Wastewater treatment of paper industry by microfiltration and ultrafiltration

Resumen

In the production of paper, an effluent with high organic load is generated, and conventional treatments alone are not able to remove all this load. Due to this problem, this research aimed to evaluate and compare the application of microfiltration and ultrafiltration filter membranes in the treatment of white water from paper industry. Trials in a pilot unit for microfiltration and ultrafiltration were performed for a later comparative analysis of apparent color removal efficiencies, COD, and turbidity of the effluent, and the permeate flow in the different filtration technologies was also evaluated. The membranes used have the same fiber length (26 cm), fiber diameter (25 mm) and filtration area (0.09 m²); however, the average pore diameter is different: 0.4 μm in microfiltration membranes and 50 kDa in ultrafiltration membranes. The results obtained indicated that microfiltration and ultrafiltration present high efficiency in reducing the parameters studied: 97% apparent color removal for both technologies, 78.26% COD for MF, and 82.75% for UF and 99% turbidity for both. The main difference between these two filtration methods is in the permeate flow, which is significantly higher in MF, indicating that with this technology it is possible to treat a higher effluent flow without losing efficiency.