Biological waste treatment

This category provides calculation for CH₄ and, where appropriate, N₂O emissions associated with composting and anaerobic digestion. These processes (especially composting) also produce CO₂, but since the carbon is of recent, biogenic origin, and therefore not a net contributor to atmospheric concentrations, these emissions are not considered here.

How to use this category

Selecting an emissions scenario

To use this category, select the type of biological treatment (composting, anaerobic digestion) using the type drill choice.

Specifying activity data

Next, set the quantity of waste treated using the mass profile item value. Users can opt to specify the mass in terms of wet or dry weight, although quantities are assumed to represent dry weights by default. To instruct that quantities represent wet weight, set the isWetWeight to 'true'.

Where methane recovery/capture is practised, this can be deducted from the emissions calculation. To specify methane recovery, set the mass of recovered methane in the recoveredMethane profile item value.

Results and calculation

The values returned represent CH₄ and N₂O emissions associated with the waste quantity specified (minus the methane recovered, where appropriate). The following discrete values are returned:

• N2O: N₂O (nitrous oxide) emissions
• CH4: CH₄ (methane) emissions
• CO2e: CO₂e emissions (both gases, converted using these global warming potential)

Notes

Methane recovery

Where recovered methane is burned for energy production, flared, or fed into a gas distribution system, users are referred to the following categories

• Stationary fuel combustion

• Methane flaring

• Oil and gas processing