PLANNING FOR NEW PROCESSES: ENVIRONMENTAL ASPECTS 999
With regard to occupational health, worker exposure to
toxic substances is a potentially serious problem which could
significantly lessen and limit the benefits of alternative fuel
technology. As such, its implications must be carefully eval-
uated in the planning and design phases of this project. The
Occupational Safety and Health Act (OSHA) contains basic
worker protection guidelines and specific regulations which
establish industry procedures for the protection of work-
ers from exposure to potentially toxic or health impairing
substances.
However, the current regulations do not specifically
address a coal gasification process and only limited operat-
ing experience is available from existing gasification plants.
Consequently, identification of potential occupational health
problems must be done in an indirect manner through com-
parison with other industries.
This occupational hazard analysis yields identification
of potential hazards, definition of possible control measures
for as many of those hazards as possible, and identification
of areas of concern where insufficient knowledge or control
methodologies exist. In addition it provides input to:1) design of worker protection programs to be imple-
mented at the plant,
2) design of engineering controls to minimize work-
er exposure to hazardous substances, for example,
isolation of process steps, ventilation changes,
pressure control, etc.Most of the procedural information, repeated from the arti-
cle by Quig and Granger (1983) remains valid today. For a
more quantitative treatment of the effluent emissions observed
during plant operation the reader is referred to the study of Holt
(1988) on the Cool Water plant and to the current Encyclopedia
article, Coal Gasification Processes.PERMITTING FOR LANDFILL GAS ENERGY
RECOVERYPurposeNew York State Air Guide 41 (1996) provides guidance on the
permitting of emissions from municipal solid waste landfills,
including the use of landfill gas for energy recovery, flares and,
also, passive venting, as per the following:BackgroundLandfill gas (LFG) is generated by the decomposition of
wastes in all municipal solid waste landfills, regardless of
age or size. The total volume of gas generated is a direct
function of the quantity of wet, decomposable refuse available;
however, the rate of gas generation can vary greatly over
time, depending on numerous factors (such as the volume
of waste, the depth of the landfill and the amount of rain-
fall the landfill receives), most of which are uncontrollable.
Landfills the accept waste water treatment plant sludge fordisposal tend to generate more LFG than those that do not.
LFG is not generated until the available oxygen supply has
been consumed and the decomposition process becomes
anaerobic. The typical composition of LFG is essentially the
same at all landfills and at all points within the landfill. The
typical composition of LFG is:Methane 50–58%
Carbon Dioxide 35–45%
Hydrogen 1–2%
Oxygen 1–2%
Nitrogen 2–5%
Non Methane Organic Compounds 3–5%
(NMOCs)^1LFG can, and should, be used for energy recovery. The energy
content of LFG comes entirely from the methane component,
which has a basic heating value of 1,000 Btu/standard cubic
foot (scf). Since the nominal concentration of methane in LFG
is approximately 55%, the heating value of raw LFG is approx-
imately 550 Btru/scf, although this figure can, and will, vary
somewhat. By comparison, natural gas is composed of 95%
methane, giving it a basic heating value of 950 Btu/scf.
At the majority of landfills in New York State, LFG is
currently uncontrolled or passively vented to the atmosphere.
Recovering and combusting such gas into useful energy will
virtually eliminate harmful emissions from a fuel that is oth-
erwise wasted. This also prevents the pollution associated
with the use of fossil fuels (i.e., SO 2 ). If LFG is not com-
busted, it will still escape to the atmosphere through the path
of least resistance (diffused from landfill, vented or flared).Federal RegulationsAir In accordance with the Clean Air Act, the U.S.
Environmental Protection Agency (EPA) has proposed New
Source Performance Standards (NSPS) under 40 CFR 60
Subpart WWW for municipal solid waste landfills. These
NSPS will affect landfills that began construction or modifi-
cation after the standard was proposed (5/30/91) or existing
landfills that have accepted waste since November 8, 1987.
It must be noted that this proposed rule is currently being
developed. The rule is subject to change and it is possible that
it will not be released. However, the guidelines contained in
this proposed rule should be used in developing a permit for
the use of landfill gas. Additional information regarding this
proposed rule is included in Appendix A.
In a recent Federal court case in Pennsylvania (Ogden
Products Inc. vs. New Morgan Landfill Co.), the court ruled
that the landfill in question is subject to New Source Review
since it has the potential to emit more than 50 tons per year
of volatile organic compounds. This decision, combined with
the NSPS for landfills proposed by the EPA, will make all
new landfills subject to the requirements of the CAA, partic-
ularly if the landfill has the potential to emit volatile organic
compounds at levels exceeding air quality standards.
Hazardous Waste When LFG is recovered, it tends to
cool, and some condensate is formed. It is stated in SectionC016_007_r03.indd 999C016_007_r03.indd 999 11/18/2005 11:01:30 AM11/18/2005 11:01:30 AM