| Zusammenfassung |
It is estimated that ~350,000 tonnes/year of waste wood is used in UK domestic wood burning acquired via the 'grey' fuel market. Most of this waste wood is likely to be clean, however, a significant, yet unknown quantity, is likely to be contaminated. Combustion of contaminated wood has been shown to generate high levels of emissions of dioxins and furans. These dioxins and furans are also associated with the soot's and chars which deposit in the combustion flue gas system or open fire chimney. Such soot deposits contaminated with dioxins and furans represent substantial environmental and health risks. However, there is very little known about the formation of dioxins and furans in the soot deposits from waste wood combustion. The aim of this present research proposal is to investigate the formation of dioxins and furans formed in the soot deposits from the combustion of biomass under the conditions simulating those of the flue duct conditions from domestic wood burning. The research will investigate how the different structure and surface chemistry of soot's produced from the main biomass components of cellulose, hemicellulose and lignin influence the formation of dioxins and furans under precursor and de novo formation conditions. In addition, soot produced from the combustion of a range of contaminated urban waste woods produced under various operational conditions will be investigated in terms of dioxin and furan formation. An integral study using model biomass aromatic and oxygenated model compounds will aid a mechanistic interpretation of the formation of dioxins and furans related to biomass components and biomass. This research is timely and important in understanding the formation mechanisms of dioxins and furans in the soot deposits from biomass combustion. It also provides critical evidence for policy formulation, recommendations and risk assessments of the potential hazards to human health and the environment of the accumulation of PCDD/PCDF and PCBs in the domestic environment. This is an ambitious proposal involving ultra-trace level organic micro-pollutants using advanced analytical techniques to fundamentally understand the important precursor and de novo reaction mechanisms which lead to the formation of dioxins and furans from biomass combustion |
