Membrane concentrate management options: a comprehensive critical review

Membrane processes have become a competitive option to conventional treatment technologies because of the high quality of the product water. In particular, nanofiltration and reverse osmosis have been found to remove materials like natural organic matter, disinfection by-products, and endocrine-disrupting compounds. However, an issue identified as one of the major drawbacks for the adoption of pressure-driven membrane processes is the need for additional treatment of the concentrate stream. Few studies dealing with membrane concentrate treatment have been published. The majority of the published studies address the disposal of concentrate into receiving waters bodies and sewer systems. In this review paper, the characteristics of membrane concentrate in terms of water quality and their impact on receiving water bodies are discussed. In addition, several approaches to the removal of pollutants and disposal options for membrane concentrates are examined.