Dewatering Sludge

Dewatering Sludges is probably the most costly and onerous task on any effluent treatment plant.

Problems such as maintenance, noise, odour, gas zone, Site cleanliness, floc handling, and cake disposal are part and parcel of a days work in the sludge house. Added to this the OPEX and whole life costs create more headaches for the Plant managers. At Huber we have been reviewing these problems and a have addressed some of these with the Screw Press.

Solution to Problem 1-Maintenance

  • Operating at 3-6 RPM the wear is considerably less than a Centrifuge at 3400 RPM approx.
  • <10% of the power requirement of Centrifuges, smaller drive and bearings.
  • All stainless construction reduces corrosion.
  • Few moving and wearing parts reduces downtime.
  • Gull wing covers under no pressure allow good accessibility.
  • Flexibility in operation as multiple units can be used.
  • Less weight and vibration therefore smaller foundations

  • Solution to Problem 2 -Noise

  • Lower operating speed.
  • Less vibration than centrifuges.
  • Lower power.
  • Spray bars inside covers.

  • Solution to Problem 3- Odour

  • Totally enclosed casings which can be kept under low negative pressure.
  • Bagging units available to enclose cake.
  • Aerosols from washing are contained.

  • Solution to Problem 4-Gas Zone

    There is no solution to this problem. However the area will be cleaner and the screw press will generally produce less odour.

    Solution to Problem 5-Site Cleanliness

  • Totally enclosed to keep sludge inside press unlike Belt Presses.
  • Good filtrate drainage, at the lowest point of Press.
  • Elevated discharge therefore conveyors are not always necessary to transport the cake to the skip or storage area.
  • Wear parts are on the outside of drum inside covers.
  • Wash spray /splash back contained inside covers

  • Solution to Problem 6-Polymer Consumption

  • Consumption is 5-20% lower than that associated withCentrifuges as there is little shear on the floccs to break them down.
  • Liquid polymers may be used to reduce dust and mixing requirements

  • Solution to Problem 7- Cake Discharge

  • Comparable moisture content in most cases.
  • Elevated discharge under gravity to drop straight into a skip.
  • Positive discharge requiring no scrapers or carry over.

  • Solution to Problem 8- OPEX

  • Lower power.
  • Less Polymer.
  • Lower carbon emission.
  • Less operator attendance as plant is fully automatic.
  • Less maintenance.
  • Less corrosion.

  • Solution to Problem 9- Whole Life Costs

    The CAPEX is comparable however recent independent reports have shown that the savings in power, flocc and OPEX make the Screw Press a very good whole life investment.


    Whilst Huber cannot resolve all of the problems in the sludge house the Screw Press has considerable advantages over other sludge Dewatering technologies such as Centrifuges, Filter Presses and Belt Presses.

    Tony Clutten

    Process Sales Manager
    Huber Technology

    Tel 01249 765050

    For further information please email Huber Technology

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