Division 1.5.2.3 Emissions of NOX, N2O, CO and NH3

United Kingdom

BAT 29. In order to reduce channelled NO_X emissions to air while limiting the emissions of CO and N₂O from the incineration of waste and the emissions of NH₃ from the use of SNCR and/or SCR, BAT is to use an appropriate combination of the techniques given below.

	Technique	Description	Applicability
(a)	Optimisation of the incineration process	See Section 2.1	Generally applicable.
(b)	Flue-gas recirculation	See Section 2.2	For existing plants, the applicability may be limited due to technical constraints (e.g. pollutant load in the flue-gas, incineration conditions).
(c)	Selective non-catalytic reduction (SNCR)	See Section 2.2	Generally applicable.
(d)	Selective catalytic reduction (SCR)	See Section 2.2	In the case of existing plants, the applicability may be limited by a lack of space.
(e)	Catalytic filter bags	See Section 2.2	Only applicable to plants fitted with a bag filter.
(f)	Optimisation of the SNCR/SCR design and operation	Optimisation of the reagent to NO_X ratio over the cross-section of the furnace or duct, of the size of the reagent drops and of the temperature window in which the reagent is injected.	Only applicable where SNCR and/or SCR is used for the reduction of NO_X emissions.
(g)	Wet scrubber	See Section 2.2. Where a wet scrubber is used for acid gas abatement, and in particular with SNCR, unreacted ammonia is absorbed by the scrubbing liquor and, once stripped, can be recycled as SNCR or SCR reagent.	There may be applicability restrictions due to low water availability, e.g. in arid areas.

Table 6

BAT-associated emission levels (BAT-AELs) for channelled NO_X and CO emissions to air from the incineration of waste and for channelled NH₃ emissions to air from the use of SNCR and/or SCR

Parameter	BAT-AEL		Averaging period
The lower end of the BAT-AEL range can be achieved when using SCR. The lower end of the BAT-AEL range may not be achievable when incinerating waste with a high nitrogen content (e.g. residues from the production of organic nitrogen compounds).
The higher end of the BAT-AEL range is 180 mg/Nm³ where SCR is not applicable.
For existing plants fitted with SNCR without wet abatement techniques, the higher end of the BAT-AEL range is 15 mg/Nm³.
(mg/Nm³)
Parameter	New plant	Existing plant	Averaging period
NO_X	50–120 ^f1	50–150 ^f2	Daily average
CO	10–50	10–50
NH₃	2–10	2–10 ^f3

The associated monitoring is in BAT 4.

Annotations

Footnotes

f1: The lower end of the BAT-AEL range can be achieved when using SCR. The lower end of the BAT-AEL range may not be achievable when incinerating waste with a high nitrogen content (e.g. residues from the production of organic nitrogen compounds).
f2: The higher end of the BAT-AEL range is 180 mg/Nm³ where SCR is not applicable.
f3: For existing plants fitted with SNCR without wet abatement techniques, the higher end of the BAT-AEL range is 15 mg/Nm³.