Fine particle emissions from waste incineration can be purified

“Efficient flue gas purification equipment at large waste incineration plants can reduce flue gas emissions, and cut the amounts of fine particles and heavy metals containing harmful compounds, to the levels required by the Waste Incineration Directive,” explains senior research scientist Carl Wilen of the Technical Research Centre of Finland. Fine particle emissions from waste incineration and their purification have been studied as part of the Tekes FINE Particles technology programme.

Increasing waste recovery rates also places demands on the use of waste as a source of energy. The new EU Waste Incineration Directive which comes into force at the beginning of 2006 carefully defines what waste incineration plants are allowed to release into the air.

“We are studying the formation of fine particles in waste incineration and the role played by the quality of waste in the reduction of fine particle emissions. Fine particle emissions from waste incineration are a more serious problem than other emissions because they can be inhaled deep into the lungs and they contain heavy metals, for example,” explains Carl Wilen.

Wilen has been in charge of a project in the FINE Particles technology programme in which fine particle emissions in waste incineration, purification techniques and the impact of the waste quality have been studied.

In addition to the Technical Research Centre of Finland, Åbo Akademi, the University of Oulu, the Finnish Meteorological Institute, and ten companies ranging from manufacturers of recovered fuel and incineration boilers to suppliers of flue gas filters are involved in the project.

In the project, fine particle emissions have been studied at five plants; at a pilot plant, two full-scale waste incineration plants and two parallel waste incineration plants.

Strict EU limits for waste incineration emissions

Tests were carried out at the pilot plant to study how sorting and pre-treating waste influences the formation of fine particles. More studies will be carried out on whether sorting of waste has any effect on reducing particle emissions so that less money would have to be spent on the purification process. Under the EU Waste Incineration Directive which comes into force at the beginning of 2006 strict emission requirements must be met before any waste is incinerated.

“In incineration of sorted waste the level of fine particle emissions before flue gas purification is smaller than in what is called mass incineration of mixed waste. Is the sorting of waste therefore necessary if the flue gas purification technology is so effective? The EU directive sets very strict limits for emissions and these limits are far stricter than those applying to emissions from coal-fired or biomass plants.”