The cork planks used in the production of cork wine
stoppers must be boiled in water for at least 75 minutes in
order to remove any extraneous materials and to render the
planks softer and more flexible. This process consumes a
large amount of water and generates a highly pollutant
wastewater that is rich in tannins, sugars and salts. Tannins
are organic compounds containing phenolic groups. These
polyphenolic compounds do not decompose easily, and