Hazardous, Non-Hazardous and Inert Waste — and What WEEE Covers

Three classes, and putting something in the wrong one is an offence rather than an untidiness. Two items in particular are not where people expect them to be.

The short answer

The four the paper asks you to classify: solvents — hazardous; tiles — inert; electrical equipment — hazardous; water based glue — non hazardous.

The regulations covering the disposal of motors, fluorescent tubes and printed circuit boards are the Waste Electrical and Electronic Equipment Regulations, known as WEEE.

The three classes exist because of what they cost

Landfill tax is charged at two rates, and the gap between them is the reason anybody sorts anything. The standard rate is now well over £100 a tonne. The lower rate, for inert waste that will not react with anything, is a few pounds a tonne. Hazardous waste costs more again, because it needs separate containers, a licensed carrier, a licensed site and its own paperwork.

A mixed skip is charged at the worst thing in it. One tin of solvent tipped into a skip of rubble converts the whole load, which is the commercial version of the same point the exam is making.

Same product, different class

The pairing of solvents and water based glue is not an accident. It is the whole idea the question is built on: what decides the class is not the type of item but what is in it. Solvent weld cement and the cleaner beside it are hazardous. The water based adhesive on the next shelf of the same van is not.

So you cannot answer from the name of the product. Read the tin, and where it matters, read the safety data sheet the supplier has to provide.

Inert is worth taking literally: chemically dead. It will not rot, burn, react or leach. Tiles are fired ceramic and nothing further is ever going to happen to them — bury one for a century and it is still a tile. That is why inert waste is the cheapest to be rid of and the most likely to be reused as fill.

Why a fluorescent tube must never go in a skip

A fluorescent tube makes light by passing current through mercury vapour. There are only a few milligrams in a tube, but they are milligrams of a metal that is toxic and that evaporates at room temperature. Break one in the back of a van and you have released it into the space you then sit in for the rest of the day.

Tubes are hazardous waste. They go to a lamp recycler, where they are crushed inside a sealed machine that captures the mercury and separates the glass, the phosphor powder and the metal end caps. Most merchants and civic sites will take them, but they want them whole and they want warning.

Of the three items the paper names, the tube is the one most often got wrong, because it looks like glass rather than like electrical equipment.

What happens to the rest at a WEEE plant

Depollution comes first, and it is done by hand: batteries out, capacitors out, mercury switches and lamps out, refrigerant recovered from anything that holds any. Only then does the material go to the shredder, where a magnet lifts the steel out, an eddy current throws the aluminium sideways, and the plastics are separated by density.

Printed circuit boards go somewhere else again, for metal recovery. A tonne of circuit boards holds far more gold, silver and palladium than a tonne of mined ore, which is why recovering them is worth doing rather than merely required. Motors go the same way for their copper windings.

Refrigerant is the one to be careful about on site. A fridge, an air conditioning unit or a heat pump holds gas that must be recovered by a certified person before the appliance is scrapped. It has never been a skip item, and the fine for treating it as one is not small.

What comes next

Level 2 turns this into COSHH: assessing a substance before you use it, reading a safety data sheet properly, and the control hierarchy that puts protective equipment last rather than first. Asbestos gets a lesson of its own, because it is the hazardous waste most likely to be sitting in an old boiler you are about to strip out.