bacteria, fungi, algae, and their enzymes, are utilized to degrade and transform the
organic pollutant into harmless products. Being a natural process, it is economically
favorable (Shaw and Burns 2003). Recently, several articles are reported on the
photocatalytic degradation of organic pollutants. Photocatalyst which is responsive
to photons generates oxidative species for nonselective oxidation and degradation of
organic contaminants (Areerachakul et al. 2019).
13.2 Sources of Various Organic Pollutants
The major source of organic pollutant is the industries which produce and process
these chemicals. Mostly, synthesis of organic compounds involves more than one
step and, in each step, there may be formation of byproducts. Once the desired
product is synthesized, it must be separated from other byproducts and purified using
different organic solvents. On the whole, from the starting compound till the final
desired product, numerous chemicals are used, and only few chemicals are recycled
back or treated before discharge into the environment.
The synthetic organic compounds of different classes, such as pesticides, insecticides, phthalates, phenolic compounds, and nitrogen-containing compounds, are
often found as pollutants in water. Halogenated hydrocarbons, such as trichloroethylene, tetrachloroethylene, and 1,1,1- trichloroethane can sweep into the soil and end
up in ground water. Even in surface water, lower concentrations of dioxins and
polynuclear aromatic hydrocarbons are found. Moreover, disinfection byproducts,
such as N-halamines, trihalomethanes, and haloacetic acids, which are produced
during disinfection process by the reaction of chlorine and organic materials, are
often found in drinking water.
Apart from the organic pollutants discussed above, there are other organic
contaminants, which enter the water cycle through human activities. Generally,
drugs administered to the patients and the extent of elimination from the human
body decide the concentration levels of such residues in waste water. The drug
diclofenac prescribed as analgesic and antirheumatic has been detected as one
among the most important drug residues in the water cycle (Heberer 2002a,
2002b). The analgesic drug ibuprofen has been detected in sewage effluent plants
of countries, such as Spain, France, and Germany (Farré et al. 2001). The
cancerogenic and mutagenic antineoplastic agent cyclophosphamide found in the
hospital sewage water sample has been analyzed using GC/MS. The concentration
ranging from 20 ng L
À1 to 4.5 μg L
À1 is found in the sewage water sample (StegerHartmann et al. 1997). Kolpin et al. has reported the detection of 29 pharmaceutical
residues across 139 rivers and streams in 30 states of the United States (Kolpin et al.
2004). From the reported works, it is well known that the major source of pharmaceutical residues in water is due to the medication given to humans and feed
supplements provided for livestocks. The administration of medications to livestocks
and humans is considered as one of the main sources of pharmaceutical residues in
the environment (Boxall et al. 2004). As of now, more than 100 pharmaceutical
13 Remediation of Organic Pollutants in Water
503
organic pollutant into harmless products. Being a natural process, it is economically
favorable (Shaw and Burns 2003). Recently, several articles are reported on the
photocatalytic degradation of organic pollutants. Photocatalyst which is responsive
to photons generates oxidative species for nonselective oxidation and degradation of
organic contaminants (Areerachakul et al. 2019).
13.2 Sources of Various Organic Pollutants
The major source of organic pollutant is the industries which produce and process
these chemicals. Mostly, synthesis of organic compounds involves more than one
step and, in each step, there may be formation of byproducts. Once the desired
product is synthesized, it must be separated from other byproducts and purified using
different organic solvents. On the whole, from the starting compound till the final
desired product, numerous chemicals are used, and only few chemicals are recycled
back or treated before discharge into the environment.
The synthetic organic compounds of different classes, such as pesticides, insecticides, phthalates, phenolic compounds, and nitrogen-containing compounds, are
often found as pollutants in water. Halogenated hydrocarbons, such as trichloroethylene, tetrachloroethylene, and 1,1,1- trichloroethane can sweep into the soil and end
up in ground water. Even in surface water, lower concentrations of dioxins and
polynuclear aromatic hydrocarbons are found. Moreover, disinfection byproducts,
such as N-halamines, trihalomethanes, and haloacetic acids, which are produced
during disinfection process by the reaction of chlorine and organic materials, are
often found in drinking water.
Apart from the organic pollutants discussed above, there are other organic
contaminants, which enter the water cycle through human activities. Generally,
drugs administered to the patients and the extent of elimination from the human
body decide the concentration levels of such residues in waste water. The drug
diclofenac prescribed as analgesic and antirheumatic has been detected as one
among the most important drug residues in the water cycle (Heberer 2002a,
2002b). The analgesic drug ibuprofen has been detected in sewage effluent plants
of countries, such as Spain, France, and Germany (Farré et al. 2001). The
cancerogenic and mutagenic antineoplastic agent cyclophosphamide found in the
hospital sewage water sample has been analyzed using GC/MS. The concentration
ranging from 20 ng L
À1 to 4.5 μg L
À1 is found in the sewage water sample (StegerHartmann et al. 1997). Kolpin et al. has reported the detection of 29 pharmaceutical
residues across 139 rivers and streams in 30 states of the United States (Kolpin et al.
2004). From the reported works, it is well known that the major source of pharmaceutical residues in water is due to the medication given to humans and feed
supplements provided for livestocks. The administration of medications to livestocks
and humans is considered as one of the main sources of pharmaceutical residues in
the environment (Boxall et al. 2004). As of now, more than 100 pharmaceutical
13 Remediation of Organic Pollutants in Water
503