Fosse Septique en France

Compact Sewage Treatment Plants

Diamond sewage treatment plants are specifically designed for domestic properties situated away from wastewater mains drainage.

Diamond Compact Sewage Treatment Plants



French Sewage Treatment Plants for 1 to 55 habitants.


View 2012 WPL Diamond 5 EH Brochure

The WPL Diamond sewage treatment plants are specifically designed for domestic properties situated away from wastewater mains drainage.

The Diamond range of sewage treatment plants is CE marked and type tested in Germany by PIA GmbH in accordance to NF EN12566-3, the new European standard covering wastewater treatment plants, making it fully compliant with European and French Regulations for waste water treatment regulations.

diamond5 eh sewage plant installation

Utilising a unique design, each purposely sized sewage treatment plant offers high quality, discreet wastewater treatment whilst ensuring value for money, low ongoing running costs and complete peace of mind.

Benefits of Diamond Sewage Treatment Plants

  • Outstanding value for money
  • Reliable operation with its simple design
  • No internal moving parts
  • No metalic parts inside the tank to corrode
  • You can walk on the lid unlike many competitor sewage treatment plants
  • Low running cost of the small, quiet air blower
  • Continuous bacterial digestion gives the DMS range up to 3 year de-sludging intervals
    (the larger capacity DMC range generally requires annual de-sludging)
  • No odours as the sewage treatment process does not require primary settlement
  • Excellent performance meeting normal environment agencies consent standards
  • Low visual impact with the sewage treatment plant lid flush with the ground
    (You can walk on the Diamond sewage treatment plant lids unlike many of the competitors)
  • Easy installation as the unique design minimises labour and materials
  • Robust construction reduces the need for concrete backfill where ground conditions permit
  • Compact design does not require large plant for excavation or handling
  • Reduced soakaway and can reject into ditches/streams
  • Over 40,000 sewage treatment plants installed world wide
  • CE approved sewage treatment plant to EN 12566-3
  • Irish Agrément certified

Optional Integral Pump Chamber

Diamond Compact Sewage Treatment Plants


All the existing features of the Diamond sewage treatment plant, but with an integral pump chamber. Specially designed for sites which require a means of delivery for treated effluent where the existing terrain and invert levels of the pipework prevent normal gravitational discharge.

Applications include sites with an incline, a high water table or a distance to the soakaway.

The Diamond Internal Pump Chamber comes complete with a submersible pump which can deliver up to 80 litres per minute of effluent at a head of 3.5m, and has a standard invert of 500mm.

Integral Pump Chamber consists of:

  • 240v, 0.25kw Submersible pump, integral float switch, with stainless steel internals and non-return valve
  • High level floatswitch and mounting tube
  • High level alarm beacon with 1m of lead and plug
  • Floatswitch adaptor socket
  • Extension kit for an increased invert to 800mm (optional extra)

Installation of Diamond Sewage Treatment Plants

A stepped excavation minimises the amount of backfill material required and the amount of excavated material to dispose of. The Diamond sewage treatment plants lightweight design allows for ease of movement around the site, they can be man handled with relative ease. The Diamond sewage treatment plants also do not require a concrete backfill, unlike many other brands.

Diamond Sewage Treatment Plant 5 eh Flow Rates

Population Range (persons) 1-6
BOD/day maximum charge polluantt Kg/day 0.36
Maximum Daily Flow (litres)* 1200
Max blower power consumption 0.12


Sewage Treatment Plant Process Description

Diamond Compact Sewage Treatment Plants

  • The central aeration chamber is a circular tank with a sloped open base, which empties into the bottom of the outer clarifier chamber .
  • Located in the centre of the aeration chamber is a 200mm diameter draft tube, which extends to 100mm from the bottom of the clarifier. Air is released at the bottom of the draft tube through a disc plate diffuser.
  • As the diffused air rises in the draft tube it causes an upward flow of process fluid. This draws the settled solids from the bottom of the clarifier up through the draft tube where they are discharged at the surface of the aeration chamber.
  • The design of the draft tube ensures continuous and complete mixing of oxygen with the sewage. This oxygenation allows the various aerobic organisms that biologically degrade the wastewater contaminants to grow.
  • Gravity causes the aerated solids to settle at the bottom of the tank where they are again drawn back up through the draft tube.
  • As raw sewage enters the aeration chamber, it displaces biological solids from the aeration compartment to the clarifier. Less turbulent conditions in the clarifier allow the digested solids to settle to the base where they are returned back to the aeration compartment.
  • The clarified (treated) effluent flows slowly up through the clarifier and over a weir, which extends around the periphery of the tank.
  • The effluent collects in an outer trough where it is discharged through a 110mm pipe connection. The scum baffle located inside the overflow weir prevents floating solids from passing over the weir.

Sewage Treatment Plant Process Performance

The Diamond sewage treatment plant is designed to “clean” the wastewater to a standard of 20mg/l Biological Oxygen Demand (BOD) and 30mg/l Suspended Solids (SS) 20mg Ammoniacal Nitrogen (AMM-N) on a 95 percentile basis. Additional filtration equipment is available to extend the treatment process to meet standards as high as 10mg/l BOD and 15 mg/l SS.

If more stringent environmental requirements are specified, please contact us for details.

We will also supply a data sheet to assist you with soakaway construction.

Technical Data and Dimensions



Height to 

*Inlet invert 

Height to outlet

In ground depth

Weight empty

Total capacity







120 Kg

2271 ltr

Blower Installation


Each blower is supplied complete with an alarm and an enclosure to protect it from outdoor conditions. It should be connected to a single-phase supply (240v) via a suitable weatherproof socket or fused spur (not supplied) by a competent electrician. Included is 10m of airline to connect between the blower and the sewage treatment plant, however, blower installations of up to 30m from the sewage treatment plant can be accommodated. Please contact us for advice on.

Sewage Treatment Plant Service & Maintenance

Each sewage treatment plant is supplied complete with a service and maintenance manual. The sewage treatment plant requires less than two hours annual maintenance. Service and maintenance agreements are available from us for WPL sewage treatment plants in France. Continuous bacterial digestion gives the DMS range od sewage treatment plants up to 3 year de-sludging intervals (the DMC range generally requires annual de-sludging).

WPL Sewage Treatment Plant Availability

WPL manufactures the full range, and units are delivered ex-stock to France if we do not already have your required unit available from our stock of WPL sewage treatment plants in France.

WPL Sewage Treatment Plant Guarantee

The Diamond DMS sewage treatment plants come with a comprehensive Two year parts and workmanship warranty on the blower and sewage treatment tank. The Diamond DMC sewage treatment plants come with a comprehensive two year parts and workmanship warranty on the blower and sewage treatment tank. The unit’s sturdy Glass Reinforced Plastic (GRP) construction and WPL’s quality assurance procedures permit a minimum life expectancy of 25 years.