# Commission Implementing Decision (EU) 2017/1442 of 31 July 2017 establishing best available techniques (BAT) conclusions, under Directive 2010/75/EU of the European Parliament and of the Council, for large combustion plants (notified under document C(2017) 5225) (Text with EEA relevance), Division BAT 15: In order to reduce emissions to water from flue-gas treatment, BAT is to use an appropriate combination of the techniques given below, and to use secondary techniques as close as possible to the source in order to avoid dilution.

Extent: E+W+S+N.I.

The descriptions of the techniques are given in Section 8.6
Technique
Typical pollutants prevented/abated
Applicability
Primary techniques
a.
Optimised combustion (see BAT 6) and flue-gas treatment systems (e.g. SCR/SNCR, see BAT 7)
Organic compounds, ammonia (NH3)
Generally applicable
Secondary techniques
b.
Adsorption on activated carbon
Organic compounds, mercury (Hg)
Generally applicable
c.
Aerobic biological treatment
Biodegradable organic compounds, ammonium (NH4 +)
Generally applicable for the treatment of organic compounds. Aerobic biological treatment of ammonium (NH4 +) may not be applicable in the case of high chloride concentrations (i.e. around 10 g/l)
d.
Anoxic/anaerobic biological treatment
Mercury (Hg), nitrate (NO3 –), nitrite (NO2 –)
Generally applicable
e.
Coagulation and flocculation
Suspended solids
Generally applicable
f.
Crystallisation
Metals and metalloids, sulphate (SO4 2–), fluoride (F–)
Generally applicable
g.
Filtration (e.g. sand filtration, microfiltration, ultrafiltration)
Suspended solids, metals
Generally applicable
h.
Flotation
Suspended solids, free oil
Generally applicable
i.
Ion exchange
Metals
Generally applicable
j.
Neutralisation
Acids, alkalis
Generally applicable
k.
Oxidation
Sulphide (S2–), sulphite (SO3 2–)
Generally applicable
l.
Precipitation
Metals and metalloids, sulphate (SO4 2–), fluoride (F–)
Generally applicable
m.
Sedimentation
Suspended solids
Generally applicable
n.
Stripping
Ammonia (NH3)
Generally applicable
The BAT-AELs refer to direct discharges to a receiving water body at the point where the emission leaves the installation.
Table 1
BAT-AELs for direct discharges to a receiving water body from flue-gas treatment
Either the BAT-AEL for TOC or the BAT-AEL for COD applies. TOC is the preferred option because its monitoring does not rely on the use of very toxic compounds.
This BAT-AEL applies after subtraction of the intake load.
This BAT-AEL only applies to waste water from the use of wet FGD.
This BAT-AEL only applies to combustion plants using calcium compounds in flue-gas treatment.
The higher end of the BAT-AEL range may not apply in the case of highly saline waste water (e.g. chloride concentrations ≥ 5 g/l) due to the increased solubility of calcium sulphate.
This BAT-AEL does not apply to discharges to the sea or to brackish water bodies.
Substance/Parameter
BAT-AELs
Daily average
Total organic carbon (TOC)
20–50 mg/l
Chemical oxygen demand (COD)
60–150 mg/l
Total suspended solids (TSS)
10–30 mg/l
Fluoride (F–)
10–25 mg/l
Sulphate (SO4 2–)
1,3–2,0 g/l
Sulphide (S2–), easily released
0,1–0,2 mg/l
Sulphite (SO3 2–)
1–20 mg/l
Metals and metalloids
As
10–50 μg/l
Cd
2–5 μg/l
Cr
10–50 μg/l
Cu
10–50 μg/l
Hg
0,2–3 μg/l
Ni
10–50 μg/l
Pb
10–20 μg/l
Zn
50–200 μg/l

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Source: https://www.legislation.gov.uk/eudn/2017/1442/annex/division/1/division/1.5/division/3 (the official version)
Page: https://openlegislation.uk/eu-decision-2017-1442/annex/division-1/division-1.5/division-3
Contains public sector information licensed under the Open Government Licence v3.0. Source: legislation.gov.uk, The National Archives.