EN 14742:2015

Characterization of sludges - Laboratory chemical conditioning procedure

The laboratory assessment of 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, degree of shearing and dewatering device.
The scope of this European Standard applies for 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 (as defined in Directive 91/271/EEC);
- water supply plants.
This method is applicable to sludge and suspensions of other origin.

Charakterisierung von Schlämmen - Laborverfahren zur chemischen Konditionierung

Die labortechnische Beurteilung der Entwässerbarkeit von Schlamm wird durch das für die Konditionierung angewendete Verfahren beeinflusst. Da sich die Rangordnung der Produkte in Abhängigkeit vom Schlammtyp, von der Dosierung des Konditionierungsmittels, vom Schergrad und vom Entwässerungsgerät ändert, kann keine allgemeine Rangfolge der Produkte nach deren Wirksamkeit angegeben werden.
Der Anwendungsbereich der vorliegenden Europäischen Norm gilt für Schlämme und Suspensionen aus:
-   der Behandlung von Regenwasser;
-   Kanalisationssystemen für kommunales Abwasser;
-   Anlagen für die Behandlung von kommunalem Abwasser;
-   der Behandlung von industriellem Abwasser, die auf ähnliche Weise erfolgt wie die von kommunalem Abwasser (wie in der Richtlinie 91/271/EWG festgelegt);
-   Aufbereitungsanlagen für die Wasserversorgung.
Dieses Verfahren ist auch auf Schlämme und Schlammsuspensionen von anderer Herkunft anwendbar.

Caractérisation des boues - Mode opératoire de conditionnement chimique en laboratoire

L’évaluation en laboratoire de la déshydratation des boues est sensible au mode opératoire adopté pour l’étape de conditionnement. Aucun classement généralisé des produits par ordre d’efficacité ne peut être fourni puisque le classement varie en fonction du type de boues, du dosage du produit de conditionnement, du degré de cisaillement et du dispositif de déshydratation.
Le domaine d'application de la présente Norme européenne s'applique aux boues et suspensions issues :
- de la collecte des eaux pluviales ;
- de systèmes de collecte des eaux usées urbaines ;
- des stations d’épuration des eaux usées urbaines ;
- de l'épuration des eaux usées industrielles, traitées de la même manière que les eaux usées urbaines (comme défini dans la Directive 91/271/CEE) ;
- d’usines de production d’eau potable.
Cette méthode s’applique aux boues et aux suspensions d’autres origines.

Karakterizacija blata - Laboratorijski postopek kemijskega kondicioniranja

General Information

• Status: Published
• Publication Date: 28-Apr-2015
• Withdrawal Date: 30-Oct-2015
• ICS: 13.030.20 - Liquid wastes. Sludge
• Technical Committee: CEN/TC 308 - Characterization of sludges
• Drafting Committee: CEN/TC 308/WG 1 - Characterization methods
• Current Stage: 9093 - Decision to confirm - Review Enquiry
• Start Date: 07-Dec-2020
• Completion Date: 23-Sep-2025
• Ref Project: SIST EN 14742:2015 - Characterization of sludges - Laboratory chemical conditioning procedure

Relations

• Replaces: CEN/TR 14742:2006 - Characterization of sludges - Laboratory chemical conditioning procedure
• Effective Date: 14-Dec-2011

Overview

EN 14742:2015 - Characterization of sludges: Laboratory chemical conditioning procedure - is a CEN standard that defines a reproducible laboratory method for chemically conditioning sludges and suspensions prior to dewatering tests. It standardizes the mixing, dosing and maturation steps used to evaluate sludge dewaterability, enabling meaningful comparison of conditioning products (coagulants, polyelectrolytes) and operational settings for subsequent tests (e.g., drainage, filtration).

Applicable sludges include:

• storm water handling; urban wastewater collection and treatment;
• industrial wastewater treated like urban wastewater (Directive 91/271/EEC);
• water supply plant sludges; and other sludge types.

Key topics and technical requirements

• Principle: Batch conditioning to determine reagent type, dosage, sequence and mixing that optimise thickening/dewatering.
• Apparatus: Mechanical stirrer (magnetic stirrers not recommended), beakers (200–1 000 ml), pipettes/syringes or automatic injection, analytical balance, pH-meter and drainage cell.
• Stirring recommendations:
  • Prefer a 4-horizontal-blade impeller for polymer dispersion; blade length = 1/4–1/3 of beaker diameter.
  • For shear-sensitive flocs use a tilted 3‑blade axial impeller.
  • Typical mixing regimes cited: high-energy dispersion for inorganic coagulants (e.g. 80–100 W/m3), lower energy for polyelectrolytes (e.g. 40–50 W/m3); example speeds: 1 700 rpm (rapid dispersion) and 700 rpm (floc growth).
• Procedure highlights:
  • Measure and, if needed, adjust sludge pH (EN 15933) and dry residue (EN 12880).
  • Fill beaker to 25–50% capacity; position stirrer ~1/3 from bottom.
  • Add conditioning agent precisely (report TB1/TE1), use polymer solutions prepared per supplier and within 3 hours.
  • Allow floc maturation, then transfer whole flocculated sludge to a drainage cell (EN 14701‑4) for drainability testing and further dewatering characterization.
• Reporting & precision: Test report must detail sludge ID, reagent, mixing conditions and results. Validation trials reported average relative repeatability SD ≈ 1.8% and reproducibility SD ≈ 2.9%.

Applications and users

EN 14742:2015 is used to:

• Screen and compare chemical conditioners (polymers, coagulants) in laboratory scale.
• Produce reproducible flocculated/thickened sludge samples for dewatering tests (CST, SRF, drainage).
• Support wastewater plant operators, laboratory analysts, polymer/coagulant suppliers, consultants and researchers in specifying dosing strategies and equipment selection.
• Provide repeatable inputs for design or optimization of full-scale dewatering (centrifuge, belt press, filter press).

Keywords: EN 14742:2015, sludge characterization, chemical conditioning, sludge dewaterability, flocculation, laboratory procedure, drainage cell, polymer dosing.

Related standards

• EN 12832 - Sludge vocabulary
• EN 12880 - Dry residue and water content
• EN 14701-4 - Drainability of flocculated sludges (drainage cell)
• EN 15933 - Sludge pH and loss on ignition references
• ISO 5725-2 - Precision (repeatability & reproducibility)

Standards Content (Sample)

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.Karakterizacija blata - Laboratorijski postopek kemijskega kondicioniranjaCharakterisierung von Schlämmen - Laborverfahren zur chemischen KonditionierungCaractérisation des boues - Mode opératoire de conditionnement chimique en laboratoireCharacterization of sludges - Laboratory chemical conditioning procedure13.030.20Liquid wastes. SludgeICS:Ta slovenski standard je istoveten z:EN 14742:2015SIST EN 14742:2015en,fr,de01-julij-2015SIST EN 14742:2015SLOVENSKI
STANDARDSIST-TP CEN/TR 14742:20071DGRPHãþD

EUROPEAN STANDARD NORME EUROPÉENNE EUROPÄISCHE NORM
EN 14742
April 2015 ICS 13.030.20 Supersedes CEN/TR 14742:2006English Version
Characterization of sludges - Laboratory chemical conditioning procedure
Caractérisation des boues - Mode opératoire de conditionnement chimique en laboratoire
Charakterisierung von Schlämmen - Laborverfahren zur chemischen Konditionierung This European Standard was approved by CEN on 28 February 2015.
CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the CEN-CENELEC Management Centre or to any CEN member.
This European Standard exists in three official versions (English, French, German). A version in any other language made by translation under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC Management Centre has the same status as the official versions.
CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION EUROPÄISCHES KOMITEE FÜR NORMUNG
CEN-CENELEC Management Centre:
Avenue Marnix 17,
B-1000 Brussels © 2015 CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Members. Ref. No. EN 14742:2015 ESIST EN 14742:2015

Utilization and disposal of sludges
Vocabulary EN 12880, Characterization of sludges
Determination of dry residue and water content EN 14701-4, Characterization of sludges
Filtration properties
Part 4: Determination of the drainability of flocculated sludges EN 15933, Sludge, treated biowaste and soil
Determination of pH ISO 5725-2, Accuracy (trueness and precision) of measurement methods and results — Part 2: Basic method for the determination of repeatability and reproducibility of a standard measurement method 3 Terms and definitions For the purposes of this document, the terms and definitions given in EN 12832 and the following apply. 3.1 chemical conditioning mixing of a chemical product with the sludge in order to increase its thickenability/dewaterability 4 Principle Sludge conditioned in accordance with this procedure (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. SIST EN 14742:2015

Rapid pre-selection of conditioning agents can be made by pouring the sludge back and forth between two beakers in order to check if flocs are formed. In case of coagulant use, disperse the product at high speed (1 700 rpm) for 2 min and let the microflocs grow at 700 rpm. In case of polymer use, the mixing speed of the horizontal 4-blade impeller should be kept constant at 700 rpm since polymer dispersion and floc maturation occur simultaneously. In case of highly shear-sensitive flocs, it is recommended to disperse the flocculent in the sludge using an axial impeller (tilted 3-blade impeller) at high speed (1 700 rpm) for a very short time (2 s max), followed by a low speed (700 rpm) to enable floc growing. In this case, it is useful to differentiate: TBB1: Beginning time of polymer dispersion = TE1 TEE1: End of polymer dispersion TBB2: Beginning of polymer maturation SIST EN 14742:2015
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