Sludge drum thickening filter press

1. Sludge drum thickening filter press

Sludge drum thickening filter press is a kind of equipment used for sludge treatment, which integrates the functions of thickening and filtering.

(I) Scope of application

It is widely used in sludge dehydration in wastewater treatment processes in urban sewage treatment plants, pharmaceuticals, electroplating, papermaking, leather, printing and dyeing, metallurgy, chemical industry, slaughtering, food, wine manufacturing and environmental protection projects, as well as solid-liquid separation in industrial production.

(II) Working principle

Sludge pretreatment stage

Before the sludge enters the integrated drum thickening and belt dehydration equipment, the polymer flocculant is injected into the mixing reaction tank through the flocculant preparation and dosing system. In the mixing reaction tank, the sludge and the polymer flocculant are fully mixed by stirring, and the sludge is quickly condensed from fine particles into large particles, and forms a large cluster of floccules with a network structure, and then enters the slowly rotating pre-dehydration drum.

Concentration stage

During the process of sludge being transported to the end of the drum by a special device, most of the free water is released through the filter cloth to achieve the concentration effect, and the effluent is collected by the filter tank and separated from the solid sludge.

Filter pressing stage

Gravity dehydration zone: After the sludge enters the sludge stirring tank through the pump and mixes with the polymer coagulant, the fine suspended particles in the sludge are formed into larger colloid-like particles through the bridging effect of the polymer coagulant, and then overflow from the upper end of the stirring tank into the automatic distribution device of the dehydrator in a gravity flow manner, so that the colloid-like sludge is evenly distributed on the filter cloth in the gravity dehydration zone. The function of the gravity concentration dehydration zone is to discharge most of the free water outside the colloid-like sludge through the mesh of the filter cloth by gravity, so as to increase the sludge concentration, stabilize the properties of the colloid-like sludge, and use the subsequent squeezing and dehydration operation.

Pressure dehydration zone: After the sludge enters the pressure dehydration zone from the gravity dehydration zone, the upper and lower filter cloths begin to gradually pressurize and squeeze the sludge for dehydration.

Pressurized dehydration zone: The sludge moves with the filter cloth into the pressurized dehydration zone. Between multiple vertical rollers (such as 6), the roller diameter gradually decreases and the pressure gradually increases. As the upper and lower filter cloths change their upper and lower positions between different rollers, the shear force on the sludge is generated, and the capillary combined water in the colloid sludge is squeezed out to produce a drier sludge cake.

2. Advantages of sludge drum thickening filter press

(I) Structural design

The overall structure is compact

The reasonable structural design makes the overall structure neat, compact and beautiful, the guide rollers are staggered, and the floor space is greatly reduced. For example, some models adopt a compact frame design, and the guide rollers are installed in an S shape, which reduces the volume of the whole machine and has a better dehydration effect1. Good appearance protection

The stainless steel shield completely avoids the defects of traditional belt machines such as large size, mud leakage, water leakage and other poor working environment. For example, the drum thickening sludge dewatering machine of Shanfeng brand has a perfect design and stainless steel shield, which overcomes some disadvantages of traditional equipment4.

(II) Performance

Processing capacity and efficiency

High processing capacity and good dewatering effect. For example, the double drum thickening belt filter press adopts a drum screen thickening system, which can adapt to the treatment of low solid content sludge, eliminate the sludge thickening tank, greatly reduce the land occupation and save investment costs. Moreover, the ultra-long extrusion section design has a high solid content of the mud cake.

Different sludges use different filter belts, different flocculants and different auxiliary equipment to achieve the best dewatering effect.

Operation stability

Adopt pneumatic deviation correction (such as some models), local control, fast response, simultaneous deviation correction on both sides of the filter belt, quick reset, low action frequency of the whole system and small deviation correction amplitude. The electronic control system is equipped with a complete interlocking protection device to ensure the safety and reliability of the whole machine operation and effectively prevent the damage to the whole machine caused by wrong action.

Low energy consumption and environmental protection

Low energy consumption. The filter screen washing technology is advanced. For example, the mesh belt washing system adopts a specially designed filter screen mud cleaner. This technology can greatly reduce the amount of washing water. The effluent from the secondary sedimentation tank can be used as washing water, which completely changes the current situation of high cost of using clean water to wash the filter press, and truly achieves the purpose of environmental protection.

Low noise, less use of chemical agents.

Easy to manage and maintain

Easy to manage and maintain. For example, the NP type sludge dewatering machine has the characteristics of automatic control and continuous operation, and the tension of its filter belt is achieved by an inflatable cylinder, so that the entire filter belt maintains a constant tension, which is easy to maintain and manage.

(III) Material and durability

Excellent anti-corrosion performance

Some are made of all stainless steel (such as the Nuokun brand), ensuring a service life of more than 20 years; some parts that come into contact with water are made of stainless steel, and the frame is made of stainless steel or A3 standard steel hot-dip galvanized (zinc layer thickness is not less than 80μm) for anti-corrosion treatment, so that the whole machine has no rust parts, ensuring that it will not rust within five years (such as the Shanfeng brand).

High-quality components are used. The bearings are equipped with long service life, and high-quality filter belts and SUS nozzles (such as some products) are used to fully ensure the performance and quality of the filter press.