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Division BAT 17 In order to prevent or reduce emissions to air from the dryer, BAT is to achieve and manage a balanced operation of the drying process and to use one or a combination of the techniques given below.

United Kingdom

	Technique	Main pollutants abated	Applicability
Descriptions of the techniques are given in Section 1.4.1.
a	Dust abatement of inlet hot gas to a directly heated dryer in combination with one or a combination of the other techniques listed below	Dust	Applicability may be restricted, e.g. in cases of existing smaller wood dust burners.
b	Bag filter^f1	Dust	Applicable to indirectly heated dryers only. Due to safety concerns, special care should be taken when using exclusively recovered wood.
c	Cyclone	Dust	Generally applicable.
d	UTWS dryer and combustion with heat exchanger and thermal treatment of discharged dryer waste gas	Dust, volatile organic compounds	Not applicable to fibre dryers. Applicability may be limited for existing combustion plants not suitable for post-combustion of the partial dryer waste gas flow.
e	Wet electrostatic precipitator	Dust, volatile organic compounds	Generally applicable.
f	Wet scrubber	Dust, volatile organic compounds	Generally applicable.
g	Bioscrubber	Dust, volatile organic compounds	Applicability may be limited by high dust concentrations and high temperatures in the waste gas from the dryer.
h	Chemical degradation or capture of formaldehyde with chemicals in combination with a wet scrubbing system	Formaldehyde	Generally applicable in wet abatement systems.

Table 1

BAT-associated emission levels (BAT-AELs) for emissions to air from the dryer and for combined treated emissions from the dryer and the press

Parameter	Product	Dryer type	Unit	BAT-AELs(average over the sampling period)
This BAT-AEL does not apply when using pine as the predominant raw material.
Emissions below 30 mg/Nm³ can be achieved using UTWS dryer.
When using almost exclusively recovered wood, the upper end of the range may be up to 15 mg/Nm³.
Dust	PB or OSB	Directly heated dryer	mg/Nm³	3–30
	PB or OSB	Indirectly heated dryer		3–10
	Fibre	All types		3–20
TVOC	PB	All types		< 20–200^f2 ^f3
	OSB			10–400
	Fibre			< 20–120
Formaldehyde	PB	All types		< 5–10^f4
	OSB			< 5–20
	Fibre			< 5–15

The associated monitoring is in BAT 14.

Annotations

Footnotes

f1: Descriptions of the techniques are given in Section 1.4.1.
f2: This BAT-AEL does not apply when using pine as the predominant raw material.
f3: Emissions below 30 mg/Nm³ can be achieved using UTWS dryer.
f4: When using almost exclusively recovered wood, the upper end of the range may be up to 15 mg/Nm³.

Notes on Division 1.2.1

Footnotes

f1: When a bag filter or a cyclofilter is not applicable, the upper end of the range can be up to 10 mg/Nm³.