Wards Island Digester Tanks

Wards Island Digester Tanks

When the New York City Department of Environmental Protection (NYCDEP) partnered with Champion to remove sludge, clean and install new dome liners at eight digester tanks on Wards Island, it hadn’t anticipated the extent of repairs the tanks would require.

Once the Champion team removed the first PVC dome liner, it became abundantly clear that there were severely corroded and deteriorated sections of substrate which would need to be repaired. Many of these sections were more than six inches deep – a far cry from the one-inch repairs which were originally anticipated. 

It was also discovered that the corrosion extended down the walls of the tank, beyond the original limits of the dome areas. Ultimately, Champion and the DEP worked together to begin repairs throughout all wall and dome areas of the tank, far exceeding the original scope. Ultimately, nearly every surface of the tank received repairs, and new liner materials. 

The Champion Challenge

The Champion team adapted quickly to this dramatic change in project scope.

Having removed the first tank’s interior lining, they set to work repairing the substrate, then preparing the concrete surface – and soon achieved a surface profile of ICRI CSP 4 or greater.

The existing concrete was then resurfaced with microsilica mortar to ensure it would provide a level substrate for subsequent liner materials. 

While the first tank has been completed, tackling the remaining seven is an ongoing effort. In the end, the project will be a striking testament to Champion’s ability to stay flexible in the face of unexpected change.