Division Applicability
United Kingdom
May not be applicable to the incineration of sewage sludge depending, for example, on the water content and on the need for pre-drying or mixing with other wastes.
BAT 23. In order to prevent or reduce diffuse dust emissions to air from the treatment of slags and bottom ashes, BAT is to include in the environmental management system (see BAT 1) the following diffuse dust emissions management features:
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identification of the most relevant diffuse dust emission sources (e.g. using EN 15445);
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definition and implementation of appropriate actions and techniques to prevent or reduce diffuse emissions over a given time frame.
BAT 24. In order to prevent or reduce diffuse dust emissions to air from the treatment of slags and bottom ashes, BAT is to use an appropriate combination of the techniques given below.
| Technique | Description | Applicability | |
|---|---|---|---|
| (a) | Enclose and cover equipment | Enclose/encapsulate potentially dusty operations (such as grinding, screening) and/or cover conveyors and elevators. Enclosure can also be accomplished by installing all of the equipment in a closed building. | Installing the equipment in a closed building may not be applicable to mobile treatment devices. |
| (b) | Limit height of discharge | Match the discharge height to the varying height of the heap, automatically if possible (e.g. conveyor belts with adjustable heights). | Generally applicable. |
| (c) | Protect stockpiles against prevailing winds | Protect bulk storage areas or stockpiles with covers or wind barriers such as screening, walling or vertical greenery, as well as correctly orienting the stockpiles in relation to the prevailing wind. | Generally applicable. |
| (d) | Use water sprays | Install water spray systems at the main sources of diffuse dust emissions. The humidification of dust particles aids dust agglomeration and settling. Diffuse dust emissions at stockpiles are reduced by ensuring appropriate humidification of the charging and discharging points, or of the stockpiles themselves. | Generally applicable. |
| (e) | Optimise moisture content | Optimise the moisture content of the slags/bottom ashes to the level required for efficient recovery of metals and mineral materials while minimising the dust release. | Generally applicable. |
| (f) | Operate under subatmospheric pressure | Carry out the treatment of slags and bottom ashes in enclosed equipment or buildings (see technique a) under subatmospheric pressure to enable treatment of the extracted air with an abatement technique (see BAT 26) as channelled emissions. | Only applicable to dry-discharged and other low-moisture bottom ashes. |