Stable isotopic signatures of methane from waste sources through atmospheric measurements.

This study aimed to characterize the carbon isotopic signatures (δ 13C-CH 4) of several methane waste sources, predominantly in the UK, and during field campaigns in the Netherlands and Turkey. CH 4 plumes emitted from waste sources were detected during mobile surveys using a cavity ring-down spectroscopy (CRDS) analyser. Air samples were collected in the plumes for subsequent isotope analysis by gas chromatography isotope ratio mass spectrometry (GC-IRMS) to characterize δ 13C-CH 4. The isotopic signatures were determined through a Keeling plot approach and the bivariate correlated errors and intrinsic scatter (BCES) fitting method. The δ 13C-CH 4 and δ 2H-CH 4 signatures were identified from biogas plants (−54.6 ± 5.6‰, n = 34; −314.4 ± 23‰ n = 3), landfills (−56.8 ± 2.3‰, n = 43; −268.2 ± 2.1‰, n = 2), sewage treatment plants (−51.6 ± 2.2‰, n = 15; −303.9 ± 22‰, n = 6), composting facilities (−54.7 ± 3.9‰, n = 6), a landfill leachate treatment plant (−57.1 ± 1.8‰, n = 2), one water treatment plant (−53.7 ± 0.1‰) and a waste recycling facility (−53.2 ± 0.2‰). The overall signature of 71 waste sources ranged from −64.4 to −44.3‰, with an average of −55.1 ± 4.1‰ (n = 102) for δ 13C, −341 to −267‰, with an average of −300.3 ± 25‰ (n = 11) for δ 2H, which can be distinguished from other source types in the UK such as gas leaks and ruminants. The study also demonstrates that δ 2H-CH 4 signatures, in addition to δ 13C-CH 4 , can aid in better waste source apportionment and increase the granularity of isotope data required to improve regional modelling. • Isotopic 13C signatures from 71 waste sources in UK, NL and TR determined. • Feedstock types have an impact on carbon isotopic signature of generated biogas. • Open and active landfill status has a great impact on carbon isotopic signature. • Sewage treatment is more enriched in 13C than from other waste sources. • Average δ13C isotopic signature of waste sources is −55.1 ± 4.1‰. [ABSTRACT FROM AUTHOR]