Sir - Your correspondent Gerard McCrum (Letters, September 14) writes that "the design of incinerators has been improved by an order of magnitude since late in the last century". I would like to see the figures! Waste incinerators are inefficient electricity generators because they can only heat the turbine steam to around 450C compared to the more efficient 600C in coal-fired power stations. At higher temperatures the acidic nature of the combustion gases corrodes the heat exchanger too much.

Furthermore, these gases are treated with lime before release to neutralise the acid, releasing additional fossil-derived carbon dioxide. (Lime is made from limestone which is calcium carbonate deposited as the calcareous remains of marine animals over millions of years in ancient seas.) The only design improvement, forced by legislation, has been reduced toxic pollutants released into the local environment. These are buried in landfill instead.

Landfill is bad, but so is incineration. There is no excuse for swapping one bad practice for another. The waste treatment industry is selling this for all it is worth, not because it is the right thing to do, but because they can. There are alternatives.

Steve Gerrish, Kidlington