Belt Press Technology

Veolia Separations prepares the sludge stream for the Belt Press by screening it, mixing it, and chemically conditioning it as necessary (usually a polymer to flocculate the solid particles). The sludge is injected with the polymer “in-line” then passed through a static mixer to flocculate the solid particles. The conditioned sludge is pumped to the belt press using positive displacement feed pumps so as not to shear the “floc” formed by the polymer make-down and injection process.

Veolia owns and operates a fleet of trailer mounted and skid mounted belt presses that range from 2.1M to 2.3M in size.

The flocculated sludge is pumped onto the gravity drain section of the belt press where it is slowly rolled and spread across the belt by a series of “rakes” and “plows”. This causes the flocculated sludge to release the “bulk” of its liquid that is gravity drained through the cloth and into the liquid drain pan.

The sludge is then compressed between two porous belt cloths as it passes through a series of “S” rollers that steadily decrease in diameter. The net affect is a steady increase in pressure applied to the sludge in order to “squeeze” water out of the flocculated solids.

The dewatered belt press cake is scraped off of the belts and drops into a cake containment pan located at the end of the trailer.

Advantages of Belt Press Technology

• Continuous feed process typically requiring less labor/operator effort
• Higher sludge processing/production rates compared to filter press and centrifuge technologies
• Fairly basic and durable operation
• Best technology for bio-solids and primary/ secondary digested sludge

Disadvantages of Belt Press technology

• Typically requires more expensive polymer addition to pre-condition sludge
• Belt press cake is not as “dry” as filter press cake, therefore, less waste volume reduction
• Susceptible to cloth blinding by most oily or “tacky” sludge streams