The Application of Nanofiltration for Water Reuse in the Hybrid Nanofiltration-Forward Osmosis Process

The nanofiltration (NF) process can reject most multivalent charged species and organic molecules yet has a significantly greater permeability than the RO membrane. It demonstrates an excellent potential to hybridize with forward osmosis. The NF module can either act as a pre/post-treatment in the FO system, or it can be installed directly in the FO cell. This chapter demonstrates the performance of a hybrid NF-FO system regarding three important aspects. It includes: (1) the development of a draw solution for the NF-FO system, (2) the NF membrane development, and (3) practical applications of NF-FO systems. Compared to conventional FO and RO systems, the hybrid NF-FO system clearly exhibits an enhanced overall flux rate, a lower energy consumption, and a higher draw solution recovery rate, thus benefiting both treatment efficiency and sustainability. NF has a strong potential to hybridize with other water treatment technologies and deliver efficient, low-energy water recycling processes.