245
17 Phytoremediation Systems for the Recovery of Nutrients from Eutrophic Waters
with 100 L domestic wastewater. The results showed that
Cyperus alternifolius and Coleus blumei could grow well in
the floating phytoremediation system while Jasminum sambac could not grow well, being 125.0 % of the initial weight
of planting. The removal rate of TN by these three plants
was 68.0, 62.0, and 45.0 % and that of NO3-N, COD, Cr and
TP was 98.0, 80.0, and 92.0 %, 78.0, 66.0, and 55.0 %, and
90.6, 90.5, and 88.0 %, respectively. Cyperu salternifolius
and Coleus blumei have been shown to impose good effects
on the removal of pollutants in the floating phytoremediation
system (Liu et al. 2004).
Wetlands can be used in a cost-effective manner to treat
nutrient-rich water for release nutrients from freshwater
ecosystems using macrophyte, Ipomoea aquatic Forsskal
(swamp cabbage), in a horizontal-flow, deep flow Technique
(DFT) system. The removal of nutrients (total nitrogen and
total phosphorus) varied between 41.5 and 75.5 %. The results of this study indicate that cultivating edible, aquatic
macrophytes with nutrient-rich, eutrophic water in a DFT
system can be an effective, low-cost phytoremediation technology to treat water with undesirable levels of nitrogen and/
or phosphorus (Hu et al. 2008).
The phytoremediation potential of water hyacinth, Eichhornia crassipes (Mart.) Solms, was examined in two independent studies. A modified Hoagland solution was added
to ponds containing water hyacinths which were rated and
measured for 4 weeks. The hyacinths accounted for 60–85 %
of the N removed from solution. Tissue N increased linearly
with dry matter gain, but total nitrogen removal from the
water increased exponentially with net dry matter gain or
with an increase in canopy cover. The relation between total
N in plant tissue and N removal from the water was similar
for the two experiments (Fox et al. 2008).
There is a need to explore some “nonconventional” methods which are not only economically viable and easy to operate but ecofriendly as well. For remediation of village ponds,
the first step is to remove the excess nutrients dumped in it.
For this purpose, plant based bioremediation (phytoremediation) technology is the most promising option. Any aquatic
plant that is capable of recovering or extracting nutrients or
pollutants and has a fast growth rate coupled with high nutritive value is an excellent candidate for bioremediation of
waste water. Such plants grow very fast utilizing waste water
nutrients and also yield cost-effective protein rich plant biomass as a byproduct.
Duckweeds hold immense potential for both nutrient recovery and utilization as fodder or feed for livestock including fish. Wastewater-duckweed-aquaculture is a perfect ecofriendly integrated package for converting the waste water
nutrients into high-quality fish protein and augmenting rural
economy through generating employment opportunities and
additional food security (Ansal et al. 2010).
The aim of this study was to investigate the use of water
spinach ( Ipomoea aquatic Forsk.) with N
+
ion-beam implantation for removal of nutrient species from eutrophic water.
The mutated water spinach was grown on floating beds, and
growth chambers were used to examine the growth of three
cultivars of water spinach with ion implantation for 14 days
in simulated eutrophic water at both high and low nitrogen
levels. The specific weight growth rates of three cultivars
of water spinach with ion implantation were significantly
higher than the control, and their NO 3 -N and NH 4 -N removal
efficiencies were also greater than those of the control. Furthermore, compared with the control, the nitrogen contents
in the plant biomass with ion implantation were found to be
higher (Li et al. 2007).
When Pandanus pygmaeus, a known hyperaccumulator,
was planted in three of five setups with different treatments
and different amounts of nitrates and phosphates have been
given to allow, maximum algal growth, and are added to two
of the setups containing the plants, and to other two without plants. Results showed that the plants could reduce algal
growth, whereas the additional nutrients do not have significant adverse effects on plant growth. This proves that P. pygmaeus has a relatively high potential for removing nutrients,
especially nitrates, thereby improving the quality of eutrophic waters and preventing algal blooms (Joycel et al. 2010).
The nutrient depuration capacity of Polygonum hydropiperoides is measured by cultivating plants in water obtained
from fish ponds. The experiment simulated varying degrees
of nutrient enhancement by using pond water enriched with
nitrogen (N) and phosphorus (P). The sources of N and P
were urea and diammonium phosphate, respectively. The
best performance that has been recorded is a water depuration rate of 74 % for N and 81 % for P. These results suggest Polygonum as a good system to remove excess nutrients
from aquaculture sites (Martins et al. 2010).
17.7 Discussion
Water eutrophication has become a worldwide environmental problem in the recent years. The development of novel
technologies for controlling or remediating eutrophic water
is drawing attention of many scientists and government organizations (Yang 2009). Recently, many major technologies
have been developed for controlling or remediating water
eutrophication which include: (1) external source pollution
control, such as establishing sewage water treatment plants
and abatement of agricultural nonpoint pollution; (2) internal-source pollution control, such as sediment removal, and
immobilization of P; (3) water replacement and intensifying water flux; (4) biomanipulation approach using fish or
aquatic animals to remove nutrients and control algal bloom;
17 Phytoremediation Systems for the Recovery of Nutrients from Eutrophic Waters
with 100 L domestic wastewater. The results showed that
Cyperus alternifolius and Coleus blumei could grow well in
the floating phytoremediation system while Jasminum sambac could not grow well, being 125.0 % of the initial weight
of planting. The removal rate of TN by these three plants
was 68.0, 62.0, and 45.0 % and that of NO3-N, COD, Cr and
TP was 98.0, 80.0, and 92.0 %, 78.0, 66.0, and 55.0 %, and
90.6, 90.5, and 88.0 %, respectively. Cyperu salternifolius
and Coleus blumei have been shown to impose good effects
on the removal of pollutants in the floating phytoremediation
system (Liu et al. 2004).
Wetlands can be used in a cost-effective manner to treat
nutrient-rich water for release nutrients from freshwater
ecosystems using macrophyte, Ipomoea aquatic Forsskal
(swamp cabbage), in a horizontal-flow, deep flow Technique
(DFT) system. The removal of nutrients (total nitrogen and
total phosphorus) varied between 41.5 and 75.5 %. The results of this study indicate that cultivating edible, aquatic
macrophytes with nutrient-rich, eutrophic water in a DFT
system can be an effective, low-cost phytoremediation technology to treat water with undesirable levels of nitrogen and/
or phosphorus (Hu et al. 2008).
The phytoremediation potential of water hyacinth, Eichhornia crassipes (Mart.) Solms, was examined in two independent studies. A modified Hoagland solution was added
to ponds containing water hyacinths which were rated and
measured for 4 weeks. The hyacinths accounted for 60–85 %
of the N removed from solution. Tissue N increased linearly
with dry matter gain, but total nitrogen removal from the
water increased exponentially with net dry matter gain or
with an increase in canopy cover. The relation between total
N in plant tissue and N removal from the water was similar
for the two experiments (Fox et al. 2008).
There is a need to explore some “nonconventional” methods which are not only economically viable and easy to operate but ecofriendly as well. For remediation of village ponds,
the first step is to remove the excess nutrients dumped in it.
For this purpose, plant based bioremediation (phytoremediation) technology is the most promising option. Any aquatic
plant that is capable of recovering or extracting nutrients or
pollutants and has a fast growth rate coupled with high nutritive value is an excellent candidate for bioremediation of
waste water. Such plants grow very fast utilizing waste water
nutrients and also yield cost-effective protein rich plant biomass as a byproduct.
Duckweeds hold immense potential for both nutrient recovery and utilization as fodder or feed for livestock including fish. Wastewater-duckweed-aquaculture is a perfect ecofriendly integrated package for converting the waste water
nutrients into high-quality fish protein and augmenting rural
economy through generating employment opportunities and
additional food security (Ansal et al. 2010).
The aim of this study was to investigate the use of water
spinach ( Ipomoea aquatic Forsk.) with N
+
ion-beam implantation for removal of nutrient species from eutrophic water.
The mutated water spinach was grown on floating beds, and
growth chambers were used to examine the growth of three
cultivars of water spinach with ion implantation for 14 days
in simulated eutrophic water at both high and low nitrogen
levels. The specific weight growth rates of three cultivars
of water spinach with ion implantation were significantly
higher than the control, and their NO 3 -N and NH 4 -N removal
efficiencies were also greater than those of the control. Furthermore, compared with the control, the nitrogen contents
in the plant biomass with ion implantation were found to be
higher (Li et al. 2007).
When Pandanus pygmaeus, a known hyperaccumulator,
was planted in three of five setups with different treatments
and different amounts of nitrates and phosphates have been
given to allow, maximum algal growth, and are added to two
of the setups containing the plants, and to other two without plants. Results showed that the plants could reduce algal
growth, whereas the additional nutrients do not have significant adverse effects on plant growth. This proves that P. pygmaeus has a relatively high potential for removing nutrients,
especially nitrates, thereby improving the quality of eutrophic waters and preventing algal blooms (Joycel et al. 2010).
The nutrient depuration capacity of Polygonum hydropiperoides is measured by cultivating plants in water obtained
from fish ponds. The experiment simulated varying degrees
of nutrient enhancement by using pond water enriched with
nitrogen (N) and phosphorus (P). The sources of N and P
were urea and diammonium phosphate, respectively. The
best performance that has been recorded is a water depuration rate of 74 % for N and 81 % for P. These results suggest Polygonum as a good system to remove excess nutrients
from aquaculture sites (Martins et al. 2010).
17.7 Discussion
Water eutrophication has become a worldwide environmental problem in the recent years. The development of novel
technologies for controlling or remediating eutrophic water
is drawing attention of many scientists and government organizations (Yang 2009). Recently, many major technologies
have been developed for controlling or remediating water
eutrophication which include: (1) external source pollution
control, such as establishing sewage water treatment plants
and abatement of agricultural nonpoint pollution; (2) internal-source pollution control, such as sediment removal, and
immobilization of P; (3) water replacement and intensifying water flux; (4) biomanipulation approach using fish or
aquatic animals to remove nutrients and control algal bloom;