Pulp, Paper & Wood Product Process Water Treatment

Water is used throughout paper making, but not all of it is recycled. Wasted water can end up as sludge - and 80% of the suspended solids in that sludge maker their way there during primary treatment. Our industrial screening and treatment technologies can help you to improve process efficiency, recycle water more effectively and recover and re-use more pulp. 

The pulp and paper industry is water-intensive. Once pulp is taken in water and a sheet of paper is made, all that water still needs to be dealt with. Equipment cleaning and steam also contribute to wastewater load. 

While much of this water can be recycled, some of it is wasted and ends up as sludge. It is not uncommon for pulp and paper mills to produce up to one cubic metre of sludge for each ton of paper produced. 80% of total suspended solids (TSS) in the water treatment process is transferred to wastewater treatment sludge during the primary treatment process. Sludge treatment and disposal costs money, so these solids represent a cost to the business

Our pulp and paper processing water management solutions can help you remove solids before they reach downstream treatment systems, cutting the costs of sludge processing and handling, providing options for water recycling and re-use, and improving downstream treatment capacity and efficiency. 

Our solutions: ultrafine rotating belt filtration

The Hydro MicroScreen™ ultrafine rotating belt filter removes suspended solids with extremely high efficiency, helping pulp and paper businesses to reduce the quantities of sludge that need to be treated by expensive downstream sludge treatment processes. The system's unparalleled capture performance allows you to reclaim valuable pulp that enters wastewater flow streams and re-pulp.


  • Primary Clarification Replacement
  • TSS / BOD / COD Reduction 
  • Depending where the Hydro MicroScreen™ is installed at your plant and your site-specific operations the following removal rates may be attainable: 30-80% TSS Removal and 20-60% BOD Removal
  • Water Recycling / Reuse 
  • Captures reject material from flow streams allowing water re-use for steam production or plant wash-water
  • Material Recovery 
  • Captures lost pulp and& waste scraps and outputs clean dry product that can often be re-pulped while preventing these materials from entering sludge processes.
  • Liquid Solids Separation & Dewatering in a Single System 
  • Outputs materials with 2-4% Total Solids (TS) directly off the screen and 30-50% TS when used with the integral dewatering system

Remove suspended solids to protect and enhance downstream processes

Most plants use Dissolved Air Flotation (DAF) for wastewater treatment, and many plants are moving to much more capital-intensive treatments such as activated sludge to further reduce TSS and Biological Oxygen Demand (BOD).

Hydro MicroScreen™ is the ideal way to protect your DAF process from the impacts of excessive solids loading and preserve DAF processing capacity, potentially providing the opportunity to re-rate a DAF system for higher capacity.

See it in action

Watch our video to see the Hydro MicroScreen™ filtering particle board processing water:

Solution: coarse sludge screening and dewatering

The Hydro-Sludge® Screen removes materials such as rejects, scrap material and stringy trash, sending higher quality sludge to digestion systems preserving sludge treatment capacity.

Cut blockage risks and protect downstream processes

Removing dry solids from primary process wastewater sludge, can reduce the likelihood of blockages and help to protect other treatment processes.

Hydro International's Hydro-Sludge® Screen is a superior sludge screen which is designed for quick, simple and safe maintenance, with a self-lubricating cone to cut maintenance requirements and a discharge section with easy access for servicing and inspection.

Delivering screenings at up to 40% total solids, the Hydro-Sludge® Screen removes, compacts and dewaters coarse material in sludge to reduce the solids handling burden, cutting the cost of screen solids management, transport and disposal.

Case Studies

Oregon - particle board

An Oregon particle board plant was looking for a more effective TSS removal system that could handle larger loads, reduce required detention time for settling, protect their sedimentation system, and reduce the frequency of required cleaning. The Hydro MicroScreen™ achieved 77% TSS removal, with 25% TS on average. This allowed the solids to be fed back into the plant process, allowing the plant to reclaim solids rather than paying to send them to landfill. 

Read more: Hydro MicroScreen™ reduced solids loading for a particle board manufacturer

California - pulp and paper

A California pulp and paper plant was wasting 1,200 man-hours each year just keeping their high-maintenance existing TSS removal system operational – not to mention the impacts of the associated downtime. A trial of the Hydro MicroScreen™ system produced solids dry enough that they could be sent directly to landfill without any additional processing, and it is expected that the system will pay for itself in just over six months from maintenance savings alone. 

Read more: Hydro MicroScreen™ is drastically reducing maintenance costs for a pulp and paper plant

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