Sludge is pumped into a dynamic (or static) mixer. At a 1x3 anionic (or cationic) flocculant solution concentration of 0.050, fine solid particles (or suspended matter) in the slurry coalesce into large flocs, separating bound and surface water substances into free water. As the material is transported to the gravity pre-dewatering extension area (or belt thickener) mesh, the free water leaks through the mesh under gravity, separating the slurry and forming a non-flowing state. It reaches a high-pressure state in the pressurized dewatering zone when the conveyor belt moves, trapping it between the upper and lower belts.

1. Slurry Flocculation

To enhance the dehydration performance of slurry, alter the performance of filter cakes, and increase the permeability of materials, physical and chemical treatments of the slurry are required. The sand washing machine's mechanical wastewater treatment equipment employs a bidirectional flocculation device, which yields excellent flocculation results. This method not only produces larger, compact flocs but also saves a significant amount of chemicals, resulting in low operation costs and good economic benefits.

2. Gravity Concentration and Dewatering Zone

The slurry enters the screen evenly through a distribution hopper. As the filter belt moves forward, free water flows into the water tank under its own weight through a long gravity-free dewatering zone. The gravity dewatering section can also be referred to as a high-concentration section. The main function of the sand washing machine's mechanical wastewater treatment equipment is to remove most of the free and interstitial water from the slurry, thereby reducing the slurry's fluidity, promoting thick accumulation of the slurry on the filter screen, and increasing the slurry's pressure-bearing capacity.

3. Medium and low pressure dehydration zone

After gravity dewatering, the slurry loses its fluidity. As the conveyor belt moves forward, the slurry enters the porous roller from the wedge area. The spacing between the upper and lower filter belts gradually decreases, the material begins to be micro-compressed, and the filtrate starts to overflow from both sides of the belts. As the filter belt runs, the pressure gradually increases. At the same time, the extrusion stability of the flocculant gradually increases.

4. Wash Sanding Machine Mechanical Sewage Treatment Equipment Clamp Roller (Belt) High Pressure Dewatering Zone

Mud is separated from the medium-pressure zone and then moves into the high-pressure area. Here, the mud is compressed by 13 pairs of clamping rolls (or belts). After intense compression, the volume is significantly reduced, and free water from the mud is expelled. At this point, a filter cake with a high solid content is formed.