Water Treatment for Paper Mills

Characteristics of wastewater from paper mills

It is well known that the pulp and paper industry is among those that use the largest amount of the “blue resource”: some sources speak of as much as 50-75 m3 of water per metric ton of finished product. The industrial wastewater produced is therefore laden with pollutants and must be properly purified to avoid pollution of groundwater and rivers and lakes (and to avoid criminal penalties). Not only that. Given the large consumption of this industry, a water reuse system should be considered to minimize the “water footprint” and operating costs of the plants.

Paper mills produce water with high values of total suspended solids: cellulose fibers, colloids, minerals, sludge, but also heavy metal residues (such as zinc and copper). BOD (biological oxygen demand) and COD (biochemical oxygen demand) values are also often high. They therefore need useful treatments to dispose of most of the particles present and to break down the amount of organic pollutants by biological oxidation.