Question

why can't we compost plastic bags

Answer 1

The compost-making bacteria, fungi and actinomycetes require oxygen to function. Plastic garbage bags are made of polyethylene, which is impermeable to carbon dioxide. A sealed bag will result in the accumulation of carbon dioxide, which will replace the oxygen. The system will go anaerobic. If the bag is sealed tight, it could even explode. In addition to accumulating carbon dioxide, alcohol and acetic acid will accumulate in the bag. The odors will be sufficient to gag a maggot. What happens when plastic-coated products are composted?

The plastic-coated paper products currently being collected by many composting programs produce both macro- and micro-fragments of non-biodegradable plastic which contaminate the finished compost. Once these plastics are dispersed into the environment, they have not been shown to biodegrade and are suspected of causing detrimental effects to organisms in a variety of ecosystems. We can expect these fragments to persist indefinitely and to be so widely dispersed that it will be impossible to clean them up. Compost collection programs and compost facilities must exclude plastic-coated paper products from their guidelines to prevent future harm.