HUBER Screw Press Q-PRESS® The cost-effective sludge dewatering for self-sufficiency in sludge disposal

Sludge conditioned with flocculant is pumped via a flocculation section directly into the cylindrical filter basket of the HUBER Screw Press Q-PRESS® where a slow-rotating auger processes the material.

The auger's geometry progressively decreases the volume within the filter basket, effectively squeezing free water out of the sludge. It then pushes the thickening sludge toward an annular gap, where it passes a pneumatically adjustable pressure cone at the discharge end.

A scraper attached to the screw shaft continuously cleans the filter basket from the inside as the shaft rotates. Meanwhile, a stationary spray bar periodically backwashes the filter basket of the HUBER Screw Press Q-PRESS® segment by segment from the outside. For sizes 620.2 and above, the dewatering process remains uninterrupted during backwashing.

Adjustment and control parameters include sludge feed rate, flocculant dosing and mixing, screw shaft speed, sludge feed pressure, and the pneumatic counterpressure of the discharge cone.

Energy efficiency:

The screw drives exceed the current energy efficiency standards of electric motors. Due to maximized electrical efficiency, the HUBER Screw Press Q-PRESS® can therefore be operated with higher solids throughputs.

Dewatering results:

Specially designed scrapers on the screw shaft continuously and reliably clean the inner filter surface with each rotation, allowing free water to easily drain off. This enhances dewatering efficiency while reducing flocculant consumption. Additionally, filter baskets with the same bar spacings, thanks to their significantly enlarged open filter surface, can handle higher hydraulic loads without compromising filtrate quality.

The outer surface of the filter is cleaned without interrupting the dewatering process. The pre-dewatering and press zones can be washed independently, minimizing the risk of rewetting the pressed sludge, particularly in the press zone. At the same time, the essential cleaning in the pre-dewatering zone is not overlooked.

Maintenance:

As an option, the filter baskets are available in three axially divided segments. For maintenance, only the upper half of the basket needs to be removed. The lower half can be detached from the screw shaft using a special mechanism but remains inside the filtrate chamber of the Q-PRESS® during maintenance. This design saves time, reduces space requirements, and eliminates the need for lifting devices during maintenance.

Dewatering of thin sludges

Pump feeding allows large volumes of sludge water to be removed in the pre-dewatering zone, enabling cost-efficient dewatering of thin sludges with a solids concentration of less than 1% without the need for prior thickening. Typical dewatering results of 18–25% dry solids (DS) can be achieved, with sludge volume reduction of up to 97% in a single step. This approach saves both investment and operational costs by eliminating the need for prior sludge thickening.

Variable sludge characteristics

Dewatering performance is often affected by fluctuating sludge quality, which can require increased operator attention. However, the HUBER Screw Press Q-PRESS® automatically adjusts to both overloading and underloading conditions. A control loop ensures that optimal operation and performance are consistently maintained. As a result, the Q-PRESS® remains flexible in handling varying sludge qualities while minimizing the need for operator intervention, ensuring reliable operation.