The performance of RO or NF membranes is strongly influenced by the composition of the feed solution. Overall salt rejection is dependent upon the ratio of monovalent to polyvalent ions as well as the sum total of ions present. The permeate flow rate of RO or NF devices is also dependent upon the sum total of the ions present and the operating temperature, pressure, and recovery rate. Analyses and measurements performed in this guide will provide vital data for salt rejection and permeate flow projections of RO or NF systems for specific feedwaters.

The recovery at which a RO or NF system can be safely operated is dependent upon the composition of the feed solution. The analyses and measurements performed inthis guide will provide data for the calculation of the maximum recovery of a RO or NF system for a given feed solution.

The analyses and measurements performed in this guide will be of great assistance in determining the pretreatment requirements for a RO or NF system on a given feedwater.

1.1 This guide covers the analyses that should be performed on any given water sample if reverse osmosis (RO) or nanofiltration (NF) application is being considered.

1.2 This guide is applicable to waters including brackish waters and seawaters but is not necessarily applicable to waste waters.

1.3 This is a guide only and should not be construed as a delineation of all ions known to exist in waters.

1.4 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.

1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.