One can start with: ...
Published by Tom Eckhoff, Principal at Arrigetch Environmental Consulting LLC
One can start with:
http://www.tandfonline.com/doi/abs/10.1080/20430779.2015.1012618?journalCode=tgmm20
or
Carbon sequestration and greenhouse gases emissions in soil under sewage sludge residual effects
and
Calculator Tool for Determining Greenhouse Gas Emissions for Biosolids Processing and End Use
A web search will provide additional references.