Ecobricks

I’m Bricking It

“If the ocean dies, so do we” says Margaret Atwood, a novelist who has long been an environmental activist as well. In this, she’s not wrong.

Phytoplankton are microscopic, single-celled organisms that inhabit the sunlit layer of the sea, absorbing carbon dioxide through photosynthesis. Few people realise that organisms in our oceans provide almost as much oxygen as we get from trees.

Trouble is, humanity is busily changing the seas, just as we have done the land.

The sea is easy to overlook when considering the parts of the natural world that are threatened by human activity. Things that are thrown in either sink from sight or are borne away by tides and wind. Liquid wastes are diluted in a way that seems most convenient – if thinking only in the short term. In reality, the sea has been already seriously damaged.

The Ellen MacArthur Foundation warns us that by 2050 the plastic in our seas will outweigh the fish. Plastics are great materials with applications such as non-toxic toys, durable fittings on buildings and lightweight automotive components – but we also use plastics in many applications where their durability is a drawback. It’s entirely possible that some of the plastic items you throw away today will still be kicking around long after you’re dead and gone.

Single-use plastics come in for a lot of criticism, therefore, and while many of us try to do the right thing by sorting our waste, national recycling efforts are commonly centred upon clean, empty drink bottles: the easy job.

Few recycling centres can do anything much with plastic films, so the shrink-wrap protecting cucumbers, the individual wrappers on sweets and the peel-back tops on yoghurt pots are all just litter. These are lightweight, crinkly little oddments of plastic that blow around the place and have little real value to recyclers, so they are at an increased risk of ending up in the sea. For a long time I thought this was just the way things had to be: after all, what system could possibly cope with this assortment of plastics in small quantities?

Then I learned about making Ecobricks – taking a used plastic bottle and packing it full of waste plastic, squashed down with a stick. The practice appears to have begun in Guatemala around 2004, where the resulting ‘bricks’ were used in construction. It’s an approach that has spread – or perhaps been thought up simultaneously – throughout the developing world. In the form of an Ecobrick, plastic waste is locked away – at least for a while. If it’s built into a structure such that sunlight doesn’t reach it, it’ll be sequestered for decades… which has got to be better than letting it pollute the natural world.

Making an Ecobrick

Making an Ecobrick. I recommend using a wooden spoon to compress the contents as it’s easier to hold than a stick.

I started making Ecobricks for no particular reason other than to experiment. I knew that they wouldn’t be of much use in the UK because you’d never get a mortgage or home insurance on a building made from waste plastic. ‘Earthships’ – sustainable buildings made from recycled and natural materials – have never really caught on in the UK: there’s one in Fife and another in Brighton, but neither is residential in nature so it seems highly unlikely that anybody will ever use one of my Ecobricks in construction.

So why did I persevere, to the point where I’ve now made about ten Ecobricks? Because I discovered two remarkable things…

Firstly, a British household gets through a lot more plastic film than you probably think: those negligible quantities of crinkly plastic really add up and it’s easy to fill about two litres’ worth of Ecobricks a week. When you see all that plastic – and discover just how much it weighs – it’s not so easy to go on consigning it to landfill. Not that landfill works for plastics anyway: they photodegrade into smaller fragments and blow away, ending up in the soil or in the sea… which means our food chain.

Secondly, when you make Ecobricks you notice an immediate reduction in the total volume of waste that you produce. Taking out the trash is something you do a lot less often – and you never run out of bin space before collection is due. Clearly, when left uncompressed, all that plastic is taking up a lot of space.

You might say that I’m not helping matters because I’m taking a recyclable item (a plastic bottle) and filling it with waste that renders it non-recyclable.

Well, maybe… but there’s a good deal of difference between “recyclable” and “actually going to be recycled” – and since China closed its doors on waste imports, recycling rates have fallen. A shortage of single-use plastic bottles is not the limiting factor, so I think we can spare some.

The most absurd thing about all this is that waste plastics actually have value, and the technology to do something profitable with them already exists. Thermal depolymerisation isn’t choosy about feedstocks: waste such as mixed plastics, used tyres, sewage sludge and even abattoir leftovers can be converted into light oils, gases, steam and solid waste. This last is nicely sterilised, which significantly increases the usefulness of the process since even medical waste can be converted. There is money to be made from this.

Typical outputs from thermal depolymerisation, by feedstock

Typical outputs from thermal depolymerisation, by feedstock

As industrial processes go, this isn’t hard to do: water is added if the material is dry, and then everything is heated to 250°C in a pressure vessel. When the pressure is released rapidly the water evaporates and can be captured for reuse. Other outputs from the process include methane (typically used to fuel the heating of the next batch, although some is sold as biogas) and other hydrocarbons that can be separated by fractional distillation, yielding (among other things) a low-sulphur replacement for diesel fuel.

Or you can just pile everything in the ground and forget about it… although a landfill site isn’t always the final resting place of plastic waste; with under-investment and mismanagement it’s all too likely to end up being washed into the sea.

What I like about both Ecobricks and thermal depolymerisation is that they’re sufficiently low-tech that they can be employed anywhere – and in combination they offer the possibility of affordable energy and waste management. In a world where more than ninety percent of the plastic waste in the world’s oceans comes from just ten river systems in poorer countries, that’s got to be significant – but we all have a part to play.

Floating refuse in the Ganges

Sacred river: the Ganges

I’m going to keep on making Ecobricks, although my standards have slipped a bit now that I’m certain they won’t actually be used as building materials. (With compression resistance no longer an issue, I have decided to permit bubble wrap and expanded polystyrene in my Ecobricks. Also, if my bottles are a little less than 100% filled, it doesn’t matter.) While they’ll never be built into a wall, my “lazy Ecobricks” still offer a neat and tidy fuel source, if only I can find somebody to take them. Haig et al (2013) provides a valuable primer for those looking to understand how plastic waste can be processed into fuel, demonstrating that the solution is within our grasp if only local authorities will invest to turn a present-day liability into an asset.

So, how can they be persuaded? I’m thinking… civil disobedience. Back in 1971 a largely unknown group called Friends of the Earth achieved a publicity coup when they carried out a ‘bottle dump’ at the London offices of Schweppes, who had recently announced their intention of phasing out returnable, deposit-bearing bottles. (In those days, glass bottles.) Reuse has dwindled to almost nothing, but campaigning by groups such as FoE eventually got us bottle banks in 1977, and can banks in 1982.

Friends of the Earth protests, 1971

Friends of the Earth protests, 1971 [images: FoE]

Might a similar protest start us on the road to sorting out the plastic films problem? Not laying the materials at the feet of the manufacturers, but at the doorstep of local authorities that haven’t put in place a proper recycling solution. If they have a depolymerisation solution in place, having a few hundred thousand bottles of clean, well-packed waste delivered to council premises will be a gift… but if they’re still just piling up waste plastic, their failure will soon become highly visible.

It’s time for the Ecobrick. Everywhere.

 

 

Reference:

Haig, S., Morrish, L., Morton, R., Onwuamaegbu, U., Speller, P., and Wilkinson, S. (2013) Plastics to oil products: Final report. Available online: http://www.zerowastescotland.org.uk/sites/default/files/Plastics%20to%20Oil%20Report.pdf (accessed 24/08/18)

Advertisements

Talk to me! Leave a reply...

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google+ photo

You are commenting using your Google+ account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s