1. Overview of the water content of sludge press of plate and frame Filter Press:

In response to the national call for sludge reduction, many industrial and municipal sewage treatment stations have replaced belt sludge presses, Centrifuges, and stacking screw machines, and replaced them with high-pressure diaphragm plate-and-frame filter presses, plate-and-frame filter presses, and ultra-high-pressure plate-and-frame filter presses. Many customers have reported that after replacing the Plate and frame filter press, the moisture content of the pressed mud is very high, and even the mud is not formed, and the sandwich mud appears. Or use many different agents can not reduce the moisture content. In view of the above problems, this issue will be elaborated in detail. The reasons for the high moisture content of the mud pressed out by the plate and frame filter press:

(1) Without adding sludge conditioner, the material is directly fed

(2) There are many hydrophilic groups on the surface of the sludge, which cannot effectively release excess water.

(3) The sludge and sludge conditioner are not fully mixed, and the stirring is uneven.

(4) The solid content of sludge before filtration is low

2. Analysis of the reasons for the high moisture content of the sludge pressed out by the plate and frame filter press:

Reason 1: Sludge conditioner is not added for conditioning, and the material is fed directly

The sludge is not conditioned by adding sludge conditioner, and the sludge itself will form a large floc, especially biochemical sludge. After the large floc of biochemical sludge enters the plate and frame filter press, it will soon block the holes in the filter cloth, resulting in the water being unable to pass through the holes of the filter cloth. In this case, the water content of the mud pressed out will definitely be very high. If the physical sludge is not added, this situation will also occur without adding sludge conditioner, and the filter cloth is not only slow to press the sludge efficiency, but also the filter cloth is easy to block, requiring manpower and time to clean the filter cloth.

Reason 2: There are many hydrophilic groups on the surface of the sludge, which cannot effectively release excess water.

There will be some hydrophilic groups on the surface of the sludge itself, and if these hydrophilic groups do not destroy it, the surface of the mud will carry water into the plate and frame filter press, and it is difficult to release the water when the plate and frame filter press is pressed. The presence of absorbent groups will affect the efficiency of sludge pressing and the moisture content of the sludge pressed. Before sludge pressing, it is necessary to add a suitable type of sludge conditioner to the sludge, which can effectively remove the EPS on the sludge surface and change the sludge surface structure, thereby improving the sludge desilting efficiency and reducing the water content of the sludge.

Reason 3: The sludge and sludge conditioner are not fully mixed and stirred unevenly.

The sludge conditioner is added to the sludge and the stirring time is not enough or the dosing method is not right, resulting in the sludge conditioner and the sludge are not completely in contact with the mixing, the sludge surface structure, water filtration, and the rigidity of the particles are improved accordingly, and the sludge that is not reacted well will appear that the sludge itself is flocculent and the filter cloth hole is blocked. Therefore, before sludge dewatering, the sludge conditioner should be fully mixed with the sludge for reaction.

Reason 4: Low sludge solids content before filtration pressing

Since the filtration speed of the plate-and-frame filter press is constant, that is to say, the rate of filtering water per hour of the plate-and-frame filter press is constant. If the solid content is low, it means that there is more water, and if there is more water, the feeding speed will slow down and affect the sludge pressing efficiency. Because the plate and frame filter press extrudes the water from the mud in the plate and frame by applying pressure to the plate and frame, the more mud, the lower the moisture content of the extruded water.

3. How to solve the high moisture content of sludge pressed out by plate and frame filter press?

(1) Choose the right sludge conditioner

(2) Let the technician go to the site for debugging to determine the best addition amount and method

The moisture content of the sludge pressed out by the plate and frame filter press is lower than that of the centrifuge, the stacking screw machine and the belt filter press, but why is the moisture content high and cannot be reduced? The selection of suitable sludge conditioner feeding efficiency is greatly improved, the sludge moisture content is greatly reduced, and the sludge specific resistance is greatly reduced, which solves the situation that the sludge is not formed or sandwich mud appears.