Guidelines for treated wastewater use for irrigation projects

This document provides recommendations regarding: —   monitoring the quality of treated wastewater (TWW) for irrigation; —   monitoring irrigated plants; —   monitoring the soil with regard to salinity; —   monitoring natural water sources in neighbouring environments; —   monitoring the quality of water in storage reservoirs. It puts emphasis on sampling methods and their frequency. Regarding the methods of analysis, this document refers to standard methods or, where not available, to other bibliographical references. NOTE      In cases where a monitoring plan already exists, these recommendations can be integrated into this plan. This is notably the case when a broader approach of risk management is implemented, such as the water safety plans (serving as a model for sanitation safety plans) developed by WHO[16].

Lignes directrices pour l'utilisation des eaux usées traitées en irrigation

Le présent document fournit des recommandations concernant: —   la surveillance de la qualité des eaux usées traitées (abrégées en EUT) pour l’irrigation; —   la surveillance des cultures irriguées; —   la surveillance de la salinité du sol; —   la surveillance des sources d’eau naturelle dans les environs; —   la surveillance de la qualité de l’eau dans les réservoirs de stockage. Le présent document met l’accent sur les méthodes et la fréquence d’échantillonnage. Concernant les méthodes d’analyse, il se réfère à des méthodes normalisées ou, lorsque celles-ci font défaut, à d’autres références bibliographiques. NOTE           Dans les cas où un plan de surveillance existe déjà , les présentes recommandations peuvent être intégrées à ce plan. C’est le cas notamment lorsqu’une approche de gestion du risque de plus grande portée est mise en œuvre, par exemple les plans de gestion de la sécurité sanitaire de l’eau (qui servent de modèle aux plans de sécurité sanitaire de l’assainissement) élaborés par l’Organisation mondiale de la Santé[16].

General Information

Status
Published
Publication Date
23-May-2021
Current Stage
5060 - Close of voting Proof returned by Secretariat
Start Date
02-Apr-2021
Completion Date
02-Apr-2021
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INTERNATIONAL ISO
STANDARD 16075-4
Second edition
2021-05
Guidelines for treated wastewater use
for irrigation projects —
Part 4:
Monitoring
Lignes directrices pour l'utilisation des eaux usées traitées en
irrigation —
Partie 4: Surveillance
Reference number
ISO 16075-4:2021(E)
ISO 2021
---------------------- Page: 1 ----------------------
ISO 16075-4:2021(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2021

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
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CH-1214 Vernier, Geneva
Phone: +41 22 749 01 11
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii © ISO 2021 – All rights reserved
---------------------- Page: 2 ----------------------
ISO 16075-4:2021(E)
Contents Page

Foreword ........................................................................................................................................................................................................................................iv

Introduction ..................................................................................................................................................................................................................................v

1 Scope ................................................................................................................................................................................................................................. 1

2 Normative references ...................................................................................................................................................................................... 1

3 Terms definitions, and abbreviated terms ................................................................................................................................ 1

3.1 Terms and definitions ....................................................................................................................................................................... 1

3.2 Abbreviated terms ............................................................................................................................................................................... 2

4 Monitoring of the quality of TWW for irrigation ................................................................................................................ 2

4.1 General ........................................................................................................................................................................................................... 2

4.2 Sampling procedure ........................................................................................................................................................................... 3

4.2.1 General...................................................................................................................................................................................... 3

4.2.2 Sampling from an irrigation system ................................................................................................................ 4

4.2.3 Sampling from a storage reservoir ................................................................................................................... 5

4.2.4 Composite sample ...................................................................... ..................................................................................... 5

4.2.5 Sample handling ............................................................................................................................................................... 5

4.3 TWW monitoring plan ...................................................................................................................................................................... 6

4.4 Analytical methods for TWW ..................................................................................................................................................... 8

5 Monitoring of the irrigated crops ....................................................................................................................................................... 8

5.1 General ........................................................................................................................................................................................................... 8

5.2 Frequency of monitoring ................................................................................................................................................................ 8

5.2.1 Field crops and vegetables ...................................................................................................................................... 8

5.2.2 Perennial crops.................................................................................................................................................................. 8

6 Monitoring of the soil with regard to salinity ......................................................................................................................... 9

6.1 Soil sampling ............................................................................................................................................................................................. 9

6.2 Frequency of the soil sampling ................................................................................................................................................. 9

6.3 Sampling procedure ........................................................................................................................................................................10

6.3.1 Drip irrigation .................................................................................................................................................................10

6.3.2 Sprinkler and micro-jet irrigation .................................................................................................................10

6.4 Sample preparation .........................................................................................................................................................................10

6.5 Soil test methods ................................................................................................................................................................................10

7 Receiving environment monitoring ...............................................................................................................................................10

7.1 General ........................................................................................................................................................................................................10

7.2 Monitoring programme purpose ..........................................................................................................................................11

7.3 Groundwater sampling .................................................................................................................................................................11

7.4 Surface water sampling ................................................................................................................................................................12

8 Quality assurance and quality control ........................................................................................................................................12

Bibliography .............................................................................................................................................................................................................................14

© ISO 2021 – All rights reserved iii
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ISO 16075-4:2021(E)
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 has been established has the right to be represented on that committee. International

organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.

ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of

electrotechnical standardization.

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 documents 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).

Attention is drawn to the possibility that some of the elements of this document may be the subject of

patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of

any patent rights identified during the development of the document will be in the Introduction and/or

on the ISO list of patent declarations received (see www .iso .org/ patents).

Any trade name used in this document is information given for the convenience of users and does not

constitute an endorsement.

For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and

expressions related to conformity assessment, as well as information about ISO's adherence to the

World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT), see www .iso .org/

iso/ foreword .html.

This document was prepared by Technical Committee ISO/TC 282, Water reuse, Subcommittee SC 1,

Treated wastewater reuse for irrigation.

This second edition cancels and replaces the first edition (ISO 16075-4:2016), which has been

technically revised.
The main changes compared to the previous edition are as follows:
— editorial update.
A list of all parts in the ISO 16075 series can be found on the ISO website.

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 © ISO 2021 – All rights reserved
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ISO 16075-4:2021(E)
Introduction

The increasing water scarcity and water pollution control efforts in many countries have made treated

municipal and industrial wastewater a suitable economic means of augmenting the existing water

supply, especially when compared to expensive alternatives such as desalination or the development

of new water sources involving dams and reservoirs. Water reuse makes it possible to close the water

cycle at a point closer to cities by producing “new water” from municipal wastewater and reducing

wastewater discharge to the environment. The reuse of treated wastewater could be also a beneficial

solution to improve water body’s quality, such as for example avoiding wastewater treatment plants

discharge upstream sensitive areas (shellfish aquaculture area, swimming area).

An important new concept in water reuse is the “fit-to-purpose” approach, which entails the production

of reclaimed water quality that meets the needs of the intended end-users. In the situation of reclaimed

water for irrigation, the reclaimed water quality can induce an adaptation of the type of plant grown.

Thus, the intended water reuse applications should govern the degree of wastewater treatment

required, and inversely, the reliability of wastewater reclamation processes and operation.

Treated wastewater (TWW, also referred to as reclaimed water or recycled water) can be used for

various non-potable purposes. The dominant applications for the use of TWW include agricultural

irrigation, landscape irrigation, industrial reuse and groundwater recharge. More recent and rapidly

growing applications are for various urban uses, recreational and environmental uses and indirect and

direct potable reuse.

Agricultural irrigation was, is and will likely remain the largest TWW consumer with recognized

benefits and contribution to food security. Urban water recycling, in particular landscape irrigation,

is characterized by fast development and will play a crucial role for the sustainability of cities in the

future, including energy footprint reduction, human well-being and environmental restoration.

The suitability of TWW for a given type of reuse depends on the compatibility between the wastewater

availability (volume) and water irrigation demand throughout the year, as well as on the water

quality and the specific use requirements. Water reuse for irrigation can convey some risks for health

and environment, depending on the water quality, the irrigation water application method, the soil

characteristics, the climate conditions and the agronomic practices. Consequently, public health and

potential agronomic and environmental adverse impacts need to be considered as priority elements

in the successful development of water reuse projects for irrigation. To prevent such potential adverse

impacts, the development and application of international guidelines for the reuse of TWW is essential.

The main water quality factors that determine the suitability of TWW for irrigation are pathogen

content, salinity, sodicity, specific ion toxicity, other chemical elements and nutrients. Local health

authorities are responsible for establishing water quality threshold values depending on authorized

uses and they are also responsible for defining practices to ensure health and environmental protection

taking in account local specificities.

From an agronomic point of view, the main limitation in using TWW for irrigation arises from its

quality. Treated wastewater, unlike water supplied for domestic and industrial purposes contains

higher concentrations of inorganic suspended and dissolved materials (total soluble salts, sodium,

chloride, boron, heavy metals), which can damage the soil and irrigated crops. As dissolved salts are

not removed by conventional wastewater treatment technologies and appropriate good management,

agronomic and irrigation practices should be used to avoid or minimize potential negative impacts.

The presence of nutrients (nitrogen, phosphorus and potassium) can become an advantage due to

possible saving in fertilizers. However, the amount of nutrients provided by TWW along the irrigation

period is not necessarily synchronized with crop requirements, and the availability of nutrients

depends on the chemical forms.

This document provides guidance for healthy, hydrological, environmental and good operation,

monitoring and maintenance of water reuse projects for unrestricted and restricted irrigation of

agricultural crops, gardens and landscape areas using treated wastewater. The quality of supplied

© ISO 2021 – All rights reserved v
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ISO 16075-4:2021(E)

TWW should reflect the possible uses according to crop sensitivity (health-wise and agronomy-wise),

water sources (the hydrologic sensitivity of the project area), the soil and climate conditions.

This document refers to factors involved in water reuse projects for irrigation regardless of size,

location and complexity. It is applicable to intended uses of TWW in a given project, even if such uses

will change during the project’s lifetime; as a result of changes in the project itself or in the applicable

legislation.

The key factors in assuring the health, environmental and safety of water reuse projects in irrigation

are:

— adequate monitoring of TWW quality to ensure the system functions as planned and designed;

— design and maintenance instructions of the irrigation systems to ensure their proper long-term

operation;

— compatibility between the TWW quality, the distribution method and the intended soil and crops to

ensure a viable use of the soil and undamaged crop growth;

— compatibility between the TWW quality and its use to prevent or minimize possible contamination

of groundwater or surface water sources.

This document is not intended to prevent the creation of more specific standards or guides which are

better adapted to specific regions, countries, areas, or organizations. If such documents are published,

it is recommended to reference this document to ensure uniformity throughout the treated wastewater

use community.
vi © ISO 2021 – All rights reserved
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INTERNATIONAL STANDARD ISO 16075-4:2021(E)
Guidelines for treated wastewater use for irrigation
projects —
Part 4:
Monitoring
1 Scope
This document provides recommendations regarding:
— monitoring the quality of treated wastewater (TWW) for irrigation;
— monitoring irrigated plants;
— monitoring the soil with regard to salinity;
— monitoring natural water sources in neighbouring environments;
— monitoring the quality of water in storage reservoirs.

It puts emphasis on sampling methods and their frequency. Regarding the methods of analysis, this

document refers to standard methods or, where not available, to other bibliographical references.

NOTE In cases where a monitoring plan already exists, these recommendations can be integrated into this

plan. This is notably the case when a broader approach of risk management is implemented, such as the water

[16]
safety plans (serving as a model for sanitation safety plans) developed by WHO .
2 Normative references

The following documents are referred to in the text in such a way that some or all of their content

constitutes requirements of this document. For dated references, only the edition cited applies. For

undated references, the latest edition of the referenced document (including any amendments) applies.

ISO 20670, Water reuse — Vocabulary

ISO 16075-1, Guidelines for treated wastewater use for irrigation projects — Part 1: The basis of a reuse

project for irrigation
3 Terms definitions, and abbreviated terms
3.1 Terms and definitions

For the purposes of this document, the terms and definitions given in ISO 20670 and ISO 16075-1 apply.

ISO and IEC maintain terminological databases for use in standardization at the following addresses:

— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at http:// www .electropedia .org/
© ISO 2021 – All rights reserved 1
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ISO 16075-4:2021(E)
3.2 Abbreviated terms
BOD biochemical oxygen demand
CFU colony forming units
COD chemical oxygen demand
DO dissolved oxygen
HDPE high-density polyethylene
PP polypropylene
QA quality assurance
QC quality control
SAR sodium adsorption ratio
SS suspended solids
TKN total Kjeldahl nitrogen
TP total phosphorus
TSS total suspended solids
TWW treated wastewater
VOC volatile organic compounds
WW wastewater
WWTP wastewater treatment plant
4 Monitoring of the quality of TWW for irrigation
4.1 General

The development and implementation of an appropriate monitoring strategy is a crucial step for the

health and environmental safety of water reuse projects. This compliance monitoring is performed

usually at the outlet of the wastewater treatment plant.

Monitoring can be undertaken for a range of purposes, and for each specific objective, different

parameters may be selected. For example, water quality monitoring can be implemented for the

following purposes:

a) human health protection: monitoring programmes include selected microbial indicators at

concentrations that depend on health risk (risk of direct contact, risk related to the type of crops,

etc.), as well as few other parameters, which indicate the reliability of operation of the wastewater

treatment (e.g. turbidity, suspended solids, BOD, residual chlorine, etc.);

b) prevention of adverse effect on crops: monitored parameters (named also agronomic parameters)

include nutrients, soluble salts, sodium, trace elements, etc.);

c) prevention of adverse effects on environment (natural water sources and soil);

d) prevention of clogging of irrigation system, e.g. drip and sprinkler irrigation.

2 © ISO 2021 – All rights reserved
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ISO 16075-4:2021(E)

The selection of sampling points to control water quality and treatment performance, named

“performance control points”, should depend on the type of application and the level of health and

environmental risks.

The key water quality control point should be located at the outlet of the wastewater reclamation plant.

[2]

Sampling at the plant outlet should follow ISO 5667-4. Treated wastewater should be monitored either

through grab sampling or composite sampling (see below), depending on the monitored parameters.

Composite samples (as a rule for 24 h using refrigerated equipment) are very important for

relevant monitoring of physico-chemical parameters as they represent the average quality of TWW.

Microbiological parameters, dissolved oxygen, pH and temperature should be monitored in grab

samples in situ, if possible during diurnal peak flow.

Similarly, the sampling frequency of other parameters related to prevention of adverse effects on

crops, soils and environment should be adapted to risk associated with sensitive crops and/or sensitive

environment (e.g. shallow aquifers used for potable water supply), and/or specific irrigation equipment.

The decision about the sampling (composite or grab) for these parameters should also take into account

the daily variations in raw wastewater.
4.2 Sampling procedure
4.2.1 General

Depending on the type of the monitored parameters, there exist some basic sampling rules described

in standard methods and International Standards for water analysis or some specific analytical

procedures defined by certified laboratories.
Sampling of TWW for irrigation should follow the list below:
— The sampling should be done by skilled employee.

— The type of samples can be either grab or composite samples to be used for water quality monitoring

depending on the final objectives,

— All samples should be well labelled, indicating the type of water, site location, date, time and other

pertinent data,
— Sampling frequency should be defined by water reuse granted permit,

— For better planning and management of the irrigation scheme, seasonal samples should be taken

depending on seasons in the concerned region, in order to obtain representative data on the

variation in water quality, in particular nitrogen and salinity,

— The baseline monitoring for human health protection should be undertaken by sampling at the

[1]
outlet of the treatment facility (see ISO 16075-2:2020, Table 1 ).

To check the reliability of operation of treatment processes, additional sampling points may be added

when necessary, particularly in the case of non-compliance.

— For verification of potential contamination or regrowth in storage reservoirs and/or distribution

network, additional control points for sampling can be established as a function of the final use, site

location and irrigation method, to verify potential contamination or regrowth in storage reservoirs

and/or in the distribution network.

— Bottle type should be determined according to the parameters tested. It should be taken into

account that some types of glass bottles yield boron to the samples and to prevent it high-density

polyethylene (HDPE) or polypropylene (PP) bottles with double caps or self-sealing caps may be

used.

As the sample quantity depends on the type of analysis to be performed, for the analysis of the

basic water characteristics and the main anions and cations, 1 l of sample can be sufficient.

© ISO 2021 – All rights reserved 3
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ISO 16075-4:2021(E)

— Sampling and handling should be done safely with suitable precaution to avoid disease transmission

by means of plastic gloves or using other protection.

Quality control samples should be collected as part of any routine sampling programme. Sampling and

handling of raw wastewater and treated wastewater should follow Table 1.
Table 1 — Recommendations for sample preparation and conservation
Parameter Type of bottle Addition of Conservation Comments
chemicals
Anions and cations 1 l HDPE or PP No additive Dark, 4 °C Temperature, pH and
(chloride, sulfate), as bottles with double dissolved oxygen should
well as general physico- caps or self-sealing be measured on site.
chemical parameters caps, with or
(pH, suspended solids, without air
conductivity, turbidity)
Phosphorus and 1 l HDPE or PP H SO to pH = 2 Dark, 4 °C
2 4
N Kjeldahl bottles with double
caps or self-sealing
caps, with or
without air
Boron 100 ml HDPE or PP HNO to pH = 2 Dark, 4 °C
bottles with double
caps or self-sealing
caps
COD 100 ml HDPE or PP H SO to pH = 2 Dark, 4 °C No additive is needed if
2 4
bottles with double the samples are analysed
caps or self-sealing within 48 h.
caps, no air
BOD 500 ml HDPE or PP No additive Dark, 4 °C Na SO should be used
2 3
bottles with double for dealing with samples
caps or self-sealing with residual chlo-
caps, no air rine. Sample should be
Preserved and added
seed for chlorinated and
dechlorinated wastewa-
ter samples.

Trace elements and 250 ml HDPE or PP HNO to pH = 2 Dark, 4 °C A special bottle [such as

heavy metals bottles with double polytetrafluoroethylene
caps or self-sealing (PTFE)] and additive are
caps, with or needed for the analysis
without air of mercury (Hg).
Trace organics and pes- 1 l dark glass bottle Ascorbic acid Dark 4 °C
ticides or PTFE bottle, no air (1000 mg l ) if
rinsed with organic residual chlorine
solvents is present

Microbiological param- 1 l to 5 l sterile No additive Dark, 4 °C Additive of sodium

eters (total and faecal HDPE or PP bottles thiosulfate at a well-de-
coliforms, helminths, with double caps or fined concentration is
viruses, or other addi- self-sealing caps bot- mandatory in presence
tional microbiological tle, with air of residual chlorine and
parameters) recommended in all
cases.
4.2.2 Sampling from an irrigation system

Water quality should be checked by the end user according to the following procedure:

a) Turn on the irrigation system until the system operates to full designed pressure and let the system

irrigate until the pipes have flushed of all stagnant water from the previous irrigation event.

4 © ISO 2021 – All rights reserved
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ISO 16075-4:2021(E)

b) Collect a sample from a tap located at the entrance to the irrigation system or from an irrigation

emitter (a sprinkler, micro-jet or a dripper).

c) The water sample should be collected in bottles as provided or recommended by the analytical

laboratory or procedure and the parameters to be tested (see Table 1). For bacterial sampling, a

sterile bottle should be used. Write all necessary details on a sticker attached to the bottle (name,

address, date, location, etc.) and seal the lid.

d) Preserve samples according to standard laboratory practice and transport them to an analytical

laboratory within the time period recommended for the analysis (see Table 1).

e) Water sampling should not be taken when fertigation (fertilization through irrigation) is taking

place.
[3]
For more information about sampling from an irrigation system, see ISO 5667-10 .
4.2.3 Sampling from a storage reservoir

To evaluate a potential evolution of treated wastewater quality during storage, a sample from the

storage reservoir should be taken.

The best way to measure the quality of TWW that was stored in a reservoir is by sampling the TWW at

appropriate sampling point situated at the exit of the reservoir's pumping station.

In periods of no irrigation from the reservoir, the sample should be taken directly from the storage

reservoir, according to the following procedures:

a) It is recommended to take the sample as close as possible to the pumping point;

b) Avoid sampling downwind to prevent the collection of floating materials (plant or algae residues)

transported by water waves to the downwind side of the storage reservoir;
c) Attach an empty bottle to the sampling pole;

d) Lower the bottle so that the neck is submerged in the storage reservoir to a depth of about 10 cm

and fill the bottle;
e) Remove the bottle from the storage reservoir, seal it and label the bottle;

f) Preserve the sample if required or refer to Table 1 to determine if and what preservative is

required. Store the sample and take them to the laboratory within the time period recommended

by the analytical laboratory or procedure (see Table 1).
[2]
For more information about sampling from a storage reservoir, see ISO 5667-4 .
4.2.4 Composite sample

To characterize TWW at the outlet of the treatment plant in order to take into account the fluctuations

of WW quality, a composite sample should be taken.
Composite sampling should be taken within a 24 h duration.
A refrigerated automatic sampler should be used.
4.2.5 Sample handling

Samples should be kept in a thermally insulated container and delivered immediately to the laboratory.

If the s
...

NORME ISO
INTERNATIONALE 16075-4
Deuxième édition
2021-05
Lignes directrices pour l'utilisation
des eaux usées traitées en
irrigation —
Partie 4:
Surveillance
Guidelines for treated wastewater use for irrigation projects —
Part 4: Monitoring
Numéro de référence
ISO 16075-4:2021(F)
© ISO 2021
---------------------- Page: 1 ----------------------
ISO 16075-4:2021(F)
DOCUMENT PROTÉGÉ PAR COPYRIGHT
© ISO 2021

Tous droits réservés. Sauf prescription différente ou nécessité dans le contexte de sa mise en œuvre, aucune partie de cette

publication ne peut être reproduite ni utilisée sous quelque forme que ce soit et par aucun procédé, électronique ou mécanique,

y compris la photocopie, ou la diffusion sur l’internet ou sur un intranet, sans autorisation écrite préalable. Une autorisation peut

être demandée à l’ISO à l’adresse ci-après ou au comité membre de l’ISO dans le pays du demandeur.

ISO copyright office
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CH-1214 Vernier, Genève
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Publié en Suisse
© ISO 2021 – Tous droits réservés
---------------------- Page: 2 ----------------------
ISO 16075-4:2021(F)
Sommaire Page

Avant-propos .............................................................................................................................................................................................................................iv

Introduction .................................................................................................................................................................................................................................v

1 Domaine d’application ................................................................................................................................................................................... 1

2 Références normatives ..................................................................................................................................................................................1

3 Termes, définitions et abréviations ................................................................................................................................................ 1

3.1 Termes et définitions ........................................................................................................................................................................ 1

3.2 Abréviations.............................................................................................................................................................................................. 2

4 Surveillance de la qualité des EUT destinées à l’irrigation .................................................................................... 2

4.1 Généralités ................................................................................................................................................................................................. 2

4.2 Mode opératoire d’échantillonnage ..................................................................................................................................... 3

4.2.1 Généralités ............................................................................................................................................................................... 3

4.2.2 Échantillonnage de l’eau d’un système d’irrigation ............................................................................ 5

4.2.3 Échantillonnage de l’eau d’un réservoir de stockage ......................................................................... 5

4.2.4 Échantillon composite ................................................................................................................................................... 6

4.2.5 Manipulation des échantillons ............................................................................................................................... 6

4.3 Plan de surveillance des EUT ........................................................................................................................................... .......... 6

4.4 Méthodes d’analyse relatives aux EUT .............................................................................................................................. 9

5 Surveillance des cultures irriguées ................................................................................................................................................ 9

5.1 Généralités ................................................................................................................................................................................................. 9

5.2 Fréquence de surveillance ........................................................................................................................................................... 9

5.2.1 Cultures de plein champ et légumes ................................................................................................................. 9

5.2.2 Cultures pérennes ............................................................................................................................................................. 9

6 Surveillance de la salinité du sol .....................................................................................................................................................10

6.1 Échantillonnage du sol ................................................................................................................................................................. 10

6.2 Fréquence d’échantillonnage du sol.................................................................................................................................. 10

6.3 Mode opératoire d’échantillonnage .................................................................................................................................. 11

6.3.1 Irrigation par goutte-à-goutte............................................................................................................................. 11

6.3.2 Irrigation par arrosage et par mini-diffuseurs .................................................................................... 11

6.4 Préparation des échantillons .................................................................................................................................................. 11

6.5 Méthodes d’analyse des sols .................................................................................................................................................... 11

7 Surveillance du milieu récepteur ...................................................................................................................................................12

7.1 Généralités ..............................................................................................................................................................................................12

7.2 Objectif du programme de surveillance .......................................................................................................................12

7.3 Échantillonnage des eaux souterraines ........................................................................................................................12

7.4 Échantillonnage des eaux de surface ............................................................................................................................... 13

8 Assurance qualité et contrôle qualité ........................................................................................................................................13

Bibliographie ...........................................................................................................................................................................................................................15

iii
© ISO 2021 – Tous droits réservés
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ISO 16075-4:2021(F)
Avant-propos

L’ISO (Organisation internationale de normalisation) est une fédération mondiale d’organismes

nationaux de normalisation (comités membres de l’ISO). L’élaboration des Normes internationales est

en général confiée aux comités techniques de l’ISO. Chaque comité membre intéressé par une étude

a le droit de faire partie du comité technique créé à cet effet. Les organisations internationales,

gouvernementales et non gouvernementales, en liaison avec l’ISO participent également aux travaux.

L’ISO collabore étroitement avec la Commission électrotechnique internationale (IEC) en ce qui

concerne la normalisation électrotechnique.

Les procédures utilisées pour élaborer le présent document et celles destinées à sa mise à jour sont

décrites dans les Directives ISO/IEC, Partie 1. Il convient, en particulier de prendre note des différents

critères d’approbation requis pour les différents types de documents ISO. Le présent document

a été rédigé conformément aux règles de rédaction données dans les Directives ISO/IEC, Partie 2

(voir www.iso.org/directives).

L'attention est attirée sur le fait que certains des éléments du présent document peuvent faire l'objet de

droits de propriété intellectuelle ou de droits analogues. L'ISO ne saurait être tenue pour responsable

de ne pas avoir identifié de tels droits de propriété et averti de leur existence. Les détails concernant

les références aux droits de propriété intellectuelle ou autres droits analogues identifiés lors de

l'élaboration du document sont indiqués dans l'Introduction et/ou dans la liste des déclarations de

brevets reçues par l'ISO (voir www.iso.org/brevets).

Les appellations commerciales éventuellement mentionnées dans le présent document sont données

pour information, par souci de commodité, à l’intention des utilisateurs et ne sauraient constituer un

engagement.

Pour une explication de la nature volontaire des normes, la signification des termes et expressions

spécifiques de l'ISO liés à l'évaluation de la conformité, ou pour toute information au sujet de l'adhésion

de l'ISO aux principes de l’Organisation mondiale du commerce (OMC) concernant les obstacles

techniques au commerce (OTC), voir www.iso.org/avant-propos.

Le présent document a été élaboré par le Comité technique ISO/TC 282, Recyclage des eaux, sous-

comité SC 1, Recyclage des eaux usées traitées à des fins d’irrigation.

Cette deuxième édition annule et remplace la première édition (ISO 16075-4:2016), qui a fait l’objet

d’une révision technique.

Les principales modifications par rapport à l’édition précédente sont les suivantes:

— mise à jour rédactionnelle.

Une liste de toutes les parties de la série ISO 16075 se trouve sur le site web de l’ISO.

Il convient que l’utilisateur adresse tout retour d’information ou toute question concernant le présent

document à l’organisme national de normalisation de son pays. Une liste exhaustive desdits organismes

est disponible à l’adresse www.iso.org/members.html.
© ISO 2021 – Tous droits réservés
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ISO 16075-4:2021(F)
Introduction

Au vu des efforts croissants déployés par de nombreux pays pour pallier la rareté et la pollution

de leurs ressources en eau, les eaux usées municipales et industrielles traitées sont devenues un

moyen économique judicieux pour augmenter les quantités disponibles, notamment par rapport à

des alternatives coûteuses telles que le dessalement ou le développement de nouvelles sources d’eau

impliquant la construction de barrages et de réservoirs. La réutilisation de l’eau permet de fermer le

cycle de l’eau plus près des villes, en produisant une «eau neuve» à partir des eaux usées municipales

et en réduisant les rejets d’eaux usées dans l’environnement. La réutilisation des eaux usées traitées

pourrait également être une solution avantageuse pour améliorer la qualité des masses d’eau, par

exemple en évitant les rejets des stations d’épuration des eaux usées en amont de zones sensibles (zones

d’aquaculture (fruits de mer), zones de natation).

Un nouveau concept important en matière de réutilisation des eaux usées est l’approche «adaptée

aux besoins», qui implique la production d’eau réutilisée d’une qualité répondant aux besoins des

utilisateurs finaux prévus. Dans le cas de l’eau réutilisée destinée à l’irrigation, la qualité de l’eau peut

conduire à adapter les types de végétaux cultivés. Il convient donc que les applications prévues de

réutilisation de l’eau dictent le degré de traitement requis pour les eaux usées, et réciproquement, de

même que la fiabilité et l’entretien des systèmes de réutilisation des eaux usées.

Les eaux usées traitées (EUT, également qualifiées d’eaux réutilisées ou d’eaux recyclées) peuvent

être utilisées à différentes fins comme eau non potable. Les principales applications utilisant les EUT

comprennent l’irrigation des terres agricoles, l’irrigation des espaces verts, la réutilisation industrielle

et la recharge de nappe. Des applications plus récentes, qui se développent rapidement, ciblent

différents usages: urbain, récréatif, environnemental, ainsi que la réutilisation directe et indirecte pour

la production d’eau potable.

L’irrigation des terres agricoles a toujours été et restera probablement le secteur qui consomme le plus

d’eaux usées traitées, les avantages de cette pratique et sa contribution à la sécurité alimentaire étant

reconnus. Le recyclage de l’eau pour des applications urbaines, et notamment l’irrigation des espaces

verts, se caractérise par un essor rapide et jouera un rôle décisif pour le développement durable des

villes à l’avenir, y compris du point de vue de la réduction de l’empreinte énergétique, du bien-être de la

population et de la restauration de l’environnement.

L’adéquation des EUT à un type de réutilisation donné dépend de la correspondance entre la disponibilité

des eaux usées (leur volume) et la demande en eau d’irrigation tout au long de l’année, ainsi que de la

qualité de l’eau et des exigences spécifiques d’utilisation. La réutilisation de l’eau pour l’irrigation peut

comporter certains risques pour la santé et l’environnement, en fonction de la qualité de l’eau, de la

méthode d’application de l’eau d’irrigation, des caractéristiques du sol, des conditions climatiques et

des pratiques agronomiques. Par conséquent, il est nécessaire de considérer la santé publique et les

impacts négatifs potentiels sur l’agronomie et l’environnement comme des aspects prioritaires afin

de réussir le développement de projets de réutilisation de l’eau pour l’irrigation. Afin de prévenir de

tels impacts négatifs potentiels, il est essentiel d’élaborer et de mettre en œuvre des lignes directrices

internationales pour la réutilisation des EUT.

Les principaux critères de qualité d'eau déterminant l’adéquation des EUT pour l’irrigation sont la

teneur en agents pathogènes, la salinité, la sodicité, la toxicité d’ions spécifiques, les autres éléments

chimiques et les nutriments. Il incombe aux autorités sanitaires locales d’établir des valeurs seuils

de qualité de l’eau en fonction des utilisations autorisées et de définir des pratiques pour garantir la

protection sanitaire et environnementale en tenant compte des spécificités locales.

D’un point de vue agronomique, la principale limitation à l’utilisation des EUT en irrigation est liée à leur

qualité. Les eaux usées traitées, contrairement à l’eau destinée à des usages domestiques et industriels,

contiennent de plus fortes concentrations de matières inorganiques en suspension et dissoutes (sels

totaux solubles, sodium, chlorures, bore, métaux lourds), qui peuvent nuire au sol et aux cultures

irriguées. Les sels dissous n’étant pas éliminés par les techniques conventionnelles de traitement des

eaux usées, il convient d’adopter de bonnes pratiques en matière de gestion, d’agronomie et d’irrigation

pour éviter ou réduire le plus possible les impacts négatifs potentiels.
© ISO 2021 – Tous droits réservés
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ISO 16075-4:2021(F)

La présence de nutriments (azote, phosphore et potassium) peut constituer un avantage en raison des

économies d’engrais qu’elle permet. Cependant, la quantité de nutriments fournie par les EUT tout au

long de la période d’irrigation ne coïncide pas forcément avec les besoins des cultures et la disponibilité

des nutriments dépend de leur forme chimique.

Le présent document fournit des recommandations pour assurer le déroulement, la surveillance et

la maintenance dans de bonnes conditions, sur les plans sanitaire, hydrologique et environnemental,

des projets de réutilisation de l’eau pour l’irrigation non restreinte et restreinte de cultures agricoles,

de jardins et d’espaces verts avec des eaux usées traitées. Il convient que la qualité des EUT fournies

corresponde aux utilisations possibles en fonction de la sensibilité des cultures (sur le plan sanitaire

et sur le plan agronomique), des sources d’eau (sensibilité hydrologique de la zone concernée par le

projet), du sol et des conditions climatiques.

Le présent document porte sur les facteurs entrant en ligne de compte dans les projets de réutilisation

de l’eau pour l’irrigation, indépendamment de leur taille, de leur complexité et de leur situation

géographique. Il est applicable aux utilisations des EUT prévues dans un projet donné, même si ces

utilisations sont amenées à changer pendant la durée de vie du projet, du fait de modifications apportées

au projet lui-même ou à la législation en vigueur.

Les principaux facteurs entrant en jeu pour assurer la sécurité, en matière de santé et d’environnement,

des projets de réutilisation de l’eau en irrigation sont les suivants:

— une surveillance méticuleuse de la qualité des EUT pour garantir le fonctionnement du système

conformément aux prévisions et à la conception;

— des instructions de conception et de maintenance des systèmes d’irrigation pour garantir leur bon

fonctionnement à long terme;

— la compatibilité entre la qualité des EUT, la méthode de distribution et le type de sol et de cultures à

irriguer pour garantir une exploitation viable du sol et une croissance normale des cultures;

— l’adéquation entre la qualité des EUT et leur utilisation pour empêcher ou réduire le plus possible

toute contamination éventuelle des sources d’eaux souterraines ou d’eaux de surface.

Le présent document n’a pas vocation à empêcher l’élaboration de normes ou de guides plus spécifiques,

mieux adaptés à des régions, des pays, des zones ou des organismes particuliers. Si des documents de

ce type sont publiés, il est recommandé qu’ils fassent référence au présent document afin de garantir

l’uniformité au sein de tous les acteurs utilisant des eaux usées traitées.
© ISO 2021 – Tous droits réservés
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NORME INTERNATIONALE ISO 16075-4:2021(F)
Lignes directrices pour l'utilisation des eaux usées traitées
en irrigation —
Partie 4:
Surveillance
1 Domaine d’application
Le présent document fournit des recommandations concernant:

— la surveillance de la qualité des eaux usées traitées (abrégées en EUT) pour l’irrigation;

— la surveillance des cultures irriguées;
— la surveillance de la salinité du sol;
— la surveillance des sources d’eau naturelle dans les environs;
— la surveillance de la qualité de l’eau dans les réservoirs de stockage.

Le présent document met l’accent sur les méthodes et la fréquence d’échantillonnage. Concernant les

méthodes d’analyse, il se réfère à des méthodes normalisées ou, lorsque celles-ci font défaut, à d’autres

références bibliographiques.

NOTE Dans les cas où un plan de surveillance existe déjà, les présentes recommandations peuvent être

intégrées à ce plan. C’est le cas notamment lorsqu’une approche de gestion du risque de plus grande portée est

mise en œuvre, par exemple les plans de gestion de la sécurité sanitaire de l’eau (qui servent de modèle aux plans

[16]

de sécurité sanitaire de l’assainissement) élaborés par l’Organisation mondiale de la Santé .

2 Références normatives

Les documents suivants sont cités dans le texte de sorte qu’ils constituent, pour tout ou partie de leur

contenu, des exigences du présent document. Pour les références datées, seule l’édition citée s’applique.

Pour les références non datées, la dernière édition du document de référence s’applique (y compris les

éventuels amendements).

ISO 16075-1, Lignes directrices pour l'utilisation des eaux usées traitées dans les projets d'irrigation —

Partie 1: Les bases d'un projet de réutilisation pour l'irrigation
ISO 20670, Réutilisation de l'eau — Vocabulaire
3 Termes, définitions et abréviations
3.1 Termes et définitions

Pour les besoins du présent document, les termes et définitions de l’ISO 16075-1 et de l’ISO 20670

s’appliquent.

L’ISO et l’IEC tiennent à jour des bases de données terminologiques destinées à être utilisées en

normalisation, consultables aux adresses suivantes:

— ISO Online browsing platform: disponible à l’adresse https:// www .iso .org/ obp

— IEC Electropedia: disponible à l’adresse https:// www .electropedia .org/
© ISO 2021 – Tous droits réservés
---------------------- Page: 7 ----------------------
ISO 16075-4:2021(F)
3.2 Abréviations
AQ assurance qualité
COV composés organiques volatils
CQ contrôle qualité
DBO demande biochimique en oxygène
DCO demande chimique en oxygène
EU eaux usées
EUT eaux usées traitées
MES matières en suspension
MEST matières en suspension totales
OD oxygène dissous
PEHD polyéthylène haute densité
PP polypropylène
PT phosphore total
SAR taux d’absorption du sodium
STEP station d’épuration des eaux usées
TKN azote total Kjeldahl
UFC unités formant colonies
4 Surveillance de la qualité des EUT destinées à l’irrigation
4.1 Généralités

L’élaboration et la mise en œuvre d’une stratégie de surveillance appropriée représentent une étape

très importante pour la sécurité sanitaire et environnementale des projets de réutilisation de l’eau.

Cette surveillance de conformité s’effectue habituellement à la sortie de la station d’épuration des eaux

usées.

La surveillance peut répondre à différentes finalités et, pour chaque objectif spécifique, il est admis de

choisir des paramètres différents. Par exemple, la surveillance de la qualité de l’eau peut être entreprise

dans les buts suivants:

a) protection de la santé humaine: les programmes de surveillance incluent des indicateurs

microbiens sélectionnés, à des concentrations qui dépendent du risque sanitaire (risque de contact

direct, risque lié aux types de cultures, etc.), et quelques autres paramètres qui indiquent la fiabilité

opérationnelle des processus de traitement des eaux usées (par exemple, turbidité, matières en

suspension, DBO, chlore résiduel, etc.);

b) prévention des effets négatifs sur les cultures: les paramètres surveillés (également nommés

paramètres agronomiques) incluent les nutriments, les sels solubles, le sodium, les éléments

traces, etc.;

c) prévention des effets néfastes sur l’environnement (sources d’eau naturelle et sol);

© ISO 2021 – Tous droits réservés
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ISO 16075-4:2021(F)

d) prévention du colmatage du système d’irrigation, par exemple irrigation par goutte-à-goutte et

irrigation par arroseurs.

Il convient de sélectionner les points d’échantillonnage destinés au contrôle de la qualité de l’eau et

des performances du traitement, appelés «points de contrôle de performances» en fonction du type

d’application et du niveau des risques sanitaires et environnementaux.

Il convient que le principal point de contrôle de la qualité de l’eau se situe à la sortie de l’installation

de recyclage des eaux usées. Il convient que l’échantillonnage à la sortie de la station soit effectué

[2]

conformément à l’ISO 5667-4 . Il convient que les eaux usées traitées soient surveillées soit par

prélèvement d’échantillons ponctuels, soit par prélèvement d’échantillons composites (voir ci-après), en

fonction des paramètres surveillés.

Les échantillons composites (généralement prélevés sur 24 h en utilisant un équipement réfrigéré)

jouent un rôle essentiel pour une surveillance pertinente des paramètres physico-chimiques, car ils

représentent la qualité moyenne des EUT. Il convient que les paramètres microbiologiques, l’oxygène

dissous, le pH et la température soient surveillés par des échantillons ponctuels in situ, si possible à un

moment de la journée où le débit est à son maximum.

De même, il convient d’adapter la fréquence d’échantillonnage concernant d’autres paramètres liés à

la prévention des effets néfastes sur les cultures, les sols et l’environnement au risque associé à des

cultures sensibles et/ou à un environnement sensible (par exemple, aquifères peu profonds utilisés

pour l’alimentation en eau potable) et/ou à un équipement d’irrigation particulier. Il convient que la

décision concernant l’échantillonnage (échantillons composites ou ponctuels) destiné à la surveillance

de ces paramètres tienne également compte des variations journalières dans les eaux usées brutes.

4.2 Mode opératoire d’échantillonnage
4.2.1 Généralités

En fonction du type de paramètres surveillés, un certain nombre de règles de base pour l’échantillonnage

sont décrites dans des méthodes normalisées et les Normes internationales relatives à l’analyse de l’eau

ou certains modes opératoires d’analyse spécifiques définis par des laboratoires certifiés.

Il convient que l’échantillonnage des EUT destinées à l’irrigation réponde aux critères énumérés ci-

dessous:
— il convient que l’échantillonnage soit effectué par du personnel qualifié;

— les échantillons à utiliser pour la surveillance de la qualité de l’eau peuvent être ponctuels ou

composites, en fonction des objectifs finaux;

— il convient d’étiqueter convenablement tous les échantillons, en indiquant le type d’eau, l’emplacement

du site, la date, l’heure et d’autres données pertinentes;

— il convient que la fréquence d’échantillonnage soit définie par l’autorisation de réutilisation des

eaux;

— afin d’améliorer la spécification des besoins et la gestion du plan d’irrigation, il convient d’effectuer

des prélèvements saisonniers au gré des saisons dans la région concernée pour obtenir des données

représentatives sur la variation de la qualité de l’eau, en particulier concernant l’azote et la salinité;

— il convient que la surveillance de base, en matière de protection de la santé humaine, s’effectue par

[1]

échantillonnage à la sortie de l’installation de traitement (voir l’ISO 16075-2:2020, Tableau 1 ).

La fiabilité opérationnelle des processus de traitement peut être vérifiée en ajoutant des points

d’échantillonnage supplémentaires, si nécessaire, notamment en cas de non-conformité.

— des points de contrôle supplémentaires peuvent être établis en fonction de l’utilisation finale, de

l’emplacement du site et de la méthode d’irrigation afin de vérifier le risque de contamination ou de

reprise de la croissance bactérienne dans les réservoirs de stockage et/ou le réseau de distribution;

© ISO 2021 – Tous droits réservés
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ISO 16075-4:2021(F)

— il convient de déterminer le type de flacon en fonction des paramètres étudiés. Il convient de tenir

compte du fait que certains types de flacons en verre cèdent du bore aux échantillons; pour pallier

cet inconvénient, il est admis d’utiliser des flacons en polyéthylène haute densité (PEHD) ou en

polypropylène (PP), à bouchons doubles ou à bouchons auto-obturants;

Comme le volume échantillonné dépend du type d’analyse à réaliser, un échantillon de 1 l peut

suffire dans le cadre de l’analyse des paramètres de base de l’eau et des principaux anions et cations.

— il convient que le prélèvement et les manipulations soient effectués en toute sécurité, en prenant des

précautions appropriées pour éviter la transmission de maladies par le port de gants en plastique

ou l’utilisation d’autres types de protection.

Il convient que des échantillons destinés au contrôle de la qualité soient prélevés dans le cadre de tout

programme d’échantillonnage de routine. Il convient que le prélèvement et la manipulation des eaux

usées brutes et des eaux usées traitées soient conformes aux recommandations du Tableau 1.

Tableau 1 — Recommandations pour la préparation et la conservation des échantillons

Paramètre Type de flacon Ajout de Conservation Commentaires
substances
chimiques

Anions et cations (chlo- Flacons de 1 l Sans additif À l’abri de Il convient que la tempé-

rure, sulfate), ainsi que en PEHD ou en PP, la lumière, 4 °C rature, le pH et l’oxygène

les paramètres physico- à bouchons doubles dissous soient mesurés
chimiques généraux (pH, ou auto-obturants, sur site.
matières en suspension, avec ou sans air
conductivité, turbidité)
Phosphore et Flacons de 1 l H SO à pH = 2 À l’abri de
2 4
azote Kjeldahl en PEHD ou en PP, la lumière, 4 °C
à bouchons doubles
ou auto-obturants,
avec ou sans air
Bore Flacons de 100 ml HNO à pH = 2 À l’abri de
en PEHD ou en PP, la lumière, 4 °C
à bouchons doubles
ou auto-obturants
DCO Flacons de 100 ml H SO à pH = 2 À l’abri de Aucun additif requis
2 4
en PEHD ou en PP, la lumière, 4 °C si les échantillons sont
à bouchons doubles analysés dans les 48 h.
ou auto-obturants,
sans air
DBO Flacons de 500 ml Sans additif À l’abri de Il convient d’utiliser
en PEHD ou en PP, la lumière, 4 °C du Na SO pour traiter
2 3
à bouchons doubles les échantillons conte-
ou auto-obturants, nant du chlore résiduel.
sans air Il convient de conserver
l’échantillon et d’ense-
mencer les échantillons
d’eaux usées chlorées et
déchlorées.
Éléments traces et Flacons de 250 ml HNO
...

INTERNATIONAL ISO
STANDARD 16075-4
Second edition
Guidelines for treated wastewater use
for irrigation projects —
Part 4:
Monitoring
Lignes directrices pour l'utilisation des eaux usées traitées en
irrigation —
Partie 4: Surveillance
PROOF/ÉPREUVE
Reference number
ISO 16075-4:2021(E)
ISO 2021
---------------------- Page: 1 ----------------------
ISO 16075-4:2021(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2021

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: +41 22 749 01 11
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii PROOF/ÉPREUVE © ISO 2021 – All rights reserved
---------------------- Page: 2 ----------------------
ISO 16075-4:2021(E)
Contents Page

Foreword ........................................................................................................................................................................................................................................iv

Introduction ..................................................................................................................................................................................................................................v

1 Scope ................................................................................................................................................................................................................................. 1

2 Normative references ...................................................................................................................................................................................... 1

3 Terms definitions, and abbreviated terms ................................................................................................................................ 1

3.1 Terms and definitions ....................................................................................................................................................................... 1

3.2 Abbreviated terms ............................................................................................................................................................................... 2

4 Monitoring of the quality of TWW for irrigation ................................................................................................................ 2

4.1 General ........................................................................................................................................................................................................... 2

4.2 Sampling procedure ........................................................................................................................................................................... 3

4.2.1 General...................................................................................................................................................................................... 3

4.2.2 Sampling from an irrigation system ................................................................................................................ 4

4.2.3 Sampling from a storage reservoir ................................................................................................................... 5

4.2.4 Composite sample ...................................................................... ..................................................................................... 5

4.2.5 Sample handling ............................................................................................................................................................... 5

4.3 TWW monitoring plan ...................................................................................................................................................................... 6

4.4 Analytical methods for TWW ..................................................................................................................................................... 8

5 Monitoring of the irrigated crops ....................................................................................................................................................... 8

5.1 General ........................................................................................................................................................................................................... 8

5.2 Frequency of monitoring ................................................................................................................................................................ 8

5.2.1 Field crops and vegetables ...................................................................................................................................... 8

5.2.2 Perennial crops.................................................................................................................................................................. 8

6 Monitoring of the soil with regard to salinity ......................................................................................................................... 9

6.1 Soil sampling ............................................................................................................................................................................................. 9

6.2 Frequency of the soil sampling ................................................................................................................................................. 9

6.3 Sampling procedure ........................................................................................................................................................................10

6.3.1 Drip irrigation .................................................................................................................................................................10

6.3.2 Sprinkler and micro-jet irrigation .................................................................................................................10

6.4 Sample preparation .........................................................................................................................................................................10

6.5 Soil test methods ................................................................................................................................................................................10

7 Receiving environment monitoring ...............................................................................................................................................10

7.1 General ........................................................................................................................................................................................................10

7.2 Monitoring programme purpose ..........................................................................................................................................11

7.3 Groundwater sampling .................................................................................................................................................................11

7.4 Surface water sampling ................................................................................................................................................................12

8 Quality assurance and quality control ........................................................................................................................................12

Bibliography .............................................................................................................................................................................................................................14

© ISO 2021 – All rights reserved PROOF/ÉPREUVE iii
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ISO 16075-4:2021(E)
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 has been established has the right to be represented on that committee. International

organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.

ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of

electrotechnical standardization.

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 documents 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).

Attention is drawn to the possibility that some of the elements of this document may be the subject of

patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of

any patent rights identified during the development of the document will be in the Introduction and/or

on the ISO list of patent declarations received (see www .iso .org/ patents).

Any trade name used in this document is information given for the convenience of users and does not

constitute an endorsement.

For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and

expressions related to conformity assessment, as well as information about ISO's adherence to the

World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT), see www .iso .org/

iso/ foreword .html.

This document was prepared by Technical Committee ISO/TC 282, Water reuse, Subcommittee SC 1,

Treated wastewater reuse for irrigation.

This second edition cancels and replaces the first edition (ISO 16075-4:2016), which has been

technically revised.
The main changes compared to the previous edition are as follows:
— xxx xxxxxxx xxx xxxx;
— xxx xxxxxxx xxx xxxx;
— xxx xxxxxxx xxx xxxx.
A list of all parts in the ISO 16075 series can be found on the ISO website.

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 16075-4:2021(E)
Introduction

The increasing water scarcity and water pollution control efforts in many countries have made treated

municipal and industrial wastewater a suitable economic means of augmenting the existing water

supply, especially when compared to expensive alternatives such as desalination or the development

of new water sources involving dams and reservoirs. Water reuse makes it possible to close the water

cycle at a point closer to cities by producing “new water” from municipal wastewater and reducing

wastewater discharge to the environment. The reuse of treated wastewater could be also a beneficial

solution to improve water body’s quality, such as for example avoiding wastewater treatment plants

discharge upstream sensitive areas (shellfish aquaculture area, swimming area).

An important new concept in water reuse is the “fit-to-purpose” approach, which entails the production

of reclaimed water quality that meets the needs of the intended end-users. In the situation of reclaimed

water for irrigation, the reclaimed water quality can induce an adaptation of the type of plant grown.

Thus, the intended water reuse applications should govern the degree of wastewater treatment

required, and inversely, the reliability of wastewater reclamation processes and operation.

Treated wastewater (TWW, also referred to as reclaimed water or recycled water) can be used for

various non-potable purposes. The dominant applications for the use of TWW include agricultural

irrigation, landscape irrigation, industrial reuse and groundwater recharge. More recent and rapidly

growing applications are for various urban uses, recreational and environmental uses and indirect and

direct potable reuse.

Agricultural irrigation was, is and will likely remain the largest TWW consumer with recognized

benefits and contribution to food security. Urban water recycling, in particular landscape irrigation,

is characterized by fast development and will play a crucial role for the sustainability of cities in the

future, including energy footprint reduction, human well-being and environmental restoration.

The suitability of TWW for a given type of reuse depends on the compatibility between the wastewater

availability (volume) and water irrigation demand throughout the year, as well as on the water

quality and the specific use requirements. Water reuse for irrigation can convey some risks for health

and environment, depending on the water quality, the irrigation water application method, the soil

characteristics, the climate conditions and the agronomic practices. Consequently, public health and

potential agronomic and environmental adverse impacts need to be considered as priority elements

in the successful development of water reuse projects for irrigation. To prevent such potential adverse

impacts, the development and application of international guidelines for the reuse of TWW is essential.

The main water quality factors that determine the suitability of TWW for irrigation are pathogen

content, salinity, sodicity, specific ion toxicity, other chemical elements and nutrients. Local health

authorities are responsible for establishing water quality threshold values depending on authorized

uses and they are also responsible for defining practices to ensure health and environmental protection

taking in account local specificities.

From an agronomic point of view, the main limitation in using TWW for irrigation arises from its

quality. Treated wastewater, unlike water supplied for domestic and industrial purposes contains

higher concentrations of inorganic suspended and dissolved materials (total soluble salts, sodium,

chloride, boron, heavy metals), which can damage the soil and irrigated crops. As dissolved salts are

not removed by conventional wastewater treatment technologies and appropriate good management,

agronomic and irrigation practices should be used to avoid or minimize potential negative impacts.

The presence of nutrients (nitrogen, phosphorus and potassium) can become an advantage due to

possible saving in fertilizers. However, the amount of nutrients provided by TWW along the irrigation

period is not necessarily synchronized with crop requirements, and the availability of nutrients

depends on the chemical forms.

This document provides guidance for healthy, hydrological, environmental and good operation,

monitoring and maintenance of water reuse projects for unrestricted and restricted irrigation of

agricultural crops, gardens and landscape areas using treated wastewater. The quality of supplied

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ISO 16075-4:2021(E)

TWW should reflect the possible uses according to crop sensitivity (health-wise and agronomy-wise),

water sources (the hydrologic sensitivity of the project area), the soil and climate conditions.

This document refers to factors involved in water reuse projects for irrigation regardless of size,

location and complexity. It is applicable to intended uses of TWW in a given project, even if such uses

will change during the project’s lifetime; as a result of changes in the project itself or in the applicable

legislation.

The key factors in assuring the health, environmental and safety of water reuse projects in irrigation are:

— adequate monitoring of TWW quality to ensure the system functions as planned and designed;

— design and maintenance instructions of the irrigation systems to ensure their proper long-term

operation;

— compatibility between the TWW quality, the distribution method and the intended soil and crops to

ensure a viable use of the soil and undamaged crop growth;

— compatibility between the TWW quality and its use to prevent or minimize possible contamination

of groundwater or surface water sources.

This document is not intended to prevent the creation of more specific standards or guides which are

better adapted to specific regions, countries, areas, or organizations. If such documents are published,

it is recommended to reference this document to ensure uniformity throughout the treated wastewater

use community.
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INTERNATIONAL STANDARD ISO 16075-4:2021(E)
Guidelines for treated wastewater use for irrigation
projects —
Part 4:
Monitoring
1 Scope
This document provides recommendations regarding:
— monitoring the quality of treated wastewater (TWW) for irrigation;
— monitoring irrigated plants;
— monitoring the soil with regard to salinity;
— monitoring natural water sources in neighbouring environments;
— monitoring the quality of water in storage reservoirs.

It puts emphasis on sampling methods and their frequency. Regarding the methods of analysis, this

document refers to standard methods or, where not available, to other bibliographical references.

NOTE In cases where a monitoring plan already exists, these recommendations can be integrated into this

plan. This is notably the case when a broader approach of risk management is implemented, such as the water

[16]
safety plans (serving as a model for sanitation safety plans) developed by WHO .
2 Normative references

The following documents are referred to in the text in such a way that some or all of their content

constitutes requirements of this document. For dated references, only the edition cited applies. For

undated references, the latest edition of the referenced document (including any amendments) applies.

ISO 20670, Water reuse — Vocabulary

ISO 16075-1, Guidelines for treated wastewater use for irrigation projects — Part 1: The basis of a reuse

project for irrigation
3 Terms definitions, and abbreviated terms
3.1 Terms and definitions

For the purposes of this document, the terms and definitions given in ISO 20670 and ISO 16075-1 apply.

ISO and IEC maintain terminological databases for use in standardization at the following addresses:

— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at http:// www .electropedia .org/
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ISO 16075-4:2021(E)
3.2 Abbreviated terms
BOD biochemical oxygen demand
CFU colony forming units
COD chemical oxygen demand
DO dissolved oxygen
HDPE high-density polyethylene
PP polypropylene
QA quality assurance
QC quality control
SAR sodium adsorption ratio
SS suspended solids
TKN total Kjeldahl nitrogen
TP total phosphorus
TSS total suspended solids
TWW treated wastewater
VOC volatile organic compounds
WW wastewater
WWTP wastewater treatment plant
4 Monitoring of the quality of TWW for irrigation
4.1 General

The development and implementation of an appropriate monitoring strategy is a crucial step for the

health and environmental safety of water reuse projects. This compliance monitoring is performed

usually at the outlet of the wastewater treatment plant.

Monitoring can be undertaken for a range of purposes, and for each specific objective, different

parameters may be selected. For example, water quality monitoring can be implemented for the

following purposes:

a) human health protection: monitoring programmes include selected microbial indicators at

concentrations that depend on health risk (risk of direct contact, risk related to the type of crops,

etc.), as well as few other parameters, which indicate the reliability of operation of the wastewater

treatment (e.g. turbidity, suspended solids, BOD, residual chlorine, etc.);

b) prevention of adverse effect on crops: monitored parameters (named also agronomic parameters)

include nutrients, soluble salts, sodium, trace elements, etc.);

c) prevention of adverse effects on environment (natural water sources and soil);

d) prevention of clogging of irrigation system, e.g. drip and sprinkler irrigation.

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ISO 16075-4:2021(E)

The selection of sampling points to control water quality and treatment performance, named

“performance control points”, should depend on the type of application and the level of health and

environmental risks.

The key water quality control point should be located at the outlet of the wastewater reclamation plant.

[2]

Sampling at the plant outlet should follow ISO 5667-4. Treated wastewater should be monitored either

through grab sampling or composite sampling (see below), depending on the monitored parameters.

Composite samples (as a rule for 24 h using refrigerated equipment) are very important for

relevant monitoring of physico-chemical parameters as they represent the average quality of TWW.

Microbiological parameters, dissolved oxygen, pH and temperature should be monitored in grab

samples in situ, if possible during diurnal peak flow.

Similarly, the sampling frequency of other parameters related to prevention of adverse effects on

crops, soils and environment should be adapted to risk associated with sensitive crops and/or sensitive

environment (e.g. shallow aquifers used for potable water supply), and/or specific irrigation equipment.

The decision about the sampling (composite or grab) for these parameters should also take into account

the daily variations in raw wastewater.
4.2 Sampling procedure
4.2.1 General

Depending on the type of the monitored parameters, there exist some basic sampling rules described

in standard methods and International Standards for water analysis or some specific analytical

procedures defined by certified laboratories.
Sampling of TWW for irrigation should follow the list below:
— The sampling should be done by skilled employee.

— The type of samples can be either grab or composite samples to be used for water quality monitoring

depending on the final objectives,

— All samples should be well labelled, indicating the type of water, site location, date, time and other

pertinent data,
— Sampling frequency should be defined by water reuse granted permit,

— For better planning and management of the irrigation scheme, seasonal samples should be taken

depending on seasons in the concerned region, in order to obtain representative data on the

variation in water quality, in particular nitrogen and salinity,

— The baseline monitoring for human health protection should be undertaken by sampling at the

[1]
outlet of the treatment facility (see ISO 16075-2:2020, Table 1 ).

To check the reliability of operation of treatment processes, additional sampling points may be added

when necessary, particularly in the case of non-compliance.

— For verification of potential contamination or regrowth in storage reservoirs and/or distribution

network, additional control points for sampling can be established as a function of the final use, site

location and irrigation method, to verify potential contamination or regrowth in storage reservoirs

and/or in the distribution network.

— Bottle type should be determined according to the parameters tested. It should be taken into account

that some types of glass bottles yield boron to the samples and to prevent it high-density polyethylene

(HDPE) or polypropylene (PP) bottles with double caps or self-sealing caps may be used.

As the sample quantity depends on the type of analysis to be performed, for the analysis of the

basic water characteristics and the main anions and cations, 1 l of sample can be sufficient.

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ISO 16075-4:2021(E)

— Sampling and handling should be done safely with suitable precaution to avoid disease transmission

by means of plastic gloves or using other protection.

Quality control samples should be collected as part of any routine sampling programme. Sampling and

handling of raw wastewater and treated wastewater should follow Table 1.
Table 1 — Recommendations for sample preparation and conservation
Parameter Type of bottle Addition of Conservation Comments
chemicals
Anions and cations 1 l HDPE or PP No additive Dark, 4 °C Temperature, pH and
(chloride, sulfate), as bottles with double dissolved oxygen should
well as general physico- caps or self-sealing be measured on site.
chemical parameters caps, with or
(pH, suspended solids, without air
conductivity, turbidity)
Phosphorus and 1 l HDPE or PP H SO to pH = 2 Dark, 4 °C
2 4
N Kjeldahl bottles with double
caps or self-sealing
caps, with or
without air
Boron 100 ml HDPE or PP HNO to pH = 2 Dark, 4 °C
bottles with double
caps or self-sealing
caps
COD 100 ml HDPE or PP H SO to pH = 2 Dark, 4 °C No additive is needed if
2 4
bottles with double the samples are analysed
caps or self-sealing within 48 h.
caps, no air
BOD 500 ml HDPE or PP No additive Dark, 4 °C Na SO should be used
2 3
bottles with double for dealing with samples
caps or self-sealing with residual chlo-
caps, no air rine. Sample should be
Preserved and added
seed for chlorinated and
dechlorinated wastewa-
ter samples.

Trace elements and 250 ml HDPE or PP HNO to pH = 2 Dark, 4 °C A special bottle [such as

heavy metals bottles with double polytetrafluoroethylene
caps or self-sealing (PTFE)] and additive are
caps, with or needed for the analysis
without air of mercury (Hg).
Trace organics and 1 l dark glass bottle Ascorbic acid Dark 4 °C
pesticides or PTFE bottle, no air (1000 mg l ) if
rinsed with organic residual chlorine
solvents is present

Microbiological param- 1 l to 5 l sterile No additive Dark, 4 °C Additive of sodium

eters (total and faecal HDPE or PP bottles thiosulfate at a well-de-
coliforms, helminths, with double caps or fined concentration is
viruses, or other addi- self-sealing caps bot- mandatory in presence of
tional microbiological tle, with air residual chlorine and rec-
parameters) ommended in all cases.
4.2.2 Sampling from an irrigation system

Water quality should be checked by the end user according to the following procedure:

a) Turn on the irrigation system until the system operates to full designed pressure and let the system

irrigate until the pipes have flushed of all stagnant water from the previous irrigation event.

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ISO 16075-4:2021(E)

b) Collect a sample from a tap located at the entrance to the irrigation system or from an irrigation

emitter (a sprinkler, micro-jet or a dripper).

c) The water sample should be collected in bottles as provided or recommended by the analytical

laboratory or procedure and the parameters to be tested (see Table 1). For bacterial sampling, a

sterile bottle should be used. Write all necessary details on a sticker attached to the bottle (name,

address, date, location, etc.) and seal the lid.

d) Preserve samples according to standard laboratory practice and transport them to an analytical

laboratory within the time period recommended for the analysis (see Table 1).

e) Water sampling should not be taken when fertigation (fertilization through irrigation) is taking place.

[3]
For more information about sampling from an irrigation system, see ISO 5667-10 .
4.2.3 Sampling from a storage reservoir

To evaluate a potential evolution of treated wastewater quality during storage, a sample from the

storage reservoir should be taken.

The best way to measure the quality of TWW that was stored in a reservoir is by sampling the TWW at

appropriate sampling point situated at the exit of the reservoir's pumping station.

In periods of no irrigation from the reservoir, the sample should be taken directly from the storage

reservoir, according to the following procedures:

a) It is recommended to take the sample as close as possible to the pumping point;

b) Avoid sampling downwind to prevent the collection of floating materials (plant or algae residues)

transported by water waves to the downwind side of the storage reservoir;
c) Attach an empty bottle to the sampling pole;

d) Lower the bottle so that the neck is submerged in the storage reservoir to a depth of about 10 cm

and fill the bottle;
e) Remove the bottle from the storage reservoir, seal it and label the bottle;

f) Preserve the sample if required or refer to Table 1 to determine if and what preservative is

required. Store the sample and take them to the laboratory within the time period recommended

by the analytical laboratory or procedure (see Table 1).
[2]
For more information about sampling from a storage reservoir, see ISO 5667-4 .
4.2.4 Composite sample

To characterize TWW at the outlet of the treatment plant in order to take into account the fluctuations

of WW quality, a composite sample should be taken.
Composite sampling should be taken within a 24 h duration.
A refrigerate
...

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