Julien Van Damme, Manager at European Environmental and Safety Planning Office (EESPO) for Honda Motor Europe Ltd attended the BCF Conference in Munich towards the end of last year and made his presentation regarding the cost analysis between dismantling and post shredder separation. But which process proves more cost effective for your business?
The End-of-Life Vehicle Directive (2000/53/EC) recommends in its Annex I to remove big plastics parts at the moment of dismantling the car to facilitate recycling of the plastics.
On the other hand most, if not all, car producers (i.e. car manufacturers and car importers) recommend not to remove the plastic parts and have the plastics separated out of the shredder residue. Currently there are several separation technologies available to sort the shredder residue in different fractions ready for a last filtering before being prepared for the re-use of the material (i.e. recycling).
How the Directive sees the treatment of an End-of-Life Vehicle?
The mass flows in the treatment of an End-of-Life Vehicle can be visualised in the picture hereafter :
When an End-of-Life Vehicle arrives at the dismantler his first interest is to get as much value out of it as possible. Therefore providing parts for re-use is probably his prime business. But as the first line waste treatment centre he is also obliged to comply with the obligations expressed in Annex I of the End-of-Life Vehicle Directive.
Depollution of the car is a prime concern expressed in the Directive. This includes, amongst others, the removal of all liquids from the car and the removal of the batteries.
Further on, the Directive recommends removing big plastic parts and tyres. The main concern is that it is not obvious that those materials could be retrieved at a later process in the treatment chain. This is also the reason why catalysts must be removed at dismantling stage: after shredding the precious metals included on the brittle ceramics will be so small and diluted that no economical process will be available to concentrate the material again to such an extent to recover the material itself. So we saw that in 2000 Europe already considered aspects of the Circular Economy.
Typically the remainder of the operations at the dismantler is sold to the shredder. The main business of the shredder is recover ferrous metals as pure as possible mainly as input for the steel industry. But with the changing technologies in the supply chain of the shredder more non-ferrous metals enter into their processes, so it becomes interesting to make concentrates of the other metals too. The question arises as to what to do with the shredder fluff? Stimulated by the recycling target of the End-of-Life Directive and by the increasing landfill cost techniques which became available to extract other remaining values from that fraction, unless the shredder invested himself into such technology, he can send his shredder residue to a Post-Shredder Separation Plant. This plant is making concentrates of different types of plastics.
A compounder of recycled plastics will be happy to accept these fractions. He will further eliminate unwanted sub-fractions to produce plastics based on the client’s specifications. Here or at an earlier stage electronic circuit board fractions can be separated. This allows recovering the gold, silver and critical materials from it. It is also possible with appropriate processes to split rubber, foam, glass and other many more of residual materials.
Where to get the plastics out?
Based on the above the question comes, where to separate the plastics, at dismantler or by Post Shredder Separation Technologies?
The main driver is the cost for achieving (or exceeding) the End-of-Life Vehicle Directive recycling and recovery targets. Some costs are difficult to estimate and it is the operator’s decision whether he goes further or if he stops. But some costs are easier to estimate and these are manpower costs and landfill costs. Consequently these are the main drivers for the cost model presented here. When the plastics are recovered by dismantling it is recommended to pre-sort them by plastic family. But this requires quite a lot of space to keep those plastic parts especially when they are large (as per recommendation by the End-of-Life Vehicle Directive).
We consider that there is m0 amount of waste in a car. Typically for a standard car of 1 tonne there are approx. 250kg of non-metals in it.
Considering these non-metals are potentially for landfill, we can estimate the cost based on the amount of recovered materials during the different processes. The mass balance is easily set up :
Where as : mW : the waste mass
m0 : the non-metal materials in a car
m1 : the non metal materials removed at dismantler for recycling
m2 : the non-metal materials separated by special technologies
m3 : the remaining waste fraction
Next to the cost for landfilling stands the cost for removing the plastics. When this happens manually there is the cost of the worker doing this. To separate the materials by machine the additional cost per weight is marginal compared to labour cost.
From the equation it is clear that the more material removed during dismantling or after shredding, the less the landfill cost will be, being the mass for landfilling multiplied by a fixed landfill cost (per tonne).
An important observation is also that during dismantling one can rather easily remove the first big plastic parts, but the more plastics one wants removed the more effort it will cost and the lesser materials will come with the efforts.
Based on the considerations above the following picture of the costs comes up:
This picture integrates three processing conditions and gives an image of the cost aspect of the three basic situations.
First it considers that only the dismantler will remove plastics and the shredder will deliver the Automotive Shredder Residue directly to landfill.
The next part shows a separation of the plastics for 60% of which a portion is by the dismantler. The 60% is well chosen as per our typical car with 250 kg of non-metal content the 60% or 150 kg represents a potential of 90% recycling, i.e. some margin for achieving the 85% recycling target in the End-of-life Vehicle Directive, but not enough for the 95% recovery target!
Finally the depolluted car can go directly to the shredder and the Automotive Shredder Residue goes directly to the post-shredder separation plant with its own separation potential.
When the dismantler is not removing any materials, all non-metals go landfill at a certain cost. Instead the dismantler can remove and pre-sort plastics for recycling avoiding those plastics going to landfill. But he has to spend time on this. Although the first kilo goes off quickly a quick estimation shows that more money goes into the handling than landfill savings can be realised. As plastics are being removed it takes more and more time to remove the same amount of plastics from the car (more difficult access, smaller parts…). This graph shows clearly that plastic collection at the dismantlers is not at all a cost effective solution.
Dismantling with Post-Shredder Separation
With the post-shredder separation to 60% it just adds cost when some plastics are manually removed from the End-of-life Vehicle. This is because the technology makes it possible to identify and separate different types of plastics. But its efficiency does not depend on the volumes fed (as long as the capacity of the equipment is respected).
The 60% separation point is chosen because around that point of deviating materials from the landfill waste stream the additional cost of the Post-Shredder Separation plant is compensated by the saved cost of reduced landfilling. For the demonstration of that breakeven point I want to refer to the explanation of the next situation.
Post-Shredder Separation only
When considering the actions by the Post-Shredder Separation plant only we see an initial cost increase related to additional transport mainly and maybe a gate fee. But we see from the graph that these costs are compensated completely when 60% of the material flow can be deviated from landfill. The more material fractions can be separated for recycling the more profit there is compared to landfill.
It is important to identify that when 80% of the materials can be deviated from landfill thanks to Post-Shredder Separation Technologies the recovery target of 95% is achieved.
This article is a result of an internal study with cost elements dated around 2005, therefore we can derive that some costs have increased such as labour costs. Also additional conditions on what to accept in landfills came in place. The (hidden?) target of the legislator was to increase the landfill price especially of carbon rich waste. This must promote the recycling of materials like plastics. But the industry is not sticking on the same production technologies so new challenges are given to further enhance the separation technologies. Also the legislator’s attention on the potential health impact of certain chemicals pose new issues to be solved to facilitate material recycling. An easy solution for the legislator is to put extra tasks on dismantlers’ shoulders e.g. to pick critical parts from the End-of-Life Vehicle. The challenge is to have those material deviated by concentration from the final waste stream (i.e. landfill).
From this article it is clear that we should leave the dismantler focussed on his prime activities. Material sorting is not part of this business. We can have automated processes to make sorting efficient and cost effective.