AD & Biogas

Operating across Europe, A-­Consult has 25 years of experience installing over 8,000 precast concrete tanks of which more than 1500 have been used for primary / secondary digesters, digestate storage and mixer / reception tanks. Manufactured under factory controlled conditions, A-­Consult offer a product constructed from high strength concrete panels and being precast, installation is speedy and generally unhampered by inclement weather conditions, a real consideration for meeting tight programme dates.

Our digester tank range features diameters up to 50m, with tank heights up to 12m increasing wall heights of 100mm increments. Cast in items such as sockets, flanges and man ways can be facilitated in a factory using during panel construction, this can greatly assist with the post fixing of pipework, mixers, feeders and gas tight roofs, resulting in programme and cost reduction for on-­site working. Gas tight precast concrete roofs can be offered as an alternative to standard double membrane gas tight domes, non gas tight roofs are also available for digestate storage. Digestate storage tank diameters up to 50m and can be easily converted into digester tanks at a later date should you wish to increase the capacity of your plant.

Roof Types

With the diversity on offer by a wide range of Biogas service providers it has been critical for A-Consult to develop its precast concrete tank system to allow the different types of roof installation required by the various process techniques.


Foil Fabric Double Membrane

– Gas Tight

Manufactured from biaxel reinforced fabrics with a high grade chemically resistant PVC coating. Operational pressures varying from 0 to 5mbar, offering maximum levels of gas storage with domes available to accommodate tank structures up to 40m diameter. Available in Quarter Dome option, offering all the benefits of a standard double membrane roof but with a lower dome height to assist with potential planning restrictions.


Insulated Precast Concrete

– Gas Tight

Available as pre-insulated unit PE-Lined for concrete protection in the gasification zone. Robust construction allows pre-formed openings to support mixers, access hatch and pressure release plates. Service openings and man way access are a few options made available on this extremely flexible roof solution. Typically cheesecake or half moon segments.


Precast Concrete Roof and Foil Fabric Single Membrane

– Non Gas Tight

Reduces emissions of both gas and odour.
Available in Grey or Green.
Openings available to allow over the top mixing.
Robust construction using UV resistant reinforced foil.

Ancillaries & Features

PE-Liner and apertures through tank walls

  • Easily cast into the precast wall units to provide life-long protection to the concrete surfaces in the gasification zones.
  • Underside of concrete roofs and full internal surfaces of gas tight structures can be protected from concrete corrosion in the gasification zones.
  • PE-Liner is cast into each individual wall panel and after tank installation all joints are extrude welded to achieve both a water tight and gas tight seal.
  • Openings can be formed through the tank walls to allow fitting of mixers, pipework, pressure release valves & sight glasses.

Service Box

  • In case of maintenance, the mixers can be removed from fermenters in one piece without opening of the membrane roof, without lowering the liquid level inside the tank, and without needing to de-commission the digester
  • Avoids gas losses, providing a perfect combination, protecting the environment along with ensuring safe operation and increasing efficiency
  • Quick access and easy maintenance while complying with health & safety standards
  • Larger maintenance openings allow for the installation and removal of mixers blades of diameters up to 1.50m
  • Robust Over/Underpressure Valves- Underpressure 1 to 3 mbar (100 – 300 Pa)
  • Overpressure 1 to 8 mbar (100 – 800 Pa)
  • Frost-proof pressure valve in the Service-Box
  • Easy maintenance / cleaning by a large opening with window
  • Further reduction of methane emissions