🌿 Sampling of sludges from waste water treatment plants, water treatment works and industrial processes — guidance

Environment PN-EN ISO 5667-13

Overview

What the standard concerns. The PKN catalogue card describes the scope thus: "Detailed principles are given for the sampling of sludges from waste water treatment plants, water treatment works and from industrial processes. These principles apply to all kinds of sludge arising in those works and to sludges of similar characteristics. Guidance is also given on drawing up programmes and choosing sampling techniques". The document runs to 27 pages, published 26-08-2011, TC 119 Water Quality — Basic Matters, ICS 13.030.20 and 13.060.45 (the status of the card checked 11 September 2026: no "Date of withdrawal" and no "Superseded by" fields).

Language version — and a distinction that the "Supersedes" row alone does not give. The current edition PN-EN ISO 5667-13:2011 is ENGLISH ONLY, and a Polish translation existed: PN-EN ISO 5667-13:2004 (Polish version), which superseded PN-EN ISO 5667-13:2002 (English version). The "Supersedes" and "Superseded by" fields show this as an ordinary succession, but the "IMPLEMENTS" field says something else: the 2002 and 2004 editions implement THE SAME European document — EN ISO 5667-13:1997 [IDT] and ISO 5667-13:1997 [IDT]. The move from 2002 to 2004 was therefore A CHANGE OF LANGUAGE VERSION and not a revision: the European standard remained the same, what changed was the language of the national edition. ONLY THE 2011 EDITION IS A REVISION — it implements EN ISO 5667-13:2011 and ISO 5667-13:2011, that is a document fourteen years newer. It can also be seen in the TITLE, which grew shorter and thereby widened the scope: the 2002 and 2004 editions bore the title „Wytyczne dotyczące pobierania próbek osadów Z OCZYSZCZALNI ŚCIEKÓW I STACJI UZDATNIANIA WODY" [in English: "Guidance on sampling of sludges FROM WASTE WATER TREATMENT PLANTS AND WATER TREATMENT WORKS"], and the 2011 edition — „Wytyczne dotyczące pobierania próbek OSADÓW" ["Guidance on sampling of SLUDGES"], without the narrowing to two kinds of works; the scope on the card additionally names sludges from industrial processes. A laboratory that has the Polish title of 2004 in its documentation therefore has a title describing a NARROWER subject than the standard in force (all checked 11 September 2026). The Polish title in the heading of this entry comes from the catalogue card of the current edition — PKN gives the title in Polish also for standards issued in English — but there is no Polish TEXT for this edition.

What the legislation says — and here the difference from sewage is sharper than it seems. The Regulation of the Minister of the Environment of 6 February 2015 on municipal sewage sludge (Journal of Laws 2015 item 257) regulates the sampling of sludge IN DETAIL, and at the same time INVOKES NO STANDARD — neither on sampling nor on determination: in the whole act the string "PN-" does not occur even once, "ISO" not once, "5667" not once. We checked it twice: in the 2015 wording and in the NEW wording of Annex No 4, given by Journal of Laws 2022 item 89 — in both the result is the same (checked 11 September 2026). This proposition is therefore the only part of the entry that the amendment did not disturb. The reference methods of Annex No 4 are described IN WORDS: "electrometric determination in aqueous solution", "drying at 105 °C, weighing", "ignition at 550 °C, weighing", "distillation of ammonia and determination by a titrimetric or spectrophotometric method". With sewage (Journal of Laws 2019 item 1311) the legislation was silent only about sampling, while for the analyses it invoked a dozen or more PN standards — so its silence about a sampling standard meant something. Here the act invokes no standard ANYWHERE, so from its silence nothing may be inferred about the sampling standard itself: it is not a choice of the legislator with respect to that standard but a consistent convention of the whole regulation.

A NOTE ON THE LEGAL POSITION — A CORRECTION OF THE EARLIER WORDING OF THIS ENTRY (11 September 2026). The 2015 regulation was amended by the Regulation of the Minister of Climate and Environment of 31 December 2021 (Journal of Laws 2022 item 89, promulgated 14-01-2022), and the amendments concerning sampling took effect ONLY AFTER 48 MONTHS FROM PROMULGATION, that is on 14-01-2026. Earlier editions of this entry gave the wording from before that date. The title of the act also changed: today it is the regulation "on the USE of municipal sewage sludge".

What the legislation requires in the sampling of sludge — position as at 11 September 2026. First — WHO: a condition of using the sludge is that the tests referred to in § 5 and § 6 are carried out "in an ACCREDITED LABORATORY within the meaning of Article 5(4) of the Act of 30 August 2002 on the conformity assessment system or in a laboratory holding a QUALITY MANAGEMENT SYSTEM CERTIFICATE covering the procedure for testing municipal sewage sludge" (§ 2(5) as worded by Journal of Laws 2022 item 89). The previous wording referred to Article 147a of the Environmental Protection Law — that provision no longer applies, and the new one admits TWO routes instead of one, which for a laboratory without accreditation for these tests is a difference that decides whether it may accept a commission. Second — HOW OFTEN: tests by reference methods of sludge INTENDED FOR USE are carried out at a frequency depending on the load of the treatment plant, expressed as a population equivalent within the meaning of Article 86(3)(2) of the Water Law of 2017, NOT LESS OFTEN THAN: once every six months at a p.e. up to 2000; once every THREE months at a p.e. above 2000 up to 10 000; once every TWO months at a p.e. above 10 000 up to 100 000; ONCE A MONTH at a p.e. over 100 000 (§ 5(2)). There are therefore FOUR thresholds and not three, and the lowest of them — p.e. up to 2000 — appeared only in this wording. Third — FROM HOW MANY PLACES: the sample for testing is obtained by combining and thoroughly mixing samples taken AT THE SAME TIME from different places, their number being at least 10 for a sludge volume up to 50 m³, 15 for a volume above 50 m³ up to 100 m³ and 30 for a volume above 100 m³ (§ 5(3) — a subsection NOT CHANGED by the amendment). These are requirements for sampling written into the legislation — but they are NOT steps of a procedure and the entry does not call them that. TRANSITIONAL PROVISION: samples of a batch of sludge taken before 14-01-2026 may be tested in accordance with the previous provisions, and the results remain valid for a year from the day of sampling (§ 2 of Journal of Laws 2022 item 89) — a laboratory may therefore legally have in circulation in 2026 results obtained under the old rules.

Separately about soil, because it concerns the same laboratory. Tests of the soil are carried out each time before a given batch of sludge is directed for use (§ 6(2)), and the soil sample is obtained by mixing 25 SAMPLES taken at points regularly distributed over an area not exceeding 5 ha, of uniform structure and identical use (§ 6(3)), to a depth of 25 cm or to the maximum possible depth of not less than 10 cm if the soil layer is shallower (§ 6(4)).

What this entry does not contain. We did not have the text of the standard — PKN supplies it for a fee and we did not obtain a preview of the content (checked 11 September 2026). Unlike the entry on part 10 of this series, WE DO NOT HAVE EVEN THE CONTENTS HERE, so we give neither the structure of the chapters, nor the names of the sampling techniques, nor the kinds of samplers, nor the requirements as to containers, preservation and storage of the sludge. The entry gives: the scope of the standard from the catalogue card, its status and the path of its language versions, and the requirements of the LEGISLATION concerning the sampling of sludge and of soil. Everything that comes from the legislation says so beside itself.

WHY THIS ENTRY STANDS UNDER THE HEADING OF A STANDARD WHEN THE STEPS COME FROM LEGISLATION — the decision adopted in this Knowledge Base. A laboratory searches the knowledge base by the NUMBER OF THE STANDARD, because that is what it writes in its accreditation scope and in its report; an entry hidden under the number of a regulation would be unreachable for it. The heading of the standard is therefore an address and not a declaration that the procedure comes from it. Three things are the condition of honesty in such an entry, and all are met here: the heading gives the status of the standard with a date, every step says IN ITS TITLE where it comes from, and a separate paragraph says what the entry does not contain. An entry that does not meet all three should not stand under the number of a standard.

FOUR LABORATORIES THAT THE TAB WILL NOT SHOW — AND WHY (23.09.2026). Four laboratories cite this standard in the form "PN-ISO 5667-13:2011" (eight entries: six without an addition and two with excluded clauses — "z wyłączeniem pkt 6.3.8.5" at AB 1365 and "z wyłączeniem pkt 6.3.5, 6.3.7, 6.3.8" at AB 1214): AB 079, AB 550, AB 1214 and AB 1365. Such a designation DOES NOT EXIST in the PKN catalogue — the catalogue knows only PN-EN ISO 5667-13 in the 2002, 2004 and 2011 editions — and the year 2011 indicates that it is the same document written without the EN element. None of these four laboratories has a record with the EN element, so the tab, which matches the beginning of the value against "PN-EN ISO 5667-13", will not show any of them. A single key covering both forms cannot be set, which is why we list them here by number. The discrepancy came to light when comparing the figures (2 entries with a clause for 4 laboratories in the form without EN, 15 for 66 in the form with EN).

Method principle

Sludge is not a homogeneous liquid: it separates under gravity, changes its water content and composition over time, and differs from place to place within the same tank. Taking one portion from one place therefore does not describe a batch of sludge, and the result of a determination made on such a sample speaks about the sample and not about the sludge. The legislation solves this by means of a BULK SAMPLE: a dozen or several dozen increments taken at the same time from different places, combined and thoroughly mixed, their number growing with the volume of the batch — 10, 15 or 30. The standard describes how to plan and carry out such sampling for sludges from waste water treatment plants, water treatment works and industrial processes; we did not have its text, so we do not give the details of the techniques.

Applications

• Sampling of municipal sewage sludge before its agricultural use or land reclamation
• Sampling of sludge from waste water treatment plants for the producer’s control tests
• Sampling of sludge from water treatment works
• Sampling of sludge arising in industrial processes
• Sampling of soil before sludge is applied to it (a requirement of Journal of Laws 2015 item 257, § 6)

Key parameters

Standard

Standard number

PN-EN ISO 5667-13:2011 (wersja ANGIELSKA; wprowadza EN ISO 5667-13:2011 [IDT] i ISO 5667-13:2011 [IDT])

Title (PL)

Jakość wody — Pobieranie próbek — Część 13: Wytyczne dotyczące pobierania próbek osadów

Title (EN)

Water quality — Sampling — Part 13: Guidance on sampling of sludges

Step-by-step procedure

1. Checking who carries out the tests (§ 2(5) as worded by Journal of Laws 2022 item 89) — STEP FROM THE LEGISLATION

   Make sure that the tests are carried out by an accredited laboratory within the meaning of Article 5(4) of the Act on the conformity assessment system or by a laboratory holding a quality management system certificate covering the procedure for testing municipal sewage sludge. The provision speaks of "carrying out the tests referred to in § 5 and § 6" — and § 5(3) describes the way the sample is obtained, so sampling is part of those tests.

2. Establishing the date according to the load of the treatment plant (§ 5(2) as worded by Journal of Laws 2022 item 89) — STEP FROM THE LEGISLATION

   Establish the frequency of testing sludge INTENDED FOR USE: p.e. up to 2000 — not less often than once every six months; above 2000 up to 10 000 — once every three months; above 10 000 up to 100 000 — once every two months; over 100 000 — once a month. These are MINIMUM frequencies ("not less often than"). The p.e. is counted within the meaning of Article 86(3)(2) of the Water Law of 2017.

3. Establishing the number of increments according to the volume of the batch (Journal of Laws 2015 item 257, § 5(3)) — STEP FROM THE LEGISLATION

   Establish the volume of the batch of sludge being tested and from it the number of increments: at least 10 up to 50 m³, 15 above 50 up to 100 m³, 30 above 100 m³. The number depends on the VOLUME OF THE BATCH and not on the size of the treatment plant — a different criterion from that in the previous step, and easy to confuse with it.

4. Taking the increments and combining them into a bulk sample (Journal of Laws 2015 item 257, § 5(3)) — STEP FROM THE LEGISLATION

   Take the increments AT THE SAME TIME from different places in the batch, combine them and mix them thoroughly. The condition of simultaneity is part of the legislation: samples collected at intervals do not form a bulk sample within the meaning of this regulation. WE GIVE NEITHER THE MANNER OF TAKING A SINGLE INCREMENT, NOR THE EQUIPMENT, NOR THE SIZE OF THE PORTION — that is in the text of the standard, which we did not have.

5. Taking a soil sample before the sludge is used (Journal of Laws 2015 item 257, § 6(2)–(4)) — STEP FROM THE LEGISLATION

   Before directing a given batch of sludge onto the soil, take a soil sample: 25 samples at points regularly distributed over an area not exceeding 5 ha, of uniform structure and identical use, to a depth of 25 cm or to the maximum possible depth of not less than 10 cm. The soil is tested EACH TIME before a batch, not periodically.

6. Record of sampling (the requirements listed below follow from Journal of Laws 2015 item 257 § 5(2) and (3) and § 6 — the standard imposes no report in the scope given on the card)

   Give the volume of the batch of sludge, the number of increments taken and the date of sampling — without them compliance with § 5(2) and (3) cannot be demonstrated. For a soil sample give the area from which the 25 samples were taken and the sampling depth. Note that the result concerns a BULK SAMPLE formed by mixing and not a single place.

Required equipment and apparatus

Health and safety (OHS)

• Sewage sludge is material presenting a biological hazard — sample in gloves, with face protection against splashes, without eating or drinking in the working area.
• The regulation on municipal sewage sludge requires testing for the presence of bacteria of the genus Salmonella and of live eggs of intestinal parasites — the presence of those organisms in the sample must be assumed in advance, before a result denies it.
• When sampling from tanks and lagoons the rules for work over an open surface apply: protection against falling in, work in pairs, rescue equipment within reach.
• Methane and hydrogen sulfide may accumulate in closed digestion chambers and manholes — entry only after measuring the atmosphere and in accordance with the procedure for work in confined spaces.
• Transport sludge samples in tight containers, labelled as biologically active material; after sampling wash and disinfect the equipment so as not to carry material over to the next batch.

Frequently asked questions