ISO 5815-1:2019 水質 — n日後の生物化学的酸素要求量の決定（BODn） — Part 1: アリルチオ尿素を添加した希釈および播種法 | ページ 2

Foreword

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This document was prepared by Technical Committee ISO/TC 147, Water quality, Subcommittee SC 5, Biological methods.

This second edition cancels and replaces the first edition (ISO 5815-1:2003), which has been technically revised. The main changes compared to the previous edition are as follows:

• change of working range: 1 mg/l instead of 3 mg/l as lower limit;
• changes in test procedure;
• 5.2, option to check seeding water suitability in advance with a CGA control analysis batch;
• 5.3.2, phosphate buffer solution pH-value: requirement for preparation of a new solution if the pH value is out of the range pH 7 and pH 8;
• 5.5, range for oxygen consumption of seeded dilution water 0,2 mg/l to 1,5 mg/l instead of upper limit 1,5 mg/l;
• 5.9, allowable range BOD₅ of the CGA control solution changed to (198 ± 40) mg/l and BOD₇ (206 ± 40) mg/l;
• 6.5, electrochemical probe option to measure the dissolved oxygen concentration added;
• 8.4, interferences: subclause on presence of peroxides and peroxide compounds added;
• 9.4, options to determinate the dilutions elaborated;
• 9.7, control analysis: elaborated description of procedure;
• 10.3,"approval of results/validity criteria” added;
• Annex A: title changed and “normative” instead of “informative”
• Annex C"Direct seeding of the analysis batches" added;
• new Annex D"Performance data" included.

A list of all parts in the ISO 5815 series can be found on the ISO website.

Introduction

The incubation time specified in this document is 5 d or 7 d. The latter corresponds to the practice in several Nordic countries. Annex A describes an incubation time of (2 + 5) d.

ISO 5815-1 specifies the determination of the biochemical oxygen demand (BOD) of waters with an expected BOD in the range 1 mg/l to 6 000 mg/l using the dilution method. A lower limit of working range may result from validation data in the laboratory. For samples with an expected low BOD in the range of 0,5 mg/l to 6 mg/l ISO 5815-2 provides the option of the determination of the (BOD) of waters using undiluted samples.

1 Scope

This document specifies the determination of the biochemical oxygen demand of waters by dilution and seeding with suppression of nitrification after 5 d or 7 d incubation time.

It is applicable to all waters having biochemical oxygen demands usually between 1 mg/l and 6 000 mg/l. It applies particularly to waste waters but also suits for the analysis of natural waters. For biochemical oxygen demands greater than 6 000 mg/l of oxygen, the method is still applicable, but special care is needed taking into consideration the representativeness of subsampling for preparation of the dilution steps. The results obtained are the product of a combination of biochemical and chemical reactions in presence of living matter which behaves only with occasional reproducibility. The results do not have the rigorous and unambiguous character of those resulting from, for example, a single, well‑defined, chemical process. Nevertheless, the results provide an indication from which the quality of waters can be estimated.

2 Normative references

The following documents are referred to in the text in such a way that some or all of their content constitutes requirements 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.

3 Terms and definitions

For the purposes of this document, the following terms and definitions apply.

ISO and IEC maintain terminological databases for use in standardization at the following addresses:

Bibliography