Recycling pile at one end of Greenwich MRF
“That’s about 2 days worth of recycling”, said our guide, Danny Easton, pointing to the massive pile of rubbish that had been emptied from the Borough’s recycling trucks. We were at the start of a tour of the Greenwich Mirf, as the Materials Recycling Facility in Nathan Way is known. We’d already seen where the compostable material from the green bins is deposited, and learned that the methane from the composting waste is piped off to the gas grid.
I’d been trying to get a tour of the MRF for a while, wanting to know how the mixed-up contents of our blue top bins were separated out, but had been told that the old regular tours no longer run. A couple of years ago, in lieu of a visit, I was sent an interesting DVD describing how the recycling centre operates, but it’s not the same as seeing it for real. An enquiry card dropped into a box at the recent Great Get Together/Armed Forced Day event solved the problem, leading to an invitation to a personal guided tour.
The technology at the MRF is very impressive, and it utilises a wide variety of forces to sort the different materials: gravity, vibration, magnetism, induced electrical currents, infra-red, optical recognition and compressed air are all part of the process. The Veolia web site describes the technology and processes really well, so I won’t repeat it all here. I was most impressed by the the huge Trommel near the start of the process, after the bag splitter. The Trommel looks a bit like a massive tumble drier, 3 meters in diameter and 12 meters long, which rotates 12 times a minute separating containers from paper and cardboard. Then later on the infra-red auto-sort for plastic bottles which is able to detect the difference between coloured, clear and opaque plastic bottles whizzing past on a conveyor belt at 30-40 mph and adjust a blast of compressed air to direct them to different places. Amazing!
The MRF undergoes maintenance for 20% of the time, though it can usually be run safely at the same time. Partly this is for routine, scheduled work – for example the moving parts on the conveyor belts need to be cleared of dust and broken glass particles – but sometimes the machinery is stopped by material that shouldn’t have been put in the recycling. Textiles are a problem, particularly for a machine called the V Screen which separates mixed paper. Also old VCR tapes get broken and release hundreds of feet of tape that gets wound up in the mechanisms and need staff to come in on Sunday to cut it away with Stanley knives. So we can help by not putting VCR tapes and textiles in our blue top bins, and by removing the caps from bottles and tetrapak cartoons so they can go to the appropriate place in the MRF.
Separated bales at the other end of Greenwich MRF
As much as possible of the separated waste is sent on to UK companies for further processing, though some does go abroad: for example old tyres are shipped to Holland. Greenwich waste that cannot be reused, recycled or composted mostly goes to the South East London Combined Heat and Power energy recovery facility near Millwall Football Ground, where it is burnt to generate electricity. The train into London goes right past the SELCHP site. This means that Greenwich has one of the lowest figures for the percentage of waste that gets put into landfill in the country. For 2008/9 an FOI Request revealed that “Greenwich Council sent less waste to landfill than any other local authority in the UK. This was around 3% of the household waste generated.” However 2011 data on recycling on the Guardian Datablog indicated that Greenwich was the third lowest council for “Percentage of municipal waste sent to landfill”, with a figure of 6%.
The Guardian Datablog data also shows that Greenwich is a middling performer on amount of waste recycled, at 37%. The best council in London was neighbouring Bexley at 51% and the worst our northern neighbour Newham with just 15%. However the Greenwich percentage has shown quite an increase from the 11.5% in 2003 when it was agreed to build the MRF. There is still a way to go to meet the requirement in Chapter 5 of the London Plan to exceed exceed recycling/composting levels in municipal solid waste (MSW) of “45% by 2015, 50% by 2020 and aspiring to achieve 60% by 2031.” Greenwich is working with other South-East London boroughs to achieve this.
Snippet from Guardian Datablog: Recycling in England: the map
Another interesting thing I learned during the tour was what drove their efforts to improve recycling quality and quantities. As well helping to save the planet, obviously, the need to meet European directives is important, but also economics plays a major role. For example the best grade of recycled paper currently fetches £150 a ton, and aluminium is £700 a ton. This makes it worthwhile to recycle waxed tetrapak type cartons which contain a thin layer of Aluminium. I remember from school chemistry how energy intensive it is to extract Aluminium from Bauxite, so this is a benefit on many levels.
It was a very interesting tour and we were buzzing with fascinating facts when we handed our safety helmets and protective glasses back to Danny on the way out. Some amazing technology, and key to decreasing the amount of our rubbish that gets buried in landfill sites and increasing how much is reused in some way.
Disposal of Rubbish in England from Guardian Datablog