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#118 - New Technical Study Criticizes Epa's Incinerator Regulations, 27-Feb-1989

A new technical paper presented at a recent meeting of the Air
Pollution Control Association (but not yet published) strongly
criticizes the U.S. Environmental Protection Agency's (EPA's) budding
effort to regulate garbage incinerators. The EPA announced in August,
1987, that they plan to control air pollution from garbage incinerators
by requiring "dry" acid gas scrubbers and fabric filters, to protect
public health from the mass burning of garbage. A "dry" acid gas
scrubber tries to clean smoke stack emissions without using liquids to
wash them. A fabric filter is a huge box (called a baghouse) containing
an enormous cloth filter; all the gases leaving the combustion chamber
pass through the baghouse before escaping up the smoke stack. The
fabric filter captures much of the sooty pollution, which is then
collected and buried in a landfill. "Dry" scrubbers are much cheaper
than the alternative, which is "wet" scrubbers.

The new paper, by Craig Volland, a Kansas City civil engineer, argues
that EPA's proposal will not protect public health, and will lock
American incinerators into technologies that have already been
abandoned in Europe.

Mr. Volland attacks EPA's proposal from many points of view, among

EPA concluded incorrectly that dry scrubbers and baghouses would
protect public health because EPA used risk assessment that was flawed
in the following ways:

(a) EPA assumed that incinerators can be run for 20 years emitting
pollutants at the relatively low levels achieved by a few brand-new
incinerators operating under ideal conditions in carefully-controlled
tests. Mr. Volland says, "Those of us with many years of experience in
the pollution control industry know it is foolhardy to assume that this
incinerator [pollution control] equipment will be consistently well
operated and that it will not deteriorate over time." Mr. Volland
argues that, as time passes, the buildup of soot and "chloride-related
deterioration of the boiler tubes" will make it difficult for the
incinerator operator to maintain optimal conditions. Operator error and
carelessness are additional factors that will lead incinerators to
produce more pollution than was produced by the incinerators the EPA
studied in deciding that dry scrubbers and baghouses would adequately
control air pollution.

(b) EPA did not take into account the conditions knows as "upsets,"
"transient disturbances," and "breakdowns." These events are any
unusual condition that leads to abnormal emission of pollutants; such
conditions are readily caused by variations in the fuel fed into the
incinerator. Because garbage itself is highly variable (some wet, some
dry, some full of paper, some not, some containing flammable materials
such as paint and gasoline, some not, etc.), it is common for garbage
incinerators to experience upsets and breakdowns regularly. Mr. Volland
cites evidence from Moody's Bond Advisory Service indicating newer
incinerators are experience breakdowns more frequently than older
incinerators. EPA should take such data into consideration, Mr. Volland

(c) EPA selected dry gas scrubbers and baghouse filters on the
assumption that all incinerators will be operated to maintain a
temperature of 284 degrees Fahrenheit in the smoke stack. In reality,
because heating value of the fuel (garbage) varies considerably from
minute to minute, the temperatures in a garbage incinerator vary up and
down quite a bit. Consequently, Mr. Volland argues, the temperature in
an incinerator smoke stack may often exceed 284 degrees, with heavy
metals consequently turned into a gaseous state not captured at all by
dry scrubbers or baghouses. Arsenic, selenium, and cadmium will be
emitted in gaseous form if the temperature reaches 392 degrees F.,
which could readily occur because of operator inattention, or from
changes in the heat value of the fuel.

Even if the temperature never exceeds the standard operating
temperature of 284 degrees, mercury will be emitted into the local
environment continuously and in substantial quantities, Mr. Volland
shows. He presents data from seven modern incinerators (built 1985
through 1987) showing that they emit an average of 3590 pounds of
mercury for each million tons of garbage burned. A thousand-ton-per-day
incinerator will thus put out 1300 pounds of mercury per year into the
local environment. The toxicity of mercury to humans is measured in
micrograms, so the emission of even a few pounds is a matter of public
health concern. The dry scrubber and the baghouse filter do not capture
any of this mercury, and it is emitted directly into the local

To figure out whether this quantity of mercury is a lot or a little,
you can look at it in two different ways. The EPA looked at it this
way: they said, if this is emitted from the smoke stack and begins to
mix with clean air and becomes diluted, will the resulting air be fit
to breathe? They used a standard "air dispersion" mathematical model
(Turner's) to figure out how the mercury would mix with the fresh air.
However, as Mr. Volland points out, no one really knows how mercury
moves when it is released into the air. The standard air dispersion
model may be entirely inappropriate for estimating how the mercury will
mix with fresh air. In addition, the standard air dispersion model
assumes that the pollutant is being emitted into a rural environment
with level, open ground. The standard model does not take into
consideration the eddies and downdrafts in an urban environment--and
the majority of incinerators are being built in urban environments.
Additionally, Mr. Volland cites a recent German study showing that fog
droplets accumulate and concentrate toxic heavy metals (such as
mercury). Lastly, Mr. Volland argues that dispersion models are not
very accurate, even under ideal conditions, and the wide variations in
the characteristics of the garbage entering an incinerator make air
dispersion modeling particularly subject to error. (The mercury in
garbage will vary with the number of batteries, fluorescent light
bulbs, electrical switches and so forth that local people have thrown
away recently.)

Mercury attacks the human central nervous system, particularly the
brain. It is a potent poison, the effects of which have been well
documented. It is therefore a matter of great importance if the EPA's
air dispersion models are in error and local people are exposed to
mercury in greater concentrations than good health will allow.

The second way to ask whether a given release of mercury is large or
small, is to look at the absolute amount released. Mercury readily
enters the food chain and accumulates in fish and other wildlife. Many
waters of the United States are already contaminated with mercury at
levels that have caused health authorities to issue warnings and bans
against eating fish from those waters. The emission of tons of mercury
into the atmosphere by burning garbage represents a major new toxic
assault upon the nation's environment, and one the EPA has so far
evaluated by inappropriate methods, Mr. Volland argues.

Send $3.00 for copying and handling to: Craig S. Volland, President,
Spectrum Technologists, 616 East 63rd St., Kansas City, MO 64110; phone
(816) 523-2525. Ask for: "A Critical Review of EPA's Plan to Establish
A Dry Scrubber Technology Standard for Municipal Solid waste

--Peter Montague


Descriptor terms: air pollution; air quality standards; epa
regulations; incineration; scrubbers; heavy metals; mercury; health