Xylem will supply 92 736 sq ft of Leopold Type XA underdrains with IMS 200 media retainers, 3284 tons of sand and 5738 tons of anthracite for the project.

The plant was placed in service in 1941, initially with mono-media filters and a clay tile underdrain. As the plant was expanded concrete tee-pee underdrains were installed and all of the filters were converted to dual media filters.
 
Jim Kostelecky, Weymouth Plant manager, said: “The Xylem Leopold Type XA underdrains provided us with an opportunity to remove the old underdrains and support gravel and install substantially deeper layers of sand and anthracite, without a significant impact to the plant’s existing hydraulic profile. Based on previously conducted full scale testing it is anticipated that the new retrofit filters will provide a far more robust filtration process, which will be in service for another 75 years or more.”
 
Matt Schomaker, technical sales manager for Xylem Leopold products in North America, said: “Our application knowledge and experience as well as our filter media application and processing expertise were key factors in securing this contract. A highly specialized media specification was desired by the Metropolitan Water District to enhance filtration performance. The Leopold Type XA was the preferred underdrain on this project due to its innovative design, efficient backwash performance, and reliability that comes with the solution’s increased uplift resistance.”
 
The plant is already under construction and phase 1 of the new system is due to be operational in the first quarter of 2016.