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Circular Divider

Paper and pulp sludge dewatering

Circular Divider

An introduction to this case study

The global production of paper was 400 million tons in 2015 and is expected to reach 550 million tons in 2050. About 40–50 kg of sludge (dry) is generated in the production of 1 ton of paper at a paper mill.

Various wastes are generated in pulp and paper mills, such as ash, dregs, grits, lime mud and pulp mill sludge.

Traditionally, these wastes were typically sent to landfills or incinerated. This type of disposal can have a significant impact on the environment, damaging the water, soil, and air.

The way we can assist the industry is by using the Fournier Rotary PressTM dewatering technology to treat the sludge in such a way that it can be used to create new value-added products.

Technologies used in this case study:


Look at how we deal with the followingchallenge:

1. Paper and pulp sludge dewatering

Paper and pulp sludge dewatering


Paper and pulp mills generate various types of sludge that result from wastewater treatment procedures used in the mills: primary sludge (fibre sludge), biological sludge, mixed sludge, de-inking sludge, hydroxide (chemical precipitation) sludge and coating sludge.  

The first step in the management of paper and pulp sludge is the separation of the sludge into liquid and solid fractions. For many years the belt press and the screw press have been the standard sludge dewatering devices in the paper industry.

However, the environmental legislation of recent years has forced many mills to install secondary or biological treatment for the wastewater to reduce trade effluent charges by reducing chemical oxygen demand (COD) levels.

The addition of surplus biological sludge to the primary sludge for dewatering can be problematic for the belt press and the screw press.


Sinowatek offers a dewatering method to reduce the moisture content of the cake. This presents options in terms of handling the solids in boilers, landfill, or new products.

When using the Fournier Rotary PressTM dewatering technology the high capture rate of solids results in a relatively clean filtrate (low TSS) that allows water to be treated effectively for release or reuse.

Benefits for the client:

  • Sinowatek offers full-scale pilot testing of the Fournier Rotary PressTM. The 6 m containerized unit is quickly connected to the client’s source of sludge to give real-time results.
  • By having access to real on-site results the risk of non-performing capital purchase is eliminated.
  • Accurate production figures per channel are obtained from the test. This allows for accurate sizing of equipment with the correct number of channels.
  • For possible future expansion, a press can be ordered with extended shafts to accommodate up to 8 channels.
  • The Fournier Rotary PressTM is tolerant of feed sludge concentration changes.
  • Modularity, interchangeable channels, and the ability to expand capacity by adding single channels are attractive from a capital investment standpoint.
  • Quiet operation, effective containment of odour and suitability for automation with an unattended operation are big advantages.
  • High performance, easy operation, reduced polymer usage, low power consumption and low maintenance.
  • An automated 5 min self-cleaning procedure ensures a 24-hour continuous operating cycle.

Let's talk  about your specific challenges in this field.