ISO/DIS 25304

Plastics — Determination of the degree of biodegradation and disintegration of plastics under high-solids anaerobic-digestion conditions

Scope

This document specifies a method for determining the degree of biodegradation and disintegration of plastics when exposed to high-solids mesophilic (37 °C ± 2 °C) or thermophilic (52 °C ± 2 °C) anaerobic digestion conditions. This method is based on ISO 15985, amended with a modified approach to determine disintegration.
This method is designed to simulate typical anaerobic digestion conditions for the organic fraction of mixed municipal solid waste. The test product is exposed in a laboratory test to an inoculum derived from anaerobic digesters operating only on pre-treated household waste. The anaerobic decomposition takes place under more than 20 % total solids (TS) and static non-mixed conditions. If disintegration is not complete at the end of the anaerobic phase, the digestate can be transferred to controlled aerobic composting conditions to determine the degree of disintegration after a post-composting phase.
NOTE 1  This test method is written for “plastics”, which include raw materials, intermediates (such as films) and finished items.
NOTE 2  This test method does not consider the pre-treatment technologies applied in high-solids anaerobic digestion plants. Consequently, it does not address the question of whether a particular plastic, with its specific shape, thickness, and mechanical properties, enters the anaerobic reactor, or is rejected upstream.