Equipment for clarifiers

Radial Suction Scraper

Radial Suction Scrapers are intended for removing the activated sludge from bottom of secondary clarifiers. Radial Suction Scrapers are used in radial secondary clarifiers of wastewater treatment plants.

The Radial Suction Scraper is an integral piece of equipment and technological accessory. The main equipment include the bridge, sludge-receiving collector with sludge-intake devices and the driven trolley.

The sludge-intake devices are fastened to the sludge-receiver collector suspended on the steel braces with adjustable length, and are equipped with rubber skirting.

The bridge provides access to the centre of the sludge sucker. The driven trolley is equipped with a variable speed drive. It is installed on the external end of the girder.

Driven trolley with all wheel drive is offered as an option. Another bridge's end rests on the platform and central shaft. The metal or plastic decking enclosed by handrails is mounted on the girder top.

Auxiliary equipment can be installed in addition to the sludge intake systems.

The auxiliary equipment include:

  • electrically driven cleaner of the clarifier board lane
  • device for mechanical cleaning of clarifier's tray edges
  • device for collection and removal of floating material from the clarifier's water surface

The device for collecting and removing floating material consists of the receiving bin, the case, the pipeline and the above water scraper driving floating material to the clarifier board.

The radial suction scraper can be made movable in the vertical plane of the sludge receiver manifold pipe, on customer demand. On the sludge receiving collector's end, the wheel is installed to accommodate inconsistencies from an uneven clarifier floor.


The sludge intake system operates in a continuous mode. Movement of driven trolley along the perimeter of clarifier actuates the radial pipes with sludge intake components. The radial pipes rotate between 1 and 2 times per hour, depending on diameter of the clarifier.

Activated sludge is removed by hydrostatic pressure through the sludge intake components, and drained by the sludge receiver manifold pipes to the rotating sludge chamber. The flow can be adjusted for each sucker.

Расположение основных элементов илоудалителя в илососе типа ИРВО

  • the hydraulic characteristics of each clarifier can be individually adjusted by the static flow control of each sucker
  • complete sludge removal is ensured from the bottom of the clarifier due to the special sucker construction
  • completely manufactured from corrosion resistant materials such as AISI304 or AISI 316, aluminum alloy and polymers
  • the central bearing is designed as a rotating bearing unit that makes it simple to mount and maintain the equipment
  • because the driving trolley is all wheel driven, it maintains traction in winter time
  • according to customer requirements, the sludge receiver manifold pipe can move vertically in order to compensate for clarifier bottom irregularities

The system operates in a fully automatic mode. Alarm systems of the normal operation indication and emergency stops are provided.

It is possible to transfer equipment status data to a higher level automated process control system depending on the client’s requirements.

The radial suction scraper is supplied with a frequency inverter which allows the operator to adjust the drive speed.

Parameter Value
Internal diameter od clarifier, mm 16 000...54 000
Clarifier depth, mm 2000...6000
Bridge rotaring frequency, rph 1...3,5
Electric drive: gear-motor, type NORD, cylindrical and conical (1 or 2 pieces)
Wheel diameter, mm 2 x 380 (430)
Weight (max), kg 2500...8000
Power of electric drive 0,37...1,1
Frequency of the current, Hz 50
Voltage 380