Ensign Shallow

Select regional version:


The object content is configured for use in UK, but it may also be suitable for use in other locations.


Marsh Shallow Ensign sewage treatment plants are widely regarded as one of the most efficient, reliable and economical systems on the market.

The Ensign:Standard is a robust unit with no internal moving parts meaning simple installation and commissioning and minimal long-term maintenance and cleaning. Common sewage treatment plants on the market often exceed 2.3 m high. Shallow Ensign sewage treatment plants from 4-35PE are only 1.6 m in height, meaning installation is not only possible, but easier and safer too.


Tested and approved to BSEN12566-3/A1:2009 all Ensign units provide treatment well within national consent requirements. Published test results of 11.5:19.2:8.4mg/ltr (BOD:suspended solids:ammonia), with influent concentrations on test higher than those chosen by most competitor plants, effectively equates to 97% pollutant removal. Ranging in size from 4 to 50 PE in Ultra, Standard and Shallow versions of each, and with a wide range of ancillaries, almost all site, consent and budget requirements can be met by units from the range.


Features and benefits:

  • Inlet with ‘Forsheda seal’: Forsheda seal provides flexibility in the joint for easier installation.
  • Optional risers to increase invert depth are available.
  • Primary settlement chamber.
  • Aeration chamber.
  • Advanced compressor with alarm (Ensign:Ultra units only): Near silent compressor ensures minimal running, maintenance and servicing costs. Integral alarm detects low pressure in air line. (Regular Low-energy compressor on Ensign:Standard models).
  • Compressor housing – internal or external options available: The compressor can be housed internally or externally with no difference in cost.
  • External recommended to increase compressor life, and supplied as standard on 4PE, shallow and pumped outlet versions.
  • RCD/Electrical connection (Ensign:Ultra units only): The RCD box provides easier installation and proveds a higher degree of safety. (Regular plug/socket connection on Ensign:Standard models).
  • PVC pressure pipe/diffuser(s): Provides a protective conduit for the air diffuser line. Can be easily removed for maintenance and cleaning.
  • Bio-media: High specification bio-media (310m3 per m2) and membrane diffusers ensure even circulation to eliminate ‘dead spots’. The bio-media is contained by a stainless steel securing mesh to ensure no migration during handling or potential flooding.
  • Stainless steel mesh: Retains media in aeration chamber during transportation and handling, and in the event of flooding.
  • Final settlement chamber.
  • 32 mm sludge return: Larger diameter sludge return prevents the possibility of blockages and improves system circulation. Provides higher effluent quality whilst balancing flow over a 24 hour period or periods of intermittent use.
  • Unique Polylok tertiary filter (Ensign:Ultra units only): The Polylok tertiary filter reduces suspended solids and BOD by a further 40% helping to extend drainage field life.
  • Outlet with ‘Forsheda seal’: Forsheda seal provides flexibility in the joint for easier installation.
  • Optional pumped outlets are available.
  • Impermeable lid: Heavy duty lid/frame improves strength and durability whilst blending into the surrounding environment. (Regular lid on Ensign:Standard models).
  • Integral lifting eyes: For safe and secure on-site handling.
  • Stabilizing feet: Stabilizing feet prevents the tank from rolling and allows safe and steady transportation and installation.
  • Unique ‘keying-in’ lip: Assists anchoring into granular or concrete surrounds.
  • CE marked.


In addition to anaerobic digestion taking place in the primary settlement chamber the Ensign unit allows the clarified water to pass into a second ‘aeration’ chamber where it is treated to remove the dissolved constituents. Here aerobic bacteria, supported by diffused air and mobile media, ensures full treatment is achieved before the treated effluent and ‘sloughed off’ bacteria flows to a final settlement chamber. The final effluent is then discharged to the drainage field or watercourse via a Polylok filter.


Please see the literature section for technical drawings.

Platform Compatible Version Certified to
IFC IFC - 1 -
Revit Revit - 1 -

  • More BIM objects

More BIM objects