Well,

I quit from the undermentioned link;

The first, published in the journal Earth System Science Data, outlines the global methane budget over the 13-year period from 2000 to 2012. A consortium of researchers under the Global Carbon Project has produced a biennially-updated assessment of global methane concentrations and an analysis of known sources and sinks (sinks are natural features that neutralize methane as a GHG by breaking down CH4 molecules or absorbing the gas back into the earth’s surface).

https://globalmethane.wordpress.com/

Regards

Useful paper contain excellent information about your question, please see the following link:

Conference Paper Methane Production from Pyrolysis of Mixed Solid Wastes

and other paper

https://journals.plos.org/plosone/article/file?id=10.1371/journal.pone.0200574&type=printable

thanks for taking the time to respond Bayan Hussien Omar Ali Al-Khashman