At present, there are three main methods for the treatment of papermaking sludge, namely, natural drying method, granulation method and sludge mechanical dewatering method. The three methods have different effects on the treatment of papermaking sludge, and there are differences in the adaptation occasions, natural drying method and mechanical dewatering method can be used for the treatment of papermaking sewage sludge, and granulation method is more suitable for the flocculation and precipitation of papermaking sludge.
1. natural drying method
This treatment method is mainly to put the papermaking sludge in the sludge drying field, and reduce the moisture content by infiltration and evaporation. The sludge drying field is separated by the soil embankment, and requires the drying field to have anti-seepage measures, and a layer of good water permeability base and drainage pipe. The sewage in the paper sludge is seeped down in the drying field for 2-3 days to reduce the moisture content to about 85%, and then through several weeks of evaporation, it is reduced to 75%. This method has high requirements on the natural environment such as rainfall, evaporation, temperature and humidity, and is generally suitable for use in areas with dry, low rainfall and sandy soil. Sludge drying process to treat paper sludge cycle plant, will bring some pollution to the soil, the atmosphere, therefore,Works Chemical is not recommended to use.
2. sludge granulation method
The paper sludge first enters the granulation part of the pelletizer, under the action of its own gravity, flocculates and thickened, rolls into mud pellets by layers, and then the mud pellets and water enter the dehydration, the water is discharged from the circumferent water discharge inclined joint, and finally enters the compaction part, further dewatering, forming large dense mud pellets, and pushing out the cylinder. The water content of clay balls is generally above 70%.
3. paper sludge mechanical dewatering method
After the sludge is concentrated, it is mechanically pressed and dehydrated by plate and frame filter press, belt filter press, diaphragm filter press, sludge drying machine and other dewatering equipment. The final sludge treatment effect of this method is directly related to the choice of sludge dewatering equipment. For example, the belt filter press can usually dehydrate the paper sludge to more than 80% moisture content, the plate and frame filter press will dehydrate the sludge to more than 75% moisture content, the diaphragm filter press will treat the paper sludge to about 70% moisture content, and the high pressure sludge press dryer can treat the paper sludge to less than 50% moisture content.
At present, the mechanical dewatering method is widely used in the paper sludge treatment, and the sludge dewatering equipment mostly uses the type of high automation and high mechanical pressing force, one is to reduce the amount of manual operation, enhance the controllability of the sludge dewatering equipment, reduce the cost of sludge treatment, and the second is to improve the efficiency of paper sludge treatment and stabilize the operation of the sludge dewatering equipment.