This guide provides a comprehensive overview of contaminants in organic waste streams destined for recycling, explaining their types, impacts, and management options. Aimed at policymakers, waste planners, recycling operators, and equipment suppliers, it clarifies the definition of “contaminant” and distinguishes between three main categories: physical (e.g. plastics, metals, glass), chemical (e.g. pesticides, heavy metals, persistent organic pollutants), and biological (e.g. pathogens, weed seeds, toxins).
The guide outlines the multiple risks contaminants pose, including damage to recycling equipment, harm to workers and ecosystems, reduced product quality, regulatory non-compliance, and financial losses. To address these challenges, it introduces a contaminant management hierarchy that prioritises prevention over removal. Prevention strategies focus on optimising collection schemes (e.g. kerbside vs. bring systems), providing appropriate tools such as caddies and compostable liners, and delivering continuous awareness-raising to influence waste producer behaviour.
Where prevention is insufficient, removal technologies—such as screening, centrifugal separation, and biodegradation processes—are discussed, alongside their limitations. The guide highlights the technical difficulties of removing plastics and persistent chemicals, particularly in high-moisture organic waste. It concludes by calling for innovation and sector-specific technological development to improve contaminant removal efficiency and protect soil quality as organic recycling expands globally.
Publication year: 2023
Language: EN
Published by: International Solid Waste Association (ISWA)
Keywords: organic waste contamination, physical contaminants, chemical contaminants, biological contaminants, compost quality, anaerobic digestion, contaminant prevention, waste collection systems, removal technologies, soil protection
