Severn Trent innovates in phosphorus removal to meet tighter regulation


This is the latest in a series of advisory pieces on technology that will focus on significant developments.

Severn Trent is investing £35m to install innovative technology at its Finham Sewage Treatment Works near Coventry that will help it to meet tighter European controls on phosphorus in treated waste water effluent.

The company has started to install at its Finham site a process that removes dissolved phosphorus through precipitation enhanced by binding the precipitate to particles of magnetite – a naturally occurring form of magnetic oxide of iron. The magnetite can be reused following recovery using magnets to recover the mineral.

Phosphorus is associated with algal blooms and tighter limits – at 0.22 mg/l – on its release concentration are included in the European Union Water Framework Directive.

Severn Trent for a few years, has been trialling several phosphorous removal technologies at its site in Packington, Leicestershire. It said the work at Finham was among the first roll outs of these. It said it “hoped” for it to be in full operation in autumn 2019.

Severn Trent said: “In total we’re investing around £120m in phosphorus removal technology up until 2020, an investment that will see around 100 sewage treatment works upgraded.”

The April edition THE WATER REPORT, included coverage of how adoption of new technology to reduce phosphorous. had brought savings of £10m this AMP and created a revenue opportunity for the firm in fertiliser production.