What is the moisture content of the screw press dewatering

 

screw press dewatering is a common sludge dewatering equipment, and the moisture content of the treated sludge is generally around 80% -85%. The following are some related factors that affect the moisture content of sludge after screw press dewatering:



Sludge properties



Types of sludge: Different types of sludge have different properties such as particle size, organic matter content, and viscosity, which have a significant impact on the dewatering effect of screw press dewatering. For example, the particles of domestic sewage sludge are relatively small, the organic matter content is high, and the dehydration difficulty is relatively high. After screw press dewatering treatment, the moisture content may be between 82% and 85%; Industrial wastewater sludge varies greatly depending on the industry, with some sludge particles containing heavy metals being coarser and having a moisture content of 80% -83% after dewatering.



Sludge concentration: The higher the sludge concentration, the lower the moisture content after dewatering. Generally speaking, when the sludge concentration is between 2% and 5%, the dewatering effect of screw press dewatering is better, and the moisture content can be controlled at 80% -85%; When the sludge concentration is below 2%, there is too much water in the sludge, and screw press dewatering is difficult to effectively remove a large amount of water in a short period of time. After dewatering, the moisture content of the sludge may be higher than 85%.



Equipment operating parameters



Spiral shaft speed: The speed of the spiral shaft has a significant impact on the squeezing and conveying efficiency of sludge. If the speed is too fast, the sludge will stay in the screw press dewatering for too short, resulting in insufficient dewatering and an increase in moisture content, which may reach over 85%; If the speed is too slow, although the sludge can be fully squeezed, the processing capacity decreases and the production efficiency decreases. Generally, an appropriate speed can control the sludge moisture content at 80% -83%.



Back pressure plate pressure: Increasing the back pressure plate pressure appropriately can improve the dewatering effect of sludge and reduce its moisture content. However, excessive pressure may cause sludge to clog the filter screen, affecting the normal operation of the equipment. Generally, controlling the pressure of the back pressure plate within a certain range can achieve a good level of sludge moisture content, such as 80% -82%.



The use of coagulants



Types of coagulants: Different types of coagulants have different flocculation effects on sludge. Cationic polyacrylamide is one of the commonly used coagulants, and its molecular weight and charge density properties can affect the flocculation effect and sludge dewatering performance. Choosing the appropriate type of flocculant can form larger flocs in the sludge, which is beneficial for water removal and reduces the sludge moisture content to 80% -83%.



Dosage of flocculant: If the dosage of flocculant is too low, the flocculation effect of sludge will be poor, and the moisture content after dewatering will be high, possibly around 85%; Excessive dosage can improve the coagulation effect of sludge, but it will increase the viscosity of sludge, which is not conducive to the removal of water and will also increase treatment costs. Generally, the optimal dosage is determined through experiments to achieve a sludge moisture content of 80% -82%.

 

Note: You can write to us or leave a message at any time to get technical support or solutions.

Email: info@tnwcn.com

Feedback: Click here