The difference between sludge dewatering and sludge thickening

Date: Sep. 25, 2021

Sludge thickening is to increase the sludge concentration of about 1% to 3-4%. Sludge dewatering is to remove most of the water in about 3% of the sludge to greatly increase the dryness. There is a big difference in effect between the two. Today, the LZZG Technical Department will teach you how to distinguish between sludge dewatering and sludge thickening.

sludge thickening

Sludge thickening

The sludge thickening process usually includes three types: gravity concentration, mechanical concentration, and air flotation concentration. Among them, gravity concentration that uses natural gravity to separate sludge liquid is widely used. Sludge thickening is a process in which gravity or air flotation is used to reduce the water content of the sludge and thicken the sludge. It is an effective method to reduce the moisture content of sludge and reduce the volume of sludge. The sludge thickening mainly reduces the interstitial water of the sludge. The thickened sludge is similar to a paste and still maintains fluidity. It is the most economical and effective way to reduce the volume of sludge, but thickening is usually difficult to reduce the water content of sludge to below 90%.

sludge thickening

Commonly used sludge thickening equipment

LZZG high-efficiency deep cone thickener is based on traditional vertical flow sedimentation equipment. The structure of the inner barrel is improved, and the settlement efficiency is greatly improved. The plane of the tank is circular and suspended. It sinks into the conical sludge pond at the bottom of the pond under the action of gravity, and the clarified water is discharged from the overflow weir around the upper end of the pond. The overflow port is equipped with a scum filter device and baffle to ensure the quality of the effluent. The underflow concentration is as high as 70%, and the processing capacity is 3-8 times that of a conventional concentrator.

sludge dewatering

Sludge dewatering

Sludge dewatering is a sludge treatment method that removes water from fluid native, concentrated, or digested sludge and converts it into semi-solid or solid sludge. After dehydration, the moisture content of the sludge can be reduced to 55%-80%. Mechanical dewatering is a common method for sludge dewatering. Generally, the sludge is pretreated first to improve the dewatering performance and then dewatered. The wet sludge is filtered with a filter layer so that the filtrate permeates the filter layer, and the filter cake is trapped on the filter layer.


Commonly used sludge dewatering machinery and equipment

1. The LZZG chamber filter press is squeezed by the plate frame so that the water in the sludge is discharged through the filter cloth to achieve the purpose of dehydration. The plate and frame filter press is a commonly used equipment in the chemical industry, which has a large filtering driving force and a low moisture content of the mud cake.

2. LZZG belt filter press is a new type of filter. The sludge layer is entrained by the two tensioned filter belts up and down, passing through a series of regularly arranged rollers in an S-shape. The tension of the filter belt itself forms the squeezing and shearing force on the sludge layer, and the sludge The capillary water in the layer is squeezed out to obtain a mud cake with higher solid content, thereby achieving sludge dewatering. The belt filter press dehydrator is less affected by sludge load fluctuations and has the characteristics of low sludge water content, stable work, low consumption, relatively simple management and control, and low requirements for the quality of operating personnel.

sludge dewatering

When selecting equipment, the following aspects should be considered

1. Requirements for the solid content of the mud cake: Compared with other types of dehydrators, the general plate, and frame filter press have a higher solid content of the mud cake, up to 35%. If you consider the reduction of the land occupation of sludge stacking, Plate and frame filter press should be the solution.

2. The material of the frame: the material of the filter plate and the filter cloth shall be corrosion resistant, and the filter cloth shall have a certain tensile strength.

3. How to move the filter plate. The requirements can be completed automatically or semi-automatically through a hydraulic-pneumatic device to reduce the labor intensity of the operators.
Customers who want to know about sludge dewatering equipment can pay attention to the LZZG chamber filter press and belt filter press, and customers who want to know about sludge thickening equipment can pay attention to LZZG high-efficiency deep cone thickener (three hydrogen purifier).

If you want to know more about the functions and quotations of the equipment you need, you can contact online customers or leave a message to us, and the technicians will contact you.

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