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Bio Energy Solutions

Roof and Membranes (Covers)

Bio-Gen Solutions supply and install a variety of cover solutions, it is the next important task in assembling the best tank and cover for your digester. Pressure, vacuum, roof load and the stresses from other equipment such as rotary mixers are important design considerations in your cover choice. As sole Australian distributor with CST it brings all the different cover options, so that we can confidently provide effective cover options for design flexibility to apply the right cover for your process. Review the roof options table below for detailed information.

Bio Energy roof example
Roof and Membrane Options and Specifications
Roof Type Max Design Pressure Max Design Vacuum Max Diameter External Loads Coatings/Materials
ESR - External Supported Roof
  • 45 mbar
  • 18" WC
  • 5 mbar
  • 2" WC
  • 28 (m)
  • 92 (ft)
Accomodate heavy loads (including roof mounted mixers) Glass, Stainless, Steel, Epoxy
KR - Knuckle Roof
  • 20 mbar
  • 8" WC
  • 5 mbar
  • 2" WC
  • 9.5 (m)
  • 31 (ft)
Limited Stainless Steel
DMF - Dual Membrane Foil Covers
  • 10 mbar
  • 4" WC
  • 5 mbar
  • 2" WC
  • 36.6 (m)
  • 120 (ft)
None Various Polymers

Multiple Tank Cover Options

Bio-Gen Solutions include the industry's best cover options for digester applications. The gas zone of a digester is the most corrosive area and requires appropriate design.

Along with this corrosiveness, there are many other factors (environmental, mixer loads, pressure, vacuums, ancillary equipment loads, etc.) that need to be considered in cover selection. CST Storage can design and engineer the right solution from the multiple cover types in its portfolio.

Externally supported roof
  • Externally Supported Roof:

The most common roof design in the industry with a smooth internal roof surface and no rafters. Used when moderate to high pressure or vacuum design limits are anticipated. It is also preferred when there are heavy load conditions expected from mixers and/or other ancillary equipment is installed in the cover.

Knuckle roof
  • Knuckle Roof:

An option for smaller diameter storage tanks, a knuckle roof is best suited for lighter pressure and vacuum applications with no load bearing requirements. Fabricated from stainless steel to provide excellent gas zone longevity.

Dual membrane covers
  • Dual Membrane Covers:

Designed to operate in applications with low to moderate gas pressures where there is not a design requirement for a fixed steel or aluminium cover. Multiple layers and optional centre support structures are utilized depending on design considerations.

Membrane gas holders
  • Membrane Gas Holders:

CST can provide membrane gas holder that are commonly used in conjunction with other storage vessels to store and regulate gas form the process and send it to the generating set or flare device.

Roof and Cover Applications


CST provides the widest range of cover options available that will meet pressure ranges from 2" of vacuum pressure to 24" of positive pressure and handle loads from prop mixers and other equipment.

Biofuel Storage and Processing

CST provides roofs coated with our proprietary epoxy system , Glass-Fused-To-Steel porcelain enamel, stainless steel and other alloys. Whatever your biofuel storage design, we can provide the right roof and cover solution.

Biogas Storage

We have the storage options you need for biogas. From Odour Reduction, Gas tight Aluminium o Externally supported steel roofs and membrane gas holders all dependant on your process design and specifications.

Biomass Storage

We provide multiple roof designs that can be utilized on bolted steel modular storage tanks, welded steel,concrete and other types of storage tank designs.


We provide multiple roof designs that can be utilized on bolted steel, welded steel, concrete and other types of storage tank designs. Lightweight aluminium construction, hinged access and modular designs make CST covers easy to install, easy to use and easy to maintain. Whether the application requires extruded or formed, circular or rectangular, unsupported or supported, domed or flat, odour control or containment, full coverage, we have the right solution to match each application.

Agricultural Odour Reduction

Environmentally friendly storage systems for manure, digestate and other liquid flows, with flexible storage options Bio-Gen Solutions can supply odour reducing domes, with gas capture capabilities, for environmentally conservative requirements.

Bio-Gen Solutions Pty. Ltd. © 2015-2019
Locked Bag 5010
Caloundra  DC QLD  4551