Environmental Engineering Reference
In-Depth Information
Table 5.1
Industrie
s as sources of heavy metal contaminants
Metal
Industry
Chromium (Cr)
Mining, industrial coolants, chromium salts manufacturing, leather tanning
Lead (Pb)
Lead acid batteries, paints, e-waste, smelting operations, coal-based thermal power plants,
ceramics, bangle industry
Mercury (Hg)
Chlor-alkali plants, thermal power plants, fluorescent lamps, hospital waste (damaged thermom-
eters, barometers, sphygmomanometers), electrical appliances etc.
Arsenic (As)
Geogenic/natural processes, smelting operations, thermal power plants, fuel burning
Copper (Cu)
Mining, electroplating, smelting operations
Vanadium (Va)
Spent catalyst, sulphuric acid plants
Nickel (Ni)
Smelting operations, thermal power plants, battery industry
Cadmium (Cd)
Zinc smelting, waste batteries, e-waste, paint sludge, incinerations and fuel combustion
Molybednum (Mb)
Spent catalyst
Zinc (Zn)
Smelting, electroplating
and concentrate elements from the environment.
These metals include Fe, Mn, Zn, Cu, Mg, Mo
and Ni, essential for growth and development;
whereas Cd, Cr, Pb, Co, Ag, Se and Hg are also
reported to be accumulated in plants but have no
known biological function. Thus, green plants
being used to remove pollutants from the en-
vironment is referred to as phytoremediation.
Under phytoremediation, plants exhibit the abil-
ity to tolerate elevated levels of heavy metals and
accumulate them to unusually high concentra-
tions either independently or in combination and
have been reported for Ni, Co, Cu, Mn, Pb, Zn
and Se (Brooks et al.
1978
,
1979
,
1981
; Reeves
and Brooks
1983
; Banuelos and Meeks
1990
).
Table 5.2
Five-year cost comparison between phytore-
mediation by hybrid poplar trees, and conventional pump
and treatment with reverse osmosis system
Phytotransformation
Cost in dollars ($)
Design and implementation
50,000
Monitoring equipment
Capital
10,000
Installation
10,000
Replacement
5,000
Five-year monitoring
Travel and administration 50,000
Data collection 50,000
Reports (annual) 25,000
Sample analysis 50,000
Total 250,000
Pump and treatment (three wells and reverse osmosis
system)
Equipment
100,000
Consulting
25,000
5.2
Phytoremediation: Need
or Necessity
Installation/Construction
100,000
Five-year cost
Maintenance
105,000
Phytoremediation is very competitive with
other treatment alternatives. It is simple to use
and has high public acceptability. Due to its
advantages over microbial bioremediation it is
considered as a need of the present time, but the
industrial revolution and increasing population
manipulate this need into necessity. Efficiency
and effectiveness are the two scales that we
have compared and summarized in Table
5.2
,
in which 5-year costs are compared between
phytoremediation by hybrid poplar trees, and
conventional pump and treatment with a reverse
Operation (electricity)
50,000
Waste disposal
180,000
Waste disposal liability
100,000
Total
660,000
osmosis system. Phytoremediation costs less
than half of the pump and reverse osmosis
treatment technology. According to a report
by Phytotech (1997), phytoextraction provides
significant cost advantages over in situ fixa-
tion, excavation and landfilling in a Resource
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