Wastewater Reuse at Paper Mill Reduces Freshwater Consumption by 40%
May 12, 2014
A paper mill which produces tissue paper examined options for the reuse of wastewater so they could reduce their fresh water consumption and wastewater discharge.
The paper mill withdrew from the river and treated an average of 100 m3/h (440 gpm) of water. The river water iron concentration is often high, sometimes more than 5 ppm, which had caused holes and stains on the paper machine. The mill examined the potential to reduce the fresh water consumption by treating and recycling some of the wastewater.
Options for the control of iron contamination were also evaluated. Water collected from the paper machine during paper production, called “white water”, contains significant amounts of fiber which is removed by flotation. The white water after fiber removal is called “clarified water”. Some clarified water is immediately returned to the paper machine process while the rest is forwarded to waste treatment. Treated wastewater was evaluated for potential recycle to the influent water treatment system.