EWC Code
Other bases containing dangerous substances
EUR-Lex Commission Decision 2000/532/EC — Official Journal L 226, 06/09/2000Annual Volume (EU)
~1–2 Mt/year spent caustic and alkali streams EU-wide
Valorisation Range
Spent caustic regeneration credit €50–150/t NaOH equivalent; lime slurry disposal €20–40/t
Primary Route
Caustic regeneration and recovery
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Get contacts for EWC 06 02 05*EWC 06 02 05* is a specific sub-code under EWC 06 02 — Wastes from manufacture, formulation, supply and use of bases. The classification guidance below applies to this waste stream.
EWC 06 02 covers spent and contaminated alkali streams from manufacture and industrial use of bases, principally sodium hydroxide (caustic soda), calcium hydroxide (lime) and ammonia solutions. Sub-codes 06 02 01* (calcium hydroxide), 06 02 03* (ammonia), 06 02 04* (sodium and potassium hydroxide) are all hazardous; 06 02 05* covers other bases containing dangerous substances.
The largest volume stream is spent caustic from petroleum refining (spent sulfidic caustic — also classifiable under 05 01), kraft pulp mills (green and white liquor residues) and aluminium refining (Bayer process — spent red liquor, bauxite residue). Ammonia-containing wastes arise from nitrogen fertiliser manufacture and refrigeration system purges.
Caustic regeneration within closed-loop processes (kraft recovery boiler, Bayer liquor evaporation) is established practice and reduces waste arisings. Residual spent caustic is neutralised with CO₂ or HCl, or sold to industrial users as dilute alkali. Lime slurry from water treatment and flue gas desulphurisation is recycled as agricultural soil amendment or cement kiln feedstock.
Typical Generators
Established valorisation pathways for EWC 06 02 05*, ranked by economic value and market depth.
Kraft process green and white liquor recycled through recovery boiler — organic content provides energy, inorganic sodium chemicals recovered as smelt. Bayer liquor evaporated and causticised. Petroleum refinery spent caustic oxidised (Merox) to reduce sulphide content before reuse or sale.
Alkali neutralised with CO₂ (carbonation) or dilute acid to pH 6–9 before effluent treatment. Metal hydroxide sludges settled and filtered. Treated effluent discharged to sewer or surface water under IED/UWWTD permit limits.
Lime slurries from water softening (calcium carbonate sludge) and FGD (gypsum slurry) reused for agricultural soil pH correction under Nitrates Directive controls. Composition analysis required; application rates limited by Ca, Mg, Na and potentially heavy metal content.
These are the established routes for EWC 06 02 05*. Which one your stream qualifies for depends on its composition, volume and region.
Get the ranked options for your streamPrimary & secondary off-takers
Kraft process closes the chemical loop, regenerating white liquor for cooking
Bayer process liquor circuits regenerate caustic internally
Receives lime slurry for agricultural soil amendment
Handles ammonia-containing and other hazardous base waste streams
Sectors that valorise EWC 06 02 05* as an input material or secondary raw material.
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