Fixed digester covers can be utilized when sludge levels remain constant or only vary slightly. These covers are typically used on primary digesters but can be used on secondary digesters if sufficient gas storage capacity is provided through other means. Fixed truss or beam covers are anchored to the top of the tank wall with tube supports which are integral to the side sheet. The wall-mounted cover supports are designed to allow for thermal expansion and contraction of the cover and resist all design loads.

Beam to plate construction provides for easier access to all parts of the cover when applying paint and coatings. The single shell design cover also allows installation of viewports to visibly observe mixing, scum, and foaming conditions inside of the working digester. Fixed digester covers work very well with our Extreme Duty Sludge Mixers that can be mounted through ports on the cover. If gas storage and pressure regulation is needed for new or existing fixed covers, WesTech's slab-mounted DuoSphere™ Gasholder is a simple, modular solution.