EN 14702-2:2006

Characterisation of sludges - Settling properties - Part 2: Determination of thickenability

This document specifies a method for the determination of the thickenability of sludge suspensions. This document is applicable to sludge suspensions from:
¾   storm water handling;
¾   urban wastewater collecting systems;
¾   urban wastewater treatment plants;
¾   treating industrial wastewater similar to urban wastewater (as defined in Directive 91/271 EEC);
¾   water supply treatment plants.
This method is also applicable to sludge suspensions from other origin.

Charakterisierung von Schlämmen - Absetzeigenschaften - Teil 2: Bestimmung der Eindickbarkeit

Dieses Dokument legt ein Verfahren zur Bestimmung der Eindickbarkeit von Schlammsuspensionen fest. Diese Dokument gilt für Schlammsuspensionen aus folgenden Bereichen:
-   Behandlung von Regenwasser;
-   Kanalisationssysteme für kommunales Abwasser;
-   Anlagen für die Behandlung von kommunalem Abwasser;
-   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 Schlammsuspensionen von anderer Herkunft anwendbar.

Caractérisation des boues - Propriétés de sédimentation - Partie 2: Détermination de l'aptitude à l'épaississement

Le présent document spécifie une méthode de détermination de l’aptitude à l’épaississement de suspensions de boues. Il s’applique aux suspensions de boues provenant :
-   de la collecte des eaux pluviales ;
-   des systèmes de collecte des eaux usées urbaines ;
-   des stations d’épuration des eaux usées urbaines ;
-   de l’épuration des eaux industrielles semblables aux eaux usées urbaines (comme défini dans la Directive 91/271/CEE) ;
-   des usines de production d’eau potable.
Cette méthode s’applique également aux suspensions de boues ayant une autre origine.

Karakterizacija blata - Lastnosti usedanja - 2. del: Določanje zgoščevanja

General Information

• Status: Published
• Publication Date: 28-Mar-2006
• Withdrawal Date: 29-Sep-2006
• 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: 09-Jun-2021
• Completion Date: 14-Apr-2025
• Directive: 86/278/EEC - Protection of the environment, and in particular of the soil, when sewage sludge is used in agriculture
• Ref Project: SIST EN 14702-2:2006 - Characterisation of sludges - Settling properties - Part 2: Determination of thickenability

Overview

EN 14702-2:2006 - published by CEN - defines a laboratory method to determine the thickenability of sludge suspensions by measuring settling under gentle mechanical stirring. The standard applies to sludges from stormwater, urban wastewater collection and treatment, water supply treatment, and industrial wastes similar to urban wastewater (Directive 91/271/EEC). The method uses a stirred cylinder test to produce a stirred sludge volume index (Issv) that characterises the sludge’s ability to concentrate under gravity in a mechanically assisted thickener.

Keywords: EN 14702-2:2006, thickenability, sludge characterisation, settling properties, stirred sludge volume index, Issv, CEN.

Key topics and requirements

• Scope: Laboratory determination of thickenability for a wide range of sludge suspensions.
• Apparatus: Graduated transparent cylinder (diameter 10 cm, height 50 cm, nominal volume ~3 500 ml) equipped with a low-speed stirrer operating at 1 rpm. Stirrer design: two vertical rods (0.5–0.6 cm) arranged asymmetrically (see Annex A).
• Sampling: Representative sample taken with a 5 l scoop and filled to the 50 cm mark.
• Test conditions: Gentle stirring at 1 rpm; record sludge–water interface after 30 minutes.
• Reference concentration: Results are comparable when evaluated at a solids concentration of 3.5 g/l (dilute by supernatant liquor and homogenise if needed).
• Result expression:
  • Stirred sludge volume (Vss) is the stirred sludge volume per initial sample volume.
  • Stirred sludge volume index (Issv, ml/g) = stirred sludge volume (ml·l−1) ÷ solids concentration (g·l−1). Using test parameters, Issv can be calculated as: Issv = (H × 1000) / (50 × C0) = 20 × H / C0 where H is final sludge level in cm and C0 is initial solids concentration in g·l−1.
• Interpretation: For activated sludges at 3.5 g/l, Issv < 80 ml/g indicates good thickenability; Issv > 120 ml/g indicates poor thickenability.
• Precision: Validation trials and precision figures are summarised in Annex B (reproducibility standard deviations and repeatability).

Applications and users

• Who uses it: Wastewater treatment plant operators, environmental labs, process engineers, sludge handling consultants, equipment manufacturers, and regulatory bodies.
• Practical uses:
  • Assess suitability of a sludge for gravity thickening and predict solids loss risk.
  • Compare sludges during process optimisation, commissioning or troubleshooting.
  • Provide standardised input data for thickener design and performance assessment.
  • Support regulatory compliance and quality control in sludge management.

Related standards

• EN 14702-1: Determination of settleability (proportion of sludge volume and sludge volume index)
• EN 1085:1997 - Waste water treatment - Vocabulary
• EN 12880 - Methods for measuring solids concentration (reference for C0)
• ISO 5725-2 - Precision (repeatability and reproducibility) of measurement methods

For engineers and laboratories assessing sludge settling and thickening performance, EN 14702-2:2006 provides a reproducible, standardised test method to quantify thickenability and support operational and design decisions.

Standards Content (Sample)

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.Characterisation of sludges - Settling properties - Part 2: Determination of thickenabilityRãþHYDQMDCaractérisation des boues - Propriétés de sédimentation - Partie 2: Détermination de l'aptitude a l'épaississementCharakterisierung von Schlämmen - Absetzeigenschaften - Teil 2: Bestimmung der Eindickbarkeit13.030.20Liquid wastes. SludgeICS:SIST EN 14702-2:2006en,fr,deTa slovenski standard je istoveten z:EN 14702-2:200601-julij-2006SIST EN 14702-2:2006SLOVENSKI
STANDARD
EUROPEAN STANDARDNORME EUROPÉENNEEUROPÄISCHE NORMEN 14702-2March 2006ICS 13.030.20 English VersionCharacterisation of sludges - Settling properties - Part 2:Determination of thickenabilityCaractérisation des boues - Propriétés de sédimentation -Partie 2: Détermination de l'aptitude à l'épaississementCharakterisierung von Schlämmen - Absetzeigenschaften -Teil 2: Bestimmung der EindickbarkeitThis European Standard was approved by CEN on 3 February 2006.CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this EuropeanStandard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such nationalstandards may be obtained on application to the Central Secretariat or to any CEN member.This European Standard exists in three official versions (English, French, German). A version in any other language made by translationunder the responsibility of a CEN member into its own language and notified to the Central Secretariat has the same status as the officialversions.CEN members are the national standards bodies of Austria, Belgium, Cyprus, Czech Republic, Denmark, Estonia, Finland, France,Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania,Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.EUROPEAN COMMITTEE FOR STANDARDIZATIONCOMITÉ EUROPÉEN DE NORMALISATIONEUROPÄISCHES KOMITEE FÜR NORMUNGManagement Centre: rue de Stassart, 36
B-1050 Brussels© 2006 CENAll rights of exploitation in any form and by any means reservedworldwide for CEN national Members.Ref. No. EN 14702-2:2006: E

Stirred cylinder for determining the thickenability of sludges.8 Annex B (informative)
Results of validation trials.9 Bibliography.12
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