Environment Agency regulatory position on the use of additional waste codes to store, treat or spread sewage sludge and septic tank sludge to land.
Source
https://www.gov.uk/government/publications/waste-codes-for-sewage-sludge-and-sludge-containing-other-materials-rps-231Canonical document at the regulator. Always cite this URL — not the Vantage detail page — in compliance evidence.