Purification of process water in a thermomechanical pulp mill by nanofiltration
Process water from a Swedish thermomechanical pulp mill was purified by consecutive treatment by microfiltration, ultrafiltration and nanofiltration. In the present study the nanofiltration step was studied. The flux and retention of four nanofiltration membranes were compared. The NF99HF membrane (Alfa Laval, Lund, Sweden), had significantly higher flux and higher retention of lignin and charged