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How to choose sludge dewatering equipment?


Johnson Screen For Spiral Sludge Dewatering Machine

Belt Filter Press

The belt dehydrator is composed of two tensioned filter belts with sludge layer, passing through a series of regularly arranged roller cylinders in S shape, depending on the tension of the filter belt itself to form the squeezing and shearing force on the sludge layer, the capillary water in the sludge layer is squeezed out to obtain the sludge cake with high solid content, so as to realize the sludge dehydration.

Advantages of belt filter press dehydrator:

The belt dehydrator is less affected by the fluctuation of sludge load. It also has the characteristics of low water content of sludge, less stable startup and consumption, relatively simple management and control, and low quality requirements for operators.

Disadvantages of belt filter press dehydrator:

It is easy to be blocked. In order to prevent blocking, only a large amount of water can be used for flushing, which not only causes waste of water source, but also increases the burden of internal circulation of sewage treatment.

Once it is blocked, it must be shut down for maintenance, resulting in the continuous operation of the dehydrator, affecting the normal production and operation of the enterprise or society.

The operation cost is very high. If the water and electricity cost, labor cost and maintenance cost of two years are included, the cost is even higher than the price of equipment.

Centrifugal dehydrator

The centrifugal dehydrator is mainly composed of a transfer and a screw conveyor with a hollow shaft.

After the sludge is fed into the drum by the hollow shaft, it is immediately thrown into the hub cavity under the centrifugal force generated by high-speed rotation.

Due to the large proportion of sludge particles, the centrifugal force generated is also large, which is thrown on the inner wall of the hub to form a solid layer; due to the small water density, the centrifugal force is also small, and only a liquid layer is generated inside the solid layer.

The sludge in the solid layer is slowly pushed by the screw conveyor and transported to the cone end of the transfer. It is discharged continuously through the outlet around the transfer, and the liquid is discharged to the outside of the transfer by overflow of weir IV. after collection, it is discharged to the dehydrator.

Disadvantages of centrifugal dehydrator:

  1. The noise is loud, and the heart beats faster at the scene;
  2. The change of material concentration requires timely adjustment of speed and speed difference;
  3. The site is dirty in the high-speed service environment, and there is muddy fog;
  4. If the operation is improper, the mud outlet will be blocked, and the mud may be re pasted during backwashing.

Advantages of centrifugal dehydrator:

Continuous operation, slurry can not be concentrated.

Plate and frame filter press dehydrator

Through the extrusion of the plate and frame, the water in the sludge is discharged through the filter cloth to achieve the purpose of dehydration.

It is mainly composed of concave filter plate, frame, automatic pneumatic closing system test plate suspension system, filter plate vibration system, air compression device, filter cloth high-pressure washing device and photoelectric protection device on one side of the fuselage.

Advantages of plate and frame filter press dehydrator:

Low price, high solid content of mud cake; disadvantages: intermittent operation, large floor area, high maintenance frequency. So now most sewage treatment plants no longer use this equipment.

Spiral sludge dewatering machine

  1. The main body of the laminated screw of the dehydrator is a filtering device formed by the mutual lamination of the fixed ring and the traveling ring, through which the spiral axis penetrates. The front section is the concentration section and the back section is the dehydration section.
  2. The pitch between the fixed ring and the traveling ring is gradually reduced from the concentration part to the dehydration part.
  3. The rotation of the screw shaft pushes the sludge to be transported from the concentration part to the dehydration part, and at the same time, it also continuously takes a supporting and floating ring to clean the filter joint to prevent clogging.

The dehydration principle is: sludge is transported to the dehydration department after gravity concentration in the concentration department. In the process of advance, with the gradual decrease of filter joint and screw pitch, and the blocking effect of back pressure plate, a great internal pressure is generated, and the volume is constantly reduced, so as to achieve the purpose of full dehydration.

Disadvantages of the Spiral sludge dewatering machine: the price is too expensive and the treatment capacity is small.

Advantages of the Spiral sludge dewatering machine:

  1. It is not easy to block, and the filter screen adopts V-shaped wire structure wedge wire screen.
  2. Water saving and power saving, no need to clean to prevent filter joint blockage, low speed operation, low noise and vibration, safe operation
  3. Small design, compact design, concentration and dehydration integration, small floor area, reduce design and construction costs.
  4. Durable, stainless steel body, few replacement parts, long service life.