Typha dominigensisSaccharum strictum

lyricalwillingMécanique

22 févr. 2014 (il y a 3 années et 3 mois)

54 vue(s)





Summary


I


Summary

To detect and reduce pollution level of untreated wastewater, which
currently is in use for irrigation of uncooked vegetables and subsequently to
avoid health risks (i.e. heavy metal bioaccumulation); an outdoor investigation
was conducted close to the mai
n wastewater channel of Hewlêr (Erbil) city.
Phytoremediation, a low cost and less technology process was performed and
then evaluated, using two local and cosmopolitan distributed macrophytes,
namely;
Typha dominigensis

Pers, and
Saccharum strictum

(Host)

Spreng).
The basic principles of the present study include; sedimentation and filtration
processes. Single, double and triple sand filtration pots implanted separately
by experimental macrophytes, and then efficiency of macrophytes in waste
purification w
as evaluated in a constructed wetland implanted with both
macrophytes together.
This study was
started in April 10, 2012 and ended in
Sep
.

27, 2012.

Water samples were analyzed

following standard methods

on
biweekly interval periods,

for certain physico
-
ch
emical properties
. At the end
of experiments
heavy metal concentration (
Pb, Cu, Cd and Ni
)

in the plant
tissues (shoot and root systems) were analyzed to determine the removal
efficiency

and uptake rate of experimental macrophytes.

Furthermore,
vertical
concentration of heavy metals in sand layers was

measured from both serial
sand pots

and the constructed wetland
.
Generally, results showed that;
there is
a significant decrease (
P<0.05
) of pollutants from sedimentation unit and
control pot (contain sand o
nly). Generally, removal of pollutants may occur
through a number of processes, including sedimentation/ coagulation,
filtration, adsorption (binding to sand particles and root), formation of solid
compounds and surface straining. The sand had a higher rem
oval efficiency of
chemical contaminants. T
he
mean pH values were increased from 6.7 for the





Summary


II


raw wastewater to 7.5 and 7.4 in triple pots implanted with
T
.

dominigensis

and
S
.

strictum,
respectively and to 7.5 in

the constructed wetland implanted
by both m
acrophytes together. EC, TDS, TSS and turbidity values were
decreased significantly (
P<0.05
) between raw wastewater and reclaimed
waters. The BOD
5

value decreased from 100 mg

L
-
1
measured for raw
wastewater to 10 mg

L
-
1

calculated for triple pots and the constructed wetland
implanted with both experimental macrophytes. Always there was a
significant decrease (
P<0.05
) in COD values from 138.4 in untreated to 21.4
mg

L
-
1

in
triple pots
implanted with
S. strictum
. The value
s of NO
3

were
ranged between 29.35 in untreated and 2.19 mg

L
-
1

in treated waters.
The
PO
4

values were decreased from 87.3 to 4.3 µg at. P
-
PO
4

L
-
1
.
Chloride and Sulfate
results showed a significant decrease

(
P<0.05
) between both untreated and
treated wastewater. The concentrations of heavy metals between raw and
treated wastewaters were ranged between
0.767 and 0.249 mg

L
-
1

for lead,
0.841 and 0.386 mg

L
-
1

for copper, 0.263 and 0.072 mg

L
-
1

for cadmium and
0.241 and

0.077 mg

L
-
1
for nickel. On the other hand, the plant tissue analysis
showed that the root system was more active in bio
-
accumulation of heavy
metals than the shoot system. The values of
bio
-
accumulation factor (BAF)
and/or
translocation factor (TF)
revea
led that both plants were classified as
hyper accumulators (
BAF
or
TF
> 1).
As a result of filtration, vertical
distribution of heavy metals in sand layers showed that
there was a
considerable amount of heavy metals in the sand at studied different depths.
Generally,
metal accumulation at upper surface 5 cm depth was high
comparing to under depth (10 cm) and the lowest concentration was detected
at the depth of 15 cm.