Views: 51 Author: Site Editor Publish Time: 2018-11-22 Origin: Site
What is sludge concentration
According to the existing form of water in sludge, it can be divided into four types: interstitial water, capillary bound water, surface adsorbed water and internal water.
Interstitial water between particles: The water in the sludge particle gap is about 70% of the total moisture.
Separating methods: Concentrating
Capillary bound water: concentrated around fine sludge particles due to capillary phenomena, accounting for about 20% of total water.
Separating methods: Mechanical dehydrating
Surface adsorbed water: Water adsorbed on the surface of sludge particles. It accounts for about 7% of sludge water.
Separating methods: Heating removal
Internal water: water exists inside the sludge granules or in microbial cells. About 3% of sludge moisture.
Separating methods: High temperature heating, freezing or biological methods
Strength order of water and sludge particle binding in sewage sludge is as below, which is also the order of difficulty in sludge dewatering.
Internal water > Surface adsorbed water > Capillary bound water > Interstitial water between particles
Purpose of sludge thickening
The purpose of sludge thickening is mainly to reduce interstitial water between sludge particles and reduce sludge volume.
Sludge concentration methods are gravity belt press concentration, screw press concentration, air floatation thickening and centrifugal concentration. The choice of concentration method is based on the nature and source of sludge, the whole sludge treatment process and the final disposal mode. For example, gravity belt press thickening and screw press thickening are more effective in concentrating the mixed sludge from the initial settling sludge and the remaining activated sludge, while simple residual activated sludge is generally concentrated by air floatation.
When it comes to sludge thickening, we have to mention Gravity Belt Thickener and Screw Type Sludge Thickener.
BOEEP DN type gravity belt thickener is an automatic sludge thickener which can replace the traditional sludge concentrated tank. The sludge from the secondary sedimentation tank can be condensed rapidly and continuously. After condensed and separated, the sludge concentration can be adjusted between 90%-96% stably. There are many advantages after using this device, such as no need of concentrated tank, small footprint and less cost. This device adopts the developed technology and design, which is able to meet the different requirements in various industries.
Compared with the traditional Volute Screw Dewatering Press, Screw Sludge Thickener is also advanced in the low operating and maintenance cost, dewatering performance, smell protection, low noise, automatic control, etc. The sludge from the secondary sedimentation tank can be condensed rapidly and continuously, and the sludge concentration can be adjusted between 90% and 96% stably after being condensed and separated. The device has many advantages, such as no need concentrated tank, small footprint, less cost. Furthermore, it can effectively reduce the release of the odor and phosphorus release caused by sludge concentrated tank, simplify the following treatment process, greatly improve the capacity of sludge dewatering and deep dehydration equipment.
Next chapter, BOEEP will offer you the knowledge about sludge dewatering.