PowerDrain gravity belt thickener

ANDRITZ PowerDrain, gravity belt thickener for efficient sludge treatment

The PowerDrain gravity belt thickener is a highly efficient and economical solution for sludge thickening. Specially designed ploughs as well as the very large open area under the belt optimize the draining effect.

ANDRITZ PowerDrain belt thickener for thickening

PowerDrain belt thickener, a very efficient technology for thickening prior to dewatering processes

ANDRITZ PowerDrain belt thickener and PowerPress belt press for thickening and dewatering

PowerDrain belt thickener and PowerPress belt press for mechanical dewatering, a combined, modular system for thickening and dewatering


Engineered and supplied by ANDRITZ SEPARATION for decades, the PowerDrain belt thickener is a heavy-duty unit that operates in a size range of 5-20 m² drainage area. The large open area, special feeder, and adjustable ploughs optimize the drainage effect. ANDRITZ SEPARATION has the expertise and experience to customize the PowerDrain and its auxiliaries for any sludge treatment application.

Main benefits

  • The PowerDrain belt thickener is the most affordable and easy solution for thickening.
  • Largest range of gravity belt thickeners with the largest capacity and dimensions on the market (5 to 20 m² drainage area)
  • Very efficient for thickening prior to dewatering processes
  • Simple design, small footprint, and strong construction (entire construction in stainless steel) able to support second unit on top
  • Operator-friendly
  • The large open area, special feeder, and adjustable ploughs optimize the drainage effect
  • Low supervision and maintenance (easy access for maintenance and cleaning)
  • Uniform feed and flow for trouble-free performance
  • Flexible operation (variable-speed drive)
  • Completely enclosed system (deaeration flange)
  • Filtrate and washing water recovered separately (filtrate can be re-used as wash water)
  • Automatic cleaning brush as standard (except PDM Mini)
  • Modular design for ease of configuration and installation, as well as transport convenience and possibility of increasing the capacity of the machine installed by adding one internal module


After the sludge has been flocculated in the feed pipe, it enters the gravity zone where most of the liquids and solids are separated. A spreader plate ensures uniform distribution over the working width of the belt. PowerDrain belt thickener units can be equipped with two to four rows of ploughs, which compact, rearrange, and deflect the sludge. The thickened sludge is then scraped off the belt, while the filtrate is discharged on the drive side and could be reused for washing. A washing chamber with flat jet nozzles cleans the belt.

Thanks to a spray bar with a self-cleaning device, wash water is collected separately. The thickened sludge is now ready to be processed using dewatering equipment.

Technical features

  • Belt widths of 1, 1.5, 2, and 3m available for process flexibility
  • Our largest model with a width of 3m can treat up to 180m3 per hour and unit with solids loading of up to 350kg/h/m for waste activated sludge
  • Stainless steel, self-supported frame
  • Liftable plows for easy maintenance and process optimization
  • Covers to meet CE requirements (air suction)
  • Rolls are coated with rubber (drive and tracking rolls) or Rilsan® (tension roll) as protection against corrosion
  • Pneumatic bellows (pneumatic system)
  • Screw and bolt tensioning system (PDL-PDXL)
  • Position sensor for belt tracking
  • Floating wedge or roll to increase dryness at outlet




  • Thickening of municipal or industrial waste water sludge
  • Thickening before anaerobic digestion
  • Dewatering with PowerPress (combined system)
  • Thickening before filter press, decanter, and screw press


PowerDrain belt thickener M Mini

  • Compact version for low throughput
  • Combines ideally with PowerPress G and PowerPress E belt presses
  • Throughput up to 24 m3/hr
  • Cake dryness: 6%

PowerDrain belt thickener M and L

  • Belt thickener for the medium throughput range
  • Combines ideally with PowerPress E and Power Press S
  • Throughput up to 100 m3/hr
  • Cake dryness: 6%

PowerDrain belt thickener XL

  • The highest capacity belt thickener with an exceptionally long filtration zone (6m)
  • Combines ideally with Power Press S
  • Throughput up to 160 m3/hr
  • Cake dryness: 6%

PowerDrain gravity belt thickener

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  • Powerdrain Gravity Belt Thickener PDF : 298 KB
  • Case study: Process optimization with RheoScan at a wastewater treatment plant in Slovenia PDF : 429 KB