Did you know that every year over 115 billion
pages of paper are printed worldwide? No me neither. Why would you? Apparently if you took
all the paper produced in the United States each year you could wallpaper the Grand Canyon
107 times. I don't know why you'd do that, it seems a bit pointle... anyway according to
this report from the Environmental Paper Network the world churned through no less than 400 million
tons of paper and pulp in 2018, more than half of which was used for packaging. And I imagine
that number probably ticked up ever so slightly during the lockdowns as we all stayed
in and ordered all our stuff online. More than half of the world's paper consumption
happens in the USA and in China and Japan. Here in Europe we're responsible for about another 25
percent or so, and just for a bit of context the entire continent of Africa accounts for about
two percent. It takes an awful lot of trees and water and energy to make all that material from
scratch and none of that consumption is helpful in our current climate emergency, so the very
best thing we could all do as individuals is look for ways to absolutely minimize the
amount of paper and packaging we generate, and the best thing our local authorities can do
is to make sure that as much of it as possible is being recycled properly and effectively.
According to a European project called Paperchain, 55% of this continent's paper and pulp industry
waste is simply incinerated, albeit with energy recovery for things like district heating systems.
25% gets used in land reconstruction and other industrial applications and 15% currently just
gets chucked into landfill. They don't say what happens to the other five percent so if you've got
any clue on that one let me know. Unsurprisingly a great deal of research is going on around the
world to find ways to use the landfill paper waste in more sustainable ways and one of the
applications being proposed is in the construction of highways. So could paper roads really
become a common feature of our future world? Hello and welcome to Just Have a Think.
The European Paper Chain project was set up specifically to support and encourage
research and development into new ways of utilizing waste streams from the European
pulp and paper industry as valuable feedstocks for three resource-hungry industrial sectors -
Construction, mining and chemical manufacturing, focusing predominantly on that difficult to tackle
15% of waste that currently goes to landfill and my goodness there are some spectacular names
for some of those waste stream by products. You've got green liquor dregs for a start which
sounds like the stuff you used to down during last orders in the student union bar but which
are actually one of the main waste products of the process that converts wood chips into paper
in kraft pulp mills. The wood chips are cooked with sodium hydroxide to separate the useful wood
fibres from the not so useful lignin which is the stuff that binds wood together. Along with green
liquor dregs you also get lime slaker grits, lime mud, and fibre sludge, all of which gets sluiced
out of the mill and straight into the ground. And even the paper recycling industry produces
de-inking paper sludge which as the name suggests comes from the industrial process of removing
printing ink from paper fibres. Then there's waste paper sludge ash which is what you get left
with once you've incinerated the sludge. All those waste products are now being put to good use as
replacements for existing materials and feedstocks in those key industries and in the case of road
building it's the fly ash from the mills that's of most interest. Over in Spain a pioneering company
called Acciona have been developing sustainable infrastructure solutions especially in renewable
energy for several decades and today they've got a presence in 40 countries with an annual
turnover of almost six and a half billion euros. Their latest project is this stretch of highway
just outside Valencia. It looks normal enough doesn't? It but Acciona have been able to replace
the cement content of the road substructure with that ash from the paper mills. In a recent
interview with Euronews, Acciona's R&D Project Manager Juan Jose Cepria Pamplona, explained
"in road construction we need the strongest materials and for that we usually use cement.
This paper ash doesn't just look like cement, it meets all the technical requirements of cement,
but it's also more environmentally friendly. The potential impact of the project is enormous"
he said "we have calculated that we can save 65 to 75 percent of the associated CO2 emissions and
by scaling up we could save up to 18 000 tons of cement per year." The plan is to use the product
all over Spain and then internationally as well, making good use of Acciona's network of facilities
all over the world. Meanwhile on the other side of the Atlantic a team of researchers at the
University of British Columbia are working on a set of guidelines that aim to ensure the safe
use of these paper industry waste materials in road building. The North American paper and pulp
industry produces over a million tonnes of fly ash every year. At the moment the mill owners have to
pay to get that waste product sent to landfill and that can cost them anything from $25 to $50 a ton.
So if that liability suddenly turned into an asset you're likely to find there's a great deal of
enthusiasm for the idea from within the industry. The BC team, led by associate professor
at the University School of Engineering, DR Sumi Siddiqua, has co-published a paper with
post-doctoral research fellow Dr Chinchu Cherian investigating the use of paper flash or PFA as
it's known as an economically sustainable low carbon binder for road construction. Dr Cherian
explained "the porous nature of PFA acts like a gateway for the adhesiveness of the other
materials in the cement that enables the overall structure to be stronger and more resilient than
materials not made with PFA." The team carried out toxicology analysis on the ash to determine
whether any of the nasty by products from the sodium hydroxide process could leach out into the
subsoil beneath the road surface. Their results showed that because the PFA bonds so strongly
with the other aggregates, just like a cement, that there was little or no detectable release
of chemicals. They also calculated that using PFA as a replacement material was more energy
efficient and produced lower carbon emissions. Cement making is a very carbon heavy process as we
discovered in a previous video which you can click up there somewhere to jump back to. So anything
that can reduce the use of cement in construction projects has to be a good thing. And of course
keeping the waste products of the paper mills out of landfill isn't a bad idea either. There's
more research to be done to establish a rigorous set of guidelines for any PFA modifications
that may be necessary to ensure there's a consistent industry standard for its content
as production ramps up around the world, but Cherian and the BC team are confident
that this technology is on the right track. And it might not only be roads that benefit from
this previously landfilled waste product either. Germany's Federal Institute for Materials
Research and Testing, known as BAM, are studying the various properties of fly ash as a cement
binder for concrete in buildings and bridges. Despite a big movement back towards timber frame
buildings as a smart way to sequester carbon for long periods, concrete still remains by far the
most widely used building material in the world. Cement is the hydraulic binder in concrete. In
other words it's the agent that reacts with water to make the concrete set. Once it's set it becomes
waterproof and extremely strong in compression which is what you want for tall buildings. So it's
not difficult to see why it's such a compelling material on a practical level. It's just a shame
it's so bloody awful from a climate point of view. The BAM team's research showed that although paper
ash has a similar chemical composition to cement it's a little less reactive so they carried
out experiments to add a secondary process to activate it before it gets used as the concrete
binder. That process involved mixing the ash with water and heating it in a pressure vessel and
it was burnt at 750 degrees Celsius in a process called calcination. The result of their tests
showed that the end product behaved exactly like a traditional construction-grade cement which means
it can be certified for use in concrete for all sorts of construction projects from residential
buildings to industrial plants and road bridges. Getting any significant material changes accepted
by the ultra conservative building industry is always something of a minor miracle so there will
most likely need to be some pretty slick marketing done by whoever ends up mass producing this cement
alternative, but if they can penetrate that market then the climate and environmental benefits could
be huge. These sorts of incremental changes won't fix the climate emergency on their own of course,
but to paraphrase the strap line of a well-known British supermarket chain - "every little helps"
If you've got views on this fledgling technology then feel free to jump down to the comments
section below and leave your thoughts there. That's it for this week though as always a big
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