Scientists at Leeds University, UK, have developed a new method of cleaning wastewater from textile factories and tanneries that is contaminated with chromium compounds. They have discovered that adding dilute acetic acid stimulates the growth of naturally-occurring bacteria that are able to digest the chromium.
“The original industrial processes changed these chemicals to become soluble, which means they can easily leach into the groundwater and make it unsafe,” said one of the researchers, Ian Burke. “Our treatment method reconverts the oxidised chromate to a non-soluble state, which means it can be left safely in the ground without risk to the environment. As it is no longer bio-available it doesn’t present any risk to the surrounding ecosystem.”
It is possible to treated chromates in situ at neutral pH, but the Leeds technique is effective in extremely alkaline conditions, where they are much more difficult to treat. The researchers believe their findings can form the basis of a viable treatment for former industrial sites where chromate compounds are a problem.