Two stages reverse osmosis for zero and near zero liquid discharge of desalination plants

چکیده مقاله

In recent years, reverse osmosis (RO) has grown as an alternative to traditional potable water sources. A major disadvantage of the RO process is the huge amount of brine and its negative impact as a result of its high salinity. This brine is usually discharged to inland water bodies or to the sea and constitutes a threat to ecosystems and species; thus, further research is needed for introducing environmentally friendly and economically viable management options for RO brines if desalination is to become a major part of a sustainable water future. Among the technologies developed, zero liquid discharge ones have been utilized based on combination of dual RO with other treatment processes. The main advantages for installation of a second stage of RO is that RO is a well-established process compared to many other processes that are not available at a commercial scale. Furthermore, this technology allows minimizing brine disposal and relating costs, especially in inland plants. This review addresses different two stages RO technologies having the potential to efficiently treat RO concentrate at several scales.