Reasons and Solutions for High Moisture Content of Filter Cake

In many industries, such as the chemical industry, metallurgy, and environmental protection, the filter press is a widely used solid-liquid separation equipment that helps enterprises’ production and operation. When using a filter press for solid-liquid separation, sometimes the moisture content of the filter cake is too high. This article will discuss the reasons for the high moisture content of filter press filter cake and the treatment methods.

Reasons for High Moisture Content of Filter Cake

Low inlet sludge concentration

Sludge concentration can also be said to be the solid content of sludge. When the solid content in the sludge is less than 1%, if it is directly fed into the filter press for dehydration, the effect will be very unsatisfactory, and the demand for flocculants will increase. For instance, if the concentration of domestic sludge or sticky industrial sludge falls below 1%, it can lead to sludge leakage, inability to press out any sludge, and reduced treatment efficiency.

Improper selection of filter media

The selection of filter media has an important impact on the moisture content of the filter cake. If the fineness of the selected filter media is not appropriate or the pore size is too large, the solid particles cannot be effectively captured by the filter media, thereby increasing the moisture content of the filter cake.

Unsatisfactory flocculation effect

The filter press is highly dependent on sludge flocculation. If an inadequate amount of flocculant is added or the conditioning effect is poor, the capillary water in the sludge cannot be converted into free water and smoothly removed in the gravity zone. If the amount of added medicine is too large, the treatment cost will increase. It is possible that the filter belt will be blocked due to the increased viscosity of the sludge.

Insufficient filtration pressure

The diaphragm filter press separates solid particles from water by applying pressure. If the filtration pressure is insufficient, the water cannot be effectively discharged from the filter cake, resulting in an increase in the water content of the filter cake.

The filter cake layer is too thick

During the filtration process, the filter cake layer gradually thickens. If the filter cake is not cleaned in time, the filter cake layer will be too thick, making it impossible to fully discharge the water, thereby increasing the water content of the filter cake.

Aging or clogging of the filter cloth

The filter cloth plays a very important role in the filter press. If the filter cloth is aged or cracked, it will affect the mud discharge effect of the filter press.

Improper operation

If the operator is unfamiliar or non-standard with the operation of the diaphragm filter press, such as opening the filter press too early or over-compacting the filter cake, the water content of the filter cake will increase.

Solution to Excessive Moisture Content of Filter Cake

Build a sludge thickening tank to prevent leakage caused by low sludge concentration.
Optimize filter material selection: Select appropriate filter material according to actual conditions to ensure that its pore size can effectively capture solid particles and prevent fine particles from passing through the filter material, thereby reducing the moisture content of the filter cake.
For the sludge to be treated, the actual flocculant can be confirmed by experiment and adjusted continuously during operation.
Increase filtration pressure: Increase filtration pressure reasonably to ensure that the filter press can fully exert its separation function so that water can be discharged from the filter cake quickly and effectively.
Cleaning filter cake in time: Carry out inspections during the operation of the filter press and clean the filter cake in time to avoid excessively thick filter cake layers that hinder the discharge of water.
If the filter cloth is aged or damaged, it is necessary to replace it with a new one in time.
Standardize the operating procedures: The operator should be familiar with the operating procedures of the diaphragm filter press and operate according to the correct operating procedures. Avoid opening the filter press too early and ensure that the degree of compaction of the filter cake is moderate to ensure control of the moisture content of the filter cake.

Reasons and Solutions for High Moisture Content of Filter Cake