How does a paper mill count sludge and rejects in its footprint?
Burnt in your own boiler, they are Scope 1, with biogenic CO2 from fibre reported separately and CO2 from plastic rejects counted in full. Sent to a landfill or another company, they are Scope 3 category 5, waste generated in operations.
Where each goes
- Own boiler: fossil share of rejects, mainly plastics, in Scope 1; fibre share biogenic.
- Landfill: Scope 3 category 5, using a factor for the waste type and disposal route.
- Sold to a cement kiln or brick maker: category 5 only for any treatment you pay for.
Measure the tonnes
Weighbridge slips for sludge and rejects leaving the site, and moisture content, because wet tonnes overstate the mass.
Plastic in rejects
Plastic is fossil carbon. Burning it raises your Scope 1 even if the rest of the fuel is biomass.
What Senseible does here
Senseible reads the energy invoices behind the making stage into a fingerprinted Scope 1 and 2 record, and keeps material invoices on the Scope 3 trail. Material factors come from your supplier or a named database and are labelled with their source, so the product figure can be traced line by line.
Sources: GHG Protocol Corporate Value Chain (Scope 3) Standard, GHG Protocol Corporate Standard
Last reviewed 2026-10-21.