ISO 13205:2024

Marine technology - Seawater desalination - Vocabulary

This document defines terms and definitions for the integral seawater desalination process. It covers basic definitions, as well as specific subject matter including water intake, pre-treatment, membrane desalination, distillation desalination, post-treatment and auxiliary terms. This document applies to all types and sizes of seawater desalination facilities and systems, and to all types of stakeholders involved in seawater desalination.

Navires et technologie maritime — Dessalement de l'eau de mer — Terminologie

General Information

• Status: Published
• Publication Date: 12-Jun-2024
• ICS: 01.040.13 - Environment. Health protection. Safety (Vocabularies)
• ICS: 13.060.01 - Water quality in general
• Technical Committee: ISO/TC 8/SC 13 - Marine technology
• Drafting Committee: ISO/TC 8/SC 13 - Marine technology
• Current Stage: 6060 - International Standard published
• Start Date: 13-Jun-2024
• Due Date: 15-Mar-2025
• Completion Date: 13-Jun-2024

Overview

ISO 13205:2024 - Marine technology - Seawater desalination - Vocabulary is the first edition International Standard that establishes a unified vocabulary for the entire seawater desalination process. The document defines terms and definitions covering the full desalination flow: water intake, pre‑treatment, membrane desalination, distillation desalination, post‑treatment, and auxiliary concepts. ISO 13205:2024 applies to all types and sizes of seawater desalination systems and to all stakeholders engaged in desalination projects.

Key Topics

This vocabulary standard clarifies technical language used across desalination engineering, operations and research. Key topics included are:

• Basic definitions: seawater desalination, source water, feed water, desalinated water, product water, brine, recovery rate, concentration factor.
• Water intake: surface and subsurface intakes, vertical and slant wells, infiltration galleries, tunnelled intakes.
• Pre‑treatment: chlorination, coagulation, clarification, dechlorination, dissolved air flotation (DAF), flocculation, sedimentation, sand and multimedia filters, self‑cleaning and cartridge filters, microfiltration (MF), ultrafiltration (UF).
• Membrane desalination: reverse osmosis (RO), nanofiltration (NF), pressure vessels, membrane elements/modules, RO trains, passes and stages, permeate flux, membrane rejection, energy recovery devices (ERD) and booster pumps.
• Distillation desalination: covered as a principal desalting category alongside membranes (terminology for distillation processes and components).
• Post‑treatment and auxiliary terms: mineralization, water blending, brine management, membrane cleaning and chemical dosing.

Applications

ISO 13205:2024 is a reference tool to:

• Standardize terminology in technical specifications, design documents, regulatory frameworks and academic publications.
• Improve communication among desalination engineers, plant operators, consultants, regulators, researchers, and equipment vendors.
• Support procurement, commissioning, risk assessments and cross‑disciplinary collaboration in projects ranging from small coastal plants to large municipal or industrial desalination facilities.

Who should use it

• Design and process engineers specifying systems or writing technical reports
• Plant operators and maintenance teams
• Regulatory agencies and permitting bodies
• Standards developers, researchers and educators in marine technology and water treatment
• Equipment manufacturers and contractors preparing product datasheets or contracts

Related Standards

ISO 13205:2024 was prepared by ISO/TC 8/SC 13 and references related terminology sources such as ISO 23070:2020, ISO 6107:2021, ISO 20480‑4:2021, ISO 22519:2023 and ASTM D6161‑2019. Use ISO 13205:2024 to align language across these and other desalination documents.

Standards Content (Sample)

International
Standard
ISO 13205
First edition
Marine technology — Seawater
2024-06
desalination — Vocabulary
Navires et technologie maritime — Dessalement de l'eau de mer
— Terminologie
Reference number
© ISO 2024
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on
the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below
or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: [phone]
Email: [e-mail]
Website: www.iso.org
Published in Switzerland
ii
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
3.1 Basic definitions .1
3.2 Water intake .2
3.3 Pre-treatment .3
3.4 Membrane desalination .4
3.5 Distillation desalination . .6
3.6 Post-treatment .8
3.7 Auxiliary terms .9
Bibliography .11
Index .12

iii
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out through
ISO technical committees. Each member body interested in a subject for which a technical committee
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The procedures used to develop this document and those intended for its further maintenance are described
in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the different types
of ISO document should be noted. This document was drafted in accordance with the editorial rules of the
ISO/IEC Directives, Part 2 (see www.iso.org/directives).
ISO draws attention to the possibility that the implementation of this document may involve the use of (a)
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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.

iv
Introduction
Establishing a standardized set of terms and definitions is highly important for the production of scientific
and engineering publications in a technical area, including the development of standards. The absence of a
standardized terminology can ultimately result in inefficiencies and a high-probability of misinterpretation.
This document defines terms and definitions used in the entire process of seawater desalination. The flow
process of seawater desalination is given in Figure 1. Desalination methods are mainly categorized into
distillation processes and membrane processes. Both processes involve mutual parts of water intake, pre-
treatment and post-treatment, but differ in terms of membrane desalination and distillation desalination. In
addition, the auxiliary terms consisting of membrane cleaning and agents dosing are essential for specific
processes.
Figure 1 — Flow diagram of seawater desalination terminology
This document aims to provide guidance for unified terminology in seawater desalination; remove any
obstacles to communication in management, industry and academia; and promote multi-field cooperation in
more countries and regions. The objective of this document is to consolidate unified descriptions of seawater
desalination activities, for the benefit of all users and stakeholders.

v
International Standard ISO 13205:2024(en)
Marine technology — Seawater desalination — Vocabulary
1 Scope
This document defines terms and definitions for the integral seawater desalination process. It covers basic
definitions, as well as specific subject matter including water intake, pre-treatment, membrane desalination,
distillation desalination, post-treatment and auxiliary terms.
This document applies to all types and sizes of seawater desalination facilities and systems, and to all types
of stakeholders involved in seawater desalination.
2 Normative references
There are no normative references in this document.
3 Terms and definitions
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at https:// www .electropedia .org/
3.1 Basic definitions
3.1.1
seawater desalination
process which removes excess substances such as organisms and salts from seawater to make it usable as
municipal water, industrial water and for other applications
3.1.2
seawater desalination system
set of interrelated or interacting units for seawater desalination (3.1.1) processes, including source water
intake (3.2.1) system, pre-treatment (3.3.1) facilities, membrane and distillation separation devices, post-
treatment facilities and electronic control unit, etc.
3.1.3
source water
raw water
inlet water supplied to the seawater desalination system (3.1.2)
3.1.4
feed water
inlet water supplied to an individual component or a device of seawater desalination system (3.1.2)
3.1.5
desalinated water
freshwater produced by distillation and membrane desalination plants
3.1.6
product water
water produced by post-treatment (3.6.3) of desalinated water (3.1.5) such as mineralization (3.6.4) and
waters blending (3.6.5)
3.1.7
brine
concentrate (reject) stream from a membrane or a distillation device performing desalination, with a salinity
that is higher than seawater
3.1.8
concentration factor
CF
ratio of the concentration of components in the retentate [concentrate, brine (3.1.7)] to the concentration of
the total components in the feed
Note 1 to entry: Concentration factor (CF) is generally expressed by C /C , where C is brinewater concentration and C
b f b f
is feedwater concentration.
3.1.9
recovery rate
ratio of the permeate volume to the feed volume
[SOURCE: ISO 23070:2020, 3.10]
3.1.10
element
component containing the membrane, generally replaceable, such as hollow fibre, spiral wound cartridge or
cassette
[SOURCE: ASTM D6161-2019, 5.1, modified — “hollow fibre” has been added to the definition.]
3.1.11
module
membrane element (3.1.10) combined with the element’s housing
Note 1 to entry: The pressure vessel (3.4.3) contains the membrane element(s).
[SOURCE: ASTM D6161-2019, 5.1, modified — part of the original definition has been moved to Note 1 to entry.]
3.2 Water intake
3.2.1
water intake
process of withdrawing seawater from the source
3.2.2
surface intake
seawater collected from the open ocean above the seabed
Note 1 to entry: Surface intakes can be single purpose or collocated with a power plant as well as offshore submerged,
nearshore submerged, or nearshore surface intakes.
3.2.3
subsurface intake
seawater collected via vertical wells (3.2.3.1), infiltration galleries or other locations beneath the seabed
Note 1 to entry: Subsurface intakes can be onshore (vertical wells), including vertical beach wells or deep aquifer
wells, horizontal wells, radial or collector wells, and beach infiltration galleries; or offshore wells, including horizontal
drains (wells), and seabed infiltration galleries.
3.2.3.1
vertical well
well which is well-drilled straight down into the underlying rock or unconsolidated coastal aquifer system

3.2.3.2
slant well
well which is well-drilled at an angle from the horizontal into the underlying rock or unconsolidated coastal
aquifer system
3.2.3.3
infiltration gallery
filtering device which is a horizontal drain made from open jointed or perforated pipes, or a blocked drain,
which is laid below the water table and collects seawater
3.2.3.4
tunnelled intake
seawater collected from deep water by the tunnelled structure
Note 1 to entry: The tunnel is built over the full distance from the intake structure to the diffusers offshore.
3.3 Pre-treatment
3.3.1
pre-treatment
processes such as chlorination, filtration, coagulation, clarification, dechlorination, which may be used on
feed water (3.1.4) ahead at reverse osmosis (3.4.2) membrane devices and distillation devices to minimize
scaling (3.6.2) and blockage potential and to control biological activity
3.3.2
sterilization
process which inactivates or removes all living organisms (including vegetative and spore forms) as well
as viruses
[SOURCE: ISO 6107:2021, 3.539]
3.3.3
dissolved air flotation
DAF
flotation process by which low density particles are removed from seawater by using fine bubbles which are
produced by the reduction in pressure of a water stream saturated with air
[SOURCE: ISO 20480-4:2021, 3.2, modified — Note 1 to entry has been removed.]
3.3.4
flocculation
formation of large separable particles by aggregation of small particles; the process is usually assisted by
mechanical, physical, chemical or biological means
[SOURCE: ISO 6107:2021, 3.234]
3.3.5
sedimentation
process of settling and depositing suspended solids in water under the action of gravity
3.3.6
sand filter
device used to remove suspended solids
Note 1 to entry: Sand filter is made up of layers of inert medium, usually quartz/silica sand.

3.3.7
multimedia filter
MMF
layered filtration media in a pressurized container, used to reduce the level of suspended solids (turbidity)
in incoming feed water (3.1.4)
Note 1 to entry: Media layers can consist of anthracite, activated carbon, quartz/silica sand and garnet.
[SOURCE: ISO 22519:2023, 3.1.3]
3.3.8
self-cleaning filter
filtration system used to reduce the level of suspended solids (turbidity) in incoming feed water (3.1.4), as
well as automatically clean itself
Note 1 to entry: The self-cleaning filter starts automatic cleaning mechanisms according to the pre-set cleaning cycle
or system differential pressure due to the accumulation of suspended solids (turbidity).
3.3.9
microfiltration
MF
pressure driven membrane-based separation process designed to remove particles and dissolved
macromolecules in the approximate range of 0,05 µm to 2 µm
[SOURCE: ASTM D6161-2019, 5.1]
3.3.10
ultrafiltration
UF
pressure driven process employing a semipermeable membrane under a hydraulic pressure gradient to
separate components in a solution
Note 1 to entry: The pores of the membrane are of a size smaller than 0,1 µm, which allows passage of the solvent(s)
but will retain non-ionic solutes based primarily on physical size, not chemical potential.
[SOURCE: ASTM D6161-2019, 5.1, modified — part of the original definition has been moved to Note 1 to entry.]
3.3.11
cartridge filter
device used to further reject the remained foulants in the feed water (3.1.4) before reverse osmosis (RO)
(3.4.2) membranes
Note 1 to entry: The purpose of the cartridge filter is to protect the RO membranes from damage.
3.4 Membrane desalination
3.4.1
high-pressure feed pump
device used to deliver feed water (3.1.4) to the reverse osmosis (3.4.2) membranes at the pressure required
for membrane separation of desalinated water (3.1.5) from the seawater
3.4.2
reverse osmosis
RO
separation process where one component of a solution is removed from another component by flowing the
feed stream under pressure across a semipermeable membrane that causes selective movement of solvent
against its osmotic pressure difference
Note 1 to entry: RO removes ions based on electro chemical forces, colloids, and organics down to 150 molecular mass.
[SOURCE: ASTM D6161-2019, 5.1, modified — part of the original definition has been moved to Note 1 to entry.]

3.4.3
pressure vessel
container filled with reverse osmosis (3.4.2) membrane element(s)
3.4.4
booster pump
device used to deliver the water from the energy recovery device (3.4.5) to the reverse osmosis (RO) (3.4.2)
membranes at pressure required for RO membrane feed water (3.1.4)
3.4.5
energy recovery device
ERD
device that uses the hydraulic pressure of the brine (3.1.7) to pressurize feed water (3.1.4) in a reverse
osmosis (3.4.2) desalination unit
3.4.6
reverse osmosis train
RO train
complete reverse osmosis (3.4.2) installation, including membranes, high pressure feed pump and energy
recovery device (
...