Process water treatment at plywood mill

The forest industry, including companies like pulp and paper and plywood mills, has a strong place in Finland. One of the biggest Finnish groups in the forest industry notes environmental responsibility as one of their core values, creating a high demand for effective process water treatment solutions. At plywood mills, significant quantities of water are used for soaking logs in chemical baths.

In march 2022, Owatec started researching optimized solutions to treat process water used in chemical baths for logs at a plywood mill. The mill uses Owatec solutions to increase the performance of existing water treatment processes to gain the following objectives:

  • COD reduction of 95%
  • More effective process
  • Passing the limits of Environmental permit

The research project started with laboratory testing and continues with full-scale piloting designed for 500m3/d water flow. The following solutions are added to the original water treatment plant:

Flow capacity 500m3/d

First, the process water (COD 10 000 mg/l) is lead from the original step filter to three Owatec Air units for aeration and biological treatment, where the reduction of the chemical oxygen demand begins. The chemical treatment following next (Owatec Floc) allows the floc of impurities to form and solid removal with a flotation unit (Owatec DAF). The treatment clears the water from the solids and enables an over 95% reduction in chemical oxygen demand (COD). After the treatment, clean water is led to sewage, and the sludge management process continues dewatering the matter (Owatec Dewa).

This project is at the piloting stage, and the complete reference with more detailed information will be published in spring 2023 after finalizing the wastewater and sludge management processes. If you are eager to know more, drop a message to

Delivery of full-scale piloting
Automation in every unit for the optimized processes