Very few people would believe that they could be flushing valuable metals down the drain every day, but that is exactly what most of us do according to new research. Precious metals are increasingly used in minuscule amounts in commodities such as shampoo, detergent and clothes.
As a result, sewage sludge contains gold, silver and platinum at commercially viable levels if it can be extracted at sewage treatment plants. In fact, a previous study carried out by the Arizona State University suggested that a city of 1 million people can flush roughly £8.7m worth of precious metals down the drain each year.
However, this is not just a potential money spinner - extracting the metals could actually benefit the environment too. Sewage does contain microscopic traces of precious metals, but also of dangerous metals such as lead. Removing such metals from sewage could prevent their release into the environment especially when the sludge is used as a fertiliser. In the UK alone, approximately 500,000 tonnes of dry sewage solids are used as fertiliser each year, but that amount could increase should the harmful metals be extracted. Extraction would also reduce the amount of toxic sewage produced.
Extracting these metals from sewage waste therefore has a double benefit - it helps the environment and also creates a valuable commodity.
