Waste Incineration: A Dying Technology - GAIA

Defeating the Stack Test 64
Incinerator operators often base
their claims of safe operation upon stack
gas emissions tests that show dioxin
emissions below some regulatory level.
There are a number of flaws with this
argument: to begin with, the assumption
that any level of dioxin emissions is safe
does not take into account issues of
multiple sources, long-distance
transport, bioaccumulation,
biomagnification and the extremely
high background levels of dioxins. But
an even more fundamental flaw is in
how dioxins are measured. The standard method for measuring dioxins in an incinerator stack
is to insert a probe for a period of time from two to six hours. This probe is then removed, the
sample is sent to a lab, which analyzes the quantity of dioxins present, calculates the total
volume of gases sampled, adjusts for oxygen levels, and returns the result weeks later. The time
lag between sampling and test results defeats one of the primary purposes of measuring
emissions: to tell the operators when something is awry so that they can take action to identify
and fix the problem.
Dioxin emissions are not constant. Most incinerators see “spikes” of dioxin emissions
during warm-up, when the furnace is just starting; during shutdowns; and during “upset
conditions.” An upset condition can be anything from a batch of wet trash that causes furnace
temperatures to dip to an out-of-control fire or explosion. Dioxin tests are almost never performed
during these circumstances, so periods of high dioxin production are excluded from the test.
When the dioxin test does happen to coincide with an upset condition that produces dioxins in
excess of the legal norm, some authorities (including the US EPA) have allowed incinerator
operators to scratch out that result and try again.
In the U.S., dioxin tests are typically performed once or twice a year, at most, and require
substantial advance preparation, because of the physical requirements to place a probe in the
stack. Incinerator operators can plan their operations so that the best possible — rather than
the typical — emissions levels are recorded. As the Columbus Free Press reported, one such
incident occurred in March 1994, in Columbus, Ohio, where the incinerator operator (having
exceeded EPA dioxin guidelines by 600 times on a previous test) took special measures to
ensure a better result. The operator’s logbook recorded deliberate attempts to stockpile special,
“clean” trash to ensure a good burn, and to fluff and dry this trash to avoid problems from
dampness. The EPA had decided to test only one of the six “lines” (furnaces) of the incinerator,
which was then retrofitted with a natural gas burner; and the test was scheduled to avoid peak
dioxin production times (“soot blowing”). The Columbus Free Press reported that one EPA
official wrote that these actions “might constitute a criminal conspiracy to violate federal
environment laws” but the EPA chose to accept the results instead.
To actually control incinerator emissions requires not just continuous, but real-time
monitoring. In other words, the operating engineers must know the emissions levels as they
leave the stack, not receive a report two weeks later, if they are to take action to correct any
problems. This is not technically possible for dioxins, and is rarely implemented for mercury.
20 Waste Incineration: A Dying Technology
© Vasily Mazaev/Foundation for the Realization of Ideas