ISO/FDIS 19654
(Main)Sludge recovery, recycling, treatment and disposal — Laboratory chemical conditioning procedure
Sludge recovery, recycling, treatment and disposal — Laboratory chemical conditioning procedure
This international standard specifies a chemical conditioning procedure for sludge/biosolids thus allowing results obtained in different places and laboratories, and on different times to be compared when selecting type and dosage of a conditioning product at laboratory scale.
Valorisation, recyclage, traitement et élimination des boues — Mode opératoire de conditionnement chimique en laboratoire
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Standards Content (Sample)
FINAL DRAFT
International
Standard
ISO/TC 275
Sludge recovery, recycling,
Secretariat: AFNOR
treatment and disposal —
Voting begins on:
Laboratory chemical conditioning
2025-08-18
procedure
Voting terminates on:
2025-10-13
Valorisation, recyclage, traitement et élimination des boues —
Mode opératoire de conditionnement chimique en laboratoire
This document has not been edited by the ISO Central Secretariat.
RECIPIENTS OF THIS DRAFT ARE INVITED TO SUBMIT,
WITH THEIR COMMENTS, NOTIFICATION OF ANY
RELEVANT PATENT RIGHTS OF WHICH THEY ARE AWARE
AND TO PROVIDE SUPPOR TING DOCUMENTATION.
IN ADDITION TO THEIR EVALUATION AS
BEING ACCEPTABLE FOR INDUSTRIAL, TECHNO
FAST TRACK PROCEDURE
LOGICAL, COMMERCIAL AND USER PURPOSES, DRAFT
INTERNATIONAL STANDARDS MAY ON OCCASION HAVE
TO BE CONSIDERED IN THE LIGHT OF THEIR POTENTIAL
TO BECOME STAN DARDS TO WHICH REFERENCE MAY BE
MADE IN NATIONAL REGULATIONS.
Reference number
FINAL DRAFT
International
Standard
ISO/TC 275
Sludge recovery, recycling,
Secretariat: AFNOR
treatment and disposal —
Voting begins on:
Laboratory chemical conditioning
procedure
Voting terminates on:
Valorisation, recyclage, traitement et élimination des boues —
Mode opératoire de conditionnement chimique en laboratoire
This document has not been edited by the ISO Central Secretariat.
RECIPIENTS OF THIS DRAFT ARE INVITED TO SUBMIT,
WITH THEIR COMMENTS, NOTIFICATION OF ANY
RELEVANT PATENT RIGHTS OF WHICH THEY ARE AWARE
AND TO PROVIDE SUPPOR TING DOCUMENTATION.
© ISO 2025
IN ADDITION TO THEIR EVALUATION AS
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
BEING ACCEPTABLE FOR INDUSTRIAL, TECHNO
FAST TRACK PROCEDURE
LOGICAL, COMMERCIAL AND USER PURPOSES, DRAFT
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on
INTERNATIONAL STANDARDS MAY ON OCCASION HAVE
the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below
TO BE CONSIDERED IN THE LIGHT OF THEIR POTENTIAL
or ISO’s member body in the country of the requester.
TO BECOME STAN DARDS TO WHICH REFERENCE MAY BE
MADE IN NATIONAL REGULATIONS.
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 Reference number
ii
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Principle . 1
5 Apparatus . 2
6 Procedure . 3
7 Test report . 4
8 Precision . 4
Annex A (informative) Results of validation trials . 6
Annex B (informative) Examples for mixing devices for chemical conditioning procedure.10
Annex C (informative) Example of table summarizing the operating conditions and the results
of the characterization tests .12
Bibliography .13
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
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).
ISO draws attention to the possibility that the implementation of this document may involve the use of (a)
patent(s). ISO takes no position concerning the evidence, validity or applicability of any claimed patent
rights in respect thereof. As of the date of publication of this document, ISO had not received notice of (a)
patent(s) which may be required to implement this document. However, implementers are cautioned that
this may not represent the latest information, which may be obtained from the patent database available at
www.iso.org/patents. ISO shall not be held responsible for identifying any or all such patent rights.
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 the European Committee for Standardization (CEN) (as CEN/TR 14742:2006)
and was adopted, without modifications other than those given below, by Technical Committee ISO/TC 275,
Sludge recovery, recycling, treatment and disposal.
— The second sentence was added in the Scope;
— informative references were moved from Clause 2 to the Bibliography;
— the term “sludge” was added in Clause 3;
— in Clause 5, the reference to Annex B was replaced by reference to Figure B.1.
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
The laboratory assessment of flocculated sludge dewaterability is sensitive to the operating procedure
adopted for the conditioning step. No generalized ranking of products in order of effectiveness can be given
since the ranking changes with the sludge type, dosage of conditioning agent (inorganic coagulant, polymer),
degree of shearing and dewatering device.
v
FINAL DRAFT International Standard ISO/FDIS 19654:2025(en)
Sludge recovery, recycling, treatment and disposal —
Laboratory chemical conditioning procedure
1 Scope
This method gives a standardized procedure for the conditioning operation when selecting a conditioning
product at laboratory scale and also for the production of flocculated thickened sludge for subsequent
dewatering tests.
This document provides a method for laboratory for laboratory chemical conditioning of sludge.
The method applies to sludges and suspensions from:
— storm water handling;
— urban wastewater collecting systems;
— urban wastewater treatment plants;
— industrial wastewater that has been treated similarly to urban wastewater;
— water supply plants.
This document is applicable to all sludge that can have similar environmental or health impacts, or both,
with exclusion of hazardous sludge from industry and dredged sludge.
2 Normative references
There are no normative references in this document.
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
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
chemical conditioning
mixing of a chemical product with the sludge in order to increase its thickenability and dewaterability
3.2
sludge
accumulated settled solids separated from various types of water as a result of natural or artificial processes
[SOURCE: ISO 6707-1:2020, 3.8.27]
4 Principle
Sludge conditioned in accordance with the procedure outlined in Clause 6 can subsequently be used in
specific characterization tests in order to determine the most suitable operating conditions for each
particular sludge or suspension; these tests determine particularly the required nature of the reagent, the
dosage, and the sequence of adding the reagent.
Each test is performed as a batch process.
Variables and/or parameters that can have significant effects on the conditioned sludge are either chemical
or physical.
Chemical parameters are:
— characteristics of the sludge, e.g. pH, dry residue, loss on ignition;
— characteristics of the conditioning product, e.g. charge density, molecular weight, chemical structure;
— concentration and dosage of the chemical product;
— water used for on-site product preparation when polyelectrolytes are added.
Physical parameters are:
— method of preparing the solution and its storage;
— intensity and duration of stirring;
— characteristics of the stirrer, i.e. type, dimensions, position;
— method of injecting the conditioning product into the sludge;
— (separation) time between the end of mixing and the dewatering procedure itself.
The method of mixing the conditioning product into the sludge is particularly important since inadequate
mixing, leading to poor initial dispersion or strong floc shearing, can result in very poor test performances:
a large portion of the product can react instantly with particles upon first contact, without dispersing
throughout the mixture.
Inorganic coagulants are generally injected into a reactor with a short residence time (1 min to 5 min)
in a high shearing condition. For this purpose, the reactor is equipped with a high rotating speed stirrer
that enables an instantaneous dispersion of the product and brings the high energy needed (e.g. 80 W/m
to 100 W/m ).
Polyelectrolytes are injected into a reactor with a residence time of a few seconds to a few minutes. As far
as mechanical degradation can occur, the shearing rate is 4 to 10 times lower than for coagulants and the
3 3
energy needed lower (e.g. 40 W/m to 50 W/m ).
The conditioning procedure can concern the addition of more than one product. In that case, the addition
sequence is another parameter that requires careful instructing.
5 Apparatus
5.1 Device with control and measurement of physical parameters (variable stirrer/mixer speed and
time, position of mechanical stirrer depending on sludge volume, see Figure B.1). A magnetic stirrer should
not be used, as it does not ensure homogenous and reproducible mixing. A mechanical stirrer with 4
horizontal perpendicular blades should be used for proper polymer dispersion and floc maturation. In case
the formed flocs are very sensitive to shearing, a tilted 3-blade stirrer (see Figure B.1) should be used. The
characteristics of mechanical stirrer shall be the same in comparative tests. Length of each impeller blade
should be between 1/4 and 1/3 of the beaker diameter.
5.2 Beakers, volume 200 ml to 1 000 ml.
5.3 Volumetric pipettes or syringe or automatic polymer injection system at constant flow rate.
5.4 Analytical balance with a precision of at least 0,1 mg.
5.5 pH-meter.
5.6 Chronometer, e.g. stopwatch, computer.
5.7 Apparatus for evaluation of flocculation drainability, (e.g. drainage cell, see EN 14701-4).
6 Procedure
The procedure is as follows:
6.1 The pH of the sludge shall be measured according to validated standards. For example, the method
specified in EN 15933 can be used. If necess
...
ISO/TC 275/WG 6
Secretariat: AFNOR
Date: 2025-02
Sludge recovery, recycling, treatment and disposal — Laboratory
chemical conditioning procedure
Valorisation, recyclage, traitement et élimination des boues — Mode opératoire de conditionnement chimique
en laboratoire
FDIS stage
ISO #####-#:####(X/FDIS 19654:2025(en)
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
EmailE-mail: copyright@iso.org
Website: www.iso.org
Published in Switzerland
© ISO #### 2025 – All rights reserved
ii
Contents
Foreword . iv
Introduction . v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Principle . 2
5 Apparatus . 3
6 Procedure . 3
7 Test report . 4
8 Precision . 5
Annex A (informative) Results of validation trials . 6
Annex B (informative) Examples for mixing devices for chemical conditioning procedure . 11
Annex C (informative) Example of table summarizing the operating conditions and the results
of the characterization tests . 17
Bibliography . 18
iii
ISO #####-#:####(X/FDIS 19654:2025(en)
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).
ISO draws attention to the possibility that the implementation of this document may involve the use of (a)
patent(s). ISO takes no position concerning the evidence, validity or applicability of any claimed patent rights
in respect thereof. As of the date of publication of this document, ISO had not received notice of (a) patent(s)
which may be required to implement this document. However, implementers are cautioned that this may not
represent the latest information, which may be obtained from the patent database available at
www.iso.org/patents. ISO shall not be held responsible for identifying any or all such patent rights.
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'sISO’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 the European Committee for Standardization (CEN) [2] and was changed to
this document(as CEN/TR 14742:2006) and was adopted, without modifications other than those given
below, by Technical Committee ISO/TC 275, Sludge recovery, recycling, treatment and disposal.
— The second sentence was added in the Scope;
— informative references were moved from Clause 2 to the Bibliography;
— the term “sludge” was added in Clause 3;
— in Clause 5, the reference to Annex B was replaced by reference to Figure B.1.
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.
© ISO #### 2025 – All rights reserved
iv
Introduction
The laboratory assessment of flocculated sludge dewaterability is sensitive to the operating procedure
adopted for the conditioning step. No generalized ranking of products in order of effectiveness can be given
since the ranking changes with the sludge type, dosage of conditioning agent (inorganic coagulant, polymer),
degree of shearing and dewatering device.
v
FINAL DRAFT International Standard
Sludge recovery, recycling, treatment and disposal — Laboratory
chemical conditioning procedure
1 Scope
This method gives a standardized procedure for the conditioning operation when selecting a conditioning
product at laboratory scale and also for the production of flocculated thickened sludge for subsequent
dewatering tests.
This standarddocument provides a method for laboratory for laboratory chemical conditioning of sludge.
The method applies to sludges and suspensions from:
— — storm water handling;
— — urban wastewater collecting systems;
— — urban wastewater treatment plants;
— — industrial wastewater that has been treated similarly to urban wastewater;
— — water supply plants.
In accordance with ISO/TC 275 scope dealing with standardization of the methods for characterizing,
categorizing, preparing, treating, recycling and managing sludge and products from urban wastewater
collection systems, night soil, storm water handling, water supply treatment plants, wastewater treatment
plants for urban and similar industrial waters.
This document is applicable to all sludge that maycan have similar environmental and/or health impacts, or
both, with exclusion of hazardous sludge from industry and dredged sludge already covered by ISO/TC 190
"Soil Quality".
2 Normative references
Validated standardsThere are no normative references are quoted in the bibliographythis document.
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
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 3.1
chemical conditioning
mixing of a chemical product with the sludge in order to increase its thickenability and dewaterability
3.2 3.2
sludge
accumulated settled solids separated from various types of water as a result of natural or artificial processes
[SOURCE: ISO 6707-1:2020, 3.8.27]
4 Principle
Sludge conditioned in accordance with thisthe procedure (Clause 6)outlined in Clause 6 can subsequently be
used in specific characterization tests in order to determine the most suitable operating conditions for each
particular sludge or suspension; these tests determine particularly the required nature of the reagent, the
dosage, and the sequence of adding the reagent.
Each test is performed as a batch process.
Variables and/or parameters that can have significant effects on the conditioned sludge are either chemical
or physical.
Chemical parameters are:
— — characteristics of the sludge, e.g. pH, dry residue, loss on ignition;
— — characteristics of the conditioning product, e.g. charge density, molecular weight, chemical structure;
— — concentration and dosage of the chemical product;
— — water used for on-site product preparation when polyelectrolytes are added.
Physical parameters are:
— — method of preparing the solution and its storage;
— — intensity and duration of stirring;
— — characteristics of the stirrer, i.e. type, dimensions, position;
— — method of injecting the conditioning product into the sludge;
— — (separation) time between the end of mixing and the dewatering procedure itself.
The method of mixing the conditioning product into the sludge is particularly important since inadequate
mixing, leading to poor initial dispersion or strong floc shearing, can result in very poor test performances: a
large portion of the product can react instantly with particles upon first contact, without dispersing
throughout the mixture.
Inorganic coagulants are generally injected into a reactor with a short residence time (1 min to 5 min) in a
high shearing condition. For this purpose, the reactor is equipped with a high rotating speed stirrer that
enables an instantaneous dispersion of the product and brings the high energy needed (e.g. 80 W/m
to 100 W/m ).
Polyelectrolytes are injected into a reactor with a residence time of a few seconds to a few minutes. As far as
mechanical degradation can occur, the shearing rate is 4 to 10 times lower than for coagulants and the energy
3 3
needed lower (e.g. 40 W/m to 50 W/m ).
The conditioning procedure can concern the addition of more than one product. In that case, the addition
sequence is another parameter that requires careful instructing.
© ISO #### 2025 – All rights reserved
5 Apparatus
The apparatus are as follows:
5.25.1 5.1 Device with control and measurement of physical parameters (variable stirrer/mixer speed
and time, position of mechanical stirrer depending on sludge volume, see Figure B.1Figure B.1 - Annex B
informative).). A magnetic stirrer should not be used, as it does not ensure homogenous and reproducible
mixing. A mechanical stirrer with 4 horizontal perpendicular blades should be used for proper polymer
dispersion and floc maturation. In case the formed flocs are very sensitive to shearing, a tilted 3-blade stirrer
(see Figure B.1Figure B.1 - Annex B informative)) should be used. The characteristics of mechanical
stirrer shall be the same in comparative tests. Length of each impeller blade should be between 1/4 and 1/3
of the beaker diameter.
5.35.2 5.2 Beakers, volume 200 ml to 1 000 ml.
5.45.3 5.3 Volumetric pipettes or syringe or automatic polymer injection system at constant flow rate.
5.55.4 5.4 Analytical balance with a precision of at least 0,1 mg.
5.65.5 5.5 pH-meter.
5.75.6 5.6 Chronometer, e.g. stopwatch, computer.
5.85.7 5.7 Apparatus for evaluation of flocculation drainability, (e.g. drainage cell –, see [3]).EN 14701-
4).
6 Procedure
The procedure is as follows:
6.1 6.1 Measure theThe pH of the sludge toshall be testedmeasured according to validated
standards (e.g – see [4]). For example, the method specified in EN 15933 can be used. If necessary, adjust
the pH to meet the requirements of the conditioning agent to be used.
6.2 6.2 Measure theThe dry residue of the sludge toshall be testedmeasured according to validated
standards (e.g – see [5]). For example, the method specified in EN 12880 can be used.
NOTE The loss on ignition can be determined for additional information. For details, see validated standards (e.g –.
see [6]).EN 15935).
6.3 6.3 Put a defined amount of sludge into a beaker. The amount of sludge should be between 25 %
and 50 % of the capacity of the beaker to avoid loss of sludge during mixing and sludge height should be
between 0,5 and 1 of the diameter of the cell to ensure proper mixing. It should be taken into account that the
whole flocculated sludge will be transferred in a drainage cell and the quantity of dry matter deposited on the
2 2
filter cloth should be between 0,25 kg/m and 1,5 kg/m .
6.4 6.4 Adjust the position of the stirrer to the sludge volume (the stirrer should be positioned from
the beaker bottom at 1/3 of the sludge volume).
6.5 6.5 About polymer addition and dispersion:
6.5.1 6.5.1 Add a precise amount of conditioning agent using a volumetric pipette or syringe before
stirring. Ensure proper distribution of the polymer, across the level surface of the sludge.
6.5.2 6.5.2 If the conditioning agent injection is prepared during the stirring of the sludge, add it in the
shortest amount of time possible at a controlled and constant flow rate. The time of the beginning of the
injection (T ) and the time at the end of the injection (T ) should be reported.
B1 E1
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