Gasholder Truss Digestor Cover

Similar to the radial beam gasholder digester cover; it is also effective when sludge levels vary significantly and allows for varying gas storage.  The ballast blocks are located at the bottom of the framework and are designed to set the operating pressure.  The attic space acts as the insulation so additional insulation is not necessary.

This truss design is the most expensive design and the attic space collects condensation which will need to be removed periodically.

PROS:

• No insulation is required and is achieved through the attic space
• Allows variance in sludge volume
• Trusses are not subject to interior corrosive environment
• Provides useable and storable gas

CONS:

• The most expensive type of covers
• Will not depress scum when gas is stored (majority of operation)
• Condensation must be removed periodically from the attic space