Industrial waste water

Methane emissions vary depending on the discharge pathway/treatment system and are calculated based on the concentration of degradable organic material within the waste water as measured by the chemical oxygen demand (a standard measure of water organic concentration). Users can specify this quantity in several ways including the use of data on quantities typical to specific industries.

How to use this category

Selecting an emissions scenario

To use this category, choose between 'treated' or 'untreated' modes of waste water discharge using the type drill choice, then specify the particular system using the system drill choices.

Specifying activity data

Next, a measure of the concentration of degradable organic material within the waste water must be specified. Users can opt to express this quantity in three ways, using either 1, 2 or 3 profile item item values. In each case, measures of degradable organic concentration should represent chemical oxygen demand (COD).

By absolute mass: Waste water degradable organics can be specifed as an total absolute mass (e.g. kg) of (degradable) organic material. To specify organic discharge on the basis of a total mass, set the mass using the massOrganicWaste profile item value.

By waste water volume: Alternatively, the total quantity of waste water degradable organic material can be specifed using the volume (e.g. litres) of waste water generated together with the organic concentration (COD) of a unit volume of water (e.g. mg per litre). To use this method, set the volume of waste water discharged and the associated organic concentration using the volume and massOrganicPerVolumeWasteWater profile item values.

By industrial production: Finally, the quantity of organic material in waste water discharge can be specified by using a quantity (mass) of industrial production (e.g. tonnes), together with the volume of waste water generated for each unit (e.g. tonne) of production and the organic concentration (oxygen demand) of a unit volume of water (e.g. mg per litre). In this case, set the quantity of industrial production, the volume of water per unit of production and the waste water organic concentration (oxygen demand) using the massProduced, volumeWasteWaterPerMassProduction and massOrganicPerVolumeWasteWater profile item values.

Using industry typical values: Users can access 'typical' values for the volume-of-water-per-unit-of-production and the waste-water-organic-concentration for a variety of industries. To use these values, set either or both of the useTypicalWater and useTypicalOxygenDemand profile item values to 'true', and specify the name of the industry in the industry profile item value. Discover will look up these values using the category at /business/waste/water/industrial/industryfactors and populate the volumeWasteWaterPerMassProduction and massOrganicPerVolumeWasteWater profile items value accordingly. Values set in the industry profile item value must match those in the ''industry'' drill option here. Note: users must establish which 'typical' values are available for each industry as a small number are unavaliable in the IPCC methodology.

Sludge removal: Where removal of solid organics (sludge) is practised, this can be deducted from the emissions calculation. To specify sludge removal, set the mass of removed sludge using the massSludge profile item value.

Methane recovery: 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 quantities returned represent the methane emissions associated with waste water discharge into the treatment system specified. The following quantities are returned:

• CH4: absolute quantity of CH₄ emitted
• CO2e: emitted CH₄ to CO₂e converted using the appropriate global warming potential)

Notes

Sludge removal

Where removed sludge is incinerated, users are referred to the following category

• waste combustion

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