EN 14672:2005

Characterization of sludges - Determination of total phosphorus

This European Standard specifies a procedure for complete digestion of raw/digested sludge, suitable for the subsequent determination of phosphorus.
Phosphorus in environmental samples can be present in many forms. This method of pre-treatment enables the analyst to determine all forms - i.e. total phosphorus, by quantitative oxidation yielding an aqueous solution of orthophosphate which should be analysed for phosphate according to method EN ISO 6878, EN ISO 10304-2 or an equivalent validated method.
The range of the method is up to 50 g/kg P assuming appropriate dilution of the digest in the final measurement step.

Charakterisierung von Schlämmen - Bestimmung von Gesamtphosphor

Diese Europäische Norm legt ein Verfahren zum vollständigen Aufschluss von Roh-/Faulschlamm für die
anschließende Bestimmung von Phosphor fest.
ANMERKUNG Phosphor kann in Umweltproben in vielen Verbindungen vorhanden sein. Dieses Verfahren der
Vorbehandlung ermöglicht es dem Analytiker alle Verbindungen zu bestimmen � d. h. Gesamtphosphor durch
quantitative Oxidation unter Bildung einer wässrigen Orthophosphatlösung, die auf Phosphat gemäß dem Verfahren nach
EN ISO 6878, EN ISO 10304-2 oder einem äquivalenten validierten Verfahren analysiert werden sollte.
Das Verfahren ist anwendbar bis zu 50 g/kg P bei geeigneter Aufschlussverdünnung in der Endmessung.

Caractérisation des boues - Dosage du phosphore total

La présente Norme européenne définit un mode opératoire pour la minéralisation complète de la boue
brute/digérée, applicable pour la détermination ultérieure de la teneur en phosphore.
NOTE Le phosphore dans des échantillons prélevés dans l�environnement peut se présenter sous plusieurs formes.
La présente méthode de prétraitement permet à l�analyste d�en déterminer toutes les formes (c�est-à-dire la teneur en
phosphore total) par oxydation quantitative produisant une solution aqueuse d�orthophosphate qu�il convient d�analyser
pour déterminer la teneur en phosphate conformément à la méthode donnée dans l�EN ISO 6878, l�EN ISO 10304-2, ou
selon toute méthode validée équivalente.
Le domaine de mesurage de la méthode a pour limite maximale 50 g/kg P en partant du principe que la
dilution du produit minéralisé est appropriée pour la phase finale de mesurage.

Karakterizacija blata – Določevanje celotnega fosforja

General Information

• Status: Published
• Publication Date: 09-Aug-2005
• Withdrawal Date: 27-Feb-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: 9060 - Closure of 2 Year Review Enquiry - Review Enquiry
• Start Date: 02-Sep-2025
• Completion Date: 02-Sep-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 14672:2005 - Characterization of sludges - Determination of total phosphorus

Overview

EN 14672:2005 is a European Standard developed by the European Committee for Standardization (CEN) that outlines the procedure for the complete digestion of raw or digested sludges to determine total phosphorus content. This standard provides a reliable method for pre-treatment and subsequent analysis of sludges, converting various phosphorus forms into orthophosphate for accurate quantification. Total phosphorus measurement is critical in environmental monitoring, waste management, and sludge characterization, as phosphorus is a key nutrient influencing eutrophication and environmental health.

The method utilizes a quantitative oxidation process with sulfuric and nitric acids to ensure complete digestion of organic matter, enabling comprehensive phosphorus analysis. The digest solution obtained is then analyzed for phosphate content using validated spectrometric or chromatographic techniques, such as those described in EN ISO 6878 or EN ISO 10304-2.

Key Topics

• Scope and Application

  • Complete digestion procedure for sludge samples (raw and digested)
  • Determines total phosphorus, including condensed and organic forms
  • Applicable to a phosphorus concentration range up to 50 g/kg with appropriate dilution

• Principle of Method

  • Oxidation by boiling sulfuric and nitric acid mixture
  • Converts all phosphorus species into orthophosphate
  • Followed by neutralization and dilution for analysis
  • Compatible with phosphate determination by spectrometric and chromatographic methods

• Sample Pre-treatment

  • Sludges must be homogenized, either dried and ground or fresh and well-mixed
  • Preservation recommendations: keep samples below 4 °C and analyze within 4 weeks to ensure accuracy
  • Avoid glass containers to reduce breakage and contamination risks

• Determination and Calculation

  • Digestion in Kjeldahl flasks with sulfuric and nitric acids under controlled heating
  • Quantitative phosphate measurement with reagent blanks for quality control
  • Calculation formulas provided for total phosphorus content based on sample dry matter or wet weight

• Health and Safety Considerations

  • Handling of corrosive acids and alkalis requires protective equipment
  • Biological risks associated with sludge samples due to pathogens
  • Use of fume cupboards and flameproof equipment recommended for safe operation

Applications

• Environmental Monitoring
  EN 14672:2005 supports the evaluation of phosphorus loads in wastewater sludge, helping control nutrient discharges into aquatic ecosystems and prevent eutrophication.

• Wastewater Treatment Plant Management
  Provides essential data on sludge quality for optimizing treatment processes, phosphorus recovery, and compliance with regulatory limits.

• Soil Amendment and Agricultural Use
  Accurate phosphorus characterization informs the safe reuse of sludge as fertilizer, ensuring nutrient management without environmental harm.

• Research and Development
  Used in scientific studies to characterize phosphorus speciation and transformations in sludge and environmental samples.

Related Standards

• EN ISO 6878: Water quality - Determination of phosphorus - Ammonium molybdate spectrometric method
• EN ISO 10304-2: Water quality - Determination of dissolved anions by liquid chromatography - Phosphate determination
• EN 12880: Characterization of sludges - Determination of dry residue and water content
• EN ISO 3696: Water for analytical laboratory use - Specification and test methods

Summary

EN 14672:2005 is a vital standard for laboratories and environmental professionals involved in sludge analysis, offering a validated and internationally recognized method for total phosphorus determination. Its rigorous digestion procedure ensures the conversion of all phosphorus forms into measurable orthophosphate, enabling precise quantification crucial for environmental compliance, process optimization, and sustainable resource management. Compliance with this standard supports uniform data quality and facilitates harmonized environmental reporting across Europe.

Standards Content (Sample)

SLOVENSKI STANDARD
01-december-2005
.DUDNWHUL]DFLMDEODWD±'RORþHYDQMHFHORWQHJDIRVIRUMD
Characterization of sludges - Determination of total phosphorus
Charakterisierung von Schlämmen - Bestimmung von Gesamtphosphor
Caractérisation des boues - Dosage du phosphore total
Ta slovenski standard je istoveten z: EN 14672:2005
ICS:
13.030.20 7HNRþLRGSDGNL%ODWR Liquid wastes. Sludge
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EUROPEAN STANDARD
EN 14672
NORME EUROPÉENNE
EUROPÄISCHE NORM
August 2005
ICS 13.030.20
English version
Characterization of sludges - Determination of total phosphorus
Caractérisation des boues - Dosage du phosphore total Charakterisierung von Schlämmen - Bestimmung von
Gesamtphosphor
This European Standard was approved by CEN on 27 June 2005.
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 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 translation
under the responsibility of a CEN member into its own language and notified to the Central Secretariat has the same status as the official
versions.
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, Slovakia,
Slovenia, Spain, Sweden, Switzerland and United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
Management Centre: rue de Stassart, 36  B-1050 Brussels
© 2005 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN 14672:2005: E
worldwide for CEN national Members.

Contents Page
Foreword .3
1 Scope .4
2 Normative references .4
3 Terms and definitions.4
4 Principle.5
5 Limitations and interferences .5
6 Hazards.5
7 Apparatus .5
8 Reagents.6
9 Sample pre-treatment .6
10 Procedure .6
11 Expression of results.7
12 Test report .8

Annex A (informative) Performance data of interlaboratory comparison .9

Foreword
This European Standard (EN 14672:2005) has been prepared by Technical Committee CEN/TC 308
“Characterization of sludges”, the secretariat of which is held by AFNOR.
This European Standard shall be given the status of a national standard, either by publication of an identical
text or by endorsement, at the latest by February 2006, and conflicting national standards shall be withdrawn
at the latest by February 2006.
According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following
countries are bound to implement this European Standard: Austria, Belgium, Cyprus, Czech Republic,
Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania,
Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Slovakia, Slovenia, Spain, Sweden, Switzerland
and United Kingdom.
1 Scope
This European Standard specifies a procedure for complete digestion of raw/digested sludge, suitable for the
subsequent determination of phosphorus.
NOTE Phosphorus in environmental samples can be present in many forms. This method of pre-treatment enables
the analyst to determine all forms - i.e. total phosphorus, by quantitative oxidation yielding an aqueous solution of
orthophosphate which should be analysed for phosphate according to method EN ISO 6878, EN ISO 10304-2 or an
equivalent validated method.
The range of the method is up to 50 g/kg P assuming appropriate dilution of the digest in the final
measurement step.
2 Normative references
The following referenced documents are indispensable for the application 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.
EN 12880:2000, Characterization of sludges — Determination of dry residue and water content
EN ISO 3696, Water for analytical laboratory use — Specification and test methods (ISO 3696:1987)
EN ISO 6878, Water quality — Determination of phosphorus — Ammonium molybdat spectrometric method
(ISO 6878:2004)
EN ISO 10304-2, Water quality — Determination of dissolved anions by liquid chromatography of ions —
Part 2: Determination of bromide, chloride, nitrate, nitrite, orthophosphate and sulfate in waste water
(ISO 10304-2:1995)
3 Terms and definitions
For the purposes of this European Standard, the following terms and definitions apply.
3.1
total phosphorus
phosphorus converted to orthophosphate by oxidation.
NOTE This includes condensed phosphates (e.g. pyro and polyphosphates), organophosphorus (e.g. phosphate
esters and aminophosphonic acids) and free phosphates
3.2
dry residue
dry mass portion of the sludge obtained after the specified drying process. It is expressed as percent
[EN 12880:2000, 3.1]
3.3
dry mass (dry matter)
mass of solid obtained after the specified drying process. It is expressed as grams or kilograms
[EN 12880:2000, 3.3]
4 Principle
A boiling mixture of sulfuric and nitric acids oxidises organic matter, releasing any phosphorus present and
converting it to orthophosphate. As the mixture boils, nitric acid is lost due to the oxidation process and due to
distillation. As the proportion of nitric acid decreases, the
...