EWC chapter 11: surface treatment, electroplating and galvanising waste codes explained

Electroplating shops, anodising lines, phosphating plants and hot-dip galvanising facilities generate waste streams that are misclassified far more often than their equivalents in general metalworking. Pickling acid looks like a process chemical, not a hazardous waste — but it is. Rinsing water sounds benign — but it may not be. This guide covers every EWC chapter 11 code, the mirror-entry decision tree, and the records each stream requires.

What is EWC chapter 11?

The chapter spans the waste streams produced when metal or plastic surfaces are cleaned, coated or chemically converted: pickling baths (acid and alkali), electroplating and anodising rinse waters, phosphating sludges, ion-exchange resins used to treat process water, degreasing residues, hot-dip galvanising dross, and cyanide-bearing waste from tempering and case-hardening operations. Waste from the physical or mechanical shaping of metals — swarf, cutting fluids, grinding sludge — belongs in chapter 12, not chapter 11.

What subcategories does chapter 11 contain?

Codes 11 01 01 through 11 01 04 do not exist in the UK List of Wastes. Subcategory 11 01 opens at 11 01 05* (pickling acids). There is also no subcategory 11 04 in the chapter.

What are all the EWC chapter 11 codes?

What EWC codes apply to pickling acid and alkali cleaning baths?

Pickling uses strong mineral acids — typically hydrochloric, sulphuric or a mixed nitric/hydrofluoric acid — to remove oxide scale or rust before plating, galvanising or other surface treatment. When the bath reaches the end of its service life, the entire liquor (spent acid plus dissolved metal salts) is hazardous waste. The same applies to spent alkali baths (11 01 07*) used for descaling stainless steel or for caustic degreasing prior to surface treatment.

How do I classify rinsing water and sludge from plating or anodising?

Mirror entries require a waste assessment: you must compare the concentration of hazardous substances in the waste against the threshold values set out in the Environment Agency's WM3 classification guidance. The key parameters for plating and anodising rinse water are the dissolved concentrations of regulated metals — chromium (especially hexavalent chromium), nickel, cadmium, copper, zinc, lead and cyanide.

In practice, most rinse waters from chromium, nickel or cadmium plating lines will classify as 11 01 11* because those metals are regulated substances and plating rinse water typically contains them above threshold. Anodising rinse water from aluminium anodising operations may classify as non-hazardous (11 01 12) if the aluminium content is the only concern and the bath is free of regulated heavy metals, but an assessment is required — never assume non-hazardous without one.

What EWC codes apply to hot-dip galvanising waste?

Hot-dip galvanising produces several distinct waste streams that fall under subcategory 11 05:

• →Hard zinc (11 05 01) — the heavy zinc-iron intermetallic dross that sinks to the bottom of the galvanising bath. Relatively pure zinc, non-hazardous, routinely returned to zinc smelters for recovery.
• →Zinc ash (11 05 02) — the oxide-rich surface skimming from the bath. Non-hazardous and also recovered by zinc smelters.
• →Solid wastes from gas treatment (11 05 03*) — dust and residue captured by baghouse filters or wet scrubbers on the galvanising kettle fume extraction system. These contain zinc oxide, zinc chloride and ammonium compounds and are classified hazardous.
• →Spent flux (11 05 04*) — exhausted zinc ammonium chloride flux solution from the pre-galvanising flux bath. Classified hazardous. Flux regeneration services can treat and recover fresh flux from spent solutions.

What records does chapter 11 waste require?

Only upper-tier registered waste carriers are permitted to transport hazardous chapter 11 waste. Producers of hazardous waste have a duty under s.34 Environmental Protection Act 1990 to ensure their waste is handled only by authorised parties — passing hazardous waste to an unregistered carrier is a breach of the duty of care regardless of the carrier's own representations. Cyanide-bearing waste (11 03 01*) warrants particular care: it may require pre-notification to the Environment Agency, SEPA, NRW or NIEA before movement depending on quantity.

This guide is general information about EWC waste classification codes, not legal advice. For your specific obligations, cross-check against the primary sources below and contact the Environment Agency, SEPA, Natural Resources Wales or NIEA for advice on your situation.