Long-Term Sampling - A Method for Continuous Emission Monitoring of Dioxins/Furans and Mercury

Introduction
The continuous emission monitoring of the different compounds which are emitted by industrial facilities is an important topic to approve the compliance to different regulations like WID. However, there are several compounds which cannot be measured in real time. Specific dioxins/furans (PCCD/PCDF) and other POPs (Persistent Organic Pollutants) cannot be measured by online monitors. In any way the acceptance for continuous sampling of PCDD/PCDF as a good approach for continuous emission monitoring of these compounds increased over the last 15 years. In the meantime France followed the example of Belgium and demands by law the continuous PCDD/PCDF emission in all waste incineration plants.

The increasing interest is also supported by CEN/TC 264 WG 1 which started a project to establish a standard for long-term sampling of PCDD/F and dioxin like PCBs (as EN 1948-5). Beside the emissions of PCDD/PCDF there are other emissions of compounds which are not or not so easy to be monitored continuously. E.g. mercury can be monitored continuously, but for plants with low concentrations in the range of ug/m3 the accuracies of the existing mercury CEMs depend very strong on the experiences and maintenance efforts of the operators. Otherwise the results are not accurate enough. Additional the availability of such systems is restricted. In the United States the new Portland Cement and the upcoming utility MACT rules accept besides the installation of mercury CEMs also the installation of continuous sampling systems for mercury. This paper will give an overview of the experiences of around 15 years continuous sampling of PCDD/PCDF emissions with continuous dioxin sampling systems and the resulted success for the reduction of these emissions. Additional it presents newest results of continuous sampling of mercury emissions in the low ug/m3 range in industrial facilities.