1 Introduction
Toxic pollutants contaminate water by discharging wastewater generated through
municipal, industrial, and landfill site waste, etc. It is emerging as a worldwide
problem as it enormously affects human, fauna, and flora health of receiving water.
During last few decades, the exponential population growth, productivity variation
and consumption rates, and resource exploitation along with rapid industrial and
technical development are seen as major contributors that accompany water pollution. Though control and prevention technologies are being applied to most of these
industrial and municipal sources and there is availability of a wide range of wastewater treatment technologies for restoring and maintaining the biological, chemical,
and physical quality of wastewaters, still there is a staggering amount of these agents
released into the environment (Mohan and Pittman Jr 2007). Another major proven
threat to water is heavy metal toxicity with several associated health risks. The heavy
metals, such as cadmium, copper, lead, chromium, zinc, and nickel, are the main
environmental pollutants (United States Environmental Protection Agency 1997).
Although they do not play any big biological role, their trace present in certain form
can harm the human body and its proper functioning. The conventional technologies
that reduce and remove wastewater contaminants have limited approach due to
indulgence of high capital, operational, and maintenance cost and often lead generation of secondary wastes that hinder treatment process (Aksu 2002). An intricate
technology for wastewater treatment is constructed wetland phytoremediation which
is one such highly promising technology with competitive performance, costeffectiveness, and being environment-friendly that remediates polluted site being
aided by green plants to render them harmless in controlled environment (Raskin
et al. 1994) and can be applied both in soil and water for organic and inorganic
pollutants (Salt et al. 1998). This chapter discusses wastewater characteristics, toxic
metals added to water, and the role of plants in constructed wetlands in removal of
various pollutants to remediate the wastewaters from various sources, constraints,
and future of constructed wetland as a cleanup technique in wastewater remediation.
2 Wastewater: Natural and Anthropogenic Sources
and Characteristics
Wastewater generated from agricultural, industrial, municipal, and other activities
like extensive use of insecticides, fertilizers, and pesticides result in polluting soil
and our environment and gradually make the water resources unproductive (Hakeem
2015) as shown in Fig. 11.1. Among the different sources of pollution, industries are
the major polluters as these discharge a highly toxic wastewater containing a variety
of organic and inorganic pollutants which may cause serious toxic effects in living
beings upon exposure (Saxena et al. 2016, 2019; Goutam et al. 2018; Gautam et al.
2017; Bharagava et al. 2017a; Saxena and Bharagava 2015). The waste materials are
258
M. Rastogi and M. Nandal
Toxic pollutants contaminate water by discharging wastewater generated through
municipal, industrial, and landfill site waste, etc. It is emerging as a worldwide
problem as it enormously affects human, fauna, and flora health of receiving water.
During last few decades, the exponential population growth, productivity variation
and consumption rates, and resource exploitation along with rapid industrial and
technical development are seen as major contributors that accompany water pollution. Though control and prevention technologies are being applied to most of these
industrial and municipal sources and there is availability of a wide range of wastewater treatment technologies for restoring and maintaining the biological, chemical,
and physical quality of wastewaters, still there is a staggering amount of these agents
released into the environment (Mohan and Pittman Jr 2007). Another major proven
threat to water is heavy metal toxicity with several associated health risks. The heavy
metals, such as cadmium, copper, lead, chromium, zinc, and nickel, are the main
environmental pollutants (United States Environmental Protection Agency 1997).
Although they do not play any big biological role, their trace present in certain form
can harm the human body and its proper functioning. The conventional technologies
that reduce and remove wastewater contaminants have limited approach due to
indulgence of high capital, operational, and maintenance cost and often lead generation of secondary wastes that hinder treatment process (Aksu 2002). An intricate
technology for wastewater treatment is constructed wetland phytoremediation which
is one such highly promising technology with competitive performance, costeffectiveness, and being environment-friendly that remediates polluted site being
aided by green plants to render them harmless in controlled environment (Raskin
et al. 1994) and can be applied both in soil and water for organic and inorganic
pollutants (Salt et al. 1998). This chapter discusses wastewater characteristics, toxic
metals added to water, and the role of plants in constructed wetlands in removal of
various pollutants to remediate the wastewaters from various sources, constraints,
and future of constructed wetland as a cleanup technique in wastewater remediation.
2 Wastewater: Natural and Anthropogenic Sources
and Characteristics
Wastewater generated from agricultural, industrial, municipal, and other activities
like extensive use of insecticides, fertilizers, and pesticides result in polluting soil
and our environment and gradually make the water resources unproductive (Hakeem
2015) as shown in Fig. 11.1. Among the different sources of pollution, industries are
the major polluters as these discharge a highly toxic wastewater containing a variety
of organic and inorganic pollutants which may cause serious toxic effects in living
beings upon exposure (Saxena et al. 2016, 2019; Goutam et al. 2018; Gautam et al.
2017; Bharagava et al. 2017a; Saxena and Bharagava 2015). The waste materials are
258
M. Rastogi and M. Nandal