ISO 23446:2021

INTERNATIONAL ISO
STANDARD 23446
First edition
Marine technology — Product water
quality of seawater reverse osmosis
(RO) desalination — Guidelines for
municipal water supply
PROOF/ÉPREUVE
Reference number
ISO 23446:2021(E)
©
ISO 2021

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ISO 23446:2021(E)

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© ISO 2021
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ISO 23446:2021(E)

Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Desalted water quality . 1
5 Product water quality. 1
6 Monitoring frequency. 2
7 Test methods . 2
Annex A (informative) Calculation method of calcium hardness . 3
Annex B (informative) Calculation method of the Langelier saturation index (LSI) .4
Annex C (informative) Information of product water quality of seawater RO desalination
in specific cases . 5
Bibliography . 6
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ISO 23446:2021(E)

Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
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electrotechnical standardization.
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described in the ISO/IEC Directives, Part 1. In particular the different approval criteria needed for the
different types of ISO documents should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2. www .iso .org/ directives
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This document was prepared by Technical Committee ISO/TC 8, Ships and marine technology,
Subcommittee SC 13, Marine technology.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www .iso .org/ members .html.
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ISO 23446:2021(E)

Introduction
With population growth, urbanization, climate change impacts and increases in household and
industrial uses, fresh water scarcity will definitely affect the sustainable development of society.
Seawater desalination is an effective way to meet the water needs. In some regions, it is almost the
primary source of municipal water supply.
Because of technology and cost advantages, the reverse osmosis (RO) process has been used
increasingly for seawater desalination. However, desalted water of seawater RO desalination is low
in minerals and poorly buffered. It is usually aggressive to metallic materials used in equipment and
distribution pipelines. To solve this problem, the post-treatment of desalted water, such as the addition
of minerals and/or blending of waters, is necessary to achieve a balanced mineral content. Therefore, it
is necessary to monitor product water quality after post-treatment to confirm the safety for municipal
water supply.
Consequently, standardization of the product water quality is important and useful for the protection
of corrosive pipelines and related equipment. The key parameters are monitored to meet the related
limits and range. The product water will be compatible with municipal pipelines and related equipment.
These guidelines provide key parameters to manage the product water quality of seawater RO
desalination for municipal water supply. They are intended to assist water engineers, authorities,
decision makers and stakeholders in evaluating the compatibility of product water with pipelines and
devices.
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INTERNATIONAL STANDARD ISO 23446:2021(E)
Marine technology — Product water quality of seawater
reverse osmosis (RO) desalination — Guidelines for
municipal water supply
1 Scope
This document provides guidelines for product water quality of seawater reverse osmosis (RO)
desalination that is used for municipal water supply.
It specifies water quality parameters and ranges, monitoring
...