WPL Settlement Tanks

WPL primary (clarifiers) and final (secondary humus) settlement tanks complement existing process units for wastewater treatment in commercial, municipal sewage treatment and industrial wastewater applications.

WPL primary and secondary settlement tank options:

  • Conical settlement tank
  • Lamella plate settlement tank – including hire
  • Rectangular settlement tank

WPL primary only settlement tank option:

  • Cylindrical settlement tank

WPL Conical settlement tank

WPL Conical settlement tanks are high quality sedimentation tanks used in the primary and final stage of the wastewater treatment process.

Manufactured in glass reinforced plastic (GRP), the settlement units are custom made to meet your treatment needs.

Designed to principles established in BS 4994, WPL Conical settlement tanks are supplied complete with internal launders, diffuser drum (stilling well), scum board and piping.

Why you should choose the WPL Conical settlement tank:


  • Quality material constructed with corrosion-resistant GRP
  • Tanks can also be made to withstand very strong alkalis or acidic PH levels

Increased retention period

  • Option for extending sidewall to increase retention period

Quality design

  • 60 degree inverted cone design is the optimum angle to encourage settlement of solid particles


  • Can be installed either above ground 3m diameter or below ground to 6m diameter
  • Options are available for up-flow/cross-flow systems and scum draw-off systems
  • Connection sizes and positions tailored to customer needs

Image of WPL conical tanks installed at a Scottish Water wasterwater treatment site

Indicative drawing of a WPL Conical settlement tank*


* Tank volumes can be increased by extending the side wall height

WPL Conical tank specification information

Image of a WPL conical tank specification information table

Dŵr Cymru Welsh water infographic: at a glance 

Eight WPL Conical settlement tanks successfully installed over three Dŵr Cymru Welsh Water sites on time and on budget – read more


WPL Lamella Plate settlement tank

Lamella separators are used extensively to assist the settlement process of removing solids from municipal and industrial applications which include pharmaceutical, food processing and pulp and paper.

WPL Lamella Plate settlement and clarification tanks are the ideal solution where there is no existing primary or final settlement on site and where space is at a premium.

Used in conjunction with our biological treatment modules, the units can be designed to provide a high effluent quality.

We can design a bespoke settlement tank for your specific application. Standard size modules can be fitted with ladder / staircase and handrails and desludge pipe work can be adapted to suit specific site requirements.

Why you should choose the WPL Lamella Plate settlement tank:

Compact design

  •  Small footprint.
  • Ease of installation and delivery

High effluent quality

  • Can be designed to meet specific quality requirements for individual sites

Hire and trial/or purchased for permanent or temporary installations

Ideal for municipal and industrial applications


Scottish Water case study at a glance:

A WwTW site at Scottish Water in Kirkcowan required complete refurbishment, WPL supplied equipment including a lamella plate primary clarifier – read more

WPL lamella settlement wastewater treatment optiontemporary solution for Scottish Water in Kirkcowan Lamella plate

WPL Cylindrical (primary) settlement tank

Designed in accordance with the latest European Legislation, WPL Cylindrical settlement tanks are high quality sedimentation tanks used in the primary stage of the wastewater treatment process. Manufactured in GRP, they are light and easy to handle for installation. They are also not susceptible to rust, exhibit excellent corrosion resistant properties.

Why you should choose the WPL Cylindrical (primary) settlement tank:

Flexible installation depths

  • Variable inlet depths giving it complete flexibility for different site conditions and installation requirements

Robust design

  • Heavy and extra heavy duty tanks available

Easy access for emptying

  • Bauer coupling connections available as an option for ease of emptying

WPL Rectangular settlement tank

Designed for below ground applications, the WPL rectangular settlement tanks are used for primary or final settlement generally as part of a modular package, but can be sold separately. Bespoke solutions are available with flows of up to 6 litres per second.

Why you should choose the WPL Rectangular settlement tank:

Quality design

  • Designed with a conical end to encourage efficient settlement
  • Large cross sectional area designed to 0.7m/hr up-flow velocity
  • Incorporates the WPL forward feed airlift which can also be used for primary or humus sludge removal

 Easy access

  • Excellent access for emptying by suction tanker
  • Variable lid designs
  • Bauer connectors for ease of emptying