Mechanical dewatering equipment
Multi-disc Dehydrators (hereinafter referred to as “dehydrators”) are manufactured jointly with Tsurumi-Pump Company (Japan).
This Multi-disk Dehydrator 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.
These dehydrators are intended for use in wastewater sludge with a рН of 6.0 - 9.0.
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.
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.
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.
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.
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.
According to the dewatered sludge quality and installation conditions, there are two main constructions of screw dehydrators:
|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, kg||1000...7200|