Capacitor figures: why?
Capacitor figures, tally sheets, pollutant removal reports: for some recycling companies and dismantling facilities, these terms may not evoke entirely positive feelings. But from an environmental perspective, these figures can be very important. And an analytical view of indicators can also make financial sense.
During audits of recycling companies and dismantling facilities (DF), the audit team checks how many capacitors have been manually removed from waste electrical and electronic equipment (WEEE). The figure for capacitors from large household appliances (LHA) comes in for particularly close scrutiny. This used to be generated with tally sheets; today, the weight of the capacitors from LHA is compared with the weight of the corresponding whole devices to produce the capacitor figure.
The figure for LHA capacitors must be collected at least quarterly. Depending on the size of the company, it may even be required on a monthly basis. But sometimes it’s not clear why this figure has to be collected at all – so it is often calculated without being interpreted subsequently. Often, people ask: do we really need to record this number?
Driving 10 times around the world for one capacitor
From an environmental perspective, the capacitor figure is evaluated because capacitors may contain harmful substances or substances of concern. The aim is to check that all suspicious capacitors have been removed from WEEE in good time before mechanical processing. When WEEE that still contains capacitors with hazardous substances is shredded, these substances are distributed amongst all fractions, including those that are recycled.
The focus here is on polychlorinated biphenyls (PCBs), which are mainly found in capacitors. Although the use of PCBs has been banned in Switzerland since 1986, these pollutants can still be found in electronic waste. Even very small quantities have a considerable impact on the environment. If we assume that an item of LHA could contain 10 g of PCBs, this amount equates to 219 million environmental impact points (EIP)1. This, in turn, corresponds to the environmental impact of a car driving around the Earth 10 times. Even if capacitors suspected of containing PCBs are rare2, it is always important to remove each and every one of them from the electricals.
The figure can be too high
According to CENELEC’s technical specification 50625–3–1, the guide value for capacitors in LHA and in small household appliances is 1 kg of capacitors suspected of containing PCBs per tonne of WEEE. In practice, individual measured values for LHA are between 0.8 and 1.8 kg/t.
Here are three examples that show how the capacitor index for LHA can be interpreted:
- A plant records values that are slightly higher than the guide values, e.g. 2.5 kg/t. This raises the question of whether more components are being removed than is necessary.
- If a much higher number is captured, e.g. 30 kg/t, it is highly likely that not all of the capacitors measured or weighed come from LHA. For example, are capacitors from industrial applications being collected and weighed in the same container? If a SENS recycling company receives capacitors from sources other than WEEE from a DF with which it is associated, this recycler will be paying too much for proper disposal in a high-temperature incineration plant.
- With very small numbers, such as 0.2 kg/t, there is a risk that not all capacitors suspected of containing PCBs have been removed manually. The first step is to check whether any quantities have been forgotten (not recorded, not communicated, etc.) and to verify the composition of the devices. Some LHA, such as ovens, contain fewer capacitors. If this is not the case, the company will need to take the appropriate steps.
Figure too low: what now?
In some cases, a low capacitor figure is confirmed by higher PCB concentrations measured in the aggregate samples of dust or screen fractions. If this reaches the limit of 50 mg PCBs/kg of waste, it is categorised as hazardous waste. In addition, if the pollutants have not been removed to a sufficient extent, silver cylindrical capacitors are often seen in the pile of LHA from which pollutants have been removed. When all these indications appear simultaneously, they clearly indicate insufficient pollutant removal from LHA. The response to this should be retraining, greater awareness, more chemical analysis and more quality inspection circuits until all values are back within the expected range.
A targeted interpretation of the figures can also help in determining the cause of insufficient pollutant removal from LHA. For example, did the low numbers arise during a time when the facility was using seasonal workers who might not have been adequately trained? Or was a member of the dismantling facility’s support team on holiday, with a resulting drop in the frequency of quality inspections? One thing is clear: the detective work won’t be in vain. It protects the environment and sometimes reduces operating costs as well.
PCBs are also found in more than half of the capacitors from older magnetic ballasts in lighting equipment. For practical reasons, there have been no figures collected for these components, as lighting equipment is part of the highly diverse range of small household appliances. Other small appliances can also have components that contain PCBs. Without a figure for capacitors in small appliances, it is all the more important to have employees with trained eyes and an awareness of these pollutants on inspection circuits.