[GreenYes Home] -
[Thread Index] -
[Date Prev] - [Date Next] - [Thread Prev] - [Thread Next]
[GreenYes] Air Emissions for Landfills
- Subject: [GreenYes] Air Emissions for Landfills
- From: "Peter Anderson" <email@example.com>
- Date: Wed, 6 Feb 2002 15:21:52 -0600
Philip Fredericks suggests that we "Thank Waste Management," quoting the
company's press release in which it "announced the donation of 120,000
metric tons carbon dioxide (CO2) equivalent
emission reduction credits needed to off-set additional CO2 emissions from
the 2002 Olympic Winter Games."
The release also quoted Waste Management's Maury Myers as stating:
"For more than 15 years, Waste Management has combined
state-of-the-art technology with environmental and operational
expertise to cut greenhouse gas emissions from our landfills in
I would like, if I may, to address this issue of fugitive air emissions
from today's landfills in the abstract with regard to all landfill companies
rather than in any way to single out this company, because the situation is
common to them all.
The impression that they all seek to create is the EPA's air rules
applicable to landfills (40 CFR Part 60 Subpart WWW), requiring a piping
system and negative pressure intended to extract gas in large landfills,
resolves concerns over landfill gas emissions. Those regulations do not,
however, create any limit on the quanity of emission that are permitted
other than that piping requirement. Notwithstanding that fact, the
Environmental Protection Agency has assumed that the collection efficiency
is 75%, without any factual basis for that conclusion.
A more comprehensive attempt to evaluate the issue is found in a life cycle
analysis by environmental scientists at Proctor & Gamble:
"Estimates of collection efficiencies vary, 20-25% (De Baere et al., 1987);
40% (RCEP, 1993); 40-70% (Carra and Cossu, 1990); 40-90% (Augenstein and
Pacey, 1991), and will depend on size, shape and engineering design of the
landfill site. For the purposes of the LCI model in this book, a figure of
40% will be assumed."
The reason for this particular set of lower numbers is that much of the
gases emitted by landfills is never captured due to inherent inefficiencies
of collection systems. Landfill owners themselves, without any actual data,
rarely contend that more than 50% of the gases are captured while the
collection systems are in place and maintained.
One of the reasons why landfill gas extraction systems are so inefficient is
that the vertical collection pipe that pull some of the gas from the
landfill with a vacuum pump cannot properly be perforated to draw gas into
the line at the top a to ½ of the tube. Otherwise oxygen might also be
pulled from the surface that would be explosive when mixed with methane. Nor
can the pipes be drilled to the bottom of the waste load, which is saturated
and where most of the methane is probably produced, or the pipe will
penetrate the bottle liner when the waste load decomposes and subsides.
These factors significantly limit the draw at the top and at the saturated
bottom of the landfill, where a majority of the gas is probably generated.
In addition, variation in waste densities and barriers to gas flow in a
landfill from plastic garbage bags and other impediments makes it difficult
to uniformly draw the gas that, above the liner, aggregates in perched pools
unless the pipe happens to have, by chance, been drilled directly through or
adjacent to one of those pools. Similarly, pools of leachate that can be
found perched high in the waste load can flood the pipes, and the gravel
pack surrounding pipes can become plugged. At greater depths, the densities
become so great that permeability is reduced to the point that water and gas
flows are impeded.
An even greater set of operating limitations is not reflected in the 50%
estimates. Often, due to the geometry of the load and extraction systems,
gas collection pipes are not installed for 7-10 years after waste
emplacement begins. By that time, almost half of the first wave of gas has
been generated and emitted uncontrolled into the atmosphere. Moreover, far
more than half of the total gas generated by today's landfills will occur in
a second wave of gas generation decades in the future after the end of the
mandated post-closure period when the landfill cover will fail and rainfall
enters the site. By that time, the gas collection systems will have been
removed from service and all gas releases will be uncontrolled.
Lastly, it should be noted that EPA rules mandating the installation of gas
collection systems only covered 54% of the waste in the ground in 2000, the
rest being at sites which were closed before the effective date of the air
regulations for landfills, or are in landfills smaller than the threshold
for coverage set by the rules.
While hard data unfortunately do not exist, a claim that much more than 20%
of all the landfill gas actually gets captured is difficult to sustain when
all these limitations are combined.
Landfills' true contribution to global warming is not the 4% of U.S. manmade
greenhouse gases estimated by the EPA when assuming, without any empirical
support, a 75% gas capture efficiency in those landfills that have
extraction equipment. Landfills may actually contribute between 10% and 15%
of America's anthropogenic climate change gases when field data is finally
Of equal but little recognized concern is the fact that the methane
extracted from landfill gas is not the relatively clean form of fuel we know
as natural gas. Because of the toxic constituents in our trash, landfill gas
also contains carcinogenic volatile organic compounds such as benzene,
toluene, xylenes, carbon tetrachloride and others.
Moreover, microbes responsible for anaerobic decomposition converts
elemental mercury in discarded batteries and ballasts into its di-methylated
form that is a lethal nerve gas, and may cause other equally serious
biological or chemical interactions that are not yet understood. These
hazardous compounds are then transported by the methane into the atmosphere.
Releases of these poisons may be associated with studies that have found
fourfold increases in bladder cancer and leukemia in women living near
Lengthy though that explanation is, that just touches on one of the myriad
flaws, many of which are fatal, in current, so-called "state-of-the-art"
The major immediate problem is that there simply is no way to safely manage
decomposable matter in the ground (where not only are toxic compounds
liberated and transported into the air and greenhouse gases produced, but
also hazardous leachate is formed that ultimately breaches the barrier
systems and winds up in our drinking water). That is why -- as Europe has
already done -- it is absolutely essential that the obsolete practice of
co-disposing organic material with non-compostables be banned. In its place,
we need to begin, as San Franciso, St. Paul, Hutchenson, Guelph and Nova
Scotia have already begun to do, to source separate our organics for
composting, just like we already separate our bottles, cans and newspapers
for recycling. Taken to its conclusion, this change in practice could
increase recovery from the present 30-40% to 70-80%.
Were we to thank any landfill company for their ineffective efforts to
poorly manage the effluvia from rotting garbage that threatens the
environment, when instead that material can be recovered and productively
used to add fertility to our soil, we would be doing something that is
roundly unwise for our industry and criminal for our progeny. While it may
or may not be true that what they are doing is the best that can be done
were one to accept the archaic premise that compostables belong in
landfills, that premise is the thing that must be newly evaluated without
the horse blinders of conventional wisdom.
RECYCLEWORLDS CONSULTING Corp
4513 Vernon Blvd. Suite 15
Madison, WI 53705
Ph: (608) 231-1100
Fax: (608) 233-0011
Cell: (608) 345-0381
To post to the greenyes list,
email to: firstname.lastname@example.org
Subscription information for
this list is available here:
[GreenYes Home] -
[Date Index] -
[Date Prev] - [Date Next] - [Thread Prev] - [Thread Next]