Characterization of waste - Sampling of waste materials - Part 1: Guidance on selection and application of criteria for sampling under various conditions

This Technical Report discusses the statistical principles of sampling, and provides a number of statistical tools to assist in the design of testing programmes for application to sampling under various conditions.
NOTE 1   Given the great variety of waste types, sampling situations and objectives, this Technical Report cannot provide definitive instructions that cover all scenarios. Instead, it discusses the basic statistical approach to be followed, and provides statistical tools that can be applied to determine the amount and type of sampling (e.g. number of samples and sample size) in any given situation to achieve results of adequate reliability (i.e. precision and confidence).
NOTE 2   The document provides considerable detail on current best practice, but is not exhaustive.
NOTE 3   To clarify the text, the document provides a number of worked examples.

Charakterisierung von Abfall - Probenahme - Teil 1: Richtlinien zur Auswahl und Anwendung von Kriterien für die Probenahme unter verschiedenen Bedingungen

Caractérisation des déchets - Prélevement des déchets - Partie 1 : Guide relatif au choix et a l'application des criteres d'échantillonnage dans diverses conditions

Le présent Rapport Technique traite des principes statistiques de l’échantillonnage et propose un certain nombre d’outils statistiques aidant a la conception de programmes d’essai destinés a etre appliqués a un échantillonnage dans diverses conditions.
NOTE 1   En raison de la grande diversité des types de déchets, des situations d’échantillonnage et des objectifs, le présent document ne peut pas fournir des instructions définitives couvrant tous les scénarios. Il décrit plutôt l’approche statistique fondamentale a adopter et il propose des outils statistiques qui peuvent etre utilisés pour déterminer la quantité et le type de l’échantillonnage (par exemple le nombre d’échantillons et leur taille) dans une situation donnée quelconque afin d’obtenir des résultats présentant une fiabilité adéquate (c’est-a-dire fidélité et niveau de confiance).
NOTE 2   Le document est tres détaillé en ce qui concerne les bonnes pratiques actuelles mais il n’est pas exhaustif.
NOTE 3   Afin d’aider a la compréhension du texte, le document comporte un certain nombre d’exemples traités.

Karakterizacija odpadkov - Vzorčenje odpadkov - 1. del: Navodilo za izbiro in uporabo kriterijev za vzorčenje pri različnih pogojih

General Information

Status
Published
Publication Date
31-Mar-2007
Technical Committee
Current Stage
6060 - National Implementation/Publication (Adopted Project)
Start Date
01-Apr-2007
Due Date
01-Apr-2007
Completion Date
01-Apr-2007

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SLOVENSKI STANDARD
SIST-TP CEN/TR 15310-1:2007
01-april-2007
.DUDNWHUL]DFLMDRGSDGNRY9]RUþHQMHRGSDGNRYGHO1DYRGLOR]DL]ELURLQ
XSRUDERNULWHULMHY]DY]RUþHQMHSULUD]OLþQLKSRJRMLK

Characterization of waste - Sampling of waste materials - Part 1: Guidance on selection

and application of criteria for sampling under various conditions
Charakterisierung von Abfall - Probenahme - Teil 1: Richtlinien zur Auswahl und
Anwendung von Kriterien für die Probenahme unter verschiedenen Bedingungen

Caractérisation des déchets - Prélevement des déchets - Partie 1 : Guide relatif au choix

et a l'application des criteres d'échantillonnage dans diverses conditions
Ta slovenski standard je istoveten z: CEN/TR 15310-1:2006
ICS:
13.030.10 Trdni odpadki Solid wastes
13.030.20 7HNRþLRGSDGNL%ODWR Liquid wastes. Sludge
SIST-TP CEN/TR 15310-1:2007 en

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

---------------------- Page: 1 ----------------------
TECHNICAL REPORT
CEN/TR 15310-1
RAPPORT TECHNIQUE
TECHNISCHER BERICHT
November 2006
ICS 13.030.10; 13.030.20
English Version
Characterization of waste - Sampling of waste materials - Part 1:
Guidance on selection and application of criteria for sampling
under various conditions

Caractérisation des déchets - Prélèvement des déchets - Charakterisierung von Abfall - Probenahme - Teil 1:

Partie 1 : Guide relatif au choix et à l'application des Richtlinien zur Auswahl und Anwendung von Kriterien für

critères d'échantillonnage dans diverses conditions die Probenahme unter verschiedenen Bedingungen

This Technical Report was approved by CEN on 21 February 2006. It has been drawn up by the Technical Committee CEN/TC 292.

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
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
Management Centre: rue de Stassart, 36 B-1050 Brussels

© 2006 CEN All rights of exploitation in any form and by any means reserved Ref. No. CEN/TR 15310-1:2006: E

worldwide for CEN national Members.
---------------------- Page: 2 ----------------------
CEN/TR 15310-1:2006 (E)
Contents

Foreword............................................................................................................................................................. 4

Introduction ........................................................................................................................................................ 5

1 Scope ..................................................................................................................................................... 7

2 Terms and definitions........................................................................................................................... 7

3 Specify the objective of the Testing Programme ............................................................................ 12

4 Develop the technical goals from the objective .............................................................................. 13

4.1 General................................................................................................................................................. 13

4.2 Define the population to be sampled................................................................................................ 14

4.2.1 General................................................................................................................................................. 14

4.2.2 Overall population .............................................................................................................................. 14

4.2.3 Population ........................................................................................................................................... 14

4.2.4 Sub-population.................................................................................................................................... 14

4.2.5 Examples ............................................................................................................................................. 15

4.3 Assess variability................................................................................................................................ 16

4.3.1 General................................................................................................................................................. 16

4.3.2 Spatial variability ................................................................................................................................ 16

4.3.3 Temporal variability............................................................................................................................ 17

4.3.4 Random variability.............................................................................................................................. 17

4.4 Select the sampling approach........................................................................................................... 17

4.4.1 General................................................................................................................................................. 17

4.4.2 Probabilistic sampling........................................................................................................................ 18

4.4.3 Judgemental sampling....................................................................................................................... 18

4.5 Identify the scale................................................................................................................................. 18

4.6 Choose the required statistical parameter.......................................................................................19

4.7 Choose the desired reliability............................................................................................................ 20

4.7.1 General................................................................................................................................................. 20

4.7.2 Precision and Confidence.................................................................................................................. 20

4.7.3 Errors in the Testing Programme...................................................................................................... 20

5 Determine the Practical Instructions ................................................................................................ 21

5.1 General................................................................................................................................................. 21

5.2 Sampling pattern................................................................................................................................. 22

5.2.1 General................................................................................................................................................. 22

5.2.2 Simple random sampling ................................................................................................................... 23

5.2.3 Stratified random sampling ............................................................................................................... 23

5.2.4 Systematic sampling .......................................................................................................................... 24

5.2.5 Judgemental sampling....................................................................................................................... 24

5.3 Determine the increment and sample size (mass / volume)........................................................... 24

5.3.1 General................................................................................................................................................. 24

5.3.2 Liquids ................................................................................................................................................. 25

5.3.3 Powders and sludges......................................................................................................................... 25

5.3.4 Particulate / granular materials ......................................................................................................... 25

5.4 The use of composite versus individual samples........................................................................... 26

5.5 Determine the required number of increments and samples......................................................... 26

6 Define the Sampling Plan................................................................................................................... 27

Annex A The scale ........................................................................................................................................... 28

A.1 Scale..................................................................................................................................................... 28

A.2 Fundamental variability...................................................................................................................... 32

Annex B Statistical methods for characterising a population .................................................................... 33

B.1 Terms and Definitions ........................................................................................................................ 33

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CEN/TR 15310-1:2006 (E)

B.2 Probability distributions .....................................................................................................................35

B.3 Statistical parameters .........................................................................................................................37

Annex C Calculating the required numbers of increments and samples...................................................43

C.1 Notation ................................................................................................................................................43

C.2 Estimating a mean concentration......................................................................................................43

C.3 Estimating a standard deviation ........................................................................................................46

C.4 Estimating a percentile .......................................................................................................................47

C.5 Estimating a percentage compliance with a given limit..................................................................48

Annex D Minimum increment and sample size (mass / volume).................................................................49

D.1 Estimation of increment and sample size.........................................................................................49

D.2 Determination of the number of increments and/or samples .........................................................51

D.3 Calculation of the actual increment and/or sample size .................................................................51

Annex E Example sampling scenarios...........................................................................................................53

E.1 Sampling scenarios.............................................................................................................................53

E.2 Example 1: Waste producer to carry out a basic characterisation on the concentration of

Cr in a waste liquid during discharge to the on-site lagoon ........................................................57

E.3 Example 2: Waste producer to undertake a regular compliance testing programme to check

conformance with data obtained from the basic characterisation.................................................59

E.4 Example 3: Regulator to undertake an on-site verification of supernatant liquid in the

hazardous waste lagoon.....................................................................................................................61

E.5 Example 4: Waste producer to carry out a basic characterisation on the concentration of

Cr6+ in a waste liquid held in drum storage at the factory, for disposal purposes .....................63

E.6 Example 5: Waste producer to carry out a compliance testing of the Cr6+ concentration of

waste liquid held in drums prior to disposal, against a permitted mean limit of 100 mg/l ..........65

E.7 Example 6: Carrier or Disposal company to carry out an on-site verification of drums

containing Cr-contaminated liquid sludge prior to treatment ........................................................67

E.8 Example 7: Carrier or Disposal Company to carry out an on-site verification of the contents

of tankers containing Cr6+ contaminated liquid sludge prior to treatment ..................................68

E.9 Example 8: Treatment plant operator applying basic characterisation to identify variability of

Cr6+ in a treated waste using a two-step leaching test at LS 2 and LS 8......................................70

E.10 Example 9: Treatment plant operator to perform compliance testing to determine whether

the treated hazardous waste complies with a limit determined on the basis of the basic

characterisation, using a combined one-step leaching test at LS10 .............................................72

E.11 Example 10: On-site verification........................................................................................................74

E.12 Example 11: Compliance testing .......................................................................................................74

E.13 Example 12: On-site verification........................................................................................................74

E.14 Example 13: On-site verification........................................................................................................75

E.15 Example 14: Basic characterisation ..................................................................................................75

Bibliography......................................................................................................................................................76

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CEN/TR 15310-1:2006 (E)
Foreword

This Technical Report (CEN/TR 15310-1:2006) has been prepared by Technical Committee CEN/TC 292

“Characterization of waste”, the secretariat of which is held by NEN.

This Technical Report has been prepared under a mandate given to CEN by the European Commission and the

European Free Trade Association.

This Technical Report is one of a series of five Technical Reports dealing with sampling techniques and

procedures, and provides essential information and instructions for the application of the EN-standard:

EN 14899 Characterisation of Waste - Sampling of waste materials - Framework for the preparation and

application of a Sampling Plan

The principal component of the EN Standard is the mandatory requirement to prepare a Sampling Plan. This EN

14899 standard can be used to:

− produce standardised sampling plans for use in regular or routine circumstances (i.e. the

elaboration of daughter/derived standards dedicated to well defined sampling scenarios);

− incorporate specific sampling requirements into national legislation;
− design and develop a Sampling Plan on a case by case basis.

The Technical Reports display a range of potential approaches and tools to enable the project manager to tailor

his sampling plan to a specific testing scenario (i.e. a ‘shop shelf’ approach to sampling plan development for

waste testing). This approach allows flexibility in the selection of the sampling approach, sampling point, method

of sampling and equipment used.

This Technical Report describes the statistical principles related to sampling, and provides methods based on

these principles enabling a testing programme to be defined that will produce results sufficiently reliable for the

decision-making process for which they are required.

Wastes arise in a wide variety of types (e.g. pastes, liquids, granular materials, mixes of different materials) and

sampling situations (e.g. during a waste production process, stockpiles, tanks, drums). There can also be a

variety of sampling objectives within each of the three broad categories (basic characterisation, compliance

testing and on-site verification). Consequently the Report cannot provide definitive instructions for each and every

case on the practical details of the testing programme, such as the required number of samples, the size of these

samples, and whether they should be spot or composite samples. Instead, its aim is to expose the factors that

influence the choice of these detailed components of the sampling exercise, and to provide statistical tools that

can then be applied to determine the most appropriate testing programme for any given sampling scenario.

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CEN/TR 15310-1:2006 (E)
Introduction

Wastes are materials, which the holder discards, or intends or is required to discard, and which may

be sent for final disposal, reuse or recovery. Such materials are generally heterogeneous and it will

be necessary therefore to specify in the testing programme the amount of material for which the

characteristics of interest need to be defined. The testing of wastes allows informed decisions to be

made on how they should be treated (or not), recovered or disposed of. In order to undertake valid

tests, some sampling of the waste is required.

The principal component of the standard EN 14899 is the mandatory requirement to prepare a

Sampling Plan, within the framework of an overall testing programme as illustrated in Figure 1 of

EN 14899:2005 and can be used to:

− produce standardised sampling plans for use in regular or routine circumstances (elaboration of

daughter/derived standards dedicated to well defined sampling scenarios);

− incorporate the specific sampling requirements of European and national legislation;

− design and develop a Sampling Plan for use on a case by case basis.

The development of a Sampling Plan within this framework involves the progression through three

steps or activities:
1) define the Sampling Plan;
2) take a field sample in accordance with the Sampling Plan;
3) transport the laboratory sample to the laboratory.

This Technical Report provides information to support Key Step 1 of the Sampling Plan process map

and describes the selection of sampling approach that can be used in the recovery of a sample for a

wide variety of waste types and arisings. Specifically this Technical Report provides information to

support 4.2.7 (Select sampling approach) of the Framework Standard. Due consideration and

selection of statistical criteria is of key importance in the production of a Sampling Plan as it provides

the sole means of ensuring that, wherever possible, the type and number of samples taken will

address a clearly identified objective and will provide results that achieve a tolerable level of

reliability.
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CEN/TR 15310-1:2006 (E)

Table 1 - Main statistical steps in defining a sampling plan for a testing programme

Step Subject
Specify the objective of the Testing Programme
1 Specify the objective of the Testing
Programme
Develop the Technical Goals from the objective
2 Define the population to be sampled
3 Assess variability
4 Select the sampling approach
5 Identify the scale
6 Choose the required statistical approach
7 Choose the desired reliability
Determine the practical instructions
8 Choose the sampling pattern
9 Determine the increment/ sample size
10 Determine the use of composite or individual
samples
11 Determine required number of samples
Define the Sampling Plan
12 Define the Sampling Plan

To illustrate the application of these principles, a series of 14 examples of sampling scenarios for a

single waste stream are provided in Annex E.

This Technical Report should be read in conjunction with the Framework Standard for the

preparation and application of a Sampling Plan as well as the other Technical Reports that contain

essential information to support the Framework Standard. The full series comprises:

− EN 14899 Characterization of waste - Sampling of waste materials - Framework for the

preparation and application of a Sampling Plan;

− CEN/TR 15310-1, Characterization of waste – Sampling of waste materials – Part 1: Guidance

on selection and application of criteria for sampling under various conditions;

− CEN/TR 15310-2, Characterization of waste – Sampling of waste materials – Part 2: Guidance

on sampling techniques;

− CEN/TR 15310-3, Characterization of waste – Sampling of waste materials – Part 3: Guidance

on procedures for sub-sampling in the field;

− CEN/TR 15310-4, Characterization of waste – Sampling of waste materials – Part 4: Guidance

on procedures for sample packaging, storage, preservation, transport and delivery;

− CEN/TR 15310-5, Characterization of waste – Sampling of waste materials – Part 5: Guidance

on the process of defining the Sampling Plan.

The Technical Reports contain procedural options (as detailed in Figure 2 of EN 14899:2005) that

can be selected to match the sampling requirements of any testing programme.
---------------------- Page: 7 ----------------------
CEN/TR 15310-1:2006 (E)
1 Scope

This Technical Report discusses the statistical principles of sampling, and provides a number of

statistical tools to assist in the design of testing programmes for application to sampling under

various conditions.

NOTE 1 Given the great variety of waste types, sampling situations and objectives, this Technical Report

cannot provide definitive instructions that cover all scenarios. Instead, it discusses the basic statistical approach

to be followed, and provides statistical tools that can be applied to determine the amount and type of sampling

(e.g. number of samples and sample size) in any given situation to achieve results of adequate reliability (i.e.

precision and confidence).

NOTE 2 The document provides considerable detail on current best practice, but is not exhaustive.

NOTE 3 To clarify the text, the document provides a number of worked examples.
2 Terms and definitions

For the purposes of this Technical Report, we have used or adapted the definitions of ISO 3534

Parts 1, 2 and 3 wherever possible. In a minority of cases, however, those definitions are couched in

technical statistical language, which is likely to be unhelpful to the intended readership. In these

instances we have either supplemented the formal definition with an additional note, or provided an

alternative simpler definition.

NOTE In order to keep the list of definitions as compact as possible, some terms that are used only

occasionally in the main text have been omitted. B.1 provides an additional list of definitions that are specifically

relevant to the various annexes.
2.1
analytical error

collective term for the imprecision and bias associated with the analytical method

2.2
characteristic

property, which helps to identify or differentiate between items of a given population

[ISO 3534-1]

NOTE The characteristic may be either quantitative (by variables) or qualitative (by attributes).

2.3
coefficient of variation

for a non-negative characteristic the ratio of the standard deviation to the average

[ISO 3534-1]
2.4
compliance (and non-compliance)

compliance is achieved when the sample values from a monitoring programme meet a pre-defined

set of criteria. Conversely, non-compliance occurs when the sample values fail to meet the pre-

defined criteria
NOTE Examples of compliance criteria are:
− The estimated mean should be ≤ 20 mg/kg;
− Fewer than 3 sample values out of 20 should exceed 50 µg/l.
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CEN/TR 15310-1:2006 (E)
2.5
composite sample

two or more increments / sub-samples mixed together in appropriate proportions, either discretely or

continuously (blended composite sample), from which the average value of a desired characteristic

may be obtained
[ISO 11074-2]
2.6
confidence interval

interval within which a particular population parameter may be stated to lie at a specified confidence

level. The bounds of the confidence interval are termed the upper and lower confidence limits

2.7
fundamental variability
inherent variability shown by a material at the smallest scale of measurement
2.8
heterogeneity

degree to which a property or a constituent is not uniformly distributed throughout a quantity of

material

NOTE 1 A material may be heterogeneous with respect to one analyte or property but not with respect to

another.

NOTE 2 The degree of heterogeneity is a key-determining factor in sampling error.

2.9
increment

individual portion of material collected by a single operation of a sampling device

NOTE 1 Increments may be reduced and tested individually or combined with other increments, with the

resulting composite reduced in size and tested as a single unit.

NOTE 2 Increments are created by the sampling operation and are usually taken from parts of a lot

separated in time or space.
2.10
judgemental sampling

samples collected using at best a partially-probabilistic procedure and at worst a non-probabilistic

approach. Usually these samples are taken from a sub-population which is substantially more

restrictive than the overall population.
2.11
mean (arithmetic mean)
sum of values divided by the number of values
[ISO 3534-1]

NOTE For example, the arithmetic mean of the five values 12, 4, 11, 9 and 6 is 8.4.

2.12
overall population
entire volume of material about which information is required.

NOTE 1 For example, the overall population might be the output of waste over the whole lifetime of the plant.

NOTE 2 See ‘population’.
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CEN/TR 15310-1:2006 (E)
2.13
percentile

P-percentile of a population is the value below which P% of the values in the population fall, and hence is

exceeded by (100-P)% of the population.

NOTE For example, 95 % of the values in a population are less than or equal to the 95-percentile, and 5 %

of the population values exceed it.
2.14
physical sampling error
error attributable to the activity of taking the sample
2.15
population
totality of items under consideration. [ISO 3534-1:1993, definition 2.3]

NOTE The population will generally be a convenient, well-defined subset of the overall population (e.g. a

year’s production of waste) that is believed to be typical of that wider population.

2.16
precision

closeness of agreement between independent test results obtained under stipulated conditions

[ISO 3534-1]

NOTE 1 Precision depends only on the distribution of random errors and does not relate to the true value or

the specified value.

NOTE 2 The measure of precision usually is expressed in terms of imprecision and computed as a standard

deviation of the test results. A lower precision is reflected by a larger standard deviation.

2.17
probabilistic sampling
sampling conducted according to the statistical principles of sampling

NOTE 1 The essential principle of probabilistic sampling is that every individual particle or item in the population has an equal

chance of being sampled.

NOTE 2 Probabilistic sampling results in boundary conditions for the type of sampling equipment used, the method of

sampling (where, when, how) and the minimum size of increments and (composite) samples.

2.18
probability
real number in the scale 0 to 1 attached to a random event
[ISO 3534-1]

NOTE An event with a probability close to zero is very unlikely to happen. For example, the probability of

obtaining ‘heads’ in each of 10 consecutive spins of a coin is about 0.001. Conversely, an event with probability

close to 1 is very likely to happen. For example, the event of obtaining at least one ‘six’ when rolling 25 dice is

about 0.99.
2.19
probability distribution (of a random variable)

function giving the probability that a random variable takes any given value or belongs to a given set

of values
[ISO 3534-1]
---------------------- Page: 10 ----------------------
CEN/TR 15310-1:2006 (E)

NOTE The probability distribution is a mathematical description of the relative frequencies with which

different values arise in the population. It is commonly represented graphically, and can be thought of as the

curve that the histogram of random sample values would tend towards as the number of samples becomes

indefinitely large.
2.20
random sample

sample of n sampling units taken from a population in such a way that each of the possible

combinations of n sampling units has a particular (known) probability of being taken

[ISO 3534-1]
2.21
random sampling
process of taking a random sample
[ISO 3534-1]
2.22
reliability

collective term for the degree of precision and confidence achieved by a given sampling scheme

2.23
representative

sample resulting from a sampling plan that can be expected to reflect adequately the properties of

interest in the parent population
[ISO 11
...

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