If you were to stack up all the electronic waste produced annually around the world it would weigh as much as all the commercial aircrafts ever produced, or 5,000 Eiffel towers. This is a growing “tsunami” according to the UN, and it’s fed by all the phones, tablets and other electronic devices that are thrown away each day.
Of the 44.7 million metric tonnes of electronic waste (often shortened to “e-waste”) produced around the world in 2017, 90% was sent to landfill, incinerated, or illegally traded. Europe and the US accounted for almost half of this – the EU is predicted to produce 12 million tonnes in 2020 alone. If nothing is done to combat the problem, the world is expected to produce more than 120 million tonnes annually by 2050. Pyrometallurgy and hydrometallurgy are the current technologies used for extracting and recycling e-waste metals. They involve high temperatures and toxic chemicals, and so are extremely harmful to the environment. They require lots of energy and produce large volumes of toxic gas too, creating more pollution and leaving a large carbon footprint.
But bioleaching has existed as a solution to these problems as far back as the era of the Roman Empire. The modern mining industry has relied on it for decades, using microbes – mainly bacteria, but also some fungi – to extract metals from ores. Microorganisms chemically modify the metal, setting it free from the surrounding rock and allowing it to dissolve in a microbial soup, from which the metal can be isolated and purified. Bioleaching requires very little energy and so has a small carbon footprint. No toxic chemicals are used either, making it environmentally friendly and safe.
Source: World Economic Forum
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