Nanofiltration for the Treatment of Bleaching Effluents from the Pulp and Paper Industry: A Case Study

The present study explores the application of commercial nanofiltration (NF) membranes for the treatment of bleaching effluent from the pulp and paper (P&P) industry, within the framework of the RESURGENCE project, funded by the European Union’s Horizon Research and Innovation Programme (Grant Agreement No. 101138097). The P&P industry is a major user of water, generating effluents characterised by high organic load, elevated temperature, intense colour, and the presence of priority pollutants, all of which pose significant environmental risks. The NF process was evaluated using a lab-scale plate-and-frame membrane unit operated in full recirculation mode. Three different commercial membranes were tested under identical conditions (P = 10 bar, fixed temperature, 4-hour filtration time). The results demonstrate stable permeate flux and promising separation performance, with colour removal exceeding 99%, COD reduction above 85%, and retention (or partial retention) of key pollutants such as Cl- and Ca2+. This is particularly relevant in the context of water reuse within the industrial process. These findings confirm the potential of NF membranes for advanced industrial wastewater treatment, enabling both improved effluent quality and the potential for water reuse, thereby reducing the environmental impact and freshwater demand in the P&P sector.