Bayer's arsenic boost
1 Aug 2002
Research from Bayer and Severn Trent has led to the development of a substance which can remove arsenic from drinking water.
The product, a ferric oxide, has now been approved for use in the US, where arsenic contamination is a problem.
Arsenic compounds leach into groundwater from natural resins and minerals in California, New Mexico and Arizona, and the compounds have to be removed from drinking water supplies. The present legal threshold for arsenic in the US is 50µg/litre, but this is to be cut to 10µg/litre from 2006.
The Bayer compound, known as Bayoxide E33, has nanometre-scale pores which can adsorb arsenic. Severn Trent demonstrated its effectiveness in fixed-bed filter systems at its treatment plants in Burton Joyce, Nottingham, and Chaddesley Corbett, near Birmingham.
The company found that granules of the oxide have a higher adsorption capacity than conventional adsorbing substances like activated carbon or aluminium oxide, and therefore lasts longer in service.
Moreover, unlike ion exchange resins, the substance does not need to be regenerated.
