MORE EFFICIENT SORTING & RECYCLING THROUGH THE USE OF THE LATEST TECHNOLOGY
3.1 Increasing efficiency in sorting
Setting up efficient sorting systems and infrastructure backed up by the most advanced sorting technologies is a prerequisite for ensuring an almost 100% efficiency in the sorting of aluminium cans and thereby helping to move towards 100% recycling by 2030.
Although many cans reach sorting centres, there is still a risk that several end up in waste-to-energy plants or even worse, at a landfill site. This is due to the fact that across Europe, aluminium beverage packaging waste tends to be sorted in small sorting centres with low levels of technology. Research11 from France Aluminium Recyclage shows that, depending on the aluminium packaging, the losses during the sorting process can range from 5 to 25%. This depends on the equipment of the sorting centre and the settings of the Eddy Current Separators (ECS) in the sorting centres. For instance, in France, there are around 170 sorting centres, few of which have invested in advanced eddy current separation technology. 30 are equipped with two ECS and about 20 to 30 have only one. An assessment12 conducted by Virtus Environment in Spain found that rigid aluminium packaging recovery reaches an average of 80%, regardless of the sorting methods. Therefore, for the recycling process to bring optimal results and boost real recycling of aluminium cans, it is important that aluminium beverage packaging, after having been separately collected both from households as well as on-the-go, is sorted in smarter, high-volume and high-speed sorting centres that are equipped with the very best technology to recover aluminium.
A study13 by the independent engineering, design and consulting company HTP in Germany has shown that having the right sorting equipment can make a massive difference to aluminium recovery rates. There is a wide range of technologies and infrastructure available on the market for sorting aluminium packaging items with eddy current separation being the most cost effective and successful technology for aluminium recovery. Eddy current separators sort aluminium cans through the creation of a magnetic field which induces electrons in the aluminium, thereby pushing it off the main conveyor belt. After quality checks, it is then sent to recycling facilities.
An additional key parameter for the effective sorting of aluminium beverage packaging is the number of eddy current separators needed to recover each of the particle-size fractions of aluminium. It has been proven that having more eddy current separators in a sorting centre will increase the efficiency of sorting aluminium packaging and lead to increased recycling rates for aluminium cans. The business case for investing in eddy current separators – and to have at least two of them to treat the different sizes of the packs – is a clear one, since the extra aluminium recovered can pay back any investment very quickly. Additional induction sensor or even robot-based sorting can bring even a few more extra percentages.
The study found that by taking a representative sorting plant that processes 80,000 tonnes of material a year with an average aluminium content of 5.5%, the use of at least two eddy current separators - one for the medium / medium-low aluminium fractions (80-300 mm) and another for the fine fraction (20-80 mm) - will boost the recovery rate by 30% compared to having only a single ECS for the medium grain fraction. Using separators for the fine and medium sized fractions therefore promises to increase recovery rates from around 60% to 90%. If sorting centres progress by using induction sensor or robot-based sorters, they can expect to boost their recovery rate up to as much as 96%.
The ideal aluminium packaging sorting model
| Sorting technique | Fractions | Recovery rate: Non ferrous waste | Recovery rate: Beverage cans | |
|---|---|---|---|---|
| Basic setup | 1 ECS | Medium, Medium-low | 59.2% | 54.8% |
| Upgrade 1 | 2 ECS | Medium, Medium-low, Fines | 89.9% | 92.8% |
| Upgrade 2a | +ISS | Light and flat items | +4,3% | +2,6% |
| Upgrade 2b | +Robot sorter | Any aluminium packaging | +6,3% | +4,5% |
Source: HTP Consultancy, 2018/19 13
Source: STEINERT Eddy Current Separator
Source: TOMRA Finder Process Animation
HTP’s figures have been backed up by research in Spain from Virtus Environment, which showed that technology and automation improvements to eddy current separation technology could have the potential to cost-effectively increase recycling efficiency by up to 30% in the coming years, depending on the individual circumstances of each sorting centre. As a result, one third of the current losses could be recovered through increased treatment capacity for municipal solid waste.
3.2 Unregistered collection and recycling outside EPR systems
Additionally, we are faced with unregistered can collection and recycling in Western European countries. For example, in France, a considerable amount of cans are recycled outside the EPR systems. France Aluminium Recyclage carried out a survey on a limited geographical scope in Eastern France to assess the potential tonnage of cans collected for recycling but not included in the national data. Site visits in France confirmed that a significant number of cans were collected on-site and recycled via scrap dealers but were not taken into account in the calculation of the recycling rate since they were not declared to CITEO, the French EPR packaging recovery organisation. The first results of the survey are quite significant: if we consider this new source of recycled cans, the French recycling rate could increase from 11% to 19%. However, a more comprehensive study is needed for the whole of France to collect more solid data. This would help the industry to define the right way to go to improve its collection and recycling rates.