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Re: another question
I have worked for several years in estimating emissions from and permitting
landfill gas vents and flares. In all the literature (from EPA, EPA
contractors, and various researchers and permitting agencies) I have read
on the subject of landfill gas, I have never seen any reference to dioxin
emissions, either measured, estimated or otherwise. I would not expect to
find any appreciable concentrations of dioxins in landfill gas, as dioxins
have fairly low vapor pressures over the range of temperatures typically
encountered in landfill gas. Also, minimal particulate matter is emitted
from a typical vent, so that emissions of dioxins adsorbed on particulate
matter should not be a consideration.
Dioxins could be present in measurable quantities in emissions from LFG
flares, but again I doubt the typical flare would be a concern. EPA rules
require most flares to operate under conditions of time and temperature
which are unfavorable for to the production of dioxins. EPA rules require
monitoring and recording of flare operating parameters, so there is a means
of assuring compliance. Since there is little if any fly ash generated in
the flare, and there are no downstream air pollution control devices, there
is almost no chance of de novo dioxin formation. I am assuming that there
are traces (few ppm) of chlorinated hydrocarbons in the LFG. Sometimes
there are no measureable chlorinated hydrocarbons, sometimes there are
relatively high levels.
LFG is also frequently burned in large internal combustion engines and
boilers. I would expect similar dioxin emissions (if any) from these
devices. Landfills designated as Superfund sites (of which there are many)
are probably the ones most likely to have any dioxin emissions.
Bottom line, I would be much more concerned about other emissions from LFG
or LFG control devices than dioxins. Methane migration (underground) is a
documented health and safety problem in areas surrounding landfills.
Hydrogen sulfide has been a documented health and safety (not to mention
nuisance) problem in certain landfills (without flares), particularly those
which accepted a lot of sheet rock, animal hides, etc. Chlorinated
hydrocarbons and other air toxics are last on the list of my concerns, and
could be a consideration at industrial landfills and landfills with
histories of significant hazardous waste disposal.
I hope the above information is helpful and not excessive. Feel free to
email me with more explicit questions.
> From: CCHW <email@example.com>
> To: Multiple recipients of list <firstname.lastname@example.org>
> Subject: another question
> Date: Tuesday, November 04, 1997 11:42 AM
> Another question: Does anyone have information on dioxin in landfill
> gases - when they are vented or flared?
> CCHW Center for Health, Environment and Justice
> P.O. Box 6806 Falls Church, VA 22040
> (703) 237-2249 (703) 237-8389 (fax)