufficient units known as fecal sludge treatment units (FSTUs). ISO/PC 318 is now in the process of converting IWA 28 into an ISO standard, the future ISO 31800.

The Pollution Research Group’s Fecal Sludge Lab is a professional research facility housed in the University of KwaZulu-Natal’s School of Engineering. Photo: Gates Archive/Samantha Reinders

Framing the technology

But before we reach that milestone, let’s take a look at the history behind this IWA. After developing the concept of FSTUs, the Gates Foundation approached researchers and industry to give shape to the idea. “We worked with TÜV SÜD to create a private standard for FSTUs, which we then proposed as a seed document for ISO 31800,” explains Kim. TÜV SÜD is a German engineering and technology organization which specializes in performance testing for technology development, verification, and certification.

ISO/PC 318 developed IWA 28 for areas with sizeable populations such as larger towns and cities. Many urban areas in the developing world might have rudimentary systems to collect and transport large amounts of fecal material but may lack the means to treat the waste, with the result that it is then dumped into the environment. IWA 28 describes the processes, procedures, specifications, and test procedures underpinning the equipment that can deal with the fecal sludge safely, reliably, sustainably, and efficiently.

In essence, IWA 28 provides a framework that dovetails with the circular economy and embodies them both safely and sustainably. To that end, IWA 28 specifies requirements to ensure that there are the means in place to receive, store, and then process fecal sludge in the FSTU. The minimum requirements include the need to use the fecal material as a fuel and for energy recovery, together with controls and limits on any air emissions, odor, noise, and effluent. There are also requirements for the end products of process, for example when the treated fecal sludge is converted to material that farmers can use as a fertilizer.

The Janicki Omni Processor was installed in Dakar, Senegal, in 2015, and now treats the fecal sludge of up to 100,000 people. Photo: Gates Archive/Sam Phelps

For its part, “ISO 31800 is ‘technology agnostic’ and not specific to any one technology, such as sludge combustion, anaerobic digestion, or other forms of biological or thermal system,” adds Kim. “We even have a research partner developing a technology that uses supercritical water oxidation. It depends on what is suitable for the environmental conditions, as long as the design of FSTU uses feces as a fuel to kill pathogens, using the calorific value of the fecal sludge.”

All-in-one treatment

The engineering firm Sedron Technologies based in Washington, is represented in ISO/PC 318 and developed the first prototype FSTU that evolved in synergy with IWA 28. Known as the “Omni Processor,” this technology uses sewage sludge as a fuel to both dry the sludge and then complete the process within the FSTU. This unique technology is fast on its way to revolutionizing the waste-processing industry. For example, a pilot plant was installed in Dakar, Senegal, in 2015, and has been successfully operating at that location ever since.

The aim now is to create standards to support a variety of technologies in the hopes of replicating the Dakar success story. IWA 28 specifies stringent requirements for process control, functionality, environmental impact, and certification. What is the rationale for this? “The idea is to strike a balance between technical requirements to ensure pathogens are neutralized, together with the likelihood of acceptance in as many countries as possible, and supporting local customers such as utilities, governments, and businesses,” explains Kim.

The forthcoming ISO 31800 will also help ensure that the performance of FSTUs are maintained for the long haul. “While the standard is written for the initial evaluation of manufactured FSTUs, elements of the performance requirements could be used to monitor the system’s long-term performance too,” says Kim.

A technician controls the automated system that operates the Janicki Omni Processor. Photo: Gates Archive/Sam Phelps

It’s a winner!

In many ways, the concept of an FSTU is a win-win, with the means to provide sanitation for areas that lack sewers connected to sewage treatment plants. There are also environmental benefits; as well as eliminating water pollution caused by untreated fecal sludge, FSTUs will also reduce a major contributor to climate change. This is because untreated sewage ferments and then releases methane, which is a powerful greenhouse gas—30 times more powerful than carbon dioxide. “Instead of methane emissions produced from the natural anaerobic digestion of fecal sludge, direct treatment and conversion to carbon dioxide would have less impact on climate change,” explains Kim. “Also, since the carbon dioxide emissions would primarily be from consumed food, they are part of the ongoing carbon cycle and not a release of carbon previously locked in fossil fuels.”

Waste is transported to the Omni Processor for
treatment. Photo: Gates Archive/Sam Phelps

“We believe that an FSTU is better from a pathogen perspective, better from an environmental perspective, and when compared with letting the fecal material digest uncontrolled, it is also better from a greenhouse gas perspective,” emphasizes Kim.

But such solutions must be economically viable too, or manufacturers and potential users will not embrace them. So ISO 31800 will also provide a foundation for economic sustainability by providing the frameworks for testing and certification in addition to specifications for efficient, effective, and economic operability. These factors, in turn, will give confidence to the buyers, operators, and users of FSTUs. “From our perspective, sustainability has many different aspects,” says Kim. “But for this standard to be far-reaching, it really must support viable businesses.” And based on the experiences in Dakar, ISO 31800 has a strong potential to succeed.


About The Author

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Rick Gould

Rick Gould is a contributing writer for ISO Focus magazine.


You can't have clean water without a sewage system

I love this! You can't have clean water without a functional sewage system, whatever form that may take. If you're interested in learning more about sewage and fecal waste, I strongly endorse the book, "The Big Necessity: The Unmentionable World of Human Waste and Why It Matters," by Rose George. I learned so much from this: not only is this a huge health concern, but it is a social concern (consider the number of women and children who are sexually assaulted on their way to public toilets) and an infrastructure concern (even the US has aging sewage and water systems that are in dire need of maintenance and upgrades).