Incinerators remain net dioxin sources

[Alan Watson <alanwatson@gn.apc.org>]

  The UK incineration lobby, with Professor 'Pyro' Porteous leading the way 
  and supported by Gev Edulgee of ERM, have been claiming that MSW 
  incinerators are dioxin sinks.  This was never really a sustainable 
  argument and even ETSU have now decided that they should distance 
  themselves from it.  You may find the report below useful.  I am slightly 
  surprised by the findings of the study that UK MSW contains 3-13ng/TEQ 
  dioxin (above 'background' soil contamination levels) whilst incinerator 
  bottom ash is claimed to contain 7.5 - 28 ng/kg. Any other data on levels 
  of dioxin in modern incinerator residues would be very useful.  When I 
  went round SELCHP (a 'state of the art' UK incinerator with Maddy Cobbing 
  from Greenpeace and Ralph Ryder of Communities Against Toxics they 
  refused to provide us with a bottom ash sample and seemed very touchy 
  about providing any data.
  
  
  ENDS Report 273 October 1997 
  
  Incinerators remain net dioxin sources, says ETSU
  
  The new generation of municipal waste incinerators produce 15 times as 
  much dioxin as they destroy, according to the Energy Technology Support 
  Unit (ETSU). The finding contradicts claims by the Energy from Waste 
  Association (EWA) that modern plants act as d toxin sinks.
  
  Dioxin releases to air from municipal incinerators have fallen 
  considerably as a result of new emission limits introduced at the end of 
  1996. As a result, the EWA has claimed, modern, well-managed plants now 
  "act as net destroyers of dioxin. "
  
  The Association's claim is based on dioxin balances published by the 
  International Ash Working Group (IAWG) which suggested that a modern 
  German incinerator destroys more than 78% of the dioxins present in the 
  incoming waste.
  
  Dioxin measurements in household waste and incinerator residues, carried 
  out for the Environment Agency by AEA Technology, paint a different 
  picture.' In the latest issue of waste journal 117armer Bulletin, Stephen 
  Burnley, a senior consultant with ETSU, part of AEA, uses these data to 
  calculate dioxin balances for a modern UK incinerator fitted with a 
  semi-dry scrubber and bag filter.
  
  According to his best estimate, a modern incinerator produces about 15 
  times as much dioxin as that in the incoming wastes (see table). Using 
  pessimistic assumptions, the overall dioxin loading could be increased 
  170-fold. And even on optimistic assumptions, the incinerator remains a 
  net dioxin source.
  
  Dioxin balance for a 100,000tpy incinerator, gTEQ/y
  
  	                   Optimistic     	Pessimistic   	Neutral
  
  Input waste	                2.1	   0.05	      0.41
  Output:
  Bottom ash	               0.22	    0.83	     0.62
  Air pollution 
  control residues	         3.1	     6.9	      5.2
  Flue gas	                0.025	    0.61	     0.25
  Total output	            3.35	     8.34	     6.07
  Net dioxins	             1.25     	8.29	     5.66
  
  
  The main reason that Dr Burnley came to a different conclusion from IAWG 
  is that dioxin levels in UK household wastes were found to be relatively 
  low - possibly reflecting a reduction in environmental levels of dioxins. 
  Earlier overseas reports put dioxins levels in whole waste at 
  10-250ngTEQ/kg.
  
  Waste from Woking, Glasgow and Colwyn Bay generally showed fairly 
  consistent dioxin concentrations of 313ngTEQ/kg, although Dr Burnley used 
  the full data spread of 0.5-21ngTEQ/kg. Only small differences between 
  the waste fractions were found, apart from fines in the Colwyn Bay area, 
  which contained around 70ngTEQ/kg.
  
  According to ETSU, most of the dioxins end up in residues from the air 
  pollution control system, typically at 8101,821 ngTEQ/kg. Dioxins are 
  also present in bottom ash at levels of 7.5-28ng/kg. A plant taking in 
  100,000 tonnes of waste annually will produce 3,800 and 29,600 tonnes of 
  these residues, respectively, most of which are sent to landfill.
  
  ~ A preliminary assessment of trace organic compounds in household waste, 
  CWM 133/95, from Waste Management Information Bureau, AEA Technology, F6 
  Culham, Abingdon, Oxfordshire OXI4 3DB.
  
  
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         _\\|//_                Alan Watson C.Eng                  
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