Evaluation of the operation seawater and brackish water desalination system using two-pass nanofiltration

ABSTRACT The lack of freshwater supply in the rural coastal village in Chile has motivated the implementation of a pilot-size nanofiltration desalination plant. The objective of this study was to evaluate the seawater and brackish water desalination system using two-pass nanofiltration. The system achieved a permeate recovery of 21.0 L/(m 2 h) and 51.3 L/(m 2 h) in the first pass at 40 bar and in the second pass at 15 bar, respectively. As the quality of water obtained in the first pass was satisfactory, it was mixed with water from the second pass, resulting in safe drinking water that conforms to local and international standards. At present, this system supplies drinking water to a coastal village of Chile and can be used to treat different types of brackish water and be coupled with renewable energies. It can provide potable water at a cost of US $ 0.70/m 3 , which is a competitive price considering the small size of the system.