Division BAT 20 In order to reduce water consumption and waste water generation from aqueous processes (e.g. degreasing, cleaning, surface treatment, wet scrubbing), BAT is to use technique (a) and an appropriate combination of the other techniques given below.

United Kingdom

Technique	Description	Applicability
(a)	Water management plan and water audits	A water management plan and water audits are part of the EMS (see BAT 1) and include: flow diagrams and a water mass balance of the plant; establishment of water efficiency objectives; implementation of water optimisation techniques (e.g. control of water usage, water recycling, detection and repair of leaks). Water audits are carried out at least once every year.	The level of detail and nature of the water management plan and water audits will generally be related to the nature, scale and complexity of the plant. It may not be applicable if the STS activity is carried out within a larger installation, provided that the water management plan and the water audits of the larger installation sufficiently cover the STS activity.
(b)	Reverse cascade rinsing	Multiple stage rinsing in which the water flows in the opposite direction to the work-pieces/substrate. It allows a high degree of rinsing with a low water consumption.	Applicable where rinsing processes are used.
(c)	Reuse and/or recycling of water	Water streams (e.g. spent rinse water, wet scrubber effluent) are reused and/or recycled, if necessary after treatment, using techniques such as ion exchange or filtration (see BAT 21). The degree of water reuse and/or recycling is limited by the water balance of the plant, the content of impurities and/or the characteristics of the water streams.	Generally applicable.

Technique

Description

Applicability

(a)

Water management plan and water audits

A water management plan and water audits are part of the EMS (see BAT 1) and include:

flow diagrams and a water mass balance of the plant;
establishment of water efficiency objectives;
implementation of water optimisation techniques (e.g. control of water usage, water recycling, detection and repair of leaks).

Water audits are carried out at least once every year.

The level of detail and nature of the water management plan and water audits will generally be related to the nature, scale and complexity of the plant. It may not be applicable if the STS activity is carried out within a larger installation, provided that the water management plan and the water audits of the larger installation sufficiently cover the STS activity.

(b)

Reverse cascade rinsing

Multiple stage rinsing in which the water flows in the opposite direction to the work-pieces/substrate. It allows a high degree of rinsing with a low water consumption.

Applicable where rinsing processes are used.

(c)

Reuse and/or recycling of water

Water streams (e.g. spent rinse water, wet scrubber effluent) are reused and/or recycled, if necessary after treatment, using techniques such as ion exchange or filtration (see BAT 21). The degree of water reuse and/or recycling is limited by the water balance of the plant, the content of impurities and/or the characteristics of the water streams.

Generally applicable.

Table 4

BAT-associated environmental performance levels (BAT-AEPLs) for specific water consumption

Sector	Product type	Unit	BAT-AEPL(Yearly average)
The BAT-AEPL may not apply where the coil coating line is part of a larger manufacturing installation (e.g. steelworks) or for combilines.
Coating of vehicles	Passenger cars	m³/vehicle coated	0,5–1,3
	Vans		1–2,5
	Truck cabins		0,7–3
	Trucks		1–5
Coil coating	Steel and/or aluminium coils	l/m² of coated coil	0,2–1,3 ^f1
Coating and printing of metal packaging	Two-piece DWI beverage cans	l/1 000 cans	90–110

The associated monitoring is given in BAT 20 (a).

Annotations

Footnotes

f1: The BAT-AEPL may not apply where the coil coating line is part of a larger manufacturing installation (e.g. steelworks) or for combilines.