Recycling: where waste really goes

The image of waste container ships plying the world’s oceans in search of a home for their toxic cargo has polluted the debate about recycling in recent years. This hasn’t been helped by reports that waste, such as plastics from UK households, has ended up in Chinese incinerators, rather than in more useful by-products, and that co-mingled recyclate has been dumped in UK landfill.

But there is a brighter side to the UK’s recycling story. Even the global recession has its benefits. Commodity price fluctuations and crashing demand in export markets such as China can only encourage the development of a more stable domestic market for recycled waste, while lower prices for low quality output act as a spur to improve the quality of UK recyclate.

The key to profitability is quality. Some estimate up to a fifth of material from co-mingled collection, where waste streams are mixed and sorted later, can end up in landfill, while mixed glass, for example, often ends up as aggregate rather than new containers.

On the other hand, there is kerbside separation. Here, householders separate waste by type and, crucially, collection crews ensure any contamination is removed before waste enters the collection truck. This is the approach used by May Gurney to collect and sort the contents of local authority recycling bins.

Here, we have chosen the example of the London borough of Ealing to follow the journey made by each type of recyclate to its ultimate destination.

GLASS
Where does it go? O-I Manufacturing (Harlow, Essex)
Distance travelled 35.7 miles
What happens? The Harlow plant handles all three main colours of glass. First, a preliminary visual inspection is made to weed out any poor quality load. Then manual picking on a conveyor belt allows Harlow staff to pick out larger contaminant items, such as bottles of the wrong colour or drinks cans. The next stage is automatic sorting by detection equipment that uses beams of light to distinguish between transparent glass and items such as ceramic chips and stones. Magnets pull out any metal waste, which is itself sent for recycling at Gillett Recycling in Harlow. This means that, while 8.5% of total input is classed as “contamination”, very little is actually thrown away.
Where does the recyclate end up? Most of the bottles made at Harlow are lightweight glass containers supplied to brewers, cidermakers and soft drinks companies throughout the UK. Recent investment will enable the plant to start manufacturing wine bottles.
Pro This kind of closed-loop recycling is highly energy efficient. The key is to maintain colour separation of the glass.

CANS
Where do they go? AMG Resources (Llanelli, mid-Wales)
Distance travelled 194.2 miles
What happens? After visual inspection, the material is shredded using AMG’s patented Cutler shredder. This uses an attrition shearing process to scrape off paint and lacquer and produce clean metal fragments. Ferrous magnets pull out steel content, while rare-earth magnets are used to repel aluminium. At the same time, air jets are used to blow lighter material such as paper and plastics away. Then, the fine layer of tin on steel cans is removed using an electrochemical detinning process.
Where does the recyclate end up? The base steel is sold on the open market to steel mills, while tin is melted into ingots on site. This is sold into the commodities market for specialised electronics and other consumer uses. AMG has its own aluminium recycling plant that produces a pure aluminium bale, which is sold on to an aluminium can-making company. This part of the process is totally closed-loop. AMG is also planning to incinerate the lacquer residue for energy generation.
Pro Steel and aluminium can be recycled indefinitely, are easy to sort and the energy savings are significant – up to 95% for aluminium.

LIQUID CARTONS
Where does it go? Various paper/carton mills (Sweden and mainland Europe)
Distance travelled Varies
What happens? Ealing’s drinks cartons are collected by Bywaters in Leyton, east London, as part of Tetra Pak’s National Carton Recycling Scheme. Bywaters bales the material and bulks it up into a full load, which is then shipped to a carton mill for recycling. At the mill, baled cartons are shredded and dropped into a pulper, where they are mixed with water for about 20 minutes. This breaks down the packaging to produce a grey-brown mixture. The aluminium foil and polyethylene are then separated from the fibre.  
Where does the recyclate end up? The carton paper fibres are used to make paper products such as recycled plasterboard liner, tissue papers, envelopes and packaging cores. The remaining mix of plastic and aluminium can then go to an energy-from-waste plant or be separated out into pure aluminium and paraffin.
Con Falling demand means it is difficult to find a cost-effective destination for the recyclate. Tetra Pak is negotiating with a paper mill in Italy to try to establish a permanent recycling route for its cartons.

CARDBOARD
Where does it go? Edwards Recycling (Barking, Essex), then Smurfit Kappa (Snodland, Kent)
Distance travelled 53.4 miles (total)
What happens? Ealing’s cartonboard and corrugated board makes a pit stop at Edwards Recycling’s Barking depot for sorting and baling before onward delivery to Smurfit Kappa’s Kent recycled paper mill. The cardboard is added to mixed paper from other council kerbside collections and paper banks to make the bottom ply of the recycled paper product. Both cardboard and paper are pulped into a 4% solution, filtered to remove contaminants such as staples and then fractionated to ensure a good mix of fibre lengths in the manufacturing process. Further dilution of the pulp spreads ink from the newsprint evenly over the fibres, which gives the final product its grey tinge. For the top layer of the paper, cardboard alone is pulped.
Where does the recyclate end up? On 18-tonne paper reels. After quality inspection, the paper is transferred to smaller reels of up to three tonnes for despatch to Smurfit Kappa’s own cardboard manufacturing operation.
Pro Cardboard’s bulk means it takes up a lot of room in landfill and recycling it is relatively simple.

PAPER
Where does it go? Aylesford Newsprint
(Aylesford, Kent)
Distance travelled 39.8 miles
What happens? Aylesford uses a 14-stage cleaning process on the paper supplied from Ealing, which is largely old newsprint and magazines as well as material such as envelopes, printer paper and fresh magazine stock. Paper is first pulped and screened to separate the fibres and water from large contaminants such as cans, plastic bottles and free magazine gifts which are ejected on to a conveyor belt for disposal to landfill. Cyclone screening then removes smaller particles such as plastic and staples using fine screens and centrifugal force. Detergents and compressed air are added to
create soap bubbles that remove ink and lift it to the surface of the pulp as a residue that can be scooped off. The fibres are lightened using hydrogen peroxide, then distributed evenly and dried to make paper.
Where does the recyclate end up? As recycled newsprint-grade paper, sold into the open market. Excess energy created for the process supplies local businesses and is returned to the National Grid.
Con Process is vulnerable to contamination from glass, which turns into a sandy grit that abrades and destroys the filters.

PLASTIC
Where does it go? Jayplas (Loughborough)
Distance travelled 113.7 miles
What happens? Plastic from Ealing’s green boxes is baled at the May Gurney depot for transport to Jayplas in Loughborough. There the plastic is separated into its different polymers and processed using the EREMA TVE plastic recycling system. The polymer is fed into a cutter compactor, then cut, mixed, dried and densified. After melting, the material is extruded and filtered before being degassed and granulated. Jayplas also operates a sophisticated bottle-sorting plant in South Normanton near Derby that can separate polymers by type and colour using TiTech optical sorting technology. This analyses plastics on a conveyor using a fast-moving scanning sensor, after which different types are blown into the correct stream using air jets.
Where does the recyclate end up? The polymer pellets become feed stock for new plastic materials. Jayplas also produces recycled polythene film.
Con Ealing collects a wide range of plastic types, which eats into the value of the recyclate and means there is a bigger problem with contamination by unwanted plastic such as films.

LEFTOVERS
Where do they go? Brogborough Landfill site, Bedfordshire
Distance travelled 50.1 miles
What happens? A steadily increasing range of items that can be recycled, together with the high quality recyclate produced by May Gurney’s kerbside sorting operation, means that very little of Ealing’s recycling collection actually ends up as waste. One category used to be the plastic bags that were used by residents to keep different kinds of recyclate separate, but these are a diminishing by-product as Ealing provides different boxes to help keep material separate. Any that are used are sorted by the kerbside crew and added to the general plastic waste, which is recycled by Jayplas. The
only items that can cause real problems for the recycling stream are textiles that get too wet, as these are difficult to process and can contaminate dry textiles.
Where does the waste end up? Of all the material produced by Ealing’s green boxes, only 0.8% has to be discarded. This is returned to Ealing’s municipal waste stream, ending up in Bletchley landfill site, near Milton Keynes.
Con Landfill is increasingly expensive, thanks to government intervention such as the Landfill Directive which sets challenging targets for reduction.

FOOD WASTE
Where does it go? BiogenGreenfinch (Milton Earnest, Bedfordshire)
Distance travelled 61 miles
What happens? Food waste from Ealing’s residents, which makes up some 24% of the whole, is delivered to BiogenGreenfinch’s Twinwood anaerobic digestion plant in Bedfordshire. The waste is mixed with pig slurry from the adjacent Bedfordia farm and turned into a porridge-like mixture. This then undergoes pasteurisation by being heated to 70°C for an hour to kill harmful bacteria. The mixture is fed slowly into digesters where fresh bacteria break down the waste to generate a gas made up of 60% methane and 40% carbon dioxide, which is fed to a combined heat and power generator on the premises.
Where does the recyclate end up? The Twinwoods plant generates 1.1 MWe (electricity) and 1.6 MWt (heat) continually. The renewable electricity is fed into the national grid and about a third of the heat is used back in the AD process. The electricity generated can power up to 1,700 homes. The other by-product is 30,000 tonnes of biofertiliser a year, from a total of 45,000 tonnes of food waste.
Con Too much green garden waste gives the anaerobic process indigestion.

Popular Articles