Page 27 - Materials Chemistry, Second Edition

8 Life Cycle Assessment of Wastewater Treatment

2015; Forgacs et al., 2004). Dyes are classified into three types: Anionic, cationic,
and non-ionic. The anthraquinone dyes are complex to synthesize, resulting in a high
cost of production. The decomposition of the anthraquinone dyes is difficult, and it
depends on the type of microbial community used. The anthraquinone dyes are the
second biggest class of dyes, possessing a complicated aromatic structure, which
provides strong resistance against degradation (Rizi et al., 2017).

1.3.3 Microbial conTaMinaTion
Microbial contamination is also one of the major sources of water pollution. It is
caused by harmful microorganisms in drinking water. Improper sanitation is the rea-
son for the spreading of noxious pathogens in drinking water. The waste materials
excreted by human beings and animals contain Escherichia coli (E. coli), which is
a basic organism habitually present in drinking water. Moreover, E. coli is a marker
for the presence of other pathogens, such as Vibrio cholerae, Salmonella typhi, and
S. paratyphi, in drinking water. According to WHO reports, on average, nearly 1.1
billion people around the world consume perilous drinking water for their survival.
Lack of cleanliness, contaminated unsafe drinking water, and improper sanitation
are responsible for 88% of diarrheal illness on the planet and, moreover, are the
major reason for 3.1% of deaths annually (i.e., 1.7 million) and 3.7% of illnesses
annually (i.e., 54.2 million) of human beings globally. This microbial contamina-
tion causes many harmful diseases in various developing nations, and it is necessary
to monitor these noxious microorganisms and remove them from potable water to
prevent the transmission of toxic disease-causing strains in drinking water, even in
many developed nations (Ashbolt, 2004; Fawell and Nieuwenhuijsen, 2003).

1.3.4 agriculTural runoff
The pesticides and chemicals released from agricultural land during crop cultivation
are one of the major sources of water pollution. Agriculture is the practice through
which a civilized society cultivates and manufactures food, and it consequently
incorporates ranger service, trim culture, and biomass creation for the cultivation
of fuel and livestock. The relationship between agriculture and fresh water is unpre-
dictable, and they are interrelated in various dimensions. Moreover, agricultural
practices contribute to some of the water-related environmental problems, such as a
deficit of fresh water for irrigation purposes, leakage of pesticides into fresh water
sources, suspended loads from soil erosion, alteration in the water cycle, destruc-
tion of aquatic life, and alteration in the food cycle. The most important contami-
nants originating from agricultural land are nitrogen and phosphorus compounds.
The release of nitrogen compounds such as nitrate and nitrite is found to be toxic
to human health, and they can cause many dreadful disorders, such as blue baby
syndrome and methemoglobinemia, which seriously affects children. Knowing the
harmful effects of nitrate, WHO has restricted the allowable limit of nitrate to 50 mg
−1
L in drinking water, but nowadays, the levels of nitrate appear to be elevated from
−1
50 to 100 mg L . The usage of many modern pesticides and fertilizers for enhancing
crop production has also created a major concern. The runoff from agricultural land