Modification of a paper manufacturing process resulted in a reduction of process wastewater discharged.
Pulp is produced by chemical digesting wood chips with caustic soda and reduction in a disk refiner.
The liquors are concentrated and processed with lime to recover the caustic soda. Fibers extracted from the resultant sludge can be commercialized. The pulp is then bleached and the water is settled, and the sludge is incinerated in a lime kiln. Paper is made from pulp with lime carbonate as a filler. The sludge generated here is also incinerated.