Bsi bs en 14671 2006 (2007)

untitled BRITISH STANDARD BS EN 14671 2006 Characterization of sludges — Pre treatment for the determination of extractable ammonia using 2 mol/l potassium chloride The European Standard EN 14671 2006[.]

BRITISH STANDARD BS EN

14671:2006

Characterization of

sludges —

Pre-treatment for the

determination of

extractable ammonia

using 2 mol/l potassium

chloride

The European Standard EN 14671:2006 has the status of a

British Standard

ICS 13.030.20

12&23<,1*:,7+287%6,3(50,66,21(;&(37$63(50,77('%<&23<5,*+7/$:

This British Standard was

published under the authority

of the Standards Policy and

Strategy Committee

on 30 April 2007

© BSI 2007

National foreword

This British Standard was published by BSI It is the UK implementation of

EN 14671:2006

The UK participation in its preparation was entrusted to Technical Committee EH/5, Sludge characterization

A list of organizations represented on EH/5 can be obtained on request to its secretary

The UK committee has never seen the need to standardize this method at a European level and, as a consequence, has not been actively involved in the development of this standard However, the UK committee is pleased that a classic British method was selected The method has long been used as a valuable operational-control method and is available in existing technical literature (see reference [1] in the bibliography of this standard) Due to the difficulty and cost of sending liquid sludge samples (in such a manner that their properties do not change) to laboratories for international interlaboratory trials of the performance of this method, interested parties convened at a workshop to assess the test Their conclusion was that the results are operationally defined (e.g by the filter paper used) and, as the document does not specify all such operational details, the performance data are not really applicable outside the context of the workshop As a result, the members of EH/5 have no information to offer on the reproducibility of the results

This publication does not purport to include all the necessary provisions of a contract Users are responsible for its correct application

Compliance with a British Standard cannot confer immunity from legal obligations

Amendments issued since publication

EUROPEAN STANDARD

NORME EUROPÉENNE

EUROPÄISCHE NORM

EN 14671

June 2006

ICS 13.030.20

English Version

Characterization of sludges - Pre-treatment for the determination

of extractable ammonia using 2 mol/l potassium chloride

Caractérisation des boues - Prétraitement pour la

détermination de l'Azote ammoniacal extractible utilisant

2mol/l de chlorure de potassium

Charakterisierung von Schlämmen - Vorbehandlung zur Bestimmung des extrahierbaren Ammoniums unter Verwendung von 2 mol/l Kaliumchlorid

This European Standard was approved by CEN on 24 May 2006.

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, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.

EUROPEAN COMMITTEE FOR STANDARDIZATION

C O M I T É E U R O P É E N D E N O R M A L I S A T I O N

E U R O P Ä IS C H E S K O M IT E E FÜ R N O R M U N G

Management Centre: rue de Stassart, 36 B-1050 Brussels

© 2006 CEN All rights of exploitation in any form and by any means reserved

Contents Page

Foreword 3

Introduction 4

1 Scope 5

2 Normative references 5

3 Terms and definitions 5

4 Principle 5

5 Limitations and interferences 5

6 Hazards 6

7 Reagents 6

8 Apparatus 6

9 Sample pre-treatment 7

10 Procedure 7

11 Expression of results 8

12 Test report 8

Annex A (informative) Performance data of the interlaboratory comparison — Summary of sludge exchangeable ammonia results 9

Bibliography 11

EN 14671:2006 (E)

3

Foreword

This document (EN 14671:2006) 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 December 2006, and conflicting national standards shall be withdrawn

at the latest by December 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, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom

Introduction

Because sludge may be applied to land as manure or as a disposal, there is a need to monitor extractable ammonia

EN 14671:2006 (E)

5

1 Scope

This European standard specifies a procedure for the determination of extractable ammonia using a 2 mol/l potassium chloride solution in raw and digested sewage sludges The range of the method is up to 100 g/kg N assuming appropriate dilution of the potassium chloride extract in the final measurement step

NOTE The above wording will be modified once the round robin results are available It may be suitable for other types of sludges, but the user should validate the method using these sludges

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 3696:1995, Water for analytical laboratory use — Specification and test methods (ISO 3696:1987)

3 Terms and definitions

For the purposes of this European Standard, the following terms and definitions apply

3.1

extractable ammonia

ammonia that is released when the homogenised sludge is shaken with 2 mol/l potassium chloride for 1 h at room temperature

3.2

dry residue

dry mass portion of the sludge obtained after the specified drying process, expressed as a percentage

[EN 12880:2000, 3.1]

4 Principle

An aliquot of the homogenised sludge is shaken for 1 h with 2 mol/l potassium chloride at room temperature The sample is then filtered and the ammonia determined by a suitable method Potassium chloride (2 mol/l) is used rather than water to ensure that both soluble and ion exchangeable forms of the determinand are determined It also minimises biological activity in the extracted sample

All results are expressed as nitrogen

Although undried samples are taken for analysis, it is recognised practice to report results on a dry weight basis Consequently the dry residue content of the homogenised sample used for analysis should also be determined using a separate test portion (see EN 12880)

5 Limitations and interferences

Substances present at their normal concentration in these types of samples should not cause significant interference in the pre-extraction step For the vast majority of sewage sludges, the relatively high concentration of ammonia compared with potential interferences should not result in any significant

interferences in the final measurement stage The user should carry out suitable recovery checks to confirm this

6 Hazards

6.1 General

Waste and sludge samples may contain hazardous and inflammable substances They may contain pathogens and be liable for biological action Consequently it is recommended that these samples should be handled with special care The gases, which may be produced by microbiological activity are potentially inflammable and will pressurise sealed bottles Exploding bottles are likely to result in infectious shrapnel and/or pathogenic aerosols Glass bottles should be avoided whenever possible National regulations should

be followed with respect to microbiological hazards associated with this method

NOTE All equipment used in the vicinity should be flame proof to avoid any risk of ignition

6.2 Storage

It is not advisable to store samples in an open laboratory If samples are to be stored, store them between

0 °C and 4 °C Sample containers that enable the escape of any generated gas should be used

7 Reagents

7.1 Water complying with purity grade 2 of EN ISO 3696:1995

7.2 Potassium chloride c(KCl) = 2,5 mol/l

Dissolve (931,9 ± 1) g of potassium chloride (dried at (105 ± 2) °C for 1 h) in approximately 3 l of water and dilute to 5 l with water in a volumetric flask

8 Apparatus

Ordinary laboratory apparatus and the following:

8.1 Extraction bottles

Wide-necked glass or plastics bottles with secure stoppers or caps, for example 250 ml nominal capacity

8.2 Mechanical shaking apparatus

Any suitable horizontal or inversion shaker shall be used (e g horizontal shaker (20 rpm to 40 rpm with

~20 mm throw); roller table rotating at about 10 rpm; end-over-end tumbler (5 rpm to 10 rpm))

NOTE Other shaking devices may be used provided that they can be shown to provide equivalent results The material being leached should not settle or be agitated too vigorously so that particle abrasion occurs

8.3 Balance with on accuracy ± 0,05 g

8.4 Drying oven, capable of maintained at (105 ± 5) °C

8.5 Suitable apparatus for the determination of ammonia in diluted sludge filtrates

(See 10.4)

EN 14671:2006 (E)

7

8.6 Filter papers

Cellulose filter papers with a pore size of 20 µ to 25 µ (For example Whatman 5411))

9 Sample pre-treatment

Sludge samples can change composition through biological and/or chemical activity They shall be kept in cool boxes at less than 4 °C in transit to the laboratory They shall be analysed as soon as possible (within 24 h) after sampling

If prolonged storage is unavoidable, then store the samples at or below a temperature of –18 °C in a freezer for a maximum period of 4 weeks and note this on the test report

9.2 Preparation of sample

The purpose of pre-treatment is to obtain a representative and homogeneous sample Samples shall not be subject to any drying prior to homogenisation because this will result in a loss of ammonia For frozen samples see NOTE below

NOTE For frozen sludges, it is recommended that a suitable aliquot (equivalent to 0,25 g to 1 g of dry matter) of the frozen homogenised sample is directly transferred to the potassium chloride solution, as transformation of nitrogen compounds can occur during the thawing process

10 Procedure

10.1 Transfer a known weight (m gram) of suitably homogenised (as sampled) sludge (equivalent to

(0,25 to 1) g ± 2 mg of dry matter, see NOTES 1 and 2) to an extraction bottle (8.1) Add (80 ± 1) ml 2,5 mol/l

potassium chloride (7.2) and (20 – m) ± 1 ml of water (7.1) (See also 9.2, NOTE)

NOTE 1 If a dry solids result is not available and an immediate analysis is required, then visually estimate the dry solids content

NOTE 2 The maximum “as received” weight of sludge taken should not exceed 20 g

10.2 Replace the bottle cap and place on a shaker for (60 ± 5) min at room temperature (see 8.2)

10.3 Owing to the difficulty in filtering many types of sludge samples, it is recommended that a suitable

aliquot of the leached sample is centrifuged Then filter a suitable volume aliquot through a fluted filter paper (8.6) discarding at least the first 10 ml In some cases paper filtration is too slow or even impossible In such cases a validated alternative procedures for obtaining a clear supernatant are acceptable and the technique used shall be reported The filtrate is stable for some hours in a hermetically closed polyethylene bottle if stored in a refrigerator at (0 to 4) °C The filtrate can be stored for longer periods in a deep freezer at less than -18 °C

NOTE Vacuum filtration should not be used as it can result in loss of ammonia

In most instances the ammonia concentration will be sufficiently high to dilute the leached sample extract

10 times prior to this filtration step This will greatly aid the speed of the filtration step This dilution must be

1) This information is given for the convenience of users of this European Standard and does not constitute an endorsement by CEN of the product named Equivalent products may be used if they can be shown to lead to the same results

accounted for in the final calculation and the calibration standards need to be made up in 0,2 mol/l KCl rather than 2 mol/l KCl

10.4 Analyse the ammonia according to ISO 5664, EN ISO 11732 or EN ISO 14911 or equivalent validated

method within one day unless stored at less than –18 °C (4 weeks)

10.5 A reagent blank without the addition of any sludge shall be taken throughout the whole procedure 10.6 It is important to ensure that the calibration standards and blank shall be prepared in 2 mol/l potassium

chloride (Add 80 ml of reagent 7.2, (2,5 mol/l KCl) per 100 ml)

11 Expression of results

11.1 Calculation

The extractable ammonia content, EA is expressed in g of nitrogen, N per kg dry mass and is given by

equation (1):

dr

b A

10 m w

V C C

E

×

×

×

−

where

C is the ammonium nitrogen concentration in the extract, in mg/l ;

Cb is the ammonium nitrogen concentration in the reagent blank, in mg/l ;

m is the wet mass of sample taken for extraction, in g;

wdr is the dry residue of the sludge determined by method EN 12880, in %;

V is the total volume of the extractant used, in ml (100 ml)

11.2 Precision

See Annex A

12 Test report

The test report shall contain the following information:

a) reference to this European Standard;

b) all information necessary for the complete identification of the sludge sample;

c) details of sample pre-treatment, if carried out;

d) results of the determination according to Clauses 10 and 11;

e) any detail not specified in this European Standard and any other factor which may have affected the results

EN 14671:2006 (E)

9

Annex A

(informative)

Performance data of the interlaboratory comparison — Summary of

sludge exchangeable ammonia results

Due to difficulties examining sludge samples for its ammonia contents following regular interlaboratory comparisons (distribution of sub-samples to a number of participating laboratories), it was decided to follow the instructions given in clause 4 of prCEN/TR 15252:2006 Thus, two experienced laboratories examined two different sewage sludges each for the recovery of ammonia in spiked and unspiked samples as given in Table 1 and Table 2

Table A.1 — Results of confidence level evaluation (CLE) of laboratory 1

Raw sludge Dry solids 2,23 %

Digested sludge Dry solids 5,85 % Replicate

% N spiked sample

% N unspiked sample

Recovery [%] of spiked sample

% N spiked sample

% N unspiked sample

Recovery (%) of spiked sample

1 3,306 1,572 98,5 9,973 5,264 94,9

2 3,379 1,575 102,5 10,035 5,194 97,6

3 3,367 1,608 99,9 9,883 5,085 96,7

4 3,321 1,606 97,5 10,209 5,235 100,3

5 3,295 1,568 98,1 9,911 5,196 95,1 Mean 3,334 1,586 99,3 10,002 5,195 96,9 RSD (%) 1,12 1,23 2,01 1,30 1,31 2,25

NOTE Dry sample mass taken by lab 1 was 0,25 g Spike concentration (% N) 1,76

NOTE Dry sample mass taken by lab 1 was 0,25 g Spike concentration (% N) 4,96