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© Bill & Melinda Gates Foundation

The Recipe for Fake Poop

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© Bill & Melinda Gates Foundation

Researchers around the world are working to reinvent the toilet, bringing toilets to the 2.5 billion people worldwide who don't have a safe place to relieve themselves. But there's a slightly gross problem—how do you test a toilet in a sanitary and, ahem, repeatable way?

Enter "fake poop," my preferred term for what scientists call "synthetic sludge simulant." Yes, this is a material meant to simulate fecal matter, and it has to have properties very similar to real fecal matter—minus all the pathogens, odors, and grossness. For this year's Reinvent the Toilet Fair, a new recipe was developed by the Pollution Research Group at the University of KwaZulu‐Natal, South Africa. Their recipe was inspired by a research paper on simulated fecal matter used to test space toilets ("Simulated Human Feces for Testing Human Waste Processing Technologies in Space Systems," SAE Technical Paper 2006-01-2180, 2006, doi:10.4271/2006-01-2180). The Pollution Research Group developed a series of recipes, finally settling on the ninth one. Here's the breakdown of what's in "Synthetic Sludge Recipe Number 9":

1. Instant Yeast

Plain old store-bought yeast packets you'd use to make bread.

2. Psyllium Husk

Seed husks that provide mucilage, described by Wikipedia as "a thick, gluey substance produced by nearly all plants and some microorganisms." You can often buy this in the bulk aisle at grocery stores.

3. Peanut Oil

Just what it says on the tin.

4. Miso Paste

The fermented seasoning used in many Japanese recipes. Available in packet form from grocery stores.

5. Polyethylene Glycol (PEG) 400

PEG is used in all sorts of applications (including skin creams and toothpastes), but if you've ever had a colonoscopy, you'll recognize it as that gloopy stuff you have to drink to, ahem, clear out your system. Well, technically, the colonoscopy prep material is PEG 3350, the number referring to the material's molecular weight as measured in daltons.

PEG 400 is actually available on Amazon, and it's an ingredient in many non-fake-poop products, including inkjet printer ink.

6. Inorganic Calcium Phosphate

Often used as a leavening agent in baking, Calcium phosphate is also used in some cheese products. If you're looking to follow the recipe exactly, you'll want to buy this from a chemical supply company.

7. Cellulose

The recipe calls for cotton linters, a byproduct of cotton harvesting and an ingredient in paper manufacturing. The recipe also includes plain old paper tissue, shredded.

8. Water

What's a recipe without a little water? (Actually, a lot of water -- see the mass numbers below.)

What it Looks Like

The resulting product was "very sticky," according to a person close to the matter. It reportedly has a "vinegar-yeasty smell." Let's just look at a photo of the fake poop being bottled and leave it at that:

Photo courtesy of The Bill & Melinda Gates Foundation.

Putting it Together

Here's the breakdown when it's all put together:

Ingredients % Wet Mass Mass for 1kg % Dry Mass
Instant yeast 7.3 72.80 32.49
Water 77.6 776.10 --
Psyllium 2.4 24.30 10.84
Peanut oil 3.9 38.80 17.31
Miso paste 2.4 24.30 10.84
PEG 2.7 27.20 12.14
Inorganic Calcium phosphate 2.4 24.30 10.84
Cellulose (half cotton linters/half shredded tissue) 1.2 12.40 5.53
Total Mass 100.0 100.20 100.00

This year's fake poop was manufactured by Unilever and donated to the Reinvent the Toilet Fair: India. Unilever also makes the toilet cleaner Domex, and is holding a Domex Toilet Academy aiming to build 24,000 toilets by 2015.

Fake urine, on the other hand, can be less complicated. If you're just testing fluid flow in a toilet, plain old water will work. (For applications involving chemistry, well, let's just say that's a whole different story.) Here's an image from the Reinvent the Toilet Fair showing a little fake urine going in the loo:

Photo courtesy of The Bill & Melinda Gates Foundation.

For a bit more fake poop fun, check out this TEDx Talk by Professor A.J. Johannes, who didn't use this recipe for his fake poop. He said, "Mashed potatoes, curiously enough, are very, very similar [to human feces]. I know, I know."

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London's Sewer-Blocking 'Fatbergs' Are Going to Be Turned Into Biodiesel
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UK officials can't exactly transform the Whitechapel fatberg—a 143-ton trash mass lurking in London's sewer system—into treasure, but they can turn it into fuel. As The Guardian reports, Scottish biodiesel producer Argent Energy plans to convert parts of the noxious blockage into an environmentally friendly energy source.

For the uninitiated, fatbergs (which get their names from a portmanteau of "fat" and "icebergs") are giant, solid blobs of congealed fat, oil, grease, wet wipes, and sanitary products. They form in sewers when people dump cooking byproducts down drains, or in oceans when ships release waste products like palm oil. These sticky substances combine with floating litter to form what could be described as garbage heaps on steroids.

Fatbergs wash up on beaches, muck up city infrastructures, and are sometimes even removed with cranes from sewer pipes as a last resort. Few—if any—fatbergs, however, appear to be as potentially lethal as the one workers recently discovered under London's Whitechapel neighborhood. In a news release, private utility company Thames Water described the toxic mass as "one of the largest ever found, with the extreme rock-solid mass of wet wipes, nappies, fat and oil weighing the same as 11 double-decker buses."

Ick factor aside, the Whitechapel fatberg currently blocks a stretch of Victorian sewer more than twice the length of two fields from London's Wembley Stadium. Engineers with jet hoses are working seven days a week to break up the fatberg before sucking it out with tankers. But even with high-pressure streams, the job is still akin to "trying to break up concrete," says Matt Rimmer, Thames Water's head of waste networks.

The project is slated to end in October. But instead of simply disposing of the Whitechapel fatberg, officials want to make use of it. Argent Energy—which has in the past relied on sources like rancid mayonnaise and old soup stock—plans to process fatberg sludge into more than 2600 gallons of biodiesel, creating "enough environmentally friendly energy to power 350 double-decker Routemaster buses for a day," according to Thames Water.

"Even though they are our worst enemy, and we want them dead completely, bringing fatbergs back to life when we do find them in the form of biodiesel is a far better solution for everyone," said company official Alex Saunders.

In addition to powering buses, the Whitechapel fatberg may also become an unlikely cultural touchstone: The Museum of London is working with Thames Water to acquire a chunk of the fatberg, according to BBC News. The waste exhibit will represent just one of the many challenges facing cities, and remind visitors that they are ultimately responsible for the fatberg phenomenon.

"When it comes to preventing fatbergs, everyone has a role to play," Rimmer says. "Yes, a lot of the fat comes from food outlets, but the wipes and sanitary items are far more likely to be from domestic properties. The sewers are not an abyss for household rubbish."

[h/t The Guardian]

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Thinking of Disinfecting Your Sponge? It’ll Do More Harm Than Good
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Common house-cleaning wisdom advises you to clean your sponges periodically. Some experts advise running them through the dishwasher, while others suggest microwaving a wet sponge. But a new study says that both of those techniques will do more harm than good, as The New York Times reports.

A trio of microbiologists came to this conclusion after collecting used sponges from households in Villingen-Schwenningen, Germany, a city near Zurich. As the researchers write in Nature Scientific Reports, they asked the 14 houses that gave them sponges to describe how they were used—how many people in the house handled them, how often they used them, how often they replaced them, and if they ever tried to clean them.

Analyzing DNA and RNA found on those sponges, they found a total of 362 different bacterial species living on them. The sheer number of the bacterial colonies was staggering—some 82 billion total bacteria were living in a cubic inch of sponge. (As co-author Markus Egert told the Times, that’s similar to what you’d find in your poop.)

As the researchers discovered by analyzing the bacteria found on sponges whose users said they regularly cleaned them, disinfecting a sponge using a microwave, vinegar, or a dishwasher is worse than useless. It seems that when you attempt to clean a sponge, you kill off some bacteria, but in doing so, you provide an environment for the worst species of bacteria to thrive. Sponges that were regularly cleaned had higher concentrations of bacteria like Moraxella osloensis, which can cause infections in humans. (Though it’s unclear how likely you are to get infected by your sponge.) It’s also the reason dirty laundry smells. By microwaving your sponge, you’re probably just making it smellier.

Sadly, there’s not much you can do about your dirty sponge except throw it away. You can recycle it to use as part of your cleaning routine in the bathroom or somewhere else where it’s far away from your food, but the best way to get a clean sponge, it seems, is to just buy a new one. May we suggest the Scrub Daddy?

[h/t The New York Times]


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