7.1 Introduction
Since the dawn of human civilization, man has been exorbitantly using natural
resources, and this has given way to the enormous release of many wastewater in
the environment. Man is behaving extensively as a polluter. And in this process,
release of pollutants is high whether gaseous or liquid pollutants or solid pollutants.
Liquid pollutants can be largely categorized as effluents, and solid pollutants can be
categorized as sludges. Effluent is largely considered as liquid wastewater whether
treated or untreated particularly from a sewage system, industrial unit, or a nuclear
plant, whereas sewage is a type of wastewater produced by a community of people.
They are also called as gray water and black water. Sewers carry it elsewhere or into
an on-site sewage facility. The reality is that most wastewater produced globally
remains untreated causing enormous problems of water pollution. The pollutants in
the wastewater can be divided into two main groups:
• Potentially toxic elements—heavy metals (cadmium, chromium, copper, mercury, nickel, lead, zinc
• Organic pollutants—polyaromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCB), dioxins, nutrients, and pathogens contained in human feces (bacteria,
viruses, protozoans, parasites)
The sources of pollution can be categorized as:
Domestic wastewater—Wastewater from households, institutions
Industrial wastewater—Wastewater released from industries in the manufacture and
production process of goods
Urban runoff—Wash-off water during rains from roads and drains
Wastewater carries various components and impurities that are discharged from
diffuse and point sources. Pollutants generated by large point sources can be easily
identified that result from particular activities in the area. It is much more difficult to
identify and quantify the wastewater contribution from small point sources, such as
households and small businesses, compared to point sources which are usually
regulated. Sludges from different sources are found to be rich in nutrients (nitrogen
and phosphorus), organic matter, and trace elements that are highly beneficial for the
growth of plants. Due to high nutrient content in sludge, it acts as substitute for
commercial fertilizers, and the requirement for fertilizer decreases. The application
of sludge in agricultural practices depends on the amount of metal content in the
sludge that decides the quality of sludge.
Objectives:
• To identify different toxic effluents and their sources
• To identify different biological and natural processes to treat toxic pollutants
• To find out the potential of selective organisms in remediation process
108
D. Angmo et al.
Since the dawn of human civilization, man has been exorbitantly using natural
resources, and this has given way to the enormous release of many wastewater in
the environment. Man is behaving extensively as a polluter. And in this process,
release of pollutants is high whether gaseous or liquid pollutants or solid pollutants.
Liquid pollutants can be largely categorized as effluents, and solid pollutants can be
categorized as sludges. Effluent is largely considered as liquid wastewater whether
treated or untreated particularly from a sewage system, industrial unit, or a nuclear
plant, whereas sewage is a type of wastewater produced by a community of people.
They are also called as gray water and black water. Sewers carry it elsewhere or into
an on-site sewage facility. The reality is that most wastewater produced globally
remains untreated causing enormous problems of water pollution. The pollutants in
the wastewater can be divided into two main groups:
• Potentially toxic elements—heavy metals (cadmium, chromium, copper, mercury, nickel, lead, zinc
• Organic pollutants—polyaromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCB), dioxins, nutrients, and pathogens contained in human feces (bacteria,
viruses, protozoans, parasites)
The sources of pollution can be categorized as:
Domestic wastewater—Wastewater from households, institutions
Industrial wastewater—Wastewater released from industries in the manufacture and
production process of goods
Urban runoff—Wash-off water during rains from roads and drains
Wastewater carries various components and impurities that are discharged from
diffuse and point sources. Pollutants generated by large point sources can be easily
identified that result from particular activities in the area. It is much more difficult to
identify and quantify the wastewater contribution from small point sources, such as
households and small businesses, compared to point sources which are usually
regulated. Sludges from different sources are found to be rich in nutrients (nitrogen
and phosphorus), organic matter, and trace elements that are highly beneficial for the
growth of plants. Due to high nutrient content in sludge, it acts as substitute for
commercial fertilizers, and the requirement for fertilizer decreases. The application
of sludge in agricultural practices depends on the amount of metal content in the
sludge that decides the quality of sludge.
Objectives:
• To identify different toxic effluents and their sources
• To identify different biological and natural processes to treat toxic pollutants
• To find out the potential of selective organisms in remediation process
108
D. Angmo et al.