The challenge of dealing with human fecal matter

What would you do if you didn’t have access to a toilet? This is not a rhetorical question: 2.5 billion people, or 37 percent of the world’s population, do not have access to adequate sanitation, according to the UN. Even this number is misleading — the WHO definition of “adequate” is probably not what would be acceptable to you. But “taking a dump” is a human necessity, so what are your options? 

A good number, 1.1 billion people, do the most natural thing: hide behind a bush or sit by a river and practice what is euphemistically known as “open defecation.” Some use plastic bags, and throw the bags onto open areas or roofs, leading to the term “helicopter toilets,” as these bags tend to whirl like choppers. Nearly 60 percent (626 million) of those practicing open defecation live in India, but we should not be so haughty: according to 2010 UN data, eight percent of people in the Philippines (about seven million people) practice OD. 

These billions of people without adequate sanitation facilities impose a huge health burden. Diarrhea arising from waterborne, water-washed, and water-based pathogens kills more young children than HIV/AIDS, malaria, and tuberculosis. About 2.4 million deaths per year are due to poor hygiene, sanitation, and lack of access to clean water. This is 6,575 deaths per day, or 274 deaths per hour — all because people don’t have clean water and an adequate way of disposing their waste.  Most of the victims are children younger than five years old — 90 percent of infectious diarrhea afflict this demographic.

This glaringly shameful situation has caused the world to take action. In 1990, the United Nations promulgated the Millennium Development Goals, a set of targets for the world to achieve progress in a variety of human needs and issues.  The MDG for water and sanitation, MDG 7c, states that the goal is to “halve, by 2015, the proportion of the population without sustainable access to safe drinking water and sanitation.” For drinking water, that goal translates to providing access to 88 percent of the world population (up from 76 percent). That goal, according to the WHO/UNICEF, has already been met in 2012 (“only” 11 percent of the world do not have safe water). While the goal has been “met,” it is important to note that 754 million people still do not have sustainable access to safe water. For sanitation, the picture is bleak: if current trends continue, only 67 percent, as opposed to the target of 75 percent of the world will have adequate sanitation. But even if the target is met, additional population growth means that 1.7 billion people still wouldn’t have a an adequate toilet! To meet the 2015 target, the world needs to build 800,000 toilets in the next three years. To achieve 100 percent coverage, the world needs to build 2.5 billion toilets, or 1,400 toilets a day (from 2010 to 2015).

These are staggering numbers. What are the options? If we were to build modern, centralized wastewater treatment plants, providing treatment for 2.5 billion people will cost $1 trillion, and that is just for the treatment plant. The sewer system alone will be more than twice that cost. Clearly, centralized treatment is problematic, especially in developing countries that cannot allocate huge financial resources to sanitation. Decentralized treatment is probably more feasible, but would still require money, expertise, and skills to construct on a worldwide scale.

Thus on-site treatment methods, such as pit latrines, are still the dominant technologies in developing countries. These are simple systems, and while they are solutions, have tremendous disadvantages. A holistic approach to fecal sludge management includes the human interface, collection, storage, transport, treatment, and disposal. All these steps need to be solved simultaneously to achieve a sustainable solution. For example, what happens when a pit is full? In India, “manual scavengers,” mostly from the lower caste (the Dalits), have been forced to dive inside clogged sewers, or manually pick up human manure from dry pits. This is an explosive human rights issue that recently has led to mass demonstrations all across India. In Africa, pit emptiers resort to alcohol to ease the drudgery of manually emptying wet or dry pit latrines. The pit contents are typically dumped onto open fields or trenches. “Fly by night” operators often empty a pit’s contents to another pit. 

It is clear that the most sustainable way forward is to create business opportunities for fecal sludge collection, transport, treatment, and disposal. So, for example, pit emptying businesses can potentially earn decent profits by professionalizing the industry and using low-cost technologies such as screw augers or vacuum pumps. In South Africa, the e-Thekwini municipality has supported pit emptiers via a franchising model paid for by the local government. But the business model must also consider what value can be extracted from fecal sludge. In China, human fecal matter has traditionally been used as fertilizer, recycling the nitrogen and phosphorus back to vegetables and fruits. More recent applications include the production of biogas via anaerobic digestion (again, a more common practice in China).

Research on fecal sludge management has been invigorated by funding from the Bill and Melinda Gates Foundation through their “Reinvent the Toilet Challenge” and the “Grand Challenges” programs. The BMGF envisions the toilet of the future to use no water, be environmentally safe, and cost only five cents per user per day. Some of the technologies that have been funded include solar-powered toilets that can produce hydrogen, plasma-treatment of dried sludge, various technologies for disinfecting fecal sludge (such as vortexes and membranes), new materials for toilets, and technologies for emptying pit latrines. While some of the technologies seem far-fetched and may not work in slums or rural areas, it is good that researchers from all over the world are attempting to tackle this issue. Perhaps you have an idea for a new toilet, or a new technology for dealing with human fecal matter? If so, look up the Gates Foundation website. You can be a part of the solution to this worldwide problem, and help the 2.5 billion without access to adequate sanitation.

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Francis L. de los Reyes III is a professor of Environmental Engineering at North Carolina State University. His research and teaching interests include environmental biotechnology, biological waste treatment, molecular microbial ecology, and water and sanitation in developing countries. He is on the editorial boards of ASCE Journal of Environmental Engineering, and Philippine Science Letters, and is a TED Fellow. He was a Balik-Scientist of the DOST. He is a member of the Philippine-American Academy of Scientists and Engineers. E-mail him at [email protected].