Should you have a food waste disposer?

It depends heavily on where you live and how your waste is collected, because the environmental and practical case changes completely between regions — and in much of the UK, kerbside food waste collection makes the argument straightforward.

What it does. A unit fitted under the sink that grinds food waste into small particles, flushed into the drain with cold water. It does not use blades; it uses impellers forcing waste against a grind ring.

The arguments for it:

No food waste bin, removing smell, flies and the unpleasant task of emptying it.

Immediate disposal, rather than material sitting for days.

Reduced landfill where food waste would otherwise go to general waste, which matters because food decomposing in landfill produces methane.

Anaerobic digestion at the treatment works, in areas where the sewage undertaker captures biogas — which turns the waste into energy.

The arguments against, which are substantial:

It moves the problem to the water treatment works, adding organic load, solids and fats. The extent to which this matters depends entirely on local treatment capacity, and some water companies discourage them explicitly.

Water and electricity use, modest but continuous.

Fats, oils and grease. A disposer makes it easier to put greasy waste down the drain, and grease is the principal cause of blockages and fatbergs. This is the strongest practical objection.

Where separate food waste collection exists, the environmental case largely collapses: kerbside collection generally goes to anaerobic digestion or composting, producing biogas and digestate with far better resource recovery than sending it through the sewer. Composting at home is better still.

Plumbing considerations: it needs a suitable waste trap arrangement, an electrical supply, and it is incompatible with some septic tank systems.

What must never go in, regardless: fats and oils, fibrous material such as celery and onion skins in quantity, bones, coffee grounds in bulk, and anything non-food.

The honest summary: genuinely useful where there is no food waste collection and treatment capacity supports it; largely redundant where kerbside collection exists.