Single-float decanters

Baner poziomy z fragmentem logo Biox dekanter jednopływakowy.
  • draining the clarified sewage layer,
  • they replace secondary settling tanks in sewage treatment plants operating in a sequential system.

The DJ single-float decanter allows periodic or continuous discharge of the clarified surface layer of sewage in sludge lagoons or reactor chambers of small and medium-sized sewage treatment plants operating in a sequential or continuous system.

The DJ type decanter consists of a float and a drain port or a submersible pump. The clarified surface layer is collected using the suction collector, which is an integral part of the decanter float. The large surface area of the collector inlet opening ensures low inflow velocities, preventing the activated sludge from lifting and being sucked in during sewage draining. The collector’s suction opening is located at a constant depth, below the sewage surface.

The immersion depth of the intake manifold in the standard version is approximately 200 mm. The lower disk of the suction manifold allows the decanter to be equipped with any drain device, e.g. a submersible pump or a stub with a connected drain hose. The drain capacity is regulated by changing the pump capacity or adjusting the opening of the gate valve at the outlet of the drain hose. The decanter has a hook on the upper surface of the float that is used to attach a cable when dismantling or lowering the decanter to the working position.

Gravity drain – gravity drain can be implemented using the difference in the levels of the inlet and outlet of sewage in the drain hose. In the case of a gravity drain, a gate valve should be used at the outlet port. The gate valve allows you to control the capacity and tightly close the outlet after draining.

Pump drain – if gravity drainage is not possible, the sewage discharge pipe can be connected to an external pump. The pump should be capable of self-priming if it is above the operating sewage level.

Pump drain using a submersible pump – sewage can also be collected using a submersible pump mounted to the connection disc of the suction collector instead of the drain stub.


Actual efficiency should be determined for specific operating conditions and depends primarily on:
– size and settings of the decanter,
– diameter, length and type of drain pipe,
– difference in sewage inlet (intake) and outlet levels,
– local losses in the pipeline (including losses at elbows – for a rigid drain pipe).

We will help you if you need to perform appropriate performance calculations.

For safe operation and trouble-free operation of the decanter, always use a gate valve at the outlet of the drain pipe.


Single-float decanters can be equipped with two stabilization systems:

Articulated stabilizer – to maintain the horizontal position of the device, it should be equipped with a stabilization system. Due to the simplicity of installation, reliability of operation in winter conditions and very high flexibility in selecting the length of elements, it is a very good and universal solution. When using an articulated stabilizer, the device is not limited to working directly at the installation site.

Roller stabilizer – in cases where there are large fluctuations in the sewage level or the size of the tank is limited, roller guides can be used for stabilization. The rollers are mounted using the same holes in the angle brackets of the float connectors as in the case of mounting the joints.


Maximum performance: up to 205 m3/h

Internal diameter of the drain pipe: 60-135 mm

Files to download
technical card - single-float decanter DJ