A nanofiltration proposal must specify which constituents should be retained or reduced. Different nanofiltration products have different separation characteristics. Describing nanofiltration as between ultrafiltration and RO is not a sufficiently complete basis for selection.
Define output water targets before comparing membrane documentation
List target constituents, uses, and downstream limits individually. The completeness of raw water information and seasonal changes affect the assessment. A single total dissolved solids value is usually insufficient to explain every separation duty. Testing and design personnel should continue to confirm unknown parameters.
Read datasheets together with their test conditions
Match membrane models with test fluids, temperature, pressure, and recovery conditions. Rejection descriptions obtained with different test fluids should not be converted directly into one another. Also distinguish element data from complete system results on site. A candidate model change requires supporting system design and permitted-condition information.
Retain water quality records for each stream and operating trends
Feedwater, permeate, and concentrate have different roles. Retain necessary operating and test records for each. Review conditions before and after adjustments on a comparable basis to avoid interpreting temporary changes as long-term benefits. Do not add service life, water savings, or improvement percentages to promotional pages if the product documentation does not provide them.
| Item to check | Required supporting information |
|---|---|
| Target definition | Constituents to be reduced or retained and intended use |
| Selection information | Model, test conditions, and permitted system operating conditions |
| Operational verification | Data for each stream, adjustment records, and review results |
Frequently asked questions
Can nanofiltration universally guarantee retention of beneficial minerals?
No. The specific constituents, membrane model, feedwater, and actual separation results must be defined.
Products and related resources
Selection and gallery guide for all products · Describe your actual water requirements
Reference resources and limits of applicability
DuPont nanofiltration technical resources. General resources help explain treatment duties. They do not establish that models supplied by this website use that brand, have its authorization, or meet the requirements of a specific project.
Content note:Prepared with AI assistance and checked against existing product category information and illustrations on October 4, 2026. This article supports discussions of requirements and documentation; it is not testing, licensing, a quotation, or evidence of results for a corresponding model. Confirm implementation according to product documents, actual operating conditions, and applicable requirements.