Environmental Engineering Reference
In-Depth Information
Type
Compound
Main characteristics
Miscible with
water
Organic compounds that are
completely miscible with water:
polar solvents (alcohol, ketones,
aldehydes), organic acids, tensio-
active compounds
Either hydrated or aqueous organic compounds
that completely mix with water. The behavior
of the aqueous phase depends on their
concentration in organic compound. Examples:
methanol, ethanol, propanoic acid, etc.
Immiscible
with water
Non-aqueous phase liquid
(NAPL)
All immiscible organic compounds that form a
separate phase in water and form a distinct slick
DNAPL
Dense, sinking NAPL
Density higher than one. Migrate to the bottom
of the aquifer. Examples: tar and
tetrachoroethylene
LNAPL
Light, floating NAPL
Density below one, floating on aquifers or on
surface water. Examples: most hydrocarbons
including fuels, gas-oil, crude oil, oils,
cyclohexane and benzene
Volatile
pollutants
Volatile organic compounds
Forming a distinct vapor phase, including
some LNAPL and DNAPL compounds
Non-
halogenated
VOCs
Heterogenous group including
various compounds: alcohols,
aldehydes, esters, ketone, polar
solvents, aromatic hydrocarbons,
BTEX, substituted aromatic
hydrocarbons, etc.
High volatility. Circulate either in liquid or gas
phase depending on soil porosity. Examples:
acetone, formaldehyde, ether, cyclohexane, etc.
Being highly soluble, they have low volatility
when in an aqueous phase
Halogenated
VOCs
Heterogenous group including
fluorine, chlorine, bromine and
iodine elements: chloromethane,
bromo-ethane, chloroethene, etc.
Low solubility, low miscibility, density and
volatility, depending on the molecular mass.
Examples: carbon tetrachloride,
trichloroethylene, etc.
SVOC
Semi-volatile organic compounds
Smaller volatility. Other properties similar to
that of COVs. Examples: naphthalene,
nitrobenzene, benzoic acids, phtalates, etc.
Halogenated
SVOC
Heterogenous group: di- and
trichlorobenzene, etc
Low solubility, low miscibility. Properties
depending on molecular mass
Other
Low volatility and miscibility
PAH
Polyaromatic hydrocarbons with
various benzene cycles
Low solubility, good stability and strong
adsorption in soils and aquifers. Examples:
benzo(a)pyrene, fluoranthene, phenantrene,
anthracene
Phenols
Chlorinated or non-chlorinated
phenolic compounds
Significant solubility
PCB
Polychlorobiphenyls
Low solubility, very stable, medium to low
volatility according to the number of chlorines
Heavy fuels
Tar, naphtha, PAH
Pesticides
Low solubility, high stability, non-volatile
Table 14.2. Classification of organic pollutants according to their behavior [BRG 05]
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