Skip to main content
45 Person Marsh Ensign:Ultra Sewage Treatment Plant.
  • 45 Person Marsh Ensign:Ultra Sewage Treatment Plant.
  • Cross section of 45 Person Marsh Ensign:Ultra Sewage Treatment Plant.
  • Whisspurr for Ensign:Ultra Range.

45 Person Marsh Ensign:Ultra Sewage Treatment Plant



Contact your local JDP Branch for availability.

Live chat or contact us to enquire or order.

Product Details

This item is supplied to order and additional refund & returns terms apply.


Inhabitants: Up to 45 people
Length: 5200mm
Width: 1912mm (+/- 50mm)
Height: 2284mm (+/- 50mm)
Depth to inlet invert level: 770mm (+/- 50mm)
Fall between inlet & outlet: 80mm
Pipe & Fittings: 160mm

Effluent Quality

BOD5: 11.5 mg/l
NH4: 8.4 mg/l
SS: 19.2 mg/l

This Ensign:Ultra sewage treatment plant is designed to treat household wastewater for properties with up to 45 inhabitants, the Marsh Ensign:Ultra is widely regarded as one of the most efficient, reliable and economical sewage treatment plants on the market.

Class leading performance

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.

Unrivalled choice

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.

  • Optional risers to increase invert depth are available on request.
  • Optional pumped outlets are also available on request.

Why choose the Marsh Ensign:Ultra?

End users, merchants and installers alike recommend the Ensign range due to its ease of installation, reliability, and cost-effective operation and maintenance. All backed by technical support from local contacts.

  • Inlets and outlets with ‘Forsheda seal’ 
    Forsheda seals provide flexibility in the joint for easier installation.
  • Advanced compressor with alarm
    Near silent compressor ensures minimal running, maintenance and servicing costs. Integral alarm detects low pressure in air line.
  • Compressor housing - Internal or external options available
    The compressor can be housed internally or externally with no difference in cost. External compressor is recommended to increase compressor life – this is supplied as standard on 4PE, shallow and pumped outlet models.
  • RCD/Electrical connection
    The RCD box provides easier installation and provides a higher degree of safety.
  • Whisspurr acoustic vibration reduction unit
    Fitted inline between the compressor and air diffuser, the Whisspurr significantly reduces noise and vibration generated from the pulsation of the diaphragm compressor whilst enabling a consistent, unrestricted flow to the air diffuser.
  • 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'.
  • Stainless steel mesh
    Retains media in aeration chamber during transportation and handling, and in the event of flooding.
  • 32mm 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
    The Polylok tertiary filter reduces suspended solids and BOD by a further 40% helping to extend drainage field life.
  • Impermeable lid
    Heavy duty lid/frame improves strength and durability whilst blending into the surrounding environment.
  • Integral lifting eyes
    For safe and secure on-site handling.
  • Stabilising feet
    Stabilising 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.

Operating Principle

The tank utilises a three-chamber design to produce its high-quality effluent. The first chamber is where primary settlement takes place and where anaerobic digestion produces clarified water. This water then filters into a second aeration chamber where, supported by diffused air and bio-media, bacteria treats the effluent to remove the dissolved constituents. The third chamber is where final settlement takes place before the effluent is discharged into a drainage field or local watercourse. The unique Polylok tertiary filter positioned within the outlet reduces suspended solids and BOD by a further 40% helping to extend drainage field life.

General guidance

Package Sewage Treatment Plant's (or PSTP's) are often a suitable option where groundwater in the surrounding environment is vulnerable, drainage field percolation values are restrictive, or direct discharge to a water course or surface water sewer is the preferred discharge method.

  • PSTP's should be sized using the latest version of British Water Flows & Loads which provides detailed information on sewage production figures and sizing calculations.
  • Regulatory authorities for the control of pollution in the UK normally require treatment plants conforming to BSEN12566:3 to be demonstrated as capable of producing a minimum effluent discharge quality of 20:30:20 (Biochemical Oxygen Demand; Suspended Solids: Ammoniacal Nitrogen in mg/ltr), although in certain areas more stringent site-specific qualities may be required.
  • No surface water should enter the system as this can reduce the system's capacity and cause solids to be flushed out which may prematurely block drainage field or cause pollution.
  • As with septic tanks sludge should be removed annually or in line with manufacturer’s instructions.


Please Note: Tank configuration and components shown for illustration purposes. Due to production processes, dimensions of finished units are within a tolerance of +/-2.5%.

7-10 working days
25+ Persons
Install Type:
Large Capacity
Product Type:
Sewage Treatment Plant