Division BAT 51 In order to reduce emissions of organic compounds to air from wood and wood products preservation using creosote, BAT is to enclose emitting equipment or processes (e.g. storage and impregnation tanks, depressurisation, creosote reconditioning), extract the off-gases and use one or a combination of the treatment techniques given below.
United Kingdom
| Technique | Description | Applicability | |
|---|---|---|---|
| (a) | Thermal oxidation | See BAT 15 (i). Exhaust heat can be recovered by means of heat exchangers. | Generally applicable. |
| (b) | Sending off-gases to a combustion plant | Part or all of the off-gases are sent as combustion air and supplementary fuel to a combustion plant (including CHP (combined heat and power) plants) used for steam and/or electricity production. | Not applicable for off-gases containing substances referred to in IED Article 59(5). Applicability may be restricted due to safety considerations. |
| (c) | Adsorption using activated carbon | Organic compounds are adsorbed on the surface of activated carbon. Adsorbed compounds may be subsequently desorbed, e.g. with steam (often on site) for reuse or disposal and the adsorbent is reused. | Generally applicable. |
| (d) | Absorption using a suitable liquid | Use of a suitable liquid to remove pollutants from the off-gases by absorption, in particular soluble compounds. | Generally applicable. |
| (e) | Condensation | A technique for removing organic compounds by reducing the temperature below their dew points so that the vapours liquefy. Depending on the operating temperature range required, different refrigerants are used, e.g. cooling water, chilled water (temperature typically around 5 °C), ammonia or propane. Condensation is used in combination with another abatement technique. | Applicability may be restricted where the energy demand for recovery is excessive due to the low VOC content. |
Table 36
BAT-associated emission levels (BAT-AELs) for TVOC and PAH emissions in waste gases from wood and wood products preservation using creosote and/or solvent-based treatment chemicals
| The BAT-AEL refers to the sum of the following PAH compounds: acenaphthene, acenaphthylene, anthracene, benzo(a)anthracene, benzo(a)pyrene, benzo(b)fluoranthene, benzo(g,h,i)perylene, benzo(k)fluoranthene, chrysene, dibenzo(a,h)anthracene, fluoranthene, fluorene, indeno(1,2,3-cd)pyrene, naphthalene, phenanthrene and pyrene. | |||
| Parameter | Unit | Process | BAT-AEL(Average over the sampling period) |
|---|---|---|---|
| TVOC | mg C/Nm3 | Creosote and solvent-based treatment | < 4–20 |
| PAHs | mg/Nm3 | Creosote treatment | < 1f1 |
The associated monitoring is given in BAT 45.
Annotations
Footnotes
- f1
-
The BAT-AEL refers to the sum of the following PAH compounds: acenaphthene, acenaphthylene, anthracene, benzo(a)anthracene, benzo(a)pyrene, benzo(b)fluoranthene, benzo(g,h,i)perylene, benzo(k)fluoranthene, chrysene, dibenzo(a,h)anthracene, fluoranthene, fluorene, indeno(1,2,3-cd)pyrene, naphthalene, phenanthrene and pyrene.