Filter Press Technology

Veolia Separations prepares the sludge stream for the Filter Press by screening it, mixing it, and chemically conditioning it if/as necessary. The conditioned sludge is pumped to the filter press using high-pressure, fast-fill, centrifugal feed pumps to maximize the production rate and enhance the filter cake quality (high pressure).

Our filter presses are high-pressure (225-psi), recessed chamber, plate and frame presses designed to achieve the driest possible filter cake (solids) possible. The pre-conditioned “feed” sludge is pumped into the stationary head of the filter press via the feed connection. As each chamber fills with sludge, the liquid passes through the cloth medium, across the drain field, through the drain ports and exits out of the corner of each plate. As the solids build in the press, a pressure differential develops between the feed and the filtrate discharge headers. It is the pressure differential across the media which causes the filtration process to occur. The solids build in each chamber until it is full and the path for liquid to flow out of the chamber is packed off. At that point, the feed pump is secured and the filter plates are shifted to drop the solids from each chamber formed by adjacent plates/cloths.

The filter cake (solids) is dropped onto a conveyor located directly beneath the filter plates and is transferred to the rear of the press trailer where it is dropped into an appropriate container or onto a temporary containment pan.

Advantages of Filter Press Technology

• Dryer filter cake, therefore, greater waste volume reduction
• Capable of effectively dewatering a wide variety of sludge streams
• Chemical (coagulant) and/or filter aids (lime, perlite, etc.) are generally less expensive
• Fairly basic and durable operation
• Best technology for metal hydroxide, metal oxide, carbon/coal, fly ash, lime, and mill scale streams

Disadvantages of Filter Press Technology

• Batch process that typically requires more labor/operator effort
• Lower process/production rates compared to belt press technology
• Susceptible to cloth blinding on most oily or “tacky” sludge streams