Multi-Disk Screw Press


Multi-Disk Screw Presses are intended for mechanical dewatering of industrial and municipal wastewater sludge.

Multi-Disk Screw Presses (hereinafter referred to as “dehydrators”) are manufactured jointly with Tsurumi-Pump Company (Japan).

This Multi-Disk Screw Press MDQ EKOTON TSURUMI received a GRAND PRIX merit award at XXI International exhibition of machines and devices for plumbing and sewage WOD-KAN 2013 (Poland)

These dehydrators are intended for mechanical dewatering of industrial and municipal wastewater sludge. They are recommended for wastewater sludge dewatering on low-capacity municipal wastewater facilities, as well as for food, pulp-and-paper, textile, chemical, oil-refining and similar industries.

These dehydrators ar efficiently used for production rates of up to 200 kg/hr (dry solid mass).

At the operating efficiency, these dehydrators are a good alternative to traditional dewatering equipment. It provides dewatered sludge with a moisture content of less than 82% in conditions of classic wastewater treatment plants.

Description of the EKOTON Multi-Disk Screw Presses MDQ/MDC

These dehydrators are manufactured from stainless steel AISI 304 and have different dimension types. The dehydrators operate as part of larger mechanical dewatering systems. The standard system can include: the dehydrator, an external pump for initial sludge supply, a station of flocculent solution preparation, the flocculent solution dosing pump and the transporter of dewatered sludge.

Structurally, the dehydrator consists of the dewatering drum(s) with an electric drive, the flushing unit, the process tank, the dosing tank and the flocculent tank equipped with an electrically driven mixer. The dosing pump and the mixing pump for the initial sludge supply are installed in the process tank located in the bottom of the unit. The flocculation and dosing tanks, which are located above the process tank, are connected through the V-shaped calibrated overflow.

The level of the initial sludge in the dosing tank is regulated by an overflow union that is connected with the process tank. The main operating sub system of the dehydrator is the dewatering drum, which features both a set of movable and fixed rings assembled on the supporting frame. A screw with a varying pitch is located inside the drum. In the drum mouth (thickening zone), the clearances between screw flights are larger than in the next zone (wringing zone). The screw pitch gradually decreases to the wringing zone. This screw is driven by a geared motor at a low speed. The tray for filtrate receiving and draining is located under the dewatering drum.

Optionally, the dehydrators with 200 mm screws can be fitted with a rake type fine screen which is installed straight into the initial sludge inlet line in the technological chamber.

This screen allows sludge filtration, which removes large and fibrous inclusions of the sludge before entering the inner pumps and dewatering drums of dehydrator. Respectively, the initial sludge can be fed directly into the dehydrator from the clarifiers and bioreactors, without the need for an additional external sludge storage chamber.

Operating principle of EKOTON Multi-Disk Screw Presses

The dehydrator operates in continuous mode. The initial sludge is intermittently injected from the external storage tank into the dehydrator process tank. The mixing tank that is located in the process tank prevents stratification of the sludge.

The sludge is then supplied by the pump to the dosing tank, and then through the calibrate overflow to the flocculent tank. Sludge excess from the dosing tank returns into the process tank through the control overflow union.

Ekoton Multi-Disk Screw Press

The polyelectrolyte solution is supplied into the flocculent tank. The solution is mixed with initial sludge by means of a mixer to form floccules. Then the initial sludge enters into the dewatering drum(s) and moves within the screw to the zone of filter cake discharging, as a result of the screw rotation. As it moves along the drum, the sludge is dewatered and filtrate is drained through clearances between the rings.

Ekoton Multi-Disk Screw Press

Under screw rotation, the movable rings moves parallel to the fixed rings to provide self-cleaning of the filter pores. In addition, the external drum surface is flushed by water from nozzles of the flushing unit.

The drum exit is partially overlapped by the movable divider. By Changing distance between the drum exit and the divider, the counter pressure on the sludge moving inside the drum can be regulated, which influences the degree of sludge dewatering. The dewatered sludge is fed into the receiving hopper of the transporter by gravity feed. The dewatered sludge produced by this dehydrator can reach as low as 75-82% residual moisture at an average flocculent dose of 1.5-3.5 kg/t of dry sludge matter.

Ekoton Multi-Disk Screw Press Dewatering Drum

Advantages of EKOTON Multi-Disk Screw Presses MDQ/MDC

  • Energy saving + compact design. MDQ/MDC series energy saving is achieved by construction features. Machine designed to dehydrate sludge by gravity filtration and screw volume reduction. The equipment construction is compact and includes all necessary accessories controlled by control cabinet mounted on the same base. Therefore, it can be installed in very limited space.
  • Self-cleaning mechanism. The filtration surface consists of two types of discs, which assembled together make a self-cleaning mechanism. Therefore it seldom clogs and equipment can run continuously.
  • Capable to treat Oil-contained sludge. Equipment can dehydrate sludge with high oil concentration. It is optimal solution for treating oily DAF sludge at food processing factories, where filter systems and centrifugal separation is hardly possible. Thus, the equipment boasts with higher solid capture rate.
  • Minimal secondary pollution and maintenance. The dehydrator main unit – dewatering drum, is of semi-enclosed construction and runs at an extremely low speed. Therefore, sludge does not splatter from the equipment. The dehydrator is of eco-friendly design that generates low noise and vibrations, and emits no odors.
  • Capable to treat low concentration sludge. The dehydrator includes both gravity thickening and dehydration compression zones. Therefore, can cope with sludge concentration range from 0,3-0,5 to 10% of DS content.
  • Continuous automatic operation. Due to equipment is constructed to avoid clogging, washing is not needed in order to restore original filtration performance. Only showering with minor amount of water is necessary in order to wash away sludge that leaks from the dehydration zone. Thus, the amount of wash water is minimal.
  • Unattended continuous automatic operation. Operators can turn on automatic operation mode of dehydrator and related equipment by simply flushing the button on included control cabinet. In this case dehydrator is put in automatic operation according to programmed operation algorithms.
  • Wide product range. Screw dehydrators are available in wide range, with treating capacity in range from 6 to 500 lb DS/h, with maximum 5 dewatering drums. Customers can selectfrom 13 models of equip-ment according to the size of targeted wastewater treatment plant.
  • Multi-shaft construction. When two or more dewatering drums are present in one machine, any individual drum can be serviced while others are in operation without interruption. There are two types of screw dehydrators that can be used depending on the type of initial sludge and installation conditions:
    • Model MDQ-XXX which is equipped with technological chamber for initial sludge;
    • Model MDQ-XXX C which is not equipped with technological chamber for initial sludge.

Automation of Ekoton Muti-Disk Dehydrators MDQ

These dehydrators are equipped with electric drives, level sensors in the technological and flocculent tanks, and speed control systems for the screws and mixers. This allows automation of the dewatering systems on the basis of dehydration to be carried out.

All electric sensors and drives have a high level of protection against moisture and ambient air corrosive action.

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


Technical characteristics of EKOTON Multi-Disk Screw Presses MDQ/MDC

Treatment Capacity, [kgDS/h]6...288 (640)
Hydraulic Productivity, not more than [m3/h]1...40
Screw diameter, [mm]100, 200, 350
Amount of screws, [pcs.]1...5
Nominal wash water consumption, [l/min]16...99
Nominal pressure of wash water, [Mpa]0,15...0,4
Installed power, [kW]0,64...4,1
Dimensions, L [mm]1815...4180
Dimensions, W [mm]900...2100
Dimensions, H [mm]2010...2020
Weight dry, [kg]400...4100
Weight in operation, kg1000...7200
According to the dewatered sludge quality and installation conditions, there are two main constructions of screw dehydrators:

Model MDQ-XXX in which the dewatering drums are installed above the technological chamber with internal feed- and mixing pumps
Model MDQ-XXX C without a technological chamber and internal pumps