A car manufacturer and water services company have partnered to turn wastewater into sustainable biofuel.

The process employed by SEAT and Aqualia involves separating water from sludge in treatment plants, before fermenting it into a biogas.

When used in a compressed natural gas (CNG) powered vehicle, SEAT claims the fuel results in 80% less Carbon Dioxide emissions than traditional petrol engines.

This means CNG models such as the SEAT Leon TGI and SEAT Mii Ecofuel are not subject to the traffic restrictions recently put into place in cities like Madrid and Paris.

A medium-sized plant can treat around 10,000 cubic metres of water and generate 1,000 cubic metres of biomethane every day. This is enough fuel for more than 150 vehicles to drive 100 kilometres.

In Spain, where SEAT is based, the equivalent volume of more than 1.5 million Olympic-sized swimming pools of wastewater is treated each year.

A number of driverless and low carbon vehicle projects in the UK have received a share of £109.7 million of funding.