Results of continuous dioxin / furan emission control using AMESA

Since 1999, a complete network of approx. 35 AMESA units have been installed throughout Belgium. In the Walloon region of Belgium, twelve units were installed in four domestic waste incineration plants (June 2002). The results of the long-term monitoring in this region are published on the following internet homepage: http://environnement.wallonie.be/data/air/dioxines/menu/menu.htm
As the results show, some plants fulfil the low emission requirements to a very high degree while continuously monitoring results. However, the dioxin emissions of some plants may occasionally exceed the target values.


Fig. 1

The example in fig. 1 shows the dioxin emissions of one plant over the entire year 2001. Each period covers two weeks. After 30 weeks of acceptable emission levels, this plant recorded a dioxin emission peak of 3.9 ng/m3 TEQ during period 16, and after that the plant continued to operate for several weeks at levels exceeding the target values. The specific reasons for the high dioxin emission values are detailed as follows:

Period 16
1.8. – 14.8.2001

the operator’s explanations (a clogged bag filter) are accepted.
report to the Public Prosecutor

Period 17
14.8. – 29.8.2001
  • does not conform
     
  • Following this incidence of exceeding the permitted value, the operator was questioned and voluntarily stopped the furnace on 13 September 2001. The contractor responsible for the building work was summoned.
     
  • For the record, the breach during period 16 occurred because of a clogged bag filter. The unclogging carried out should have resolved the problem. A detailed investigation into the causes of the breach revealed a defect in the bag filter’s internal by-pass joints, an unforeseeable accident. These joints were therefore replaced and a general inspection of the bag filters was carried out to ensure that they were in good condition.
     
  • Once the reasons for the breach had been identified and steps taken to remedy the defects, authorisation was granted on 19 September 2001 to start up the furnace again. The ISSeP (Institut scientifique de service public – Public Utility Scientific Institute) will take a spot check sample to confirm that the measures taken have been effective. The test will be performed on cartridge 19, because cartridge 18 was sampled before  the breach and the defect were discovered, and therefore before the problem was resolved.
Period 18
 29.8. – 12.9.2001

  • does not conform
     

  • the still existing problems were not yet assessed, therefore the furnace was
    still running before it was stopped on 13 September 2001

Period 19
12.9.- 26.9.2001

  • does not conform
     

  • A reading of 0.71 was obtained for furnace No. 2, which had already experienced
    an operational problem during periods 16 and 17. It was taken out of service. It
    appears that the problems with the operation of the bag filter, which caused the
    previous breaches, had still not been resolved. However, but steps are currently
    being taken to remedy this. Furnace No. 2 will not be started up again until the
    repairs are completed.
Period 20
26.9. – 10.10.2001

  • does not conform
     

  • A reading of 1.0 was obtained
     

  • Cartridge 20 was sampled before the results of period 19 were noted

Period 21

  • Furnace out of service
Period 22
24.10. – 6.11.2001

  • The furnace was in operation for 24 hours
     

  • Stops : stop (repair of the bag filters ) => + 294 hours
Period 23 - 26

  • Acceptable values below 0,1 ng/m3 TEQ

This example shows once again how important continuous monitoring by using AMESA is. In the case of short-term collection for eight hours over 1 – 3 days per year, the possibility that these high dioxin emissions will be monitored is very small.

However, after the modifications, the same incinerator was running over en entire year with acceptable dioxin emission values. Now the results can assist in getting more acceptance and trust by the general public in the area of the plant.



Fig.2

In general, in the Walloon region of Belgium, the total dioxin emission, which was reduced from the year 1995 to year 2001 by a factor of 100 to
0,64 g TEQ, the dioxin emissions were reduced by a factor 10 to 0,06 g TEQ in year 2002.
This shows how successful AMESA can help to reduce the PCDD/PCDF emissions in an effective way.

If you are interested to see the newest results please enter here:
http://environnement.wallonie.be/data/air/dioxines/menu/menu.htm