BS EN ISO 5815-1 pdf free download
BS EN ISO 5815-1-2019 pdf free download.Water quality – Determination of biochemical oxygen demand after n days (BODn) Part 1: Dilution and seeding method with allylthiourea addition (ISO 5815-1:2019).
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.
ISO 3696, Water for analytical laboratory use — Specification and test methods
ISO 5667-3, Water quality — Preservation and handling of water samples
ISO 5813, Water quality — Determination of dissolved oxygen — Iodometric method
ISO 5814, Water quality — Determination of dissolved oxygen — Electrochemical probe method
ISO 6060, Water quality — Determination of the chemical oxygen demand
ISO 8245, Water quality — Guidelines for the determination of total organic carbon (TOC) and dissolved organic carbon (DOC)
ISO 8467, Water quality — Determination of permanganate index
ISO 10523, Water quality — Determination of pH
ISO 15705, Water quality — Determination of the chemical oxygen demand index (ST-COD) — Small-scale sealed-tube method
4 Principle The BOD n , with inhibition of nitrification is determined, using the dilution method. A batch series with different dilutions of a sample is prepared and examined. The dilution water is enriched with oxygen and seeded with adapted aerobic microorganisms. The sample is incubated at (20 ± 1) °C for a specified period (n), 5 d or 7 d, in the dark, in a completely filled and stoppered bottle. The dissolved oxygen concentration is determined before and after incubation. The mass of consumed oxygen per litre sample is calculated.
5 Reagents
Use only reagents with the degree of purity “for analysis”.
5.1 Water, at least grade 3 in accordance with ISO 3696.
The water shall not contain more than 0,01 mg/l of copper, nor chlorine or chloramines.
5.2 Seeding water, which can be obtained in one of the following ways:
a) municipal waste water, decanted or coarsely filtered;
b) surface water containing municipal waste water;
c) settled effluent from a waste water treatment plant;
d) water taken downstream from the discharge of the water to be analysed, or water containing microorganisms that are adapted to the water to be analysed;
e) commercially available seeding material.
Use seeding water with a COD of about 300 mg/l or a TOC of about 100 mg/l (see 5.5). If the COD or TOC are higher, adapt to these concentrations with dilution water (5.4) before preparing the seeded dilution water (5.5) or use a correspondingly changed volume of the seeding waters for seeding the dilution water (5.4).
If the sample comes from a process that has been subjected to disinfection treatment (chlorination, UV, ozone or other), use inoculum, even when there is no residual disinfectant present.
For commercially available seeding material consider respective application recommendations.BS EN ISO 5815-1 pdf download.
