Anaerobic Digester Covers

Floating Covers for Digesters

WesTech anaerobic digester covers are ideal for new and retrofit installations. These custom covers are innovatively designed by engineers who have decades of experience meeting customer specifications for biogas and odor containment. Incorporating the most current structural standards, WesTech covers are economical and easy to install.

We offer three major structural designs: Steel Truss, Radial Beam, and DuoSphere™. Our Steel Truss and Radial Beam structures can be configured to fixed or buoyant configurations. Our DuoSphere Membrane Digester Cover is the most versatile cover available. The tank mount design provides an innovative and cost-effective solution for new and replacement covers.

Structural Designs

Radial Beam Structure

Beam covers are a very economical choice for anaerobic digester covers, as they have no ceiling plates and 50 percent less field weld length than a truss cover.

Steel Truss Structure

Truss covers use welded steel plates on both the top and bottom of the trusses to form an attic space, that protects the structural members from corrosion and provides insulation for the sludge.

DuoSphere

The DuoSphere membrane digester cover is the most versatile cover available. The tank mount design provides an innovative and cost-effective solution for new and replacement covers.

Additional WesTech Options:

• Geomembrane seal
• Hinged ballast block platform design

Digester Cover Types

Fixed Covers

Innovative cover designs incorporate a water launder or more advanced seal materials that overcome liquid level variation limitations. A conventional annular seal design relies on sidesheets submerged in the sludge to achieve a pressure seal and prevent odors from escaping.

Buoyant Covers

Buoyant floating covers are in contact with the sludge, which reduces the exposed liquid surface area and prevents a large scum blanket.

Gas Holder Covers

Gas holder covers can be constructed using radial beams, trusses, or engineered textiles as in the case of the DuoSphere dual membrane covers.

Slide Guides for Gas Holder and Buoyant Covers

Slide guides allow the cover to travel above the tank wall, thus increasing gas storage at high liquid levels.

WesTech’s Ultra-High Molecular Weight (UHMW) polyethylene slide plates, used on three sides of the structural steel tube, prevent covers from tipping and binding as they move vertically within the tank. They resist wind, seismic, and unbalanced loads in both radial and tangential directions. The durable, low-friction UHMW surfaces remove the need for lubrication, enabling maintenance-free operation.

Advantages of WesTech Slide Guides:

• Great for retrofits and upgrades with old cover in place
• Eliminates tipping and binding
• Corrosion-proof slide plates
• No lubrication required
• Loads re-distributed over several guides
• Adjustable for easy installation and alignment
• Minimal wear and maintenance