Morgan Est has been named preferred bidder for a £21m contract to build two Advanced Digestion Plants for Welsh Water.

The contract will cover all civil engineering aspects associated with the construction of both plants, one at Cardiff Waste Water Treatment Works and the other at Afan Waste Water Treatment Works.

The Cardiff project will involve the construction of two 22m-diameter, 22m-high reinforced concrete digester tanks which will sit on a 2,900m3 raft foundation and at the Afan site operatives will build two 18m-diameter, 18m-high post-tensioned structures on a piled base.

The Cardiff and Afan sites will both include all bases and building structures associated with the mechanical and electrical process.

All the enabling works, including service diversions, demolition and modifications to an existing structure, have already been completed.