Incineration of waste is a technology with widely differing forms and efficiency. The modern incinerator does not spew huge amounts of dioxins. Yet no existing large-scale system of treating municipal waste comes without some degree of emissions, additional waste, or by-products somewhere along the line. As with so many environmental controversies, it comes down to what is an acceptable degree of risk.

The term incineration is passe among waste managers. Thermal treatment is how it is now described. This covers a number of "energy recovery" options, including more traditional methods of waste combustion with energy recovery, and also newly available - and strictly speaking, non-incineration technologies - such as pyrolysis and gasification, which are less tried but attracting attention.

All these processes come under the terms of EU incineration regulations. Some new technologies include a process known as vitrification, which eliminates potentially troublesome by-products and moves closer to the ultimate aim, an enclosed "zero-emissions" system.

Waste combustion with energy recovery is the most common form of thermal treatment, and the one most likely to be used in the Republic. It reduces waste bulk and recovers surplus energy as heat (hot water/steam), electric power or a combination of both. Combustible material in solid waste from households, commerce and industry can be used. It has a proven track record, with the technology showing steady improvement in terms of energy efficiency and atmospheric emissions.

Older incinerators - notably those dating from the 1950s and 1960s - are less efficient, generate more pollutants in the form of dioxins or furans and, in some instances, had to be closed down on health or environmental grounds.