Project Description

FP McCann’s precast Filter Bed System utilised on Welsh waste water scheme

Status: Completed

Location: Anglesey

Division: Filter Beds

Main Contractor: Dawnus Construction

Market Sector: Energy

Llanfaethlu waste water treatment works is situated in Anglesey in North Wales and is owned and operated by Dwr Cymru Welsh Water (DCWW).

Constructed over 40 years ago, the waste treatment works consists of a single filter bed with precast concrete walls and tile bed. Waterco UK, engineering consultants to DCWW, set out the design brief to replace the existing filter bed with two new 10 metre diameter beds, at the same time keeping the Llanfaethlu works operational throughout the whole construction process. After a meeting to discuss initial proposals, FP McCann submitted structural designs and costings for the complete supply package for approval. Dawnus Construction, principal contractor, commenced the design and build project in spring 2017. The scheme was split into two phases, phase 1 is to extend the capacity of the existing waste water treatment facility whilst maintaining operations and once complete phase 2 is to undertake on-line modifications and upgrades to the existing works.

Prior to commencing the demolition of the existing filter bed, the first of the new beds was built. Each waste treatment bed consists of 37 wall units 2.50m high and 208 filter bed tiles. Individual wall units have been cored to accommodate feed pipes and washout pipes.

Each of the filter bed wall panel units are married to the other using a unique stainless steel bolting system. Props were used to support every third concrete unit while steel fixings were secured.

Phase 1 is now complete with the first new bed brought into immediate operation and the demolition of the old waste treatment plant itself replaced with a brand new filter bed. 

With a combined weight of approximatley 50 tonnes, around 500 separate pieces of precast concrete filter bed wall and tiles were supplied from FP McCann’s Littleport factory, and have been used to construct both filter beds. Day to day treatment operations continued uninterrupted and phase 2 of the scheme is scheduled for final completion later this autumn.

Iwan Pritchard , Project Manager of Dawnus Construction said ,“The speed and efficiency of installation of the precast concrete filter bed walls and tiles combined with the quality assured factory prefabricated unit, gives us the confidence we are putting in place a system that will perform very well over its 40 year design life.”

 For further information on FP McCann’s precast concrete Filter Bed Solutions, please contact our Cadeby office on 01455 290780 |