Suprafilt have helped Severn Trent Water to achieve energy and maintenance savings worth £94,000 after installing a liftable grid aeration system at Melton STW.

The aeration specialists were awarded the £150,000 contract to improve the efficiency of the aeration process on a works where the effluent is a mixture of domestic and industrial effluent from a pet food manufacturer.

The benefits:

The work, completed by Suprafilt’s knowledgeable team in 2018, has helped to achieve an energy saving of £84,000 and annual maintenance savings of around £10,000 per annum.

The improved system has also resulted in a CO2 saving of 402 tonnes a year – the equivalent of four return flights to Spain or 8 trips to the moon in a car. It has also improved the effluent quality going to the nitrifying filters biofilter, with the BOD going from over 30mg/l to consistently less than 5mg/l.

The project:

The aeration specialists recommended a liftable grid system, which allowed more efficient aeration to be installed within a live tank, and also for maintenance purposes in the future. The liftable grid system allows the operators to life the grids out to change any worn membranes without having to drain the tanks.

Graeme Fielden, Sales Director, said: “Because we were altering the aeration without interrupting the process, it needed a lot of liaison and interaction with the operators and other contractors on the site to make it happen smoothly. It was essential to have good project management on this job.”

The existing Severn Trent Water site was being aerated with surface aerators which required upgrading.

The 5 aeration zones were completed one at a time and converted to fine bubble aeration. Three stainless steel liftable grids were fitted in each aeration zone to provide tapered aeration to help deal with the bacteria. They featured OM 2m stainless steel bdd diffusers. The project also included new blowers, new air main, tank header, three lift out grids in each zone providing tapered aeration.

All pipework and installation was provided by Suprafilt’s in-house team.

What the client said:

Nigel Goerick, Consultant Engineer at Air Technology Limited, who led the project said: “Suprafilt went above and beyond the call of duty. Suprafilt carried out additional work like emptying tank and moving pumps – which was very manual work during last year’s heatwave – to ensure the project stayed on track. They kept the job going.

“A director of Severn Trent Water visited the site and was very impressed with the change. Before the old aerators used to splash everywhere and leave effluent on the walkways”.

“Suprafilt were flexible and able to get the job done despite difficult conditions, whilst maintaining their high levels of quality and safety. They just get on with the job and don’t need a lot of handholding or managing.”