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A Trip Down Your Toilet December 10, 2010

Posted by Mrs Weird Scientist in Brain Power, Environment, Human Body, Tough Stuff.
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3 comments

Nope, I’m not giving a lesson on plumbing. But I am going to give you the scoop on a secret that starts inside your toilet, all thanks to the crew at Thames Water who are helping people stay warm this winter. What’s this secret? Well, when a toilet takes your daily (or whatever frequency..let’s not go there) offering, all that human gunk can get converted into renewable gas to heat your home.

In fact, my dog Tiko got so excited about this concept, he decided to contribute. Before we see what he got up to though, let’s first find out what’s happening in the bowels of your toilet and then follow it through the twists and turns of the pipes below.

A Good Kind Of Gas

Each time you perch on the toilet, you may soon take heart that you’re not the only one who’s a bit lighter – you’re taking a burden off the environment as well. Approximately 200 homeowners in an English town called Didcot are among the first in the UK to benefit from gas made from their own waste and supplied through the national grid to heat their houses. The future plan is to make this process available throughout the UK.

So why all the fuss to find new sources of energy? Well, the UK has a goal for 2020 to have 15 percent of the energy it produces come from renewable sources. Producing gas in this way is a strong step toward that goal. Oh, and if you’re worried your house will be smelly, fear not! The gas is odorless and your house will remain toasty.

From Flush To Finish

From the time you flush your toilet to the time your house gets heat, it’s around 23 days. Let’s take it step-by-step, based on the procedure and image below that Thames Water has generously shared.

Waste has a bit of a path to travel before making your home warm. But it’s worth the trip because it brings the UK closer to its energy goals.

  1. All the muck from toilets and stuff like sinks and dishwashers gets channeled to the Didcot works. Let me tell you, with 13.8 million customers, it’s a lot of waste!
  2. Waste gets separated into sludge and water inside settlement tanks
  3. Water is put through cleaning processes and then back to the environment it goes via a local watercourse
  4. Sludge goes a different route. It gets heated in massive containers called digesters. All the heat gets anaerobic digestion going, which is where bacteria breaks down biodegradable material. Now, we’re left with biomethane – also called biogas
  5. The gas gets collected and goes into a gas cleaning machine
  6. After the biomethane gets cleaned and smells more like normal gas, it goes to the national gas grid
  7. From here, it’s just like any other gas in the grid. Off it goes to heat up your home and fuel other things like your stove

Tiko Turds

Once Tiko heard about the capabilities of poo, he did what all good and respectable dogs do – he went to relieve himself. But instead of trotting to the door for me to let him outside, he wanted to do his part to help heat up the house. The cheeky mutt raced into the bathroom and plonked himself down on the toilet.

When Tiko found out that human waste from toilets was being used as a renewable source of energy to heat homes, he decided to help out. Now, where’s the air freshener?

I appreciate that he’s determined to help the environment but I tried to explain that nobody wants to sit on a toilet seat covered in his fur. He responded by barking at me to close the door because he wanted some privacy.

On second thought, I should be grateful I have such an environmentally conscious dog, even if he is a modest one.

Whale Poo Is Good For You September 12, 2010

Posted by Mrs Weird Scientist in Animals, Brain Power, Environment, Ocean, Tough Stuff.
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10 comments

In fact, it’s good for all living things.  Australian researchers recently found that whale poo is battling one of the planet’s toughest battles ever – climate change.  The poor whales previously had a horrid reputation.  Since they breathe out a common greenhouse gas known as carbon dioxide (CO2), they were disliked for contributing to global warming.  Estimates are that they breathe out 200,000 tonnes of CO2 a year.  Eep!  It isn’t surprising people had a bad opinion of them!

But there’s way more to the story than this one fact.  Let’s start with the basics and see how something so gross can actually be good for us all.  Major science geeks can read the full study results in the Fish and Fisheries journal.

Benefits Of Whale Poo

A young sperm whale gracefully swims in the Southern Ocean. A trip up to the surface might mean a poopy feeding for the hungry phytoplankton, helping to fight global warming. Image credit: National Oceanic and Atmospheric Administration (NOAA).

In the Southern Ocean, we’ve got an estimated 12,000 sperm whales.  They hunt down fish and squid for food.  Once digested, out comes all that poo.  Why should we care about whale feces?  Well, it contains loads of iron.  All of those whales poop out approximately 50 tonnes of iron each year.

What’s so special about the iron?  It’s a fabulously delicious food for phytoplankton, which are marine plants that exist up near the surface of the ocean.  These helpful plants like to take in CO2 from the atmosphere through a process called photosynthesis.

Better still is that the whales pop out their poop (even I chuckled as I wrote that) in a liquid form that’s close to the surface of the ocean, making it easier for the phytoplankton to access.  After, the whale dives down into the ocean, presumably feeling a little – or a lot – lighter!

Let’s Do The Math

First, we have to see how much CO2 gets sucked up by the plants, which is all thanks to the whale poo.  It’s 400,000 tonnes.  Now that’s twice as much as the 200,000 tonnes they breathe out through respiration each year.  The 200,000 tonnes is equivalent to emissions from 40,000 cars!

I got in touch with Steve Nicol of the Australian Antarctic Division to find out how the study all started.  He explained:

Our research was actually looking at baleen (krill eating) whales and the iron that they release.  The research was stimulated by some ideas raised by Victor Smetacek and we had the samples and the expertise here in Hobart to do the measurements necessary to test these ideas.

When I asked Steve what we can do to help, his answer was a simple one.  Simple but not necessarily easy to attain, especially given the attraction of whale hunting in many places around the world.  According to Steve:

Many populations of great whales are recovering fairly fast – some at about the maximum rate possible.  The best assistance we can give them is to avoid killing them – either accidentally or deliberately.

Don’t Judge Too Soon

I think an important lesson here is that we can’t judge too quickly and instead, should always look at the big picture.  When we first hear about all the CO2 the whales are putting out there, it’s easy to think badly of these massive sea creatures.  But with the Southern Ocean normally being a poor source of iron, the whales are making sure those phytoplankton are happily fed.  This way, the phytoplankton can do their job of taking out the nasty CO2.

Now, if only human poo had such fantastic capabilities.

It’s Good To Look Like Poo February 22, 2008

Posted by Mrs Weird Scientist in Animals, Insects, Tough Stuff.
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5 comments

Sometimes, it’s great to look like poo. That is, if you’re a caterpillar! Say hello to the Asian swallowtail caterpillar. It has some neat tricks up its sleeve to successfully stay camouflaged from predators. The first trick comes into play quite early on – when the caterpillar is black and white, with fine spines. Here, it resembles bird droppings. Later on, the caterpillars get older and grow larger, which means it’s a lot harder for the caterpillars to pass themselves off as bird poo. So, as the little critters fatten up, their color changes to a vivid green. Hmmm. Why might being green work well as a camouflage? If you guessed it’s because they can blend in with the leaves, you got it!

Caterpllar Camouflage

Credit: Ryo Futahashi. You can see the wee caterpillar on the left side of the picture looks a lot like bird droppings! On the right, the distinguished fellow is a grown caterpillar – the bright, green color really does make the caterpillar look like the surrounding leaves.

Manipulating The Caterpillar’s Camouflage

In an interesting twist of events, Ryo Futahashi and Haruhiko Fujiwara of the University of Tokyo in Japan, discovered a special way to keep the caterpillar looking like bird droppings. This means that the caterpillar still matures and develops, but it retains its poopy camouflage instead of growing into a green caterpillar that resembles leaves. How did the researchers accomplish this task? It’s not so easy.

Caterpllar Camouflage 2

It’s All About Genes

You might already be familiar with the concept of genes. Your genes are unique instructions that tell your body how to work. They control all sorts of stuff such as your hair or eye color. Humans aren’t the only ones with genes either! Caterpillar camouflage depends on genes. There are three genes that control the caterpillar’s camouflage. One is responsible for the green color, another for the black color and finally, one for those spikes we see on the very young caterpillars.

Tinkering With Genes

If researchers can find a way to meddle with these genes, they can change the caterpillar’s color. Hint hint. In the case of our Japanese scientists, they did their meddling with a hormone that rules the expression of all three genes. It’s called juvenile hormone. Researchers smeared a synthetic version of juvenile hormone on the back of a young caterpillar. Since the hormone controls the three genes that affect the caterpillar’s color, adding more of the hormone managed to keep the caterpillar looking poopy right through its development. It’s a cool manipulation because it teaches us more about how hormones and genes interact. As for all this talk about poo, I think my next blog post will be on something a bit more pleasant!

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