ISO 16929:2019 pdf download

ISO 16929:2019 pdf download.Plastics — Determination of the degree of disintegration of plastic materials under defined composting conditions in a pilot-scale test
1 Scope
This document is used to determine the degree of disintegration of plastic materials in a pilot-scale aerobic composting test under defined conditions. It forms part of an overall scheme for the evaluation of the compostability of plastics as outlined in ISO 17088. The test method laid down in this document is also used to determine the influence of the test material on the composting process and the quality of the compost obtained. It cannot be used to determine the aerobic biodegradability of a test material. Other methods are available for this (for example, see ISO 14851, ISO 14852 or ISO 14855-1 and ISO 14855-2).
4 Principle
The disintegration test is performed under defined and standardized composting conditions on a pilot- scale level. The test material is mixed with fresh biowaste in a precise concentration and introduced into a defined composting environment. A natural ubiquitous microbial population starts the composting process spontaneously and the temperature increases. The composting mass is regularly turned over and mixed. Temperature, pH-value, moisture content and gas composition are regularly monitored. They should fulfil certain requirements to ensure sufficient and appropriate microbial activity. The composting process is continued until a fully stabilized compost is obtained. This is usually the case after 12 weeks. The compost is visually observed at regular time intervals to detect any adverse effect of the test material on the composting process. At the end of the test, the maturity of compost is determined, and the mixture of compost and test material is sieved through 2 mm and 10 mm mesh sieves. The disintegration of the test material is evaluated based on the total dry solids by comparing the fraction of test material retained by the 2 mm sieve and the amount tested. The compost obtained at the end of the composting process may be used for further measurements, such as chemical analyses and ecotoxicity tests.
5.1.1 General
The composting environment may be either a pilot-scale composting bin or nets buried in a pilot-scale composting bin. The volume of each bin shall be high enough for natural self-heating to occur. Sufficient and even aeration shall be provided by an appropriate air supply system. NOTE To standardize conditions for the test, the composting trials can be run in bins which are placed in a climatic chamber with a constant chamber temperature or in insulated bins. If during the spontaneous thermophilic phase the compost reaches temperatures higher than 65 °C, the diversity of microbial species can be reduced. To restore a full array of thermophilic bacteria, the compost can be re-inoculated with mature compost (about 1 % of the total initial biowaste mass) of recent origin (maximum 3 months old).