ISO 14852:2021 Determination of the ultimate aerobic biodegradability of plastic materials in an aqueous medium — Method by analysis of evolved carbon dioxide

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Determination of the ultimate aerobic biodegradability of plastic materials in an aqueous medium — Method by analysis of evolved carbon dioxide是ISO于2021-06发布的ISO标准，适用于全球范围。

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Determination of the ultimate aerobic biodegradability of plastic materials in an aqueous medium — Method by analysis of evolved carbon dioxide

WARNING — Sewage, activated sludge can contain potentially pathogenic organisms. Therefore, appropriate precautions should be taken when handling them. Toxic test compounds and those whose properties are unknown should be handled with care.

1 Scope

This document specifies a method, by measuring the amount of carbon dioxide evolved, for the determination of the degree of aerobic biodegradability of plastic materials, including those containing formulation additives. The test material is exposed in a synthetic medium under standardized laboratory conditions to an inoculum from activated sludge under aerobic conditions.

The conditions used in this document do not necessarily correspond to the optimum conditions allowing maximum biodegradation to occur, but this test method is designed to measure the biodegradation of plastic materials and give an indication of their potential biodegradability.

The method enables the assessment of the biodegradation to be improved by calculating a carbon balance (optional, see Annex C).

The method applies to the following materials:

— natural and/or synthetic polymers, copolymers or mixtures thereof;

— plastic materials which contain additives such as plasticizers, colorants or other compounds;

— water-soluble polymers;

— materials which, under the test conditions, do not inhibit the microorganisms present in the inoculum. Inhibitory effects can be determined using an inhibition control or by another appropriate [1]

method (see, for example, ISO 8192 ). If the test material is inhibitory to the inoculum, a lower test concentration, another inoculum or a pre-exposed inoculum can be used.

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 8245, Water quality — Guidelines for the determination of total organic carbon (TOC) and dissolved organic carbon (DOC)

3 Terms a nd definiti ons

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:

— ISO Online browsing platform: available at https:// www. iso .org/o bp

— IEC Electropedia: available at https://w ww .electropedia. org/

3.1

ultimate aerobic biodegradability

breakdown ratio by expressed as percentage of an organic compound by microorganisms in the presence of oxygen into carbon dioxide, water and mineral salts of any other elements present (mineralization) plus new biomass

3.2

activated sludge

mixture of organic materials and biomass produced in the aerobic treatment of waste water by the growth of bacteria and other microorganisms in the presence of dissolved oxygen

3.3

concentration of suspended solids

amount of solids obtained by filtration or centrifugation of a known volume of activated sludge (3.2) and drying at about 105 °C to constant mass

3.4

dissolved inorganic carbon

DIC

part of the inorganic carbon in water which cannot be removed by specified phase separation

−2

Note 1 to entry: Phase separation can be achieved for example by centrifugation at 40 000 m⋅s for 15 min or by membrane filtration using membranes with pores of 0,2 µm to 0,45 µm diameter.

3.5

theoretical amount of evolved carbon dioxide

ThCO

2

maximum theoretical amount of carbon dioxide evolved after completely oxidizing a chemical compound, calculated from the molecular formula

Note 1 to entry: It is calculated from the molecular formula.

Note 2 to entry: It is expressed as milligrams of carbon dioxide evolved per milligram or gram of test compound.

3.6

total organic carbon

TOC

amount of carbon bound in an organic compound

Note 1 to entry: It is expressed as milligrams of carbon per 100 mg of the compound.

[SOURCE: ISO 17556:2012, 3.14]

3.7

dissolved organic carbon

DOC

part of the organic carbon in water which cannot be removed by specified phase separation

−2

Note 1 to entry: Phase separation can be achieved for example by centrifugation at 40 000 m⋅s for 15 min or by membrane filtration using membranes with pores of 0,2 µm to 0,45 µm diameter.

3.8

lag phase

time from the start of a test until adaptation and/or selection of the degrading microorganisms is achieved and the degree of biodegradation of a chemical compound or organic matter has increased to about 10 % of the maximum level of biodegradation (3.9)

Note 1 to entry: It is measured in days.

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