Dewatering sludge produced from municipal and industrial wastewater treatment plants is essential for reducing volume, mass and subsequent treatment and disposal costs. Multi disk screw presses are commonly used for efficient sludge dewatering and thickening, able to generate cake solids of 20-35% from various types of sludge.
How Multi Disk Screw Presses Work
Multi disk screw presses consist of a horizontal shaft which rotates inside a stationary housing or cylinder. The shaft contains a series of parallel, closely spaced disks which act as lamellas or screw flights. The sludge is fed into one end of the unit and is conveyed along the length of the shaft between the disks by the rotation of the shaft.
As the sludge moves through the press, free water is squeezed out and collected. The dewatered cake then discharges from the end of the press housing, leaving enhanced solid concentration ready for handling, storage, treatment or disposal.
Multi disk screw press designs usually feature two or more pressing zones along the length of the shaft with alternate rotation to achieve higher dewatering performance. A dosing screw conveyor is also commonly used to feed the sludge at a controlled rate into the press unit.
Advantages of Multi Disk Screw Presses
- Produce high cake solids content up to 35% from various sludges
- Reliable and robust mechanism with few moving parts requiring little maintenance
- Short hydraulic retention time of a few minutes provides high throughput rates
- Gentle pressing action reduces possibility of solids shear and minimizes sludge damage
- Able to dewater most types of screened or thickened sludge including WAS, DAFT, FOG, etc.
Features of Quality Multi Disk Screw Presses
- Corrosion-resistant components such as stainless steel disks and housing parts
- Configurable design elements including adjustable disk pitch and press zone lengths to optimize the process
- An automatic lubrication system that decreases friction and wear
- Drive units with hydraulic or electric power and variable speed controls
- A compact and modular construction for simplified installation, operation, and maintenance