Comparison of Membrane-based Solutions for Water Reclamation and Desalination Original Research Article

The reclamation of effluents for irrigation and indirect potable water uses is rapidly developing as an alternative to seawater desalination. Two membrane-based options available to treat sewage for water reuse, tertiary filtration (TF) of the effluent from a conventional activated sludge (CAS) process and an integrated membrane bioreactor (MBR) are explored; in both cases, the level of treatment can be complemented by reverse osmosis (RO). These options are compared to desalination of seawater with both conventional multi-media membrane filtration. The capital costs for a plant producing water from seawater are about twice the costs of a plant reusing secondary sewage. Both the pretreatment costs and RO cost are higher. Similarly, the O&M costs for producing RO water from seawater are 2 times higher than the cost of reusing secondary sewage. The total life cycle costs for producing RO water from secondary effluent and seawater are 0.28US$/m3 and 0.62US$/m3, respectively.