Sludge to Landfill
Reviewed by Afonso Firmo, Co-Founder & Director · Updated 7 July 2026
Sludge sent to landfill carries a factor of 0.4 t CO₂-e per tonne under NGA Factors 2025. See worked examples, FAQs and a calculator for your reports.
Emission Factor Value
0.4 t CO₂-e/tonne
Try it with your own numbers
Estimated emissions
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Emissions from waste you send to landfill are reported under Scope 3. Calculated as tonnes of sludge × 0.4 t CO₂-e per tonne (NGA Factors 2025). Cubic metres are converted at 0.72 tonnes per m³.
Official Source & Citation
This emission factor is sourced from the Australian National Greenhouse Accounts Factors 2025 , Table 15 — Waste mix methane conversion and emission factors, published by the Department of Climate Change, Energy, the Environment and Water (DCCEEW).
Citation: DCCEEW (2025). Australian National Greenhouse Accounts Factors 2025. Commonwealth of Australia. Available at: https://www.dcceew.gov.au/climate-change/publications/national-greenhouse-accounts-factors-2025
Notes
Scope 3 factor for organisations sending sludge to landfill, from the NGA Factors 2025. Emissions arise from anaerobic decomposition producing methane. 1 tonne of sludge sent to landfill = 0.4 t CO₂-e. For volume records, apply 0.72 tonnes per cubic metre — sludge is dense compared with other waste streams. The landfill operator reports the direct methane emissions under Scope 1.
Calculation Example
If your plant sent 100 tonnes of sludge to landfill during the year:
| Working | Result |
|---|---|
| 100 t × 0.4 t CO₂-e/t | 40 t CO₂-e (Scope 3) |
Sludge from processing plants, grease traps and treatment systems is heavy, wet and expensive to cart — but in carbon terms it is one of the gentler things you can send to landfill. At 0.4 t CO₂-e per tonne, its factor is a fraction of food or paper waste, mostly because each wet tonne carries relatively little degradable carbon into your Scope 3 inventory.
Food manufacturers, wineries and industrial sites are the typical generators, and the tonnages involved mean this line still deserves a place in the waste inventory.
Quick Verdict
Sludge sent to landfill has an emission factor of 0.4 t CO₂-e per tonne under the Australian National Greenhouse Accounts Factors 2025, applying to the 2025–26 reporting year. The waste generator reports these emissions under Scope 3, while the landfill operator reports the direct methane under Scope 1. Because sludge is dense, volume records convert at 0.72 tonnes per cubic metre — the highest volume-to-mass factor of any listed stream. A Scope 3 emissions calculator can apply the factor automatically from disposal contractor records.
How to Calculate Sludge Disposal Emissions
Emissions (t CO₂-e) = Waste to landfill (tonnes) × 0.4
Worked Example 1: Processing plant
A food processing plant sends 100 tonnes of sludge to landfill over the year.
100 t × 0.4 = 40 t CO₂-e (Scope 3)
Worked Example 2: Large facility
An industrial site disposes of 250 tonnes of sludge to landfill during the reporting year.
250 t × 0.4 = 100 t CO₂-e (Scope 3)
Worked Example 3: Volume records only
A site records 50 m³ of sludge removed to landfill. Using the NGA volume-to-mass factor of 0.72 t/m³:
50 m³ × 0.72 t/m³ = 36 t
36 t × 0.4 = 14.4 t CO₂-e (Scope 3)
Sludge vs Other Landfill Streams
| Waste stream (to landfill) | Factor (t CO₂-e/t) |
|---|---|
| Paper and cardboard | 3.3 |
| Food waste | 2.1 |
| Garden and green waste | 1.6 |
| Municipal solid waste (mixed) | 1.6 |
| Wood waste | 0.7 |
| Sludge | 0.4 |
| Construction and demolition waste | 0.2 |
All factors from NGA Factors 2025, expressed in CO₂-equivalent.
NGER and AASB S2 Reporting
Sludge-to-landfill emissions are Scope 3 for the generator, so they sit outside NGER thresholds but inside AASB S2 disclosures, which require material Scope 3 categories to be reported. Keep weighbridge dockets as your audit trail and apply the NGA Factors 2025 value consistently across periods.
Related Emission Factors
Frequently Asked Questions
Disclaimer
This page is provided for general information, not professional or compliance advice. The factor shown is reproduced from the official publication cited above, and while we work to keep it current, government factors change — the publication is always the authoritative source.
- Before using this value in any formal reporting — including under the National Greenhouse and Energy Reporting Act 2007 — confirm it against the current official publication and the methods specified by the Clean Energy Regulator.
- NetNada is independent of the Australian Government, DCCEEW, and the Clean Energy Regulator. Government data is Crown copyright, Commonwealth of Australia.