Severn Trent has found a way to treat sewage quicker and cheaper at one of its sites near Gloucester, using little plastic discs.

As part of a recent three-month trial, a team of engineers based at Newent treatment works has enhanced the process by putting sewage through an additional tank containing thousands of plastic discs.

The discs, which are roughly the size of sporting medals, have a sponge-like texture and are full of holes, providing bacteria-hungry bugs with the perfect platform to do what they do best – strip away Ammonia and turn it into harmless gases. Attaching themselves to these plastic discs give the bugs a greater surface area, exposing more of them to the wastewater. This speeds up the process and reduces the amount of space that’s needed.

Project engineer Lewis McGregor said, “We introduced these sponge-like discs around three months ago and the results have been fantastic. The discs give our bugs a greater chance to react with the wastewater, which means more can be treated in a shorter time, using less space.

“We believe it could make the process of treating sewage much more cost effective and reduce the size of treatment works in the future, which is a great outcome for everyone.”

It is the first time this approach has been used by Severn Trent for this stage of the treatment process and only the second time in the UK. The encouraging results from this trial means the same technology could be rolled out across other sites in the future.0