NBD Rotary Thickener
Model NBD / NBD-T
The PEI TRIAD NBD-T Thickener and NBD Belt Press are all 304 SS construction and are designed to condition, thicken, and dewater sludge/float streams in one step. It can be connected to the clarifier, DAF or storage tank directly and work along with other processes continuously. The 304 Stainless Steel structure is made for long lasting performance. The unit is totally automated. Belt tensioning and tracking are achieved automatically by air cylinders. Our customers benefit from using NBD-T Thickeners and NBD Belt Presses not only in lower capital investment for better quality equipment, but also in the ease of Operation/Maintenance.
Sludge Conditioning - A polymer/sludge mix/aging tank is included on the press. After the sludge is pumped in and mixed with the polymer in the tank, the physical and chemical characteristics of the sludge solids are changed to reduce the affinity between the solids and water and increase the agglomeration of solids for better dewatering.
Rotary Drum Thickening - After the sludge is conditioned, it flows into the rotary drum filter screen, mounted on the press. Due to the rotating motion, additional free water is separated. On the drum, the gap water is further drained off from the sludge due to the vibration of the belt and the weight of the sludge.
Gravity Belt Thickening - As an alternative to the rotary thickening drum, an integral gravity belt thickener can be included.
Compression Dewatering After the gravity thickening section, the sludge is gradually carried into a compression dewatering section and compressed. Then the sludge passes into the shear dewatering section with a constant thickness.
Shear Dewatering - When the sludge enters the shear dewatering section, there are a number of “S” type rollers to shear the sludge cake, releasing additional water.
Pinch Compressive Dewatering - At the final dewatering, the water content of the sludge cake is further compressed by the pinch rollers at much higher compressive force.
Cake Removal - At the discharge of the press, the cake is scraped off by a doctor blade and is further disposed.