Environmental Engineering Reference
In-Depth Information
Fig. 3.7
Stabilization of mine tailings with grasses viz. miracle grass (
Vetiveria zizanoides
) lemon
grass (
Cymbopogon citratus
) and other non-edible tree crops
Monitoring parameters for landfills are: (a) Water contamination from leachate
(b) air emissions (methane and other gases), (c) immobilized hazardous waste.
Landfill Gas (LFG) is generated when organic materials in landfills are decom-
posed by bacteria. LFG is roughly 50 % methane with carbon dioxide being the
second most prevalent gas. All solid waste landfills emit this gas in amounts that
depend on a variety of factors, such as waste composition and landfill size.
Gases are formed in a landfill when buried wastes decompose (breakdown by
bacteria) or volatize (change from a liquid or solid to a vapor). These bacterial and
chemical processes produce gases that are unpleasant. The most common type of
landfill is the municipal solid waste facility, which accepts household and non-
hazardous commercial and industrial waste. It typically contains 60 % organic ma-
terial, such as food and paper. Because organic material tends to produce a great
deal of gas, municipal solid waste landfills have the potential to produce odors. At
extremely high concentrations, humans may experience eye irritation; headaches,
nausea, Sulfides and ammonia are the most common sources of odor in landfill gas.
Sulfides produce a strong, rotten-egg smell that humans can detect even at very low
concentrations. Ammonia produces a pungent odor that many people are familiar
with because it is often used in household cleaning products. Both are normally
present in the air, regardless of the presence of a landfill. There is another group
