Does the stuff you put in your recycling bin really get recycled? How is plastic separated from paper, cardboard from drinks cans?
A quick answer to the first question is: yes, it really does get recycled. For answers to the second question, read on.
The Borough Council Community Select Committee, of which I am a member, recently had a trip to the UPM Material Recovery Facility and paper mill at Shotton, in North Wales. High Peak recycling goes to Waterswallows near Buxton in the first instance and then is taken to Shotton to be separated, before travelling on and being turned into usable material.
Our guide told us that High Peak recyclate is relatively good quality, so thanks to everyone for making the effort.
After we’d collected our safety equipment, goggles, gloves, hard hat, ear protectors, we entered the site. It’s a wide area of modern industrial buildings, a collection of giant round and square boxes painted a dark cream colour, some of them connected by bridges.
The MRF is the one of the largest of its kind in the UK. Inside, the predominant colour is a dusty grey. Elevators, conveyor belts, hoppers and metal stairways, criss-cross the building in a dense and bewildering pattern.
The first step in the process is the separation of glass, by gravity. Other materials pass onto a conveyor belt while glass falls through holes to be collected below. Our guide said that glass is a problem as even tiny bits of glass which stay in the process can damage machinery. They’d prefer glass to be collected separately, as it used to be.
Further on, orange boxes cross the conveyor belts at intervals. These are optical sensors which use near-infrared light to detect specific materials. The recyclate (the recycled material) passes through a couple of sensors which detect paper. If paper is detected, a puff of air blows it up and over a roller, while the rest of the material carries on through the facility. Eventually the good quality paper (mainly newspaper and magazines) is carried over to the paper mill, where it is converted into newsprint. It was good to hear that most UK newspapers are made from 100% recycled paper – thought visiting the paper mill made it clear that a lot of water, chemicals and vast amounts of energy are also needed to produce paper.
Steel cans are pulled out by magnets, then aluminium cans are separated out with something called eddy currents, described as reverse magnets. Google if you want to know more since your writer is no physicist.
Other optical sensors deal with different sorts of plastic. Plastic is separated into coloured and plain PET (mainly bottles) and coloured and natural HDPE (larger plastic containers such as large milk bottle). We were told that, because the process was designed by process engineers, this is done very efficiently here, in a three rather than four stage process.
Among the machinery there are a few pods where manual separation takes place. This is partly to comply with environmental regulations, which require recycling facility operators to report the average (or arithmetic mean) percentage composition for different recyclable and non-recyclable materials – for this, a sample of recyclate entering the plant is taken, and people stand by a conveyor belt sorting it into the different types of material. In other pods, at different stages, contaminants are removed. It was impressive to see the speed with which the people doing this could identify different types of waste, and throw them accurately into different bins, some bins a couple of metres away. The worst contaminants are those which might clog up machines, such as textiles and videotapes. And worst of all is clinical waste and nappies.
It can’t be much fun sorting out waste as it goes by on a conveyor belt,. I was reassured to hear that workers at the plant are paid above the local living wage and are on permanent contracts.
Once the material is sorted, the various conveyor belts take it down to the bailer. This somehow knows what type of waste will arrive next, and forms it into cubes about 2 metres square. The neat bales were lines up in a warehouse ready to be taken off and converted into new materials. 90% of the materials go to recyclers in the UK, with some going to Europe and Turkey and so to places which at least theoretically must comply with EFTA standards.
There is very little residual waste. What there is goes to a state-of-the-art combined heat and power plant, which produces some of the power for the facility. The CHP plant also burns some of the residue from the paper mill, and the waste wood which households take to Waterswallows (among other places – this huge plant certainly isn’t just for High peak). I’ve read about pollution from CHP plants, but was told that this one only produces CO2. The nastier pollutants, from MDF for example, are removed. Ash from the CHP incinerator can be used as fertiliser, hard core or cement. This doesn’t seem ideal, but it’s probably better than digging new materials from the earth: like many environmental questions, it’s complicated.