Project background

Wastewater from a biological treatment stage of a paper mill is to be processed and returned to the paper process as process water.

Goal and challange

The waste water was treated to deionised water quality. This was possible despite the solid matter load from the biological treatment stage and the high biofouling potential of the wastewater.

Concept and realisation

A backwash filter followed by an OSMO-UF was implemented for the filtration of the bio-return water. Due to the special ultrafiltration system developed by OSMO, it is possible to purify the waste water without coagulation to such an extent that it can then be treated to the desired quality by reverse osmosis. The reverse osmosis is adapted to the high fouling potential of the inlet and is equipped with an OSMO CIP system for efficient rinsing of the membrane.

Advantages for customer

• Reduction of well water consumption by returning waste water to the processe
• Improvement of the process water quality through high-quality reverse osmosis permeate
• Minimization of specific water consumption through higher water quality
• Saving of energy and CO₂ by feeding back warm water (approx. 9,500 MWh/a)

Facts and figures