Radial Suction Scraper


Reliable and technologically advanced solution for removing sludge from secondary clarifiers included in the system of biological wastewater treatment plants

Esmil Radial Suction scrapers are a reliable and technologically advanced solution for removing sludge from secondary clarifiers included in the system of biological wastewater treatment plants. The design allows ensuring stable and efficient operation in accordance with the specified technological parameters of cleaning.

Advantages of Esmil Radial Sludge Scrapers

  • Esmil suction scraper provides the most efficient collection of waste-activated sludge from the bottom of the secondary clarifier. Placing all the suction units on one branch allows to minimize the sludge agitation during the rotation of the suction scraper.
  • Suction units have a special patented design without a bottom plane, which allows to achieve the “clean bottom” effect, i.e. to avoid sludge deposits at the bottom of the clarifier. It is important that the contact of the Esmil suction unit with the bottom is ensured by special elements made from reinforced rubber. Meanwhile, the suction units do not wear out and do not abrade the concrete bottom of the tank. The “Clean bottom” effect allows to avoid such negative phenomenon as the decay of sludge accumulated in hard-to-reach places, as well as the rise and passage through suspended solids.
  • The special design of Esmil suction units allows to compensate irregularities on the bottom of the clarifier up to 70 mm.
  • The use of additional central and peripheral scrapers allows to transport sludge to the outermost suction units and removes sludge from areas where the suction unit cannot capture.
  • The performance of the suction scraper is regulated in a wide range. To ensure uniform sludge collection over the entire radius of the clarifier, each suction unit is equipped with adjustment diaphragms.
  • The rotation speed of the suction scraper is regulated by the built-in automation system, which allows to choose the optimal mode of operation.
  • The suction scraper bridge is the main supporting structure for the suction pipe and other auxiliary equipment. Ergonomic bridge design provides easy access and maintenance of equipment components.
  • The suction scraper for the circular clarifier is delivered complete with a central support consisting of a base, a rotating support, a cylinder and an inlet well.
  • The rotating support is made using a polyamide plain bearing, which ensures the reliable operation of this unit without the need for constant maintenance.
  • The rotation chamber seal provides sufficient sealing in the joint between the rotation chamber and the base.
  • Esmil sludge suction pipe is equipped with a vent pipe, which allows full use of the sludge pipe cross-sectional area for sludge removal and prevents the formation of gas “pockets”.
  • Esmil suction scrapers are equipped with anti-slip devices for traction trolley wheels:
    – brush for track cleaning,
    – scraper for track cleaning,
    – electric wheels with a planetary gear reducer (optional),
    – all-wheel drive traction trolley (optional),
    – pneumatic wheels with rubber tread (optional).
  • Esmil suction scrapers are equipped with a height-adjustable inlet well that is designed to direct the flow so that the capacity of the clarifier tank is used as efficiently as possible.
  • Esmil suction scrapers can optionally be equipped with a scum removal system. In the basic version, a static skimmer collects scum from the center to the periphery, and then the scum box automatically removes collected scum from the clarifier for further disposal. In the advanced version, the collection of scum from the center is carried out by a screw with an adjustable immersion depth.
  • Esmil suction scrapers are equipped with a weir cleaner. The automatic brush can operate in effluent launders with both unilateral and bilateral overflow weirs. The rigidity of the brush is selected to ensure maximum removal of biofilm from the effluent launders during the longest possible service life.
  • Esmil suction scrapers are made from corrosion-resistant materials:
    Above water – AISI 304, AISI 316 or AlMg3.
    Sludge suction system – AISI 304, AISI 316.
    Central support– AISI 304, underwater rotation unit is made of structural steel with corrosion protection and polyamide.
  • The control system of Esmil suction scrapers allows to change operating parameters to ensure the most efficient operating modes, clean the clarifier board and effluent launders, protect all major devices from overloads. It is possible to integrate the high-level automation system (SCADA) and measure the thickness of the sludge layer.
  • Esmil Industrial Group produces various additional equipment for clarifiers, including stainless steel effluent launders for collecting cleaned water, support columns, up-flow baffles (Stamford Baffles), clarifier covers.
  • The collection of sludge is regulated by the automatic slide gate installed in the sludge chamber, which allows to change the humidity of the removed sludge.
  • The Esmil suction scrapers were designed based on calculations of mathematical models of the hydrodynamics of circular clarifiers. These calculations may also be performed taking into account the specific object conditions.

Radial Suction Scraper Esmil

We develop, produce and implement high-tech wastewater treatment equipment and offer high-quality suction scrapers with delivery and installation.

The basis of the reliability of our equipment is a combination of modern technologies used for the calculations and design of equipment, as well as many years of practical experience in the production, installation and maintenance of equipment for wastewater treatment plants.

Esmil suction scrapers successfully operate in various climatic conditions and have established themselves as reliable energy-saving equipment that does not require maintenance.

Technical characteristics of Esmil Radial Suction Scraper

Diameter of clarifiersfrom 6 to 60 m
Clarifier depthup to 10 m
Standard bridge width1000 mm
Standard rotation speed0.5-2 rotations per hour
Number of suction units3 – 12
Wheel materialoptionally rubber/polyurethane
Driveone wheel/both wheels
Reducerplanetary/worm (optional)

Does sludge collect evenly over the entire radius of the clarifier?

Yes, it does. The sludge is removed evenly through the adjustment diaphragms equipped on each suction unit. Thus, the suction units farthest from the center of the clarifier ensure sludge intake in accordance with the vast serviced bottom area. The suction units closest to the center of the clarifier run under a lower vacuum, since they service a significantly smaller bottom area.

How is it possible to ensure minimal passing out of suspended solids?

The minimum passing out of suspended solids is achieved due to: (1) the sludge is completely removed from the bottom, it does not accumulate and does not decay; (2) the only sludge suction pipe has a sufficiently low surface area compared to other systems, which allows for a laminar flow of liquid in the clarifier during the movement of the suction scraper.

What is the maintenance frequency of the standard Esmil radial suction scraper?

The standard maintenance frequencies:
  • Lubrication of the traction trolley bearings: 1 time in 3 months,
  • Oil change for drives: 1 time in 2 years,
  • Sludge pipe maintenance: 2 times a year,
  • Replacement of the track cleaner brush: 1 time in 2 years,
  • Replacement of the weir cleaner brush: 1 time in 3 years,
  • Replacement of suction unit rubber apron: 1 time in 4 years,
  • Replacement of polyurethane wheels: 1 time in 6-8 years.
  • For information only, data may vary depending on specific operating conditions.

Esmil Group

Esmil Group stands as a premier global manufacturer, crafting cutting-edge equipment for wastewater treatment and sludge dewatering. Additionally, we specialize in delivering advanced membrane systems tailored to various industries.

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