The Cities of Tomorrow

Recently, frogs, toads and newts in the Spanish National Park Picos de Europa have been dying in unprecedented numbers from a horrible disease which makes them bleed internally and which can only be described as frog Ebola. 

At the heart of this illness are agents called ranaviruses.  These usually infect only amphibians but, unlike previous ranaviruses infections which have targeted one species, these new viruses  are indiscriminately killing all kinds of amphibians and even reptiles that prey on the infected frogs and toads.  Stephen Price from University College London explained to Kat Arney what had been going on...

Stephen -   In 2005, the first observed mass mortality events were noted by rangers in the park.  Severe disease across the entire amphibian community, so systemic haemorrhaging in all six common species of amphibian which are found in the National Park.  The virus seems to affect most of the major tissues, also systemic haemorrhaging which effectively means bleeding from everywhere.  And so, the amphibians can vomit blood and it can come out at both ends.

Kat -   In this paper, what exactly were you looking at and what did you find?

Stephen -   First question was, what's causing these infections?  We found a fairly novel lineage of ranavirus which seems to have pre-exisiting capacity to infect all amphibian species present in the Picos de Europa.  Also, we report on a snake which have been feeding on the amphibians and also died.

Kat -   What does your research tell us about where these viruses might have come from?

Stephen -   It's a tough question to work out the origins of these viruses at the moment, but the fact that these viruses are quite closely related to some Chinese viruses says that there's a real long distance international component to virus movement.

Kat -   Frogs don't tend to move internationally.  So, what do you think might be spreading this virus?

Stephen -   We've seen almost simultaneous emergence at multiple sites in the Picos de Europa which is separated by many miles of rugged mountainous landscape.  And so, that picture like you say is not consistent with a picture of amphibian dispersal moving this far around.  You need to factor in something else and when you consider the pattern of relatedness of the virus in a global context, and other things that we know about ranavirus translocations globally.  So, the presence of ranaviruses in traded and farmed amphibians, it suggests that there's an important role for humans in bringing these viruses into that region.

Kat -   This sounds pretty bad news for amphibian populations if there's this virus spreading incredibly quickly across the globe, possibly moved by humans and it's causing a destruction of lots of different species.  What can we do about it?

Stephen -   It's a fairly grave situation, a really serious picture for amphibians.  So, it's difficult to know how to tackle infections at wild ponds once they're established, other than removing all the animals that are infected from the site, which is a really tough ask and probably wouldn't be very popular anyway.  So, I think the best way forward that I can see and that I can impact on is to try and get a better understanding of how these viruses are moving both globally and locally.  And so, that's definitely something that I'll be looking to pursue with my research.

When the brain learns it makes new cells called oligodendrocytes.  It's their job to wrap around and support nerve fibres.  If this process is blocked then learning can't take place as Bill Richardson explained to Chris Smith...

Bill -  What many neuroscientists have been solving is, how does the brain work, how do we learn and remember new things - new ways of moving, new practical skills?  Something must change in your head when you learn something new, but no one has the faintest idea of what that is.  Previously, it's been thought that learning was really a neuron thing.  Neurons are the cells in your brain that communicate with one another by electrical signals.  They send signals down long threads like wires called axons.  But we recently found that another type of cell in the brain called oligodendrocytes.  Its role is to insulate the wires or the axons of the neurons.  They wrap themselves around in a kind of like rolling up a sleeping bag around a snooker cue.  Now, we've discovered that these cells continue to be formed throughout adult life in mice.  There is evidence also from MRI (magnetic resonance imaging) in humans that white matter which is part of the brain where these axons are all wound up.  Those continue to grow throughout human life.  guessing that that might be something to do with oligodendrocytes.  We decided to test the idea directly that new oligodendrocytes are required for learning complex skills in mice.  So, we first of all setup a test of learning ability in mice and mice loved to run on wheels and mice will run the equivalent of 5 to 7 km every night.  What we did was, we removed rungs in a quasi-random pattern to create a more difficult task.

Chris -  These would be the rungs in the wheel.  So the mice, instead of just having to repeatedly move their feet forward by a known distance each time, they're having to second guess whether a rung is missing and adapt their stride accordingly.

Bill -  That's absolutely correct.  They have severe difficulties and when you look at them and move these, you're amazed that they actually persevere.  But they do, they persevere and within a week, they can run as fast in those wheels as they could do on a normal uncomplicated wheel.

Chris -  And this is by adapting their running technique.  They're having to learn to move at a new way to compensate for the missing rungs.

Bill -  That's right.

Chris -  So, having engineered this pretty tricky motor learning task for these mice, how do you then tell whether these oligodendrocytes are involved?

Bill -  Well, the idea is very simple.  If you prevent new oligodendrocytes from forming then they should not be able to learn.  We devised a genetic trick that allow the mice to develop normally to adulthood and then inject a drug to flick a genetic switch that would delete a gene required for new oligodendrocytes forming without affecting oligodendrocytes formed previously.

Chris -  So, if your theory is correct and learning involves these oligodendrocytes making new contacts and so on, if you block the production of new oligodendrocytes in the brain, you should impair learning.  Is that what you found?

Bill -  That's what we found.  The mice were seriously impaired to learn to run its feet on this complex wheel.

Chris -  So, these oligodendrocytes that are being impacted by deleting this gene, they're coming from some kind of stem cell in the brain that produces new oligodendrocytes and you stop that happening so you therefore impair future learning but you don't alter established learning, things you know already.

Bill -  Exactly.  These new oligodendrocytes are formed by precursor cells, kind of like stem cells and these cells are very numerous in our brains.  They're about 5% of all of our brain cells and it was initially a mystery as to why we should have so many of these precursor cells in our brains during adulthood.  They are there apparently to provide new oligodendrocytes for learning new practical tasks and maybe they're involved in other types of learning like arithmetic learning and that kind of thing.

Chris -  So, what do you think the implications of what you found are?

Bill -  What we've uncovered is an additional refinement which is nevertheless essential and that provides us with a new target perhaps that would allow us in time to be able to tweak learning, maybe enhance learning or since it's difficult to forget things.  Once you've learned to ride a bicycle, you never forget.  It's also very difficult to forget bad habits.  So, maybe if we could manipulate oligodendrocytes, we could more easily forget bad habits and relearn them in a better way.

As more and more people move to cities every day, where are they all going to live? One of the main options is to build up.  But, with steel prices climbing, engineers are looking to another resource which literally grows on trees.  Wood isn't strong or stiff enough to be used in construction past a certain height. But a team at Cambridge University are working to try to change the molecular properties of wood to turn it into something suitable for building skyscrapers.  Georgia Mills spoke to Michael Ramage who's heading up the project...

Michael -   We're working on a project using natural materials, in particular from plants to make large buildings.  The very short story is going from seeds to skyscrapers.  We are hoping to be able to modify wood in such a way that it will be strong enough to last a lifetime and work at the forces that you would have in a large skyscraper.

Georgia -   Why change it from steel and concrete?  Why do we need to have wooden skyscrapers?

Michael -   Well, we think wood is a good alternative to steel and concrete for a number of reasons.  It's a carbon sink. The wood absorbs carbon dioxide while it grows and stores it as the structural material of the wood itself.  There is a limited amount of steel in the world.  So, we actually need to find something to replace it.  there is a growing amount of wood in the world and these are crop forests.  They're not virgin forests.  In general, people feel very good about wood.  They feel comfortable in wood, with wood surrounding them.  So, we think it will make for better buildings in the long run.

Georgia -   So, why don't we have wooden skyscrapers already?

Michael -   We don't have wooden skyscrapers primarily because steel and concrete are pretty good materials for making skyscrapers.  So, we haven't had the need to figure out how to make them with wood.  Wood has worked extremely well on a domestic scale.  So, people have been doing that very happily for hundreds of years.  But we're reaching a point where we need to innovate more with wood and do things that it hasn't done before.

Georgia -   What would happen if you try to build a skyscraper out of wood now?

Michael -   What the tallest skyscraper out of wood at the moment is 10 storeys tall.  We've designed a 70-storey tall building, but we know that it will collapse.  Part of the reason we designed it is to figure out how and why it collapses so we have a better understanding of what properties wood needs to have in order to make it possible to build at those scales.  Wood is very good in tension and compression so when you pull on it or push on it, along the length of the wood.  But if you push across the length - so imagine squeezing the trunk of a tree.  It's not very strong.  So, in technical terms, we call that perpendicular to the grain.  So, that needs to be made stronger.  Wood is very flexible so we need to make it stiffer.  If you think about a tree in a storm, most of the time, they don't fall over but they bend a lot in the wind.  Buildings can't do that because people would get sick.

Georgia -   So wood, we just find from trees.  How on earth are you going to change its properties?

Michael -   We're going to look at two ways of changing their properties.  We'll look at a biochemical perspective and a chemical perspective.  So, the biochemical approach will be looking at the cells themselves.  Are there things from what we know about plants and plant science that we can genetically encourage the trees to have stronger cells.  Chemically, we'll be looking at the same cells and see if there are things we can do chemically to make the cell wall stronger for example or the connection between various cells stronger.  If we can do that, we can make the microproperties of the wood better and we would be looking for a translation to the large scale properties.  We're looking at every single aspect of the science and the engineering at the same time.  so, we're looking at the micro scale of the cells.  At the same time, we're looking at the mega scale design of buildings.  We end up with some very interesting conversations between microbiologists, and biochemists and structural engineers because at the outset, we speak of different language, but we all work on the same material.  Those conversations we think are a new approach to thinking about the material.

Georgia -   I know in some people's minds, wood is definitely linked with fire.  Would these buildings pose an extra risk in terms of flammability?

Michael -   That's a perception that we will certainly need to deal with.  These very large wooden buildings are not flammable at all.  Anyone who's built a campfire knows that we have to use small kindling to get it started and the big logs won't burn without any help.  So, big wooden buildings never catch fire.  They char, but we know how much they char.  It's well-documented so we just make the structure a little bit larger and then the charred wood is actually an insulator for the structural material inside.  There are some examples where wood has outperformed steel in very big fires.

Georgia -   How long do you expect it to be before we see our first wooden skyscraper?

Michael -   We would love to see one in the next 5 to 10 years.  There are designs from practices around the world for 20, 30 storey buildings in timber.  No one has completed one yet, but certainly, in the next 5 years, I think it would be a possibility.

A problem with big cities is quite simply what to do with all of the waste.  In London, the big stink of the 1800s was caused by raw sewage being dumped directly into the river Thames as the population grew.  This led Joseph Bazalgette to build London's sewers in the 1850s to clean up the city and they worked brilliantly for many years.  But now, the population has grown to the extent that the same thing is happening again with raw sewage overflowing into the Thames. To prevent another big stink, London's Thames Water announced plans to build a new super sewer called the Thames Tideway Tunnel.  Georgia Mills went to Abbey Mills Pumping Station to speak to Andy Mitchell, Chief Executive of Thames Tideway Tunnel to find out why we need a new sewer...

Andy -  When Bazalgette built the sewer systems that we recognise here, the population of London was about 2 million.  He had the foresight to build a capacity for a London that had 4 million people in.  Our issue now is, we've got more than 8 million and over the past 15 years, an increasing population.  But of course, it's not just the volume of people and the volume of sewage.  We are using much more water per capita than we ever did when these designs were done.  And of course, there's a lot more buildings.  A lot more of the natural land has been surfaced over time on concrete.  So, a lot of the runoff that would normally have gone into the ground can't make it there anymore and it's all channelled into the Bazalgette sewage system.

Georgia -  What happens when the sewage system can't cope with the amount of material that's being flushed away?

Andy -  The sewer system takes both sewage and surface water runoff. Increasingly, with the extra volumes, we're starting to see raw sewage being discharged into the Thames again.  Now, on a normal year, on an average year, that's about 39 million tons of sewage going into the Thames.  Last year was actually 55 million.  The situation is only going to get worse and the condition of the river is going to get worse and worse unless we do something about it.

Georgia -  This is pre-treated sewage.  So, this is anything people flush down the toilets, ending up in our river.

Andy -  This is raw sewage, untreated being discharged straight into the Thames. 

Georgia -  And so, what's being done about this?

Andy -  For about 10 years now, Thames Water have been developing a scheme to build a new capacity to intercept all of those overflows.  It comes in the form of a new tunnel, a new sewer that runs under the river, following the line of the river, and it runs all the way down to about Tower Hill where it crosses over to where we are here now at Abbey Mills to join up with the lead tunnel, which has been built in the last couple of years.  The combined effect of all of that is to stop pretty much all of the overflows that are currently going into the river from happening, capturing all and feeding it ultimately to Beckton Sewage Treatment Works which has been upgraded to handle the additional capacity, such that we just won't see sewage in the Thames again.

Georgia -  This super sewer is going to be 25 km long and will stretch right through London, running underneath the River Thames, right along to the sewage works at Beckton.  But processing all these waste is going to consume a lot of energy.  But it turns out there's a source of energy people are literally throwing down the drain.  A major component of sewage includes fats, oils and greases, otherwise known as fogs which are so substantial, they are causing costly blockages underground.  But 2OC are a company who are turning these oil-rich fatbergs into fuel to actually power sewage plants.  I went along to speak to Richard Liden from 2OC to find out how waste is no longer being wasted.

Richard -  We're here in Beckton in the east of London and in front of us, you can see the giant engine shed behind the walls there.  There's a huge 2-stroke marine diesel engine, the sort that would normally sit in a super tanker.  But as you can see from those giant steel tanks in front of it, that's the fuel.  That's going to be coming from the famous fogs, fats, oils and greases, and that giant 2-stroke engine will run 24/7, providing renewable power via private wire to the nearby Beckton Sewage Works and the UK's only desalination plant.

Georgia -  Tell me about these fogs, fats and greases.  Where are they from?

Richard -  Fats, oils and greases and I have to apologise to anybody who's eating as they listen to this.  They're basically the sort of the waste products from the food industry, the restaurant industry, the top end you have, quite good quality used cooking oil and then you've got the muck, the really greasy horrible stuff.  A lot of that grease ends up in the sewage network.  My poor friends at Thames Water will tell you that every year, they have some 40,000 blockages caused by (yuck!) fat building up in the sewer pipes causing blockages and sewage backing up and making the most awful mess.  It costs them about a million pounds a month to cleanout those fats, oils and greases that build up in the sewage network.

Georgia -  Now, I've heard about these and some of them get so big.  They're actually called 'fatbergs' aren't they?

Richard -  They are.  That was coined by Thames Water to describe some of these monsters.  Thames have got guys who go down into the sewers and they have picks and shovels, and high pressure hoses, and they blast off from the sides of the brickwork and the pipe work, the fats which have built up.  A bit like the way that fat builds up around a blood vessel.  It's absolutely vile but they hack it off.  It drops down into the sewage flow and then can be collected and removed.

Georgia -  And so, before this engine came along, what was happening to these 'fatbergs'?

Richard -  Well, the other went to landfill or now, we're using them to create a liquid fuel so that horrible sludge and muck actually can be turned into renewable power.

Georgia -  So, how can you get energy from these fatbergs?

Richard -  Well, if you think about what fat is like, if you melt it, it is reasonably flammable.  So, if you collect it up, centrifuge it to get a lot of the water out of it, filter it to get out - well, we're in polite company  we probably won't discuss the sort of things you have to get out to it if it's being done in the sewer.  You can actually turn it into a fuel.  Our engine in here can deal with really quite low quality fuels.  It doesn't have to be a refined product like diesel or petrol.  Our manufacturer said to us, "If you can melt it, this engine could burn it."  So, that's what we're doing.

Georgia -  The energy required to centrifuge this fat and take all the products out of it, does it still provide enough energy when you burn it to justify all these?

Richard -  Absolutely.  The amount of power coming out of here would power 40,000 homes.  What's more, it's baseload electricity so it's generating around the clock.  It's not intermittent like most renewables.  And as I say, because the sewage works is only a kilometre away, we're able to send the power underground, which means you also cut down on transmission losses which you'd get if it was cabling going overhead.  I think the days of waste of being waste are over and that these days waste is now a resource.  That means, even crazy things on the face of it, the stuff that has been chucked out of restaurants, what have you, or (heaven help us) is going into a sewer, we got to do something about that.  We can't just dump it into landfill.  If we can make use of this horrible gunky stuff to produce power and heat, well, it's just one of those mix of renewable options that we're just going to have to take in the future.

Georgia -  Alongside this plant being powered with renewable sources of energy, there's also hope that the new super sewer could lead to the river Thames becoming clean once again.  Maybe as soon as 3 months after it opens as Andy Mitchell explained...

Andy -  What we're doing with the tunnel is capturing the most damaging of the overflows and limiting what actually does go into the Thames too are very, very diluted rainwater which is much less harmful and much less noticeable.

Georgia -  When will the sewer be operational?

Andy -  We intend to turn it on if you like in 2023 and it's interesting to think that if you were to put a rubber duck on the Thames at Hammersmith, in the summer, it'll take about 3 months to get out to sea.  In the first tide, it could from Hammersmith, all the way down to Tower Bridge.  But of course, it comes back again as the tide comes in and it ends up 500 or 600 yards away from where it started.  Of course, that's what the sewage is doing as well.  Going down the river, it sort of swipes its way down the river, killing fish along the way and the fish that it hasn't killed on the way down, it tries to pick up on the way back up.  So, it's quite a damaging effect.  But if you think of that 3 months, what that means is that once we've turned the sewer on, within 3 months, there will be no sewage in the Thames for the first time in generations.