German study finds compostable biowaste bags no threat to compost quality

A new study from the Witzenhausen institute and the University of Bayreuth in Germany suggests that compostable biowaste bags do not impact negatively on the quality of compost produced by industrial composting processes.

The study shows that compostable bags disintegrate completely in the composting process after composts from eight different biowaste treatment plants with an upstream fermentation stage were examined for film plastics, particularly compostable film plastics.

The number of film particles in the compost (mean value from three repetitions) varied between 2.3 and 74.3 film particles per litre of compost. The area sum index of the composts varied between 0.7 cm²/l FM and 13 cm²/l FM; the mean value of all 10 composts was 5 cm²/l FM.

In seven of the 10 composts or in 25 of 30 samples no compostable plastic films particles could be detected. The number of plastic film per compost sample (one litre of test substrate each) varied between one and 111 film particles, altogether 446 plastic film particles were found in the 30 compost samples (10 compost samples with three repetitions each).

Over 98 per cent of the film plastic particles found in the composts were attributable to PE or other plastics.

If it is assumed that compostable plastic bags make up around 39 per cent of the film plastics in biowaste input material, only an average of 1.8 per cent of compostable plastic films were detected in the composts, supporting the assumption that the use of compostable plastic bags for biowaste consumption significantly reduce plastic contamination in compost.

By |2020-07-28T10:30:45+00:00July 28th, 2020|Our news|Comments Off on German study finds compostable biowaste bags no threat to compost quality

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