Sludge dewatering system
Gravity table GTSludge screw presses SCS

Sludge dewatering

Applications for a wide range of dewatering and thickening applications for fibrous and biological paper industry sludges

Proven and effective technology for sludge dewatering applications

The ANDRITZ sludge dewatering system portfolio covers all types of dewatering machines for all fibrous and biological paper industry sludges. Different types of sludges have different dewatering potential. ANDRITZ assists in finding the suitable solution for each and every application.

To evaluate the dewatering characteristics of these sludges, ANDRITZ can test the sludge at its pilot plant in Graz, Austria. As an alternative, a test run at your mill can be arranged by utilizing the ANDRITZ mobile test unit.

Gravity table GT: effective pre-dewatering of sludge with low solids in filtrate

The ANDRITZ gravity table is used as a first dewatering stage for sludge prior to subsequent pressing operations (e.g. pressure filters of sludge screw presses). Gravity is utilized to thicken the sludge from a feed consistency of 0.6–5% to a discharge consistency of 12–22%. The gentle treatment of the gravity table keeps the flocculent consumption low and results in a lower filtrate load compared to other pre-dewatering systems.

Benefits

  • High thickening capacity
  • Low energy consumption
  • Minimum flocculent consumption
  • Low solids load in filtrate
  • Optional floating roll to increase discharge consistencies

ANDRITZ thickening drum TD

The ANDRITZ TD, a rotary screen thickener, is an excellent alternative to gravity belt thickeners for continuous dewatering of sludge thanks to its small space requirement.

Due to the efficient and reliable thickening process and the high hydraulic capacity, the TD can remove up to 90% of the water in the sludge. The compact design results in low investment costs and the low specific power consumption, easy maintenance, and low wear of key components help to keep the operating costs down.

Benefits

  • Low investment costs due to smart machine design
  • High thickening efficiency (outlet consistencies of 8-20%)
  • Low energy consumption and operating costs
  • Easy maintenance and fast wire change
  • Small footprint due to compact design

Sludge screw press SCS: highest capacity, highest dryness

The ANDRITZ sludge screw press is designed for high throughput and for high dryness requirements. It utilizes a conical shaft and a decreasing pitch of flights on the screw to dewater sludge through a reinforced screen basket. Backpressure is automatically controlled at the discharge end to prevent blockage and achieve the highest dryness content even with changing sludge characteristics. The addition of a shaft dewatering zone at the end and optional steam heating can bring the sludge dryness up to 70%.

Benefits

  • Single-line solution with a throughput up to 180 t/d
  • Shaft dewatering for higher final dryness
  • Patented wear shoes to minimize downtime and maintenance costs
  • Optional steam feeding boosts dryness to maximum
  • Self-adjusting backpressure unit
  • Fully closed system
  • Minimal flocculent consumption due to fully automatic control (see: Polyscan)

Continuous pressure filter CPF: flexible dewatering of a wide range of sludges

The ANDRITZ continuous pressure filters (CPF) are double-wire presses with a modular design. The continuous pressure filter allows optimized dewatering of even hard-to-dewater sludges.

Depending on the sludge characteristics different machine concepts are applied: The CPF Rhino is well suited for a wide range of mixed sludges with low fiber and significant biological content. The CPF Hippo is used for very press-stable fibrous sludges. All ANDRITZ continuous pressure filters can be delivered with an integrated pre-dewatering table or, ideally, are combined with the ANDRITZ gravity table.

Benefits

  • Modular design adapts to varying conditions
  • High dryness content of thickened sludge
  • Low specific energy consumption
  • High throughput with excellent filtrate quality
  • Flexible press forces
  • Easy accessibility for maintenance
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