💧 Sampling of waste waters — guidance: the sampling programme, spot and composite samples, sampling in sewers, treatment plants and on industrial sites

Water and waste water PN-ISO 5667-10

Overview

What this standard is. It is not a method of determination but GUIDANCE on sampling — the document on which it depends whether the result of any determination in waste water makes sense at all. In accreditation scopes sampling is a separate, accredited activity and not an appendix to a test method.

What it covers — per the contents of the edition ISO 5667-10:2020 (the iTeh catalogue page, see the sources): general matters (designing the sampling programme, choice of the sampling point and its representativeness, frequency and time of sampling, number of samples, sampling time for the effluent stream), sampling at particular places (sewers, open channels and manholes; waste water treatment plants; industrial sites; cooling systems), the two main kinds of sampling (spot and composite samples), the sampling itself (preparation of the measurement campaign, arrival on site, automatic and manual composite sampling, reconstitution of the sample, spot sampling in the effluent stream — direct and indirect, automatic event-triggered sampling, sampling from tanks during planned discharges), equipment (automatic sampler, equipment for manual sampling, weighted sample collector, bucket and vertical sampler, equipment for sampling from tanks), handling of the sample (homogenisation of the volume taken, distribution into laboratory bottles, preservation and packing, transport and receipt, time and temperature, security and traceability — separately for routine samples and for samples that may be used for legal purposes), quality assurance (avoiding cross-contamination, identification of the sample and records, quality control), reports (analytical reports and sampling records) and safety (safety of persons and of equipment). Informative annexes: examples of sampling from tanks, and the advantages and disadvantages of the main kinds of waste water sampling.

Edition and language version — the third variety of the translation question. The current edition PN-ISO 5667-10:2021-11 is ENGLISH ONLY, but that does not mean the standard was never translated: the catalogue card gives in the "Supersedes" row the item "PN-ISO 5667-10:1997 - Polish version". A Polish translation therefore existed and became out of date together with the edition. HERE THE CHANGE IS REAL AND NOT LINGUISTIC — and we checked it by the "Implements" field on both cards: the 1997 edition implemented ISO 5667-10:1992 [IDT], and the current edition implements ISO 5667-10:2020 [IDT]. Between the one and the other lie twenty-eight years of development of the international document, so the Polish translation of 1997 does not describe the same standard but its predecessor. The distinction matters, because in the neighbouring part of the same series (13) two successive national editions implemented THE SAME European document and differed solely in language — the "Supersedes" and "Superseded by" fields look identical in both cases and do not allow them to be told apart. The card of PN-ISO 5667-10:1997 also gives a different title: „Jakość wody -- Pobieranie próbek -- Wytyczne pobierania próbek ścieków" [in English: "Water quality -- Sampling -- Guidance on sampling of waste waters"], without the number of the part in the title (checked 11 September 2026). The Polish title in the heading of this entry is a translation of the title of the current edition, not an official title — the official Polish title belongs to the 1997 edition, which this standard no longer describes.

What the legislation says — and here the answer differs from that with analyses. The Regulation of the Minister of Maritime Economy and Inland Navigation of 12 July 2019 on substances particularly harmful to the aquatic environment and the conditions to be met when discharging sewage into water or into the ground (Journal of Laws 2019 item 1311) invokes a dozen or more specific PN standards for the ANALYSES, but for SAMPLING it invokes none: the string "5667" does not occur in the whole act even once (checked 11 September 2026). The requirements concerning sampling are written directly into the legislation — in § 5 and the following. A NOTE ON THE TWO WORDS: the Polish original uses one word throughout („ścieki"); in English we keep "waste water" where the standard speaks and "sewage" where the legislation does, but the material is the same. For a laboratory this means that the legal basis of sampling is the REQUIREMENTS OF THE LEGISLATION, and the standard is good technical practice telling how to meet them.

THE LEGISLATION ALSO SAYS SOMETHING ABOUT THE MANNER OF SAMPLING, not only about the number of samples — and this is the place where it is easy to miss, because it stands not in § 5 but in the DEFINITIONS. The definition in § 2(4) reads: a daily composite sample is "a sample of sewage, taken for the purposes of establishing the values of polluting substances, with the exception of establishing the values of pH and temperature, formed from the mixing of samples taken manually or automatically at intervals of at most two hours, proportional to the flow, over a period of twenty-four hours". There are three technical requirements here: the manner (manually or automatically), the MAXIMUM INTERVAL between portions (two hours) and PROPORTIONALITY TO THE FLOW. There is also an exclusion with a practical consequence: pH and temperature are NOT determined in a daily composite sample — those two parameters require measurement in a spot sample, because averaging would falsify them.

THE FREQUENCY DEPENDS ON THE KIND OF SEWAGE, not only on the size of the treatment plant. Besides the figures for domestic and municipal sewage (§ 5(2)) the legislation sets separate requirements: industrial sewage containing substances from Table I of Annex No 4 — sampling DAILY, at a representative place (§ 5(6)); industrial sewage from water treatment stations, biologically degradable sewage, waters from the drainage of mining plants and sewage treated by reverse osmosis — at least ONCE EVERY TWO MONTHS (§ 5(7)). If industrial sewage is treated outside the plant in which it arose, sampling is permitted at the place where it leaves the treatment plant (§ 5(8)).

EVERY FREQUENCY HAS AN ASSIGNED RANGE OF SUBSTANCES — and this is the thing without which the figures alone are true but useless. Paragraph 5 does not contain one rule with exceptions but a dozen or more subsections, EACH of which names a different kind of sewage, a different annex and different exclusions from Table II of Annex No 4. A laboratory must first settle which subsection concerns it, and only then read the figure: — subsections 1–2: DOMESTIC and MUNICIPAL sewage, determinations per Annexes No 2 and 3 — four thresholds for the number of daily composite samples (4/12/12/24); — subsection 4: municipal sewage constituting a MIXTURE of domestic sewage with industrial sewage or with rainwater or meltwater, Annex No 4 EXCLUDING items 3, 5, 6, 11 and 12 in Table II — not less often than once every two months; — subsection 5: industrial sewage and sewage of similar composition, arising from activity OTHER than commercial, industrial, storage, transport or service activity, discharged INTO WATER, Table II of Annex No 4 excluding items 1 and 2 — at regular intervals, at least once every two months, at a fixed place; — subsection 6: industrial sewage containing substances from TABLE I of Annex No 4 — DAILY, at a representative place; — subsection 7: sewage from water treatment stations, biologically degradable industrial sewage, waters from the drainage of mining plants and sewage from reverse osmosis, Annex No 4 excluding items 1 and 2 in Table II — at least once every two months; — subsection 9: sewage referred to in § 4(4), Annex No 3 AND Annex No 4 excluding items 1, 2, 3, 5, 6, 11 and 12 in Table II — at regular intervals over a period of a year, at a fixed place; — subsection 12: the same sewage, but determinations solely per Annex No 4 with the same exclusion — at least once every two months; — subsection 13: sewage referred to in § 4(9), discharged into water — here the frequency depends on the SUBSTANCE from Annex No 6 and is the strictest in the whole paragraph: CONTINUOUSLY for the substances of items 1 and 2; ONCE A DAY for item 3; at least once a month for items 4–12; at least once every six months for item 13, and in the FIRST 12 MONTHS OF OPERATION OF THE INSTALLATION — at least once every three months. Place: where the sewage is discharged into water, and if necessary — at another representative place. Sampling "continuously" is the only place in this paragraph where the legislation excludes periodic sampling altogether — and it stands in subsection thirteen, that is where few people get to when looking for the number of samples. An entry that gave the figures alone, without saying what they concern, would be true in every word and unusable.

THE SAME THRESHOLDS STAND TWICE IN THE ACT AND DIFFER IN THE NUMBER OF POINTS. Besides § 5(2) (four thresholds: below 2000 — 4 samples; 2000–9999 — 12; 10 000–49 999 — 12; 50 000 and more — 24) the same figures are repeated by § 5(10) — for sewage under § 4(4) and determinations per Annex No 3 — but it has THREE points: 2000–9999 (12, with the possibility of 4), 10 000–49 999 (12) and 50 000 and more (24). THE THRESHOLD BELOW 2000 IS NOT IN SUBSECTION 10. Quoting "four thresholds" at the wrong subsection therefore imposes on small treatment plants an obligation which was not established in that place — or, with the opposite mistake, removes an obligation that exists.

TWO SAMPLING POINTS INSTEAD OF ONE. If the water permit sets minimum PERCENTAGES OF REDUCTION of polluting substances, the sampling concerns the sewage FLOWING INTO the treatment plant AND that discharged into water or into the ground (§ 5(3)) — that is, the number of samples under § 5(2) then relates to two streams and not to one. Treated separately is municipal sewage that is a mixture of domestic sewage with industrial sewage or with rainwater or meltwater: for it the frequency is at least ONCE EVERY TWO MONTHS, always at the same representative place (§ 5(4)).

FROM WHEN AND FOR HOW LONG. The annual sampling period runs from the day on which the decision granting the water permit or the integrated permit became final — or from another date, if the permit indicates one. Samples are taken throughout the period of validity of the permit (§ 5(11)). The year under this provision is therefore not a calendar year, and the sampling schedule must be counted from the date in the decision. This is the same situation as with 12457-2 and the opposite of that with PN-ISO 10381-5, where the standard is itself a reference methodology named by a regulation.

What this entry does not contain. We did not have the full text of the standard — PKN supplies it for a fee and we did not obtain a preview with the content; the iTeh catalogue page gave the contents and the chapter headings but not the content of the chapters (checked 11 September 2026). The entry therefore says WHAT the standard covers and not HOW to carry out the individual operations: there are no sample volumes here, no storage times, no temperatures, no bottle materials, no methods of preservation for particular determinations, and no criteria for choosing a sampler. The steps in the "procedure" field come from the LEGISLATION and from the CONTENTS of the standard — each of them says which of those two sources it comes from.

WHERE EXACTLY THE STRUCTURE COMES FROM — a proviso about the numbering of chapters. The contents on which we base the description of the coverage and the chapter numbers comes from the catalogue page of the INTERNATIONAL edition ISO 5667-10:2020, while the heading of this entry concerns PN-ISO 5667-10:2021-11. Identical implementation [IDT] usually preserves the numbering of chapters, but we did not check that and had nothing to check it with — we do not have the text of the PN. So if a laboratory opens the Polish standard and finds a different number at the same matter, that is not an error of the entry but the limit of what could be established without the text.

Method principle

A sample of sewage is to be representative of the stream being assessed and not of the moment at which the sampler arrived. The standard distinguishes two main kinds of sampling: the spot sample, taken once at a defined place and time, and the composite sample, formed by combining many portions taken over time — manually or with an automatic sampler, including one triggered by an event. The choice between them, the frequency and time of sampling and the point of sampling follow from the design of the sampling programme and not from convenience. After sampling, the volume is homogenised and distributed into bottles proper to the individual determinations, preserved, packed and transported with control of time and temperature, keeping records that allow the path of the sample to be reconstructed — separately and more strictly for samples that may be used for legal purposes.

Applications

• Sampling of municipal and domestic sewage discharged into water or into the ground
• Control of industrial sewage discharged into the sewerage system and into the environment
• Sampling at the inflow and outflow of a treatment plant to assess the percentage of reduction of pollutants
• Sampling from tanks during planned discharges
• Sampling from cooling systems
• Samples taken for the purposes of proceedings in which the result may have legal consequences

Key parameters

Standard

Standard number

PN-ISO 5667-10:2021-11 (ISO 5667-10:2020 [IDT])

Title (PL)

Jakość wody -- Pobieranie próbek -- Część 10: Wytyczne dotyczące pobierania próbek ścieków

Title (EN)

Water quality — Sampling — Part 10: Guidance on sampling of waste waters

Step-by-step procedure

1. Designing the sampling programme (contents of the standard, chapter 4.1)

   Establish the purpose of the investigation and on that basis the sampling programme. THE STEP IS NAMED IN THE CONTENTS OF THE STANDARD — we did not have its content.

2. Choosing the sampling point and checking its representativeness (contents, chapter 4.2; requirement from Journal of Laws 2019 item 1311, § 5(1)(2))

   The standard names representativeness as a separate matter. The legislation adds a requirement of its own: sample always at the same place of discharge of the sewage or at another place representative of its quality, and when sampling at the inflow to a treatment plant — likewise always at the same places.

3. Establishing the frequency and number of samples (contents, chapter 4.3; THE FIGURES from Journal of Laws 2019 item 1311, § 5(2))

   The standard discusses the frequency and time of sampling and the number of samples. The specific figures for domestic and municipal sewage are given by the LEGISLATION, not by the standard: 4, 12 or 24 daily composite samples a year depending on the p.e. of the treatment plant, with a rule for reduction to 2 or 4 samples in the following year if the required conditions are met and for return to the initial number after a sample not meeting the conditions. The legislation also requires sampling at regular intervals over a period of a year (§ 5(1)(1)).

4. Choosing the kind of sampling: spot or composite (contents, chapter 6)

   The standard distinguishes spot and composite sampling and discusses their advantages and disadvantages in informative Annex B. WE DO NOT GIVE THE CRITERIA OF CHOICE — they are in the content of the standard.

5. Preparing the campaign and arriving on site (contents, chapter 7.1)

   The standard sets out the preparation of the measurement campaign and the activities after arrival on site as separate points. We did not have the content.

6. Taking the sample (contents, chapters 7.2–7.4)

   Automatic or manual composite sampling, with reconstitution of the sample; spot sampling in the effluent stream — direct or indirect; automatic event-triggered sampling; sampling from tanks during planned discharges. WE DO NOT GIVE THE DETAILS OF EXECUTION.

7. Homogenisation and distribution into bottles (contents, chapters 9.1–9.2)

   Homogenise the volume taken and distribute it into laboratory bottles. WE GIVE NEITHER THE KINDS OF BOTTLES NOR THE VOLUMES.

8. Preservation, packing, transport (contents, chapters 9.3–9.4)

   Preserve and pack the samples, transport them with control of TIME and TEMPERATURE — the standard sets out both of those factors as separate points. WE DO NOT GIVE THE VALUES.

9. Security and traceability of samples (contents, chapter 9.5)

   The standard divides this point into ROUTINE samples and samples THAT MAY BE USED FOR LEGAL PURPOSES — for the latter the requirements are separate. It is the only place in the contents where the standard distinguishes the intended use of a sample.

10. Quality assurance (contents, chapter 10)

    Avoiding cross-contamination, identification of the sample and records, quality control.

11. Report (contents, chapter 11)

    The standard sets out the analytical report and the SAMPLING RECORD as two separate documents. A test report without a sampling record does not say how the sample it concerns came about.

Required equipment and apparatus

Health and safety (OHS)

• Sewage is material presenting a biological hazard — gloves, eye protection, hand hygiene, vaccinations proper to work with infectious material.
• Manholes and sewers are confined spaces: before descending, measure the atmosphere, provide a standby person and rescue equipment; the standard has a separate chapter on the safety of persons and of equipment.
• Risk of drowning and of being swept away by the stream when sampling from open channels — work in pairs, wear a life jacket.
• Industrial sewage may contain corrosive, volatile or flammable substances — establish the character of the discharge before sampling.
• Automatic samplers with mains supply in a manhole: risk of electric shock; use a reduced-voltage or battery supply.

Frequently asked questions