ISO 16929:2021 pdf – Plastics — Determination of the degree of disintegration of plastic materials under defined composting conditions in a pilot-scale test

ISO 16929:2021 pdf – Plastics — Determination of the degree of disintegration of plastic materials under defined composting conditions in a pilot-scale test.
3.5 composting aerobic process designed to produce compost (3.4) 3.6 compostability property of a material to be biodegraded in a composting (3.5) process 3.7 maturity of compost assignment of the maturity of a compost (3.4) based on the measurement of the maximum temperature in a self-heating test using Dewar vessels Note 1 to entry: It is expressed in terms of the so-called “Rottegrad” (see 6.2.3.1). 3.8 total dry solids amount of solids obtained by taking a known volume of test material or compost (3.4) and drying at about 105 °C to constant mass 3.9 volatile solids amount of solids obtained by subtracting the residues of a known volume of test material or compost (3.4) after incineration at about 550 °C from the total dry solids (3.8) content of the same sample Note 1 to entry: The volatile solids content is an indication of the amount of organic matter present. 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.
5.1.2 Composting bins 5.1.2.1 Volume and material The bins shall: — have a minimum volume of 35 l; — consist of a sturdy, heat-resistant and non-biodegradable material; — not affect the composting process or the quality of the compost. 5.1.2.2 Drainage The drainage shall consist of a layer of drains with a thickness of at least 5 cm at the bottom of the bins. 5.1.3 Sample nets, if used, shall consist of mesh-like material with a mesh size of 1 mm made of non- degradable plastic which is resistant to temperatures up to 120 °C. The minimum volume shall be 20 l. 5.2 Apparatus for temperature measurement. 5.3 pH-meter. 5.4 Apparatus for oxygen measurement. 5.5 Sieves, of suitable shape with screens of 2 mm and 10 mm mesh (as specified, for example, in ISO 3310-2). 6 Test procedure WARNING — Compost can contain potentially pathogenic organisms. Therefore, appropriate precautions should be taken when handling it. Aspergillosis, farmer ’s lung, histoplasmosis, Legionnaire ’s disease, paronychia and tetanus are some of the more common physical ailments that can result from unprotected contact with compost. The following general safety precautions should be followed in order to avoid transmission of dangerous fungi, bacteria and other pathogens found in compost. — Always wear gloves to avoid direct contact with the skin. — Always wear protective footwear that covers your skin adequately. — When stirring and tilling the compost, which is required on a regular basis in order for it to process and break down, always wear a nose and mouth guard or dust mask to avoid inhaling the various spores that will become airborne during tilling and turning. — Do not store compost in fully closed or airtight containers. — Always wash your hands after dealing with compost.
6.1 Actions before and during incubation 6.1.1 Start-up of the test 6.1.1.1 Preparation of biowaste As a carrier matrix, use biowaste, if possible from the input material of a composting plant treating predominantly municipal waste, or, less satisfactorily, biowaste directly from households or grocery stores for example. NOTE be used: Alternatively, a representative artificial biowaste with, for example, the following ingredients can — — — — — freshly mixed fruit and vegetable waste; rabbit feed (seeds and extruded dried-vegetable pellets); mature compost; sufficient water to attain a good moisture content; a bulking agent (such as wood chips or bark). It is important that for all test series a homogeneous biowaste of the same age and origin is used. Reduce the biowaste to particle sizes of maximum 50 mm, for example by shredding or sieving. Depending on the type of waste, add about 100 g/kg to 600 g/kg of bulking agent (structurally stable components such as wood chips or bark with a particle size between 10 mm and 50 mm). To ensure a good composting process, the biowaste shall meet the following criteria: — the C:N ratio of the fresh biowaste/bulking agent mixture shall be between 20 and 30; — the moisture content shall be above 50 % mass fraction, with no free water present; — the volatile solids content of the total dry solids shall be above 50 % mass fraction; — the pH shall be above 5. Adjust the C:N ratio with urea, if required. 6.1.1.2 Preparation of the test material a) If the purpose of the test is to measure the degree of disintegration of the test material and to determine the effects on the composting process and the compost quality, use the test material in an identical form (e.g. shape, thickness) as for the intended final use.