Division 1.5 Emissions to water

United Kingdom

BAT 19. In order to optimise water consumption, to reduce the volume of waste water generated and to prevent or, where that is not practicable, to reduce emissions to soil and water, BAT is to use an appropriate combination of the techniques given below.

Technique		Description	Applicability
a.	Water management	Water consumption is optimised by using measures which may include: water-saving plans (e.g. establishment of water efficiency objectives, flow diagrams and water mass balances); optimising the use of washing water (e.g. dry cleaning instead of hosing down, using trigger control on all washing equipment); reducing the use of water for vacuum generation (e.g. use of liquid ring pumps with high boiling point liquids).	Generally applicable.
b.	Water recirculation	Water streams are recirculated within the plant, if necessary after treatment. The degree of recirculation is limited by the water balance of the plant, the content of impurities (e.g. odorous compounds) and/or the characteristics of the water streams (e.g. nutrient content).	Generally applicable.
c.	Impermeable surface	Depending on the risks posed by the waste in terms of soil and/or water contamination, the surface of the whole waste treatment area (e.g. waste reception, handling, storage, treatment and dispatch areas) is made impermeable to the liquids concerned.	Generally applicable.
d.	Techniques to reduce the likelihood and impact of overflows and failures from tanks and vessels	Depending on the risks posed by the liquids contained in tanks and vessels in terms of soil and/or water contamination, this includes techniques such as: overflow detectors; overflow pipes that are directed to a contained drainage system (i.e. the relevant secondary containment or another vessel); tanks for liquids that are located in a suitable secondary containment; the volume is normally sized to accommodate the loss of containment of the largest tank within the secondary containment; isolation of tanks, vessels and secondary containment (e.g. closing of valves).	Generally applicable.
e.	Roofing of waste storage and treatment areas	Depending on the risks posed by the waste in terms of soil and/or water contamination, waste is stored and treated in covered areas to prevent contact with rainwater and thus minimise the volume of contaminated run-off water.	Applicability may be constrained when high volumes of waste are stored or treated (e.g. mechanical treatment in shredders of metal waste).
f.	Segregation of water streams	Each water stream (e.g. surface run-off water, process water) is collected and treated separately, based on the pollutant content and on the combination of treatment techniques. In particular, uncontaminated waste water streams are segregated from waste water streams that require treatment.	Generally applicable to new plants. Generally applicable to existing plants within the constraints associated with the layout of the water collection system.
g.	Adequate drainage infrastructure	The waste treatment area is connected to drainage infrastructure. Rainwater falling on the treatment and storage areas is collected in the drainage infrastructure along with washing water, occasional spillages, etc. and, depending on the pollutant content, recirculated or sent for further treatment.	Generally applicable to new plants. Generally applicable to existing plants within the constraints associated with the layout of the water drainage system.
h.	Design and maintenance provisions to allow detection and repair of leaks	Regular monitoring for potential leakages is risk-based, and, when necessary, equipment is repaired. The use of underground components is minimised. When underground components are used, and depending on the risks posed by the waste contained in those components in terms of soil and/or water contamination, secondary containment of underground components is put in place.	The use of above-ground components is generally applicable to new plants. It may be limited however by the risk of freezing. The installation of secondary containment may be limited in the case of existing plants.
i.	Appropriate buffer storage capacity	Appropriate buffer storage capacity is provided for waste water generated during other than normal operating conditions using a risk-based approach (e.g. taking into account the nature of the pollutants, the effects of downstream waste water treatment, and the receiving environment). The discharge of waste water from this buffer storage is only possible after appropriate measures are taken (e.g. monitor, treat, reuse).	Generally applicable to new plants. For existing plants, applicability may be limited by space availability and by the layout of the water collection system.

BAT 20. In order to reduce emissions to water, BAT is to treat waste water using an appropriate combination of the techniques given below.

Technique^f1		Typical pollutants targeted	Applicability
The descriptions of the techniques are given in Section 6.3.
Preliminary and primary treatment, e.g.
a.	Equalisation	All pollutants	Generally applicable.
b.	Neutralisation	Acids, alkalis
c.	Physical separation, e.g. screens, sieves, grit separators, grease separators, oil-water separation or primary settlement tanks	Gross solids, suspended solids, oil/grease
Physico-chemical treatment, e.g.
d.	Adsorption	Adsorbable dissolved non-biodegradable or inhibitory pollutants, e.g. hydrocarbons, mercury, AOX	Generally applicable.
e.	Distillation/rectification	Dissolved non-biodegradable or inhibitory pollutants that can be distilled, e.g. some solvents
f.	Precipitation	Precipitable dissolved non-biodegradable or inhibitory pollutants, e.g. metals, phosphorus
g.	Chemical oxidation	Oxidisable dissolved non-biodegradable or inhibitory pollutants, e.g. nitrite, cyanide
h.	Chemical reduction	Reducible dissolved non-biodegradable or inhibitory pollutants, e.g. hexavalent chromium (Cr(VI))
i.	Evaporation	Soluble contaminants
j.	Ion exchange	Ionic dissolved non-biodegradable or inhibitory pollutants, e.g. metals
k.	Stripping	Purgeable pollutants, e.g. hydrogen sulphide (H₂S), ammonia (NH₃), some adsorbable organically bound halogens (AOX), hydrocarbons
Biological treatment, e.g.
l.	Activated sludge process	Biodegradable organic compounds	Generally applicable.
m.	Membrane bioreactor	Biodegradable organic compounds	Generally applicable.
Nitrogen removal
n.	Nitrification/denitrification when the treatment includes a biological treatment	Total nitrogen, ammonia	Nitrification may not be applicable in the case of high chloride concentrations (e.g. above 10 g/l) and when the reduction of the chloride concentration prior to nitrification would not be justified by the environmental benefits. Nitrification is not applicable when the temperature of the waste water is low (e.g. below 12 °C).
Solids removal, e.g.
o.	Coagulation and flocculation	Suspended solids and particulate-bound metals	Generally applicable.
p.	Sedimentation
q.	Filtration (e.g. sand filtration, microfiltration, ultrafiltration)
r.	Flotation

Table 6.1

BAT-associated emission levels (BAT-AELs) for direct discharges to a receiving water body

Substance/Parameter		BAT-AEL^f2	Waste treatment process to which the BAT-AEL applies
The averaging periods are defined in the General considerations.
Either the BAT-AEL for COD or the BAT-AEL for TOC applies. TOC monitoring is the preferred option because it does not rely on the use of very toxic compounds.
The upper end of the range may not apply: when the abatement efficiency is ≥ 95 % as a rolling yearly average and the waste input shows the following characteristics: TOC > 2 g/l (or COD > 6 g/l) as a daily average and a high proportion of refractory organic compounds (i.e. which are difficult to biodegrade); or in the case of high chloride concentrations (e.g. above 5 g/l in the waste input).
The BAT-AEL may not apply to plants treating drilling muds/cuttings.
The BAT-AEL may not apply when the temperature of the waste water is low (e.g. below 12 °C).
The BAT-AEL may not apply in the case of high chloride concentrations (e.g. above 10 g/l in the waste input).
The BAT-AEL only applies when biological treatment of waste water is used.
The BAT-AELs only apply when the substance concerned is identified as relevant in the waste water inventory mentioned in BAT 3.
The upper end of the range is 0,3 mg/l for mechanical treatment in shredders of metal waste.
The upper end of the range is 2 mg/l for mechanical treatment in shredders of metal waste.
Total organic carbon (TOC)^f3		10-60 mg/l	All waste treatments except treatment of water-based liquid waste
Total organic carbon (TOC)^f3		10-100 mg/l^f4 ^f5	Treatment of water-based liquid waste
Chemical oxygen demand (COD)		30-180 mg/l	All waste treatments except treatment of water-based liquid waste
Chemical oxygen demand (COD)		30-300 mg/l	Treatment of water-based liquid waste
Total suspended solids (TSS)		5-60 mg/l	All waste treatments
Hydrocarbon oil index (HOI)		0,5-10 mg/l	Mechanical treatment in shredders of metal waste Treatment of WEEE containing VFCs and/or VHCs Re-refining of waste oil Physico-chemical treatment of waste with calorific value Water washing of excavated contaminated soil Treatment of water-based liquid waste
Total nitrogen (Total N)		1-25 mg/l^f6 ^f7	Biological treatment of waste Re-refining of waste oil
Total nitrogen (Total N)		10-60 mg/l ^f8	Treatment of water-based liquid waste
Total phosphorus (Total P)		0,3-2 mg/l	Biological treatment of waste
Total phosphorus (Total P)		1-3 mg/l	Treatment of water-based liquid waste
Phenol index		0,05-0,2 mg/l	Re-refining of waste oil Physico-chemical treatment of waste with calorific value
Phenol index		0,05-0,3 mg/l	Treatment of water-based liquid waste
Free cyanide (CN^-)^f9		0,02-0,1 mg/l	Treatment of water-based liquid waste
Adsorbable organically bound halogens (AOX)		0,2-1 mg/l	Treatment of water-based liquid waste
Metals and metalloids	Arsenic (expressed as As)	0,01-0,05 mg/l	Mechanical treatment in shredders of metal waste Treatment of WEEE containing VFCs and/or VHCs Mechanical biological treatment of waste Re-refining of waste oil Physico-chemical treatment of waste with calorific value Physico-chemical treatment of solid and/or pasty waste Regeneration of spent solvents Water washing of excavated contaminated soil
	Cadmium (expressed as Cd)	0,01-0,05 mg/l
	Chromium (expressed as Cr)	0,01-0,15 mg/l
	Copper (expressed as Cu)	0,05-0,5 mg/l
	Lead (expressed as Pb)	0,05-0,1 mg/l^f10
	Nickel (expressed as Ni)	0,05-0,5 mg/l
	Mercury (expressed as Hg)	0,5-5 μg/l
	Zinc (expressed as Zn)	0,1-1 mg/l^f11
	Arsenic (expressed as As)	0,01-0,1 mg/l	Treatment of water-based liquid waste
	Cadmium (expressed as Cd)	0,01-0,1 mg/l
	Chromium (expressed as Cr)	0,01-0,3 mg/l
	Hexavalent chromium (expressed as Cr(VI))	0,01-0,1 mg/l
	Copper (expressed as Cu)	0,05-0,5 mg/l
	Lead (expressed as Pb)	0,05-0,3 mg/l
	Nickel (expressed as Ni)	0,05-1 mg/l
	Mercury (expressed as Hg)	1-10 μg/l
	Zinc (expressed as Zn)	0,1-2 mg/l

The associated monitoring is given in BAT 7.

Table 6.2

BAT-associated emission levels (BAT-AELs) for indirect discharges to a receiving water body

Substance/Parameter		BAT-AEL^f12 ^f13	Waste treatment process to which the BAT-AEL applies
The averaging periods are defined in the General considerations.
The BAT-AELs may not apply if the downstream waste water treatment plant abates the pollutants concerned, provided this does not lead to a higher level of pollution in the environment.
The BAT-AELs only apply when the substance concerned is identified as relevant in the waste water inventory mentioned in BAT 3.
The upper end of the range is 0,3 mg/l for mechanical treatment in shredders of metal waste.
The upper end of the range is 2 mg/l for mechanical treatment in shredders of metal waste.
Hydrocarbon oil index (HOI)		0,5-10 mg/l	Mechanical treatment in shredders of metal waste Treatment of WEEE containing VFCs and/or VHCs Re-refining of waste oil Physico-chemical treatment of waste with calorific value Water washing of excavated contaminated soil Treatment of water-based liquid waste
Free cyanide (CN^-)^f14		0,02-0,1 mg/l	Treatment of water-based liquid waste
Adsorbable organically bound halogens (AOX)		0,2-1 mg/l	Treatment of water-based liquid waste
Metals and metalloids	Arsenic (expressed as As)	0,01-0,05 mg/l	Mechanical treatment in shredders of metal waste Treatment of WEEE containing VFCs and/or VHCs Mechanical biological treatment of waste Re-refining of waste oil Physico-chemical treatment of waste with calorific value Physico-chemical treatment of solid and/or pasty waste Regeneration of spent solvents Water washing of excavated contaminated soil
	Cadmium (expressed as Cd)	0,01-0,05 mg/l
	Chromium (expressed as Cr)	0,01-0,15 mg/l
	Copper (expressed as Cu)	0,05-0,5 mg/l
	Lead (expressed as Pb)	0,05-0,1 mg/l^f15
	Nickel (expressed as Ni)	0,05-0,5 mg/l
	Mercury (expressed as Hg)	0,5-5 μg/l
	Zinc (expressed as Zn)	0,1-1 mg/l^f16
	Arsenic (expressed as As)	0,01-0,1 mg/l	Treatment of water-based liquid waste
	Cadmium (expressed as Cd)	0,01-0,1 mg/l
	Chromium (expressed as Cr)	0,01-0,3 mg/l
	Hexavalent chromium (expressed as Cr(VI))	0,01-0,1 mg/l
	Copper (expressed as Cu)	0,05-0,5 mg/l
	Lead (expressed as Pb)	0,05-0,3 mg/l
	Nickel (expressed as Ni)	0,05-1 mg/l
	Mercury (expressed as Hg)	1-10 μg/l
	Zinc (expressed as Zn)	0,1-2 mg/l

The associated monitoring is given in BAT 7.

Annotations

Footnotes

f1

The descriptions of the techniques are given in Section 6.3.

f2

The averaging periods are defined in the General considerations.

f3

Either the BAT-AEL for COD or the BAT-AEL for TOC applies. TOC monitoring is the preferred option because it does not rely on the use of very toxic compounds.

f4

The upper end of the range may not apply:

when the abatement efficiency is ≥ 95 % as a rolling yearly average and the waste input shows the following characteristics: TOC > 2 g/l (or COD > 6 g/l) as a daily average and a high proportion of refractory organic compounds (i.e. which are difficult to biodegrade); or
in the case of high chloride concentrations (e.g. above 5 g/l in the waste input).

f5

The BAT-AEL may not apply to plants treating drilling muds/cuttings.

f6

The BAT-AEL may not apply when the temperature of the waste water is low (e.g. below 12 °C).

f7

The BAT-AEL may not apply in the case of high chloride concentrations (e.g. above 10 g/l in the waste input).

f8

The BAT-AEL only applies when biological treatment of waste water is used.

f9

The BAT-AELs only apply when the substance concerned is identified as relevant in the waste water inventory mentioned in BAT 3.

f10

The upper end of the range is 0,3 mg/l for mechanical treatment in shredders of metal waste.

f11

The upper end of the range is 2 mg/l for mechanical treatment in shredders of metal waste.

f12

The averaging periods are defined in the General considerations.

f13

The BAT-AELs may not apply if the downstream waste water treatment plant abates the pollutants concerned, provided this does not lead to a higher level of pollution in the environment.

f14

The BAT-AELs only apply when the substance concerned is identified as relevant in the waste water inventory mentioned in BAT 3.

f15

The upper end of the range is 0,3 mg/l for mechanical treatment in shredders of metal waste.

f16

The upper end of the range is 2 mg/l for mechanical treatment in shredders of metal waste.