to increase reduction of wastewater contaminants; this means that the natural
microbial communities of the wetlands have been exposed to high levels of antibiotics (Dordio et al. 2010).
A number of chemical, biological, and physical factors exist in the wetland
ecosystem that collectively degrade, sorb, precipitate, and remove a number of
contaminants, BOD, and organic materials. High organic soil can develop in wetland
system due to lower rates of oxidation of organic contents and can provide a sorption
medium for removal of the organic contaminants. In general, high microbial mass
and activity in the wetland soil can develop higher degradation of pharmaceuticals
(White et al. 2006).
Constructed wetland in pharmaceuticals degradation: Constructed wetland can
assist in the degradation of pharmaceuticals through natural processes involving
plants, microorganisms, solid matrix components, and UV radiation. CWs rely on
physical, biological, and chemical process in a natural environment to treat the
wastewater (Matamoros and Boyona 2006). It has been found in several studies
that wetlands can remove these pharmaceutical compounds with a number of
mechanisms including photolysis, plant uptake, microbial degradation, and sorption
to the soil (White et al. 2006).
Plants Plants in CWs play a significant role in direct uptake of many organic
pollutants in wastewater (Li et al. 2014). Plants can remove micro-pollutants in
different ways, either by directly taking up and assimilating contaminants or by
creating conditions favorable for their removal within these ecosystems (Verlicchi
and Zambello 2014). After being taken up into plant tissues, the internal pharmaceutical compounds can be degraded through the process like metabolism, e.g.,
phyto-degradation (Li et al. 2014). The most common investigated species which
are used are Phragmites australis and Typha (Verlicchi and Zambello 2014).
Microbial Degradation Microbes in constructed wetlands usually play the main
role in the processes of transformation and mineralization of nutrients and organic
pollutants (Li et al. 2014). Most researchers have always known that microbes play
major roles in removal, and in recent years, special focus has been given to other
parameters. These parameters affect redox potential which is related to the diversity
and density of microbial populations within a constructed wetland. Both biological
and chemical functions of wetlands are controlled to a large degree by oxidationreduction chemical reactions. During biodegradation, pharmaceutical compounds may
change into (i) mineralization; (ii) transformation to more hydrophobic compounds,
which partition into the solid phase; and (iii) transformation to more hydrophilic
compounds, which remain in the liquid phase (Zhang et al. 2014). Microbial density
and diversity can be enhanced by the presence of plants. Wetland plants shift the
oxygen to their root system and discharge a fraction of this oxygen into the rhizosphere
of the plants. Microbial diversity is important; this is because some of the microbes
will use certain compounds as an energy source in degradation process (Tatum 2015).
Photodegradation Photolytic degradation is chemical degradation induced by light
or other radiant energy. Pharmaceuticals generally consist of aromatic rings and
6 Constructed Wetlands: A Clean-Green Technology for Degradation and. . .
145
microbial communities of the wetlands have been exposed to high levels of antibiotics (Dordio et al. 2010).
A number of chemical, biological, and physical factors exist in the wetland
ecosystem that collectively degrade, sorb, precipitate, and remove a number of
contaminants, BOD, and organic materials. High organic soil can develop in wetland
system due to lower rates of oxidation of organic contents and can provide a sorption
medium for removal of the organic contaminants. In general, high microbial mass
and activity in the wetland soil can develop higher degradation of pharmaceuticals
(White et al. 2006).
Constructed wetland in pharmaceuticals degradation: Constructed wetland can
assist in the degradation of pharmaceuticals through natural processes involving
plants, microorganisms, solid matrix components, and UV radiation. CWs rely on
physical, biological, and chemical process in a natural environment to treat the
wastewater (Matamoros and Boyona 2006). It has been found in several studies
that wetlands can remove these pharmaceutical compounds with a number of
mechanisms including photolysis, plant uptake, microbial degradation, and sorption
to the soil (White et al. 2006).
Plants Plants in CWs play a significant role in direct uptake of many organic
pollutants in wastewater (Li et al. 2014). Plants can remove micro-pollutants in
different ways, either by directly taking up and assimilating contaminants or by
creating conditions favorable for their removal within these ecosystems (Verlicchi
and Zambello 2014). After being taken up into plant tissues, the internal pharmaceutical compounds can be degraded through the process like metabolism, e.g.,
phyto-degradation (Li et al. 2014). The most common investigated species which
are used are Phragmites australis and Typha (Verlicchi and Zambello 2014).
Microbial Degradation Microbes in constructed wetlands usually play the main
role in the processes of transformation and mineralization of nutrients and organic
pollutants (Li et al. 2014). Most researchers have always known that microbes play
major roles in removal, and in recent years, special focus has been given to other
parameters. These parameters affect redox potential which is related to the diversity
and density of microbial populations within a constructed wetland. Both biological
and chemical functions of wetlands are controlled to a large degree by oxidationreduction chemical reactions. During biodegradation, pharmaceutical compounds may
change into (i) mineralization; (ii) transformation to more hydrophobic compounds,
which partition into the solid phase; and (iii) transformation to more hydrophilic
compounds, which remain in the liquid phase (Zhang et al. 2014). Microbial density
and diversity can be enhanced by the presence of plants. Wetland plants shift the
oxygen to their root system and discharge a fraction of this oxygen into the rhizosphere
of the plants. Microbial diversity is important; this is because some of the microbes
will use certain compounds as an energy source in degradation process (Tatum 2015).
Photodegradation Photolytic degradation is chemical degradation induced by light
or other radiant energy. Pharmaceuticals generally consist of aromatic rings and
6 Constructed Wetlands: A Clean-Green Technology for Degradation and. . .
145