Does recycling have a real impact on emissions from landfill?

Councils are constantly (and rightly) on a continued crusade to reduce the amount of waste they collect from homes and take to landfill. There are several factors in this

  • the increasing landfill taxes make reduction or diversion to recycling economically essential
  • landfill space is running out (although some dispute this) and alternative facilties such as waste-to-energy and incineration take a long time to implement
  • landfill sites are a significant contributor to global warming due to production of methane, a more potent ‘greenhouse gas’ than carbon dioxide

Councils clearly have to persuade people to reduce their waste outputs and the most effective method in recent times has been restriction of residual waste collection.  This has been done by switching to alternate weekly collections, reducing bin sizes and enforcing stricter policies on overloading bins and collection of side waste.  All of these things reduce the volume of waste collected, and of course the first thing people do with a full bin is squash everything in tighter!

Measurement of recycling performance is nothing to do with volume, but is based on data collected at disposal site weighbridges.  This leaves Councils with a problem -it is necessary to deeply cut volume capacity to have any effect at all on weights.  These deep cuts have a strong and potentially negative effect on the Council’s relationship with the public. So far, so obvious.  But the question I have is whether weight or volume is in any way relevant?  To answer that question I have to go back to the very reasons why we wish to reduce residual waste.  The landfill tax is simply a man-made tool to pressure local government and so is not a justification of itself.  The question of available space in landfill is subject to some discussion.  And that leaves climate change and global warming as the strongest reason for our obsession with reducing residual waste.

The UK has certainly had some success in this.  Kerbside collection of recyclables has increased from almost nothing to over 50% in some areas.  But what types of waste have we diverted?  In my own backyard my recycling bins contain glass, tin cans and paper.  In the summer we send a small amount of green waste to compost, although most is composted in the garden.

My question is how much methane this has saved – I am no expert on this but I believe glass hardly breaks down at all and cans will oxidise over a very long period to rust without releasing any carbon (as methane or any other gas).   That leaves the paper, which does have a high organic content and will decompose to methane, amongst other gases, in a relatively short timescale.

This leaves a rather paradoxical situation for the waste collection authority.  If I were to stop recycling glass and put it all in my black bin then the effect on methane emissions at the landfill site would be nil1. Perversley, under any variable charging scheme I would be heavily penalised and the Council landed with a large landfill tax bill.

It is hard to conceive of a collection scheme that can measure waste both quantitavely and qualitatively, but any justification to the public of variable charging and specifically ‘pay by weight’ which hinges on the climate change effect of landfills should address the long term changes not just to the volume and mass of landfill, but also the composition of it.

Tim Hobbs

1 This argument does ignore the energy benefits of reusing glass instead of processing sand to create ‘virgin’ glass, which is in part offset by the carbon and energy costs of the additional collection process.

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