Variability in physical contamination assessment of source segregated biodegradable municipal waste derived composts.
Physical contaminants (glass, metal, plastic and 'other') and stones were isolated and categorised from three finished commercial composts derived from source segregated biodegradable municipal waste (BMW). A subset of the identified physical contaminant fragments were subsequently reintroduced into the cleaned compost samples and sent to three commercial laboratories for testing in an inter-laboratory trial using the current PAS100:2011 method (AfOR MT PC&S). The trial showed that the 'other' category caused difficulty for all three laboratories with under reporting, particularly of the most common 'other' contaminants (paper and cardboard) and, over-reporting of non-man-made fragments. One laboratory underreported metal contaminant fragments (spiked as silver foil) in three samples. Glass, plastic and stones were variably underreported due to miss-classification or over reported due to contamination with compost (organic) fragments. The results are discussed in the context of global physical contaminant test methods and compost quality assurance schemes.
School of Energy, Geoscience, Infrastructure and Society, Heriot Watt University, Edinburgh EH14 4AS, Scotland, UK.
Virginia
V
Echavarri-Bravo
The Food and Environment Research Agency, Sand Hutton, York YO41 1LZ, UK.
Helene H
HH
Thygesen
School of Energy, Geoscience, Infrastructure and Society, Heriot Watt University, Edinburgh EH14 4AS, Scotland, UK. Electronic address: t.j.aspray@hw.ac.uk.
Thomas J
TJ
Aspray
D001673:Biodegradation, Environmental; D005898:Glass; D008670:Metals; D010209:Paper; D012037:Refuse Disposal / Q000379:methods; D015203:Reproducibility of Results; D012987:Soil; D006113:United Kingdom
D008670:Metals; D012987:Soil
Compost quality; Ex situ; Impurities; In-vessel composting; Inter-laboratory trial; Physical contaminants