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Settling tanks are devices used in pre-treatment of wastewater and suspended solids of density higher than 1 kg/dm3.

OS settling tanks with horizontal flow are characterized by simple construction and effective disposal of suspended solids for the following flows:

  • up to 130 dm³/s – the construction is based on EU chambers of up to ID 3000 mm (types according to Polish Technical Approval IOŚ: AT/2009-08-0231/A1 – catalogue pages)
  • over 130 dm³/s – the construction is based on DZB chambers of ID over 3000 mm (custom designed).


Horizontal flow settling tank cross-section


Settling tanks have a watertight concrete chamber of the diameter of EU chambers  or are made of DZB modular reinforced concrete retention tanks or can be installed as a separate chamber in a DZB chamber with pre-treatment system.  Depending on the location of the device there are different cast iron or cast iron concrete manholes used in A15, B125 and C250 classes. When used in overrun areas (road, car park, maneuver area etc.) heavy manholes class D400 are used.


When the sewer system is located deep in the ground, a reduction-slab and a chimney made of ID 1000 rings can be used.

The inlet and outlet are located in the axis of a settling tank. In certain types of settling tanks it is possible to deviate inlet and outlet axes (see the catalogue for details).

In order to inform about the amount of sediment collected in a tank, alerting installations are used such as sediment level sensor (Fig. 1) which informs about the need to clean the settling tank. This solution significantly reduces operating costs.

sediment_level_sensorFig. 1. Sediment level sensor


OS settling tanks slow down water flow and collect sediment. Suspended solids and other impurities are kept inside due to the phenomenon of sedimentation. Here wastewater is separated from solid particles the density of which is higher than the density of water.

The intake of a settling tank has a deflector that increases the effectiveness of the device.


The advantages of OS settling tanks:

  • technical approval of Institute of Environmental Protection – National Research Institute
  • easy operation,
  • lack of replaceable parts,
  • possibility to be installed into a hrd shoulder,
  • possibility to adapt the setting depth,
  • adapted to Customer’s needs.


certyfikat EPD


The Environmental Product Declaration (EPD) Type III underscores the supreme ecological standards of our products. As the pioneering company in the water and sanitation industry, Ecol-Unicon ensures products of unmatched quality and commitment to environmental responsibility, thus fulfilling the requirements of EN 15804 and ISO 14025 standards.


Settling tanks operating as part of a pre-treatment system can be linked up to Bumerang, an intelligent rainwater management system.

Technical solutions for settling tanks designed by Ecol-Unicon are characterised by high pre-treatment efficiency, low operating costs and easy access while cleaning.








Depending on the watershed type and the required degree of pre-treatment, Ecol-Unicon offers the following settling tanks:

  • OS horizontal-flow settling tanks;
  • EOW high-performance vortex settling tanks.



Settling tanks are used for pre-treatment of rainwater coming from:

  • roads,
  • car parks,
  • industrial areas,
  • petrol stations,
  • storage and handling areas,
  • indoor garages,
  • carwashes,
  • watersheds,
  • harbours etc.