Marsh Ultra:Polylok L – 6 and 12

Sewage treatment plants

Marsh Ultra:Polylok L Industrial performance with domestic simplicity

Introducing the latest innovation in domestic sewage treatment technology, the Marsh Ultra:Polylok L (UPL).

The UPL draws upon Marsh Industries’ extensive experience in the industrial and commercial sewage treatment sectors bringing its outstanding performance and added-value engineering to the domestic sector.

The Marsh UPL is available in 6PE and 12PE models, is approved to BS EN12566-3 and carries an impressive effluent quality of 20:30:20, within national consent standards.

Why choose the Marsh UPL

End users, merchants and installers alike recommend the UPL 6 or 12 due to its compact shape, ease of installation, reliability, and cost-effective operation and maintenance. All backed by technical support from local contacts.

Marsh Ultra:Polylok L sewage treatment plants

The UPL uses a similar operating principle as the Marsh:Ensign.

In addition to anaerobic digestion taking place in the primary settlement chamber [2] the UPL unit allows the clarified water to pass into a second ‘aeration’ chamber [3] 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 [8]. The final effluent is then discharged to the drainage field or watercourse via a Polylok filter.


  1. Inlet
  2. Primary settlement chamber
  3. Aeration chamber
  4. Compressor with alarm
  5. Compressor housing
  6. Air diffuser
  7. Bio-media
  8. Final settlement chamber
  9. Polylok tertiary filter
  10. Outlet
  11. Heavy duty lid

Marsh UPL process overview

  • Tested and approved to the most stringent European Standards: EN12566-3: 2005+A1:2009
  • Small footprint and shallow dig for easy installation provides enhanced health and safety benefits
  • Heavy duty shell as standard enables installation in all ground conditions. Unique ‘keying-in’ lip assists anchoring into granular or concrete surrounds
  • Near silent, energy efficient compressor (located externally) with integral alarm (approximate annual running costs of £35 p/annum)
  • High specification bio-media (310m3 per m2) and membrane diffuser ensures even circulation and maximum treatment efficiency
  • Unique Polylok tertiary filter reduces suspended solids and BOD by a further 40% helping to extend drainage field life
  • Sludge return pipe improves system circulation
  • Variable inverts for ease of installation at various depths – 250, 500 and 750mm risers available
  • Pumped outlets available

Marsh Ultra:Polylok L drawings

Model (pop) Length
Inlet invert Inlet dia Outlet invert Outlet dia
UPL 6 1700 1700 2050 650 110 725 110
UPL12 2300 2000 2050 650 110 725 110

For precise tank sizes and configurations, please contact Marsh Industries.
All dimensions in mm.
Due to production processes, dimensions of finished units are within a tolerance of +/-2.5%.

Marsh product portfolio and specifications
Marsh product portfolio and specifications

Ultra:Polylok CE Certificate