Treatment Of Backwash Waters Associated With Ceramic Membrane Filtration

Siltbuster Process Solutions, the UK’s leading provider of modular and packaged water treatment systems for the municipal and industrial wastewater sectors, has been called in to treat the backwash waters associated with the use of ceramic membrane filtration at South West Water’s £60million state-of-the-art Mayflower Water Treatment Works.

Two Siltbuster HB300 lamella systems have been installed to remove particulate material being generated during the backwashing process.

Described as a pioneering treatment process which will take UK surface water treatment into a new era, the Mayflower project is building a new water treatment works to supply up to 250,000 people in Plymouth with exceptionally high-quality drinking water.

The project is being delivered by infrastructure group Balfour Beatty as the main construction contractor, working in partnership with Interserve, who are responsible for the construction of all infrastructure, buildings and pipelines.

The works will use an innovative combination of treatment processes supplied by Dutch water company PWNT, consisting of suspended ion exchange, inline coagulation and ceramic membrane filtration. In addition, granular activated carbon filtration and UV disinfection are being provided downstream of the PWNT processes.

The ceramic membranes, which were installed as part of the main Treatment Plant, have extremely small pores less than 1/10,000th of a millimetre in diameter, in order to catch almost all particles including any bacteria and harmful organisms, such as cryptosporidium.

The use of a membrane means that backwashing must take place in order to remove the particulate material that is collected. Historically, this water was discharged directly to surface water supplies, however it is now highly regulated and heavily discouraged.

By using two of Siltbuster’s HB300 lamella systems, the site is able to provide an effective separation of suspended particulates from the water, treating up to 270m3/hr. The packaged system includes flocculation tanks to improve settlement rates and access steelwork, providing a complete design and build solution.

Siltbuster Process Solutions was an attractive option, not only because of the offsite manufacturing, but also because its customised solution uses Drinking Water Inspectorate (DWI) approved materials and utilises a stainless lamella cassette.

Neil Heard, MEICA Project Manager at Interserve, said: “The Mayflower Water Treatment Works is capable of producing up to 90 million litres (megalitres) of drinking water every day ensuring a sustainable supply of high quality drinking water for homes and businesses for decades to come.

SPS’s range of industrial lamella clarifiers provided us with a compact solution that allows us to safely and effectively remove the particulate material from the treatment process. Through its meticulous planning and experience within the sector, Siltbuster Process Solutions was not only able to deliver on all of its promises, but also complete the works ahead of schedule.”

Dr Richard Coulton, CEO of Siltbuster Group, commented:

“We were pleased to be given the opportunity to work on the Mayflower Water Treatment Works – another pioneering project that is benefitting from our innovative treatment solutions.”