How to Calculate Waste Emissions for Your Business (Scope 3 Category 5)
What Are Waste Emissions and Where Do They Sit in Carbon Reporting?
Waste emissions in business carbon reporting are classified as Scope 3 Category 5 — Waste Generated in Operations. This category covers greenhouse gas emissions from the disposal of all solid waste and wastewater generated by your business operations during the reporting year.
Waste emissions are distinct from: - Scope 1 emissions from on-site waste incineration (if you burn waste directly) - Scope 3 Category 12 (end-of-life treatment of sold products — your customers' waste)
Category 5 covers waste your business generates and sends off-site for treatment.
Which Waste Streams Generate Carbon Emissions?
Different disposal routes produce very different emission levels. DEFRA 2023 waste emission factors:
| Waste Type & Disposal Route | DEFRA 2023 Factor | Unit |
|---|---|---|
| General waste — landfill | 467 | kgCO2e per tonne |
| General waste — incineration | 21 | kgCO2e per tonne |
| Mixed recycling | 21 | kgCO2e per tonne |
| Paper/cardboard — recycling | −1,098 | kgCO2e per tonne (negative — avoided) |
| Paper/cardboard — landfill | 1,061 | kgCO2e per tonne |
| Food waste — composting | 10 | kgCO2e per tonne |
| Food waste — anaerobic digestion | −116 | kgCO2e per tonne (negative) |
| Food waste — landfill | 686 | kgCO2e per tonne |
| Plastics — recycling | 25 | kgCO2e per tonne |
| Metals — recycling | −671 | kgCO2e per tonne (negative) |
Key insight: Landfill generates far more emissions than any other disposal route. Recycling generates modest positive emissions (from collection and reprocessing). Some routes like paper recycling and anaerobic digestion generate negative emissions (i.e., they avoid more emissions than they produce).
How to Find Your Waste Data
Most businesses do not weigh their own waste. Your waste data comes from:
- Waste contractor invoices — many commercial waste contractors issue annual waste tonnage reports by stream (general, mixed recycling, cardboard). Request this from your contractor.
- Waste transfer notes — legal documents required for all commercial waste collections, showing waste type, quantity, and disposal route.
- Skip hire invoices — skip sizes have standard weight capacities (a 6-yard skip ≈ 1–1.5 tonnes).
If your contractor cannot provide tonnage data, use volume-to-weight conversions:
| Container | Approximate Weight |
|---|---|
| 240L wheelie bin (general waste) | 40–60 kg |
| 240L wheelie bin (paper/card) | 20–30 kg |
| 1,100L Euro bin (general waste) | 200–250 kg |
| Standard skip (6 yard) | 1,000–1,500 kg |
Worked Example: Office Waste Emissions
Sample company: A 25-person UK office
- 3.2 tonnes general waste to landfill: 3.2 × 467 = 1,494 kgCO2e = 1.5 tCO2e
- 0.8 tonnes cardboard recycled: 0.8 × (-1,098) = -878 kgCO2e = -0.9 tCO2e (avoided)
- 0.5 tonnes mixed recycling: 0.5 × 21 = 10.5 kgCO2e = 0.01 tCO2e
- 0.2 tonnes food waste composted: 0.2 × 10 = 2 kgCO2e = 0.002 tCO2e
Net waste emissions: 0.6 tCO2e (landfill minus avoided recycling)
How DeCarbonOPS Handles Waste Emissions
DeCarbonOPS calculates waste as Scope 3 Category 5 using DEFRA 2023 factors. Enter your annual waste tonnage and disposal route split — or use the headcount-based estimate if you do not have contractor tonnage data. The platform applies the correct factor per waste stream and includes the result in your Scope 3 total. Your Carbon Passport shows the complete breakdown.
Frequently Asked Questions
What Scope is waste in carbon reporting?
Waste generated in your operations is Scope 3 Category 5 in the GHG Protocol Corporate Standard. This covers solid waste and wastewater sent off-site for disposal or treatment. On-site incineration of waste that you operate directly would be Scope 1. Waste from products you sell after customers use them is Scope 3 Category 12 — a different category.
Which waste disposal route produces the most carbon emissions?
Landfill produces by far the highest emissions — 467 kgCO2e per tonne for general waste (DEFRA 2023). Incineration produces 21 kgCO2e per tonne. Mixed recycling produces 21 kgCO2e per tonne. Some routes produce net negative emissions (avoided carbon): paper recycling (-1,098 kgCO2e per tonne), metal recycling (-671), and anaerobic digestion of food waste (-116). Diverting waste from landfill reduces your Scope 3 Category 5 significantly.
How do I find my waste tonnage if I don't weigh my bins?
Request an annual waste tonnage report from your commercial waste contractor — most provide this for free. Alternatively, ask for your waste transfer notes (legally required for all commercial waste), which show weight per collection. If neither is available, use volume-to-weight conversions: a 240L wheelie bin of general waste weighs approximately 50 kg; a 1,100L Euro bin weighs approximately 220 kg; a 6-yard skip weighs approximately 1,250 kg.
Do I need to include wastewater in my Scope 3 Category 5?
Wastewater (Category 5 also covers wastewater treatment) is relevant for businesses with significant water use — food manufacturers, laundries, chemical processors. For standard office-based businesses, wastewater emissions are negligible and typically omitted as immaterial. DEFRA 2023 wastewater factor: approximately 0.708 kgCO2e per m³ treated.
How do waste emissions compare to other Scope 3 categories for a typical office?
For a typical 20-person UK office, waste emissions (Scope 3 Category 5) are usually the smallest Scope 3 category — often under 1 tCO2e per year. Commuting (Category 7) is typically the largest at 8–15 tCO2e. Business travel (Category 6) varies widely. Understanding this proportion helps prioritise reduction efforts — reducing commuting or flights has far greater impact than waste reduction for most office businesses.
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