Only 4.5 billion people in the world have access to clean toilets. That may sound like a lot, but compare that to a different statistic: 6 billion people have access to cell phones. This lack of toilets is a major cause of sanitation-related diseases, which is why the Gates Foundation has long worked to promote the cause of better toilets for the developing world.
But it's impossible to test how well a new toilet functions without filling it with poop. Instead of asking researchers to test their own toilets for its 2012 Reinvent the Toilet Fair, a competition to create create safe, inexpensive, and hygienic waterless toilets, the Gates Foundation sourced synthetic feces from a company called Maximum Performance. "I think they were either told about our testing or they saw the website, or both. Otherwise, we didn't go out of our way to contact them," John Koeller of Maximum Performance tells Co.Exist in an email.
While its name suggests that it might be a kind of protein for bodybuilders, Maximum Performance (MaP) actually produces synthetic feces from soybean paste and rice. The sausage-like fake poop (it is actually extruded with a sausage machine) is flushed down the toilet en masse along with toilet paper. If a toilet can't handle a certain amount of soy poop, it's not up to par. MaP explains on its website: "Each toilet is tested to failure—that is, soybean paste is repeatedly added to the toilet until the fixture can no longer remove it in a single flush."
The soy mixture was chosen after extensive testing. "It is purchased in bulk in large containers and then mixed with whatever is needed to achieve the specified formula. For example, if it comes from the supplier too dry, then mix with a small bit of water. If it comes too moist, then it is mixed with a powdered version to reduce the moisture content," writes Koeller. The soy and rice mixture, he writes, "is the closest thing we have found to 'the real thing' both in weight as well as the way it begins to break apart when flushed."
MaP also offers a version of its synthetic feces encased in a latex membrane. This allows the feces to be reused, but it also means that it won't break apart like real poop. The membrane-encased feces product, writes Koeller, "was developed only for convenience and cost control." The U.S. Environmental Protection Agency (EPA) relies on MaP's poop for high-efficiency toilet testing—but only the membrane-free version, because it's more realistic.
There's good news in the toilet world, apparently. When MaP began performing tests in 2003, the average tested toilet could flush down 336 grams of waste in a single flush. These days, the average is over 650 grams. The average maximum fecal size for a male is 250 grams (according to a 1978 medical study), so that's more than enough flushing power. The minimum that MaP considers to be acceptable, however, is 350 grams.
The Gates Foundation procured 50 gallons of fake poop for its Reinvent the Toilet Fair, flushing it down all sorts of new kinds of commodes. When MaP isn't supplying feces for developing world toilet prototypes, it performs "flush performance" tests on all sorts of conventional toilets.
Since it was founded, the company has tested more than 2,600 toilets—low-flow, single flush, dual flush, gravity-fed, wash-down, pressure assist, and every other kind of toilet you could think of. If you're curious about your toilet's ability to handle poop, all of the ratings are available here. And If you're in the market for a new toilet, MaP suggests that you be wary of suspicious (but silly) claims like "this toilet will flush 20 golf balls!"